Core Logs from Searles 

Lake, San Bernardino 

County, California

By DAVID V. HAINES

GEOLOGIC INVESTIGATIONS IN THE MOJAVE DESERT 

AND ADJACENT REGION, CALIFORNIA

GEOLOGICAL SURVEY BULLETIN 104S-E

Detailed logs of drill cores 

of Quaternary evaporites and 

sediments

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1959
UNITED STATES DEPARTMENT OF THE INTERIOR 

FRED S. SEATON, Secretary

GEOLOGICAL SURVEY 

Thomas B. Nolan, Director

The U. S. Geological Survey Library has cataloged this publication as follows:

Haines, David Vincent, 1922-

Core logs from Searles Lake, San Bernardino County, 

California. Washington, U. S. Govt. Print. Off., 1959.

iii, 139-317 p. maps, diagrs. 25 cm. (U. S. Geological Survey. 

Bulletin 1045-E. Geologic investigations in the Mojave Desert and 

adjacent region, California)

Part of illustrative matter in pocket. 

Bibliography: p. 152-153.

1. Borings California San Bernardino Co. i. Title. (Series: 

U. S. Geological Survey. Bulletin 1045-E. Series: U. S. Geological 

Survey. Geologic investigations in the Mojave Desert and adjacent 

region, California)

622.24

For sale by the Superintendent of Documents, U.S. Government Printing Office 

Washington 25, D.C. - Price $2 (paper cover)
CONTENTS

	Page 

Abstract...___..._______.__........_.__._.__...... 1391

Introduction..____________________________________________________ 1391

Acknowledgments. -.___-.._______-----_-----__--_-_--__--.-_.-.-._ 140

Location.______________-___-____-__----____-.___--__-______._-___ 140

Surface features._______--_____-_--_--_------__----__--_-_-----__-- 140

Ownership and production________________________________________ 142

Mineralogy-__-_________-_--_-___-_---------___-._-____._____._.._ 142

Geology.----------.---_----_-_--------------_----_---_--.--_----. 144

Salt bodies._._._.._.._____-.--__--.-.___._____-__ 144

Brine.. .._.___-..--.--.-______..-..-._.____.______. 146

Drilling methods______.__.______.-__.____________-__._____.___._._ 147

Core logs...__.__.__.___-__-.____--__-__----_.--_-_.-__.____._-... 148

Graphic logs.__--_-___-_-----_-__---------_--__------__--_--_--_-_ 149

Compilation of logs____---________-_-_-__-__-_-___-_____-____ 149

Lost core.__-_____-_--_-_____--_..--__-------_-__--_____-_-____ 150

Literature cited----.____--_----__-___-_._______-_-_._-_.__.__.__._ 150

Core logs.________________________________________________________ 152

ILLUSTRATIONS

[Plates 5-8 in pocket]

PLATE 5. Isopach map of upper salt body.

6. Isopach map of lower salt body.

7. Graphic logs of cores from drill holes GS-1 to GS-18.

8. Graphic logs of cores from drill holes GS-19 to GS-41.

Page

9. Core from hole GS-26.---------------------------- Facing 150

10. Core from hole GS-21......_._......_..._..___ Facing 151

FIGURE 6. Index map of Searles Lake...____________________________ 141

7. Generalized graphic core log of mineral data from holes GS-14,

GS-15, and GS-16_._ ._.._....._------------------- 145

in

GEOLOGIC INVESTIGATIONS IN THE MOJAVE DESERT AND 

ADJACENT REGION, CALIFORNIA

CORE LOGS FROM SEARLES LAKE 

SAN BERNARDINO COUNTY, CALIFORNIA

By DAVID V. HAINES

ABSTRACT

Forty-one drill holes in the saline deposit on Searles Lake, San Bernardino 

County, Calif., were cored and logged. Drill holes averaged about 100 feet in 

depth; the majority are located around the margins of the dry lake. The saline 

deposit consists of an upper salt body about 39 square miles in area, of which 12 

.sqtiare miles are exposed in the central part of the lake, and a lower salt body of 

approximately the same areal extent found at greater depth. The 2 salt bodies 

are separated by a seam of clay or marl averaging about 12 feet thick. Isopach 

maps show the salt bodies are slightly elongated to the north; maximum thicknesses of the upper and lower salt bodies are 95 and 54 feet, respectively. Core 

logs, in written and graphic form, show the chief minerals of the saline bodies are 

halite, trona, hanksite, borax, and burkeite; relatively minor quantities of 13 

additional minerals are described. The 41 drill-hole logs are shown graphically 

in columnar sections which give thicknesses, mineralogy, and mineral percentages; 

15 representative written logs are published in full.

INTRODUCTION 

This report presents in preliminary form some of the results of 

drilling done on private contract on Searles Lake, San Bernardino 

County, Calif., for the Geological Survey from July 1954 to November 

1955. The drilling was undertaken to obtain basic information on 

the shape, thickness, and character of the saline deposit, particularly 

near the margins. This report is limited to the detailed core logs and 

drilling methods and to a summary of the salient geologic features of 

the deposit; variations in the thickness of the saline deposit are shown 

by means of isopach maps. Further study and a more comprehensive 

report are in progress.

A total of 41 holes were drilled on Searles Lake, representing 3,412 

feet of coring and reaming and averaging 77.6 percent core recovery. 

The average depth of the majority of holes drilled was about 100 feet, 

though several shallow holes were drilled to depths of about 30 feet.

139
140 GEOLOGIC INVESTIGATIONS IN MOJAVE DESERT REGION

ACKNOWLEDGMENTS

The drilling program was carried out with the cooperation of the 

American Potash & Chemical Corp., the West End Chemical Co., 

the Searles Lake Chemical Corp., and the San Bernardino Borax 

Mining Co., Ltd., all of whom permitted drilling of their properties 

on Searles Lake.

Microscopic and X-ray determinations of many mineral specimens 

were made by Robert D. Alien, of the Geological Survey.

About 1,200 samples were taken by the writer for chemical analysis. 

These chemical determinations, chiefly for boron, were made by 

Henry Kramer, Sol Berman, and Hy Almond, chemists, of the U. S. 

Geological Survey. Results of these chemical analyses are in 

preparation.

LOCATION

Searles Lake is in the northwest corner of San Bernardino County, 

Calif., in Tps. 25 and 26 S., Rs. 43 and 44 E., Mount Diablo base line 

and meridian (fig. 6). It is about 130 miles airline northeast of Los 

Angeles and 50 miles airline southwest of Death Valley, and may be 

reached by paved highways. The area is shown on the 15-minute 

Trona and Searles Lake topographic quadrangle maps published by 

the U. S. Geological Survey. The towns of Trona and Westend are 

on the west side of the lake and are supported chiefly by the plants 

processing brine from Searles Lake. The Searles Lake deposit has 

been described in various reports (Gale, 1914; Dyer, 1950; Ryan, 

1951; Smith and Pratt, 1957).

The location of the 41 holes drilled under contract for the U. S. 

Geological Survey are shown on plates 5 and 6.

® SURFACE FEATURES

Searles Lake is located physiographically near the boundary of the 

Great Basin section and the Sonoran Desert section of the Basin and 

Range province as defined by Fenneman (1931). This area consists 

chiefly of isolated short ranges separated by desert plains. It is in 

the northwestern part of the Mojave Desert region as defined by 

Thompson (1929) and Hewett (1954). The dry lake forms the floor of 

an intermontane basin which lies between the Argus Range on the 

west and the Slate Range on the east. The highest elevation on the 

west side of the basin is represented by Argus Peak at an altitude of 

6,562 feet; the highest altitude in the Slate Range is 5,578 feet. The 

playa surface of Searles Lake is at an altitude of 1,616 feet in the center 

and rises gradually to approximately 1,624 feet near the edges.

The present surface of Searles Lake is a playa which is slightly 

elongated toward the north. In its dimensions, the playa is about 9 

miles in greatest length and 7 miles in greatest width, and covers an
CORE LOGS FROM SEARLES LAKE, CALIFORNIA 141

INYO CO. 

NARDINOj CO

FIGURE 6. Index map of Searles Lake, San Bernardlno County, Calif.
142 GEOLOGIC INVESTIGATIONS IN MOJAVE DESERT REGION

area of about 41 square miles. Of this area, 12 square miles consists of 

exposed halite in the center of the lake, and 29 square miles consists of 

soft smooth moist clay around the margins. At the margins of the 

lake, the clay grades into silt, sand, and eventually into the coarser 

alluvium on the surrounding slopes. Locally, the clay areas are 

covered by a level hard porous crust consisting of a cellular massive 

intergrown mixture of halite, trona, gaylussite, clay, and possibly 

other minerals. A prominent zone of rough hard cavernous crust 

known as the Trona Reef is present at the margin of the playa surface 

on the east and northeast side of the lake.

Travel by vehicle over the central area of exposed halite is possible 

throughout most of the year. A leached zone of salts characterized 

by easily collapsible cavernous holes is present, however, in section 28 

and the northern part of section 33, and travel over this salt surface 

is not possible with ordinary vehicles or tractors. The clay areas 

surrounding the exposed halite are generally accessible only by means 

of sleds pulled by tractors. In some places, the clay areas are inaccessible even by these means. Many drill holes were possible only near 

roads which have been built over the clay areas. Therefore some drill 

holes were located in part by the accessibility of the area.

Rainfall at Trona averages about 4 inches per year and is mostly 

confined to the winter months. At that time of year, the playa 

surface may be covered with a thin sheet of water several inches to a 

few feet deep. Drainage into the playa is derived largely from the 

slopes of the Argus and Slate Ranges.

Near the contact of the exposed halite and marginal clay, pools of 

stagnant brine are commonly present. These brine pools are usually 

discolored red or reddish brown.

OWNERSHIP AND PRODUCTION

The greater part of the saline deposit at Searles Lake is presently 

held by four companies; namely, the American Potash & Chemical 

Corp., the West End Chemical Co., the San Bernardino Borax Mining 

Co., and the Searles Lake Chemical Corp. The history of ownership 

at Searles Lake and the problems encountered in early development 

and production are described by Dyer (1950) and Teeple (1929).

MINERALOGY

The following minerals, in approximate order of abundance, were 

identified at Searles Lake from cores obtained from the U. S. Geological 

Survey drill holes shown on plates 5 and 6 :

Halite_._.._-..-_......-____ NaCl

Trona___......................... Na2C03-NaHC03 -2H2 0

Hanksite..._...._....._........_. 9Na2S04 -2Na2C03-KCl

Gaylussite...... __...._..._-.._. CaC03-Na2C03 .5H2O
CORE LOGS FROM SEARLES LAKE, CALIFORNIA 143

--------------------- CaC03 .Na2C03.2HsO

Borax ___ ..-._.._-....-_.----. . Na2B4 07 -10H2 0

Dolomite ____ _ _____ _. _ ._. CaMg(C03) 2

Burkeite _-----.--_-__----_---_- Na2C03-2Na2S04

Northupite. ______________________ MgC03-Na2C03 -NaCl

Aragonite __ ____________________ CaC03

Nahcolite ----------._--------_- NaHC03

Thenardite. .._..._.. _ _ _ .._._. Na2S04 

Sulfohalite-- . _____________________ 2Na2S04 -NaCl.NaF

Aphthitalite (glaserite). ____________ K3Na(S04) 2

Tychite. --_------.-___---------_- 2MgC03-2Na2C03 -Na2S04

Schairerite __ ______ ________ - Na2S04 -Na(F,Cl)

Tincalconite- ____________ _ . ___ Na2B4O7 -5Hj,0

Calcite. ____ __ ____ __. ____ CaC08

Most of these minerals were precipitated as a result of evaporation 

of the lake water during interpluvial substages of late Quaternary 

time. Pluvial substages of late Quaternary time are generally believed 

to be represented by seams of clay and marl. (The term "clay" as 

used in the core logs and throughout this report refers only to particle 

size and not to mineral composition.)

The minerals usually found in the evaporite bodies are halite, 

trona, hanksite, borax, burkeite, thenardite and aphthitalite (glaserite); minerals usually associated with clay and marl seams are 

gaylussite, pirssonite, dolomite, aragonite, nahcolite, tychite, and 

schairerite; minerals which occur about equally in both environments 

are northupite and sulfohalite.

The evaporite bodies consist of a mesh of minerals with the interstices filled with brine that is saturated in the various compounds 

that make up these minerals.

Discolorations and inclusions of predominantly reddish-orange to 

reddish-brown material commonly occur in the evaporite bodies and 

in clay-marl seams. These discolorations occur in the form of irregular 

stringers, seams, and nodules or as discrete inclusions in many of the 

evaporite minerals. The material is believed to be a pigment (Vallentyne, 1956), possibly derived from bacteria or algae. Brine in stagnant pools at the surface is similarly discolored.

In addition to the minerals listed above, searlesite (Na2O.B203 .- 

4Si02 .2H20) and mirabilite (Na2S04 .10H20) have been found in deeper 

parts of the basin fill (Gale, 1914; Smith and Pratt, 1957), and galeite 

(Na_S04 .Na(F,Cl)) has been described by Pabst and others (1955). 

Gale (1914, p. 297) also reports the occurrence of natron, gypsum, 

anhydrite, and glauberite, but these minerals have not been recognized 

in the cores obtained in the present drilling. Mirabilite is artificially 

produced from brine during the winter months. Tincalconite, apparrently precipitated from the brine, was described by Pabst and
144 GEOLOGIC INVESTIGATIONS IN MOJAVE DESERT REGION

Sawyer (1948), though it commonly occurs as a secondary dehydration product of borax.

GEOLOGY

SALT BODIES

The saline deposit consists principally of two major beds of saline 

minerals separated by a seam of clay and marl. Figure 7 illustrates 

graphically a core log generalized from holes GS-14, GS-15, and GS16. These cores adequately represent the character of most of the 

saline deposit. Both major salt beds conform closely in area and shape 

with the present playa surface.

The uppermost salt body, known locally as the "upper salt," "upper 

structure," or "upper crystal body," is exposed over an area of about 

12 square miles in the central part of the lake (fig. 6). Around this 

central area of exposed halite is a deposit of clay which overlies an 

additional 27 square miles of salt. This clay is locally referred to as 

the "overburden mud" and reaches a thickness of 30 to 40 feet near 

the margins of the playa. It grades from a brown color at the surface 

through green to black at the base and contains disseminated pirssonite crystals in the lower few feet; laminae are not present.

The upper salt body consists chiefly of halite, hanksite, trona, and 

borax and a prominent zone of clay near the top of the section. The 

maximum thickness of this salt body is about 95 feet (pi. 5).

Underlying the upper salt body is a seam of finely to coarsely laminated dense moist generally black clay and marl. This is known as 

the "parting mud," and it averages about 12 feet thick. Within the 

parting mud are seams containing disseminated crystals of gaylussite 

or pirssonite. X-ray determinations of certain laminae have shown 

them to contain halite, aragonite, and dolomite; possibly much of the 

parting mud consists of these minerals. Borax occurs at some places 

within the parting mud in the form of seams, veins, and disseminated 

crystals.

In general, the parting mud is high in organic matter and contains 

coprolitic pellets, pollen grains, and fragments of unidentified organic 

matter (W. H. Bradley, written communication, 1955).

Underlying the parting mud seam is a second major salt body known 

as the "lower salt," "lower structure," or "lower crystal body," which 

has a maximum thickness of about 54 feet (pi. 6). The lower salt 

differs from the upper salt in containing more clay and marl seams; 

by the presence of burkeite and northupite, which are either absent 

or scarce in the upper salt body; and by a virtual lack of hanksite, 

which is abundant in the upper salt body. The lower salt body is 

also characterized by the presence, near its base, of tychite^and 

schairerite.
CORE LOGS FROM SEARLES LAKE, CALIFORNIA 145

Feet 

0

110-

130-

--

UPPER 

SALT

MUD 

PARTING

LOWER 

SALT

EXPLANATION

Holite

Honksite

Trono

Borox 

Goylussite

Pirssonite

Burkeite

IBOTTOM 50 so 20

MUD Estimoteof minerol percentoges

FIQUBE 7. Generalized graphic core log of mineral data from holes QS-14, G8- 

15, and GS-16.
146 GEOLOGIC INVESTIGATIONS IN MOJAVE DESERT REGION

A finely laminated clay containing disseminated gaylussite crystals 

immediately underlies the lower salt body. This clay, together with 

various seams of trona, halite, and other minerals found at deeper 

horizons, is known as the "bottom mud" and comprises the remainder 

of the lake fill to a known depth of 875 feet. The bottom mud to 

this depth is described in a report by Smith and Pratt (1957). Geophysical surveys indicate that the lake fill reaches a total depth of 

about 3,300 feet beneath the surface (Mabey, 1956).

BEINE

Permeating the pore spaces, vugs, and cavities of both the upper 

salt and lower salt bodies is a stratified brine having a specific gravity 

between 1.24 and 1.34, a salinity between 34 and 36 percent, and a 

pH from 9.1 to 9.4. The constituents of the brine, in addition to the 

water, are chiefly chlorine, sodium, sulfate, bicarbonate and carbonate, potassium, and borate hi order of decreasing concentration 

by weight in the upper salt; minor amounts (less than 0.5 percent) 

of strontium, phosphorus, bromine, arsenic, tungsten, lithium, fluorine, 

ammonia, iron and aluminum oxides, iodine, and antimony, in approximate order of decreasing concentration by weight, are also present. 

Calcium and magnesium are not present in detectable amounts. The 

brines in each salt body are prevented from mixing with each other 

by the impermeable parting mud seam. These brines differ in then* 

chemical character, the lower salt brine containing a higher percentage 

of borate and bicarbonate and a lower percentage of potassium than 

the upper salt brine. Measurements of brine temperatures made by 

the American Potash & Chemical Corp. indicate that the brine near 

the base of the upper salt body remains between 73°F (22.7°C) and 

76°F (24.5°C) throughout the year.

The total porosity of the upper salt body is approximately 44 

percent (J. M. Fox, C. F. Bitchie, and E. J. Watson, American Potash 

and Chemical Corp., written communication 1935). No measurements of porosity within the lower salt body have been made, but a 

visual comparison with the upper salt suggests a similar value. In 

general, the highest commercial grade of brine occurs at the base of 

the upper salt in the central part of the lake; lower grade brine occurs 

at the surface and on the margins of the salt bodies.

Gas pockets are commonly present in the salt bodies just above the 

parting mud seam and the bottom mud. This gas is combustible 

and consists of methane or a similar compound, ammonia, and 

hydrogen sulfide. The pressure exerted by this gas is sufficient, hi 

some places, to force brine from the hole several feet into the air and 

maintain a vigorous flowage for several hours.

Brine from both upper and lower salt bodies is pumped into plants
located at Trona and Westend. Sodium carbonate, sodium sulfate, 

potassium chloride, borax, lithium carbonate, bromine, and phosphoric acid are produced at Trona (Ryan, 1951); sodium cabonate, 

sodium sulfate, and borax are produced at Westend. No solid 

minerals are mined, except the winter crop of mirabilite which is 

derived from brine and a small tonnage of halite which is scraped from 

the surface and shipped to local users.

DRILLING METHODS ;

From July 1954 to November 1955, 41 holes were drilled on Searles 

Lake. Core drilling was done by a private contractor for the U. S. 

Geological Survey who used several types of portable rotary-drill rigs 

equipped with pneumatic tires and "A" rods. For most of the drilling, 

only 1 drill was in operation at a tune, except for a period of 6 months 

when 2 drills were operating simultaneously.

Because of the porous and friable nature of much of the salt, special 

equipment was used in coring. This consisted of steel core barrels 

having a diameter of 10 inches and serrated at one end with teeth 

reinforced with "stoodite" alloy; the core barrels ranged in length 

from 2 to 4 feet. During drilling, the bit is cooled by the lake brine 

which permeates the salt body; no additional circulating fluids are 

needed. Ryan (1951) has described in detail the drilling methods 

used.

No attempt was made to core the overburden mud; descriptions of 

this body in the core logs were obtained chiefly from cuttings; Holes 

located in areas covered with overburden mud were drilled with the 

following procedure: The overburden mud is first reamed with a cutting tool having a maximum diameter of 15 inches. The resulting 

hole is about 16 inches across. As the overburden mud is reamed, 

successive lengths of casing, 16 inches in diameter, are inserted to 

prevent caving. Reaming is continued until brine begins to enter 

the hole, indicating that the hole is at, or near the top of, the upper 

salt body. The casing is pounded down by means of a heavy drop 

hammer until it is firmly embedded in the resistant top of the upper 

salt body. Casing, 10 inches hi diameter, with casing guides welded 

at the sides, is then lowered into the hole temporarily and joined to 

the 16-inch casing at the top of the hole by a circular 16-inch plate 

containing a hole 10 niches in diameter in its center. The core barrel 

can then be lowered through this 10-inch casing; the casing serves as 

a guide for the cutting tool. Coring is continued until the core 

barrel becomes filled and plugged with core. After removing the core, 

which has a diameter near 9% inches, coring is continued in this manner 

until the entire upper salt body has been cored; in addition, coring 

continues for 2 or 3 feet into the parting mud seam.
148 GEOLOGIC INVESTIGATIONS IN MOJAVE DESERT REGION

The core barrel and 10-inch casing are then removed, and the 

reamer inserted again into the hole to widen it to 16-inch diameter to 

form a collar at the top of the parting mud seam which will later 

hold a cement plug designed to prevent the upper and lower salt 

brines from mixing. After reaming, the chips are removed by compressed air and the 10-inch casing reinserted in the hole; additional 

lengths of casing are welded in place until the casing reaches the depth 

cored. Coring is then resumed through the parting mud and the 

lower salt bodies. The casing temporarily prevents the upper and 

lower salt brines from mixing during the coring operations.

On completion of the hole, a pipe 3 inches in diameter, equipped 

with a circular rubber flange, 10 inches in diameter, near the base, is 

lowered into the hole through the 10-inch casing until the flange lies 

at the base of the parting mud. Cement is then pumped into the 

hole between the 10-inch casing and the 3-inch pipe; the rubber flange 

at the base of the pipe supports the cement, which is filled to the top 

of the parting mud seam. The 10-inch casing is then removed from 

the hole. After hardening, the cement forms a seal in the parting 

mud which prevents mixing of the upper and lower salt brines. 

Holes were left open for future sampling. The lower salt brine can 

be sampled by lowering a rubber hose through the 3-inch pipe; the 

upper salt brine can be sampled in the uncased upper part of the 

hole. The foregoing method of drilling was used in the majority of 

holes drilled for the Geological Survey, though minor modifications 

were adopted where necessary.

The average depth of the 29 "deep" holes is 103 feet; 12 additional 

"shallow" holes were drilled to depths of about 30 feet. The deeper 

holes penetrated both salt bodies and extended several feet into the 

bottom mud. The shallower holes tested the upper part of the upper 

salt body for the occurrence of near-surface crystalline borax.

CORE LOGS

The detailed written core logs included in this report represent 

logs from holes selected on the basis of location, contrasting mineralogy, and number of chemical analyses performed on core and brine 

samples. The core logs contain descriptions of the minerals, state 

of consolidation, color, texture, gram sizes and crystal forms, and 

percentages of each mineral, wherever possible, as observed in the 

9%-inch core shortly after recovery, and while still moist.

The percentage of minerals present are estimates made by visual 

inspection of the core. The terms "well-consolidated," "friable," 

and "poorly consolidated" are relative terms used to indicate the 

state of consolidation. If the core is not easily crumbled or deformed 

by hand, the term "well-consolidated" is used; core easily disaggre-
CORE LOGS FROM SEARLES LAKE, CALIFORNIA 149

gated into individual crystals is described as "friable"; core consisting 

of soft plastic aggregates or virtually unconsolidated material is 

described as "poorly consolidated." . The term "fractured core" refers to core recovered in fragments 

as a result of fracturing during drilling.

About 300 mineral determinations were made by Robert D. Alien, 

of the U. S. Geological Survey, using immersion oils and the petrographic microscope. These determinations are denoted in the core 

logs by an asterisk (*) following the mineral identified. Several 

determinations made by X-ray diffraction methods are denoted in 

the core logs by two asterisks (**) following the mineral so identified.

Sediment names are in accord with those suggested by Wentworth 

(1922).

Colors have been named and numbered according to the "RockColor Chart" distributed by the Geological Society of America in 

1951. All colors refer to the color of the core when wet or moist, 

and generally in sunlight.

Sizes of nonequidimensional minerals, as hanksite, were measured 

in the direction of the longest dimension.

If core recovery on any given run was not 100 percent, the recovered core was arbitrarily placed in the upper end of the run and the 

missing portion was placed at the bottom, except where evidence for 

other distribution is present.

Between runs, material commonly caved from the walls higher in 

the section. The caved materials recovered in the core barrel were 

saved and included in the log, but they have been designated as 

"probably cuttings, not core" wherever the combination of poor 

compaction and position at the top of the run have suggested the 

above origin.

Megascopic fossils were sought throughout the core, but none were 

found except a few twigs and roots embedded in clay seams.

GRAPHIC LOGS 

COMPILATION OF LOGS

The 41 drill holes shown on plates 5 and 6 are represented by a 

series of graphic logs (pis. 7, 8), which have been compiled from the 

written core logs at a scale which requires some generalization of the 

core descriptions. To allow for legibility no seams less than 0.5 foot 

in thickness nor any mineral percentage less than 10 percent are shown 

on the graphic logs. In preparing the graphic logs from the data 

in the written core logs, seams less than 0.5 foot have been combined 

with seams immediately adjacent until a minimum thickness of 

0.5 foot is obtained. In such cases, the mineral percentages in each 

seam have been combined and properly weighted according to the
150 GEOLOGIC INVESTIGATIONS IN MOJAVE DESERT REGION

thickness of each seam combined. The thickness and weighted 

mineral percentages were then plotted on the graphic log. Recovered 

core is shown on the graphic logs by a black outline; core lost or partly 

recovered in fragmentary form is not outlined.

Research on the chemical composition, mineralogy, and distribution 

of the lake beds is in progress. The formations present in the lake 

have not been named by standards of the U. S. Geological Survey nor 

have their boundaries been defined. Cross sections through the saline 

deposit and correlations of strata across the lake are hi preparation.

LOST CORE

During drilling, core may be "lost" in several ways, as follows:

1. Certain strata within the salt bodies, especially the hanksite 

zone in the upper salt, contain cavities of various sizes, some of which 

may be a foot or more in diameter (pi. 9). In drilling through such 

a zone, if there was not enough surrounding material to preserve the 

cavity enclosed in the core barrel, the structure collapsed and the 

consequent interval was considered as "lost" core.

2. Throughout most of the salt bodies there exist smaller interstitial openings with the saline minerals loosely consolidated. During 

drilling, the pressure applied to the core barrel is sufficient, in some 

places, to compact this core; this also results in "lost" core. In 

methods 1 and 2, the "lost" core is apparent, not real.

3. Core may actually be destroyed by grinding, and the ground 

material washed into cavities at the sides of the hole or at the bottom. 

This method of loss was particularly common in the soft beds of trona, 

especially the thick bed at the base of the upper salt body (pi. 10). 

The "mushy" character of this zone permits it to be easily compacted 

and ground away.

The sections of the graphic logs designated as lost core are estimates 

of the material lost. In most cores, it is difficult or impossible to 

determine accurately the type of loss and the materials lost, though 

little doubt exists within the vuggy hanksite zone (pi. 9) in the upper 

salt, and in the soft massive trona seam at the base of the upper salt 

(pi. 10). The mineral composition and percentages in lost core have 

been estimated by taking the above factors into consideration, by 

noting the character of core recovered just above and below the lost 

section, and by noting the character of core in holes nearby at approximately the same horizon.

LITERATURE CITED

Dyer, B. W., 1950, Searles Lake development: Colorado School Mines Quart.,

v. 45, no. 4B, p. 39-44. 

Fenneman, N. M., 1931, Physiography of western United States: New. York,

McGraw-Hill Book Co.
GEOLOGICAL SITRVEY Uri.LKTIN 1045 PLATE ft

CORE FROM HOLE GS-26 

Vuggy aggregate of hanksite crystals typical of hanksite zone in upper salt body.
GEOLOGICAL SURVEY BULLETIN 1045 PLATE 10

CORE FROM HOLE GS-21 

White massive trona with discolored seams (a) in contact with top of dark "parting mud" (6).
CORE LOGS FROM SEARLES LAKE, CALIFORNIA 151

Gale, H. S., 1914, Salines in the Owens, Searles, and Panamint basins, southeastern

California: U. S. Geol. Survey Bull. 580-L, p. 251-323. 

Goddard, E. N., chm., and others, 1948, Rock-color chart: Washington, Natl.

Research Council (republished by Geol. Soc. America, 1951). 

Hewett, D. F., 1954, General geology of the Mojave Desert region, California:

California Div. Mines Bull. 170, chap. 2, p. 5-20. 

Mabey, D. R., 1956, Geophysical studies in the intermontane basins in Southern

California: Geophysics, v. 21, p. 839-853. 

Pabst, A., and Sawyer, D. L., 1948, Tincalconite crystals from Searles Lake, San

Bernardino County, Calif.: Am. Mineralogist, v. 33, p. 472-481. 

Pabst, A., Sawyer, D. L., and Switzer, George, 1955, Galeite, a new mineral from

Searles Lake, Calif, [abs.]: Geol. Soc. America Bull., v. 66, p. 1658. 

Ryan, J. E., 1951, Industrial salts; production at Searles Lake: Mining Eng.,

v. 3, p. 447-452. 

Smith, G. L, and Pratt, W. P., 1957, Core logs from Owens, China, Searles, and

Panamint basins, California: U. S. Geol. Survey Bull. 1045-A. 

Teeple, John E., 1929, The industrial development of Searles Lake brines with

equilibrium data: New York, Chemical Catalog Co., 192 p. 

Thompson, D. G., 1929, The Mohave Desert region, California: U. S. Geol.

Survey Water-Supply Paper 578, 759 p. 

Vallentyne, J. R., 1956, Carotenoids and chlorophyll-like pigments in a

20,000 year old sediment from Searles Lake, Calif, [abs.]: Geol. Soc. America

Bull., v. 67, p. 1740. 

Wentworth, C. K., 1922, A scale of grade and class terms for clastic sediments:

Jour. Geology, v. 30, p. 377-392.

491349 59 2
CORE LOGS

Searles drill hole GS-1

LOCATION: Searles Lake, Calif., sec. 10, T. 25 S., R. 43 E., Mount Diablo base 

line and meridian, about 1,580 ft S. 9° W. of common cor., sees. 2, 3, 10, and 11.

ELEVATION AT TOP OF HOLE: 1,621 ft.

ELEVATION AT BOTTOM OP HOLE: 1,528.2 ft.

TOTAL DEPTH: 92.8 ft.

DATE OF DRILLING: July 13-26, 1954.

CASING USED: 51 ft of 10-in. casing; 30 ft of 16-in. casing.

MINERAL DETERMINATIONS: Minerals identified microscopically are denoted by 

an asterisk (*).

Depth. Unit thick-

(feet) ness (feet) Description

8. 0 8. 0 Overburden mud, not cored. Moderately yellowish-brown

(10 YR 6/4) tenacious clay, locally silty.

16. 0 8. 0 Overburden mud, not cored. Dusky yellow-green (5(?F 5/2) 

clay, locally silty.

28. 2 12. 2 Overburden mud, not cored. Black (N 1) tenacious clay 

("gumbo") with 3-in. halite seam at 25.8 ft; 2 percent 

loose disseminated halite crystals from 20 to 25.8 ft; 6 percent loose disseminated halite crystals from 25.8 to 28.2 ft.

29. 1 .9 Clay and halite. Black (N 1) clay with 20 percent disseminated colorless halite crystals from 2 to 75 mm.

29. 6 .5 Halite* and trona. Well-consolidated slightly vuggy aggregate of colorless halite crystals from 1 to 4 mm in length 

discolored dark gray (N 3) by clay; trace of fibrous trona 

disseminated throughout.

30. 1 .5 Halite*. Poorly consolidated aggregate of halite cubes 

modified by octahedron with thin black (N 1) clay streaks.

30.8 .7 Halite and trona. Well-consolidated aggregate of halite 

crystals averaging 2 mm in length, with 5 percent interstitial colorless fibrous trona; halite discolored by trace of 

interstitial black (N 1) clay.

31. 2 .4 Halite. Poorly consolidated aggregate of halite crystals up 

to 4 mm in length.

31. 4 .2 Clay. Black (N 1) clay.

31. 9 .5 Halite. Poorly consolidated aggregate of halite crystals up 

to 4 mm in length; 2 percent hanksite crystals disseminated 

throughout.

35. 6 3. 7 No core.

36. 0 .4 Hanksite and clay. Poorly consolidated aggregate of hanksite 

crystals up to 15 mm in length, with a few fragments of 

granular massive hanksite; 25 percent interstitial black (N 1) 

clay; trace of interstitial trona.

36. 4 .4 Hanksite and trona. Well-consolidated aggregate of hanksite 

crystals averaging 10 mm in length; pockets of fibrous trona 

in vugs. Hanksite 97 percent, trona 3 percent. 

152
CORE LOGS FROM SEARLES LAKE, CALIFORNIA 153

J)epth Unirthick- 

(feet) ness (feet) Description

36. 9 0. 5 Hanksite, trona, and clay. Well-consolidated aggregate of 

hanksite crystals cemented by black (N 1) clay; pockets of 

fibrous trona. Hanksite 90 percent, trona 5 percent, clay 

5 percent.

37. 6 . 7 Trona. Fractured core. Fragments of light gray (N 7) to 

white (AT 9) trona 2-8 cm across, with much interstitial soft 

unconsolidated massive trona.

44. 2 6. 6 No core.

44. 5 . 3 Trona. Soft unconsolidated massive trona, discolored black 

(N 1) by trace of intermixed clay.

44. 8 . 3 Trona. Well-consolidated massive trona discolored medium 

light gray (N 6) by trace of intermixed clay.

45. 6 .8 Trona. Well-consolidated white (N 9) to very light gray

(N 8) massive trona. 

45.8 .2 Trona. Well-consolidated light olive-gray (5Y 6/1) hard

massive trona.

46. 0 . 2 Clay and trona. Black (N 1) tenacious clay with seams of 

white (N 9) massive trona. Clay 50 percent, trona 50 

percent.

47. 4 1. 4 Clay and pirssonite*. Black (N 1) to grayish olive-green 

(5GY 3/2) dense clay, with closely spaced thin laminations 

of moderate yellowish-brown (10YJ? 5/4) to medium lightgray (N 6) to very light gray (N 8) clay; disseminated 

crystals of pirssonite* ranging from 2 to 10 mm in length. 

Clay 95 percent, pirssonite 5 percent.

-47. 6 . 2 No core.

47. 7 . 1 Clay, pirssonite*, and borax. Black (N 1) to dark-gray 

(N 3) dense finely laminated clay with 30 percent disseminated pirssonite* crystals up to 10 mm in length; 10 percent 

borax crystals from 5 to 10 mm in length. 

48.4 .7 Clay and pirssonite*. Grayish olive-green (5GY 3/2) to 

black (N 1) dense clay with fine laminations of greenish 

and grayish clay; 10 percent disseminated crystals of pirssonite averaging 10 mm lin length.

 49. 6 1. 2 Clay and aragonite. Black (N 1) dense clay with a few 

widely spaced laminae of white (N 9) to dark greenish-gray 

(5GY 2/1) soft massive aragonite. Clay 95 percent, 

aragonite 5 percent.

-51. 2 1. 6 Clay and aragonite. Black (N 1) dense clay, coarsely laminated in upper 0.9 ft, finely laminated in lower 0.7 ft, with 

laminae of white (N 9) to dark greenish-gray (5GY 4/1) 

soft massive aragonite less than 1 mm wide. Clay 95 

percent, aragonite 5 percent.

 51. 6 . 4 Clay, aragonite, and pirssonite*. Black (N 1) dense clay 

with fine laminae of white (N 9) to dark greenish-gray 

(5GY 4/1) to grayish olive-green (5GY 3/2) soft massive 

finely crystalline aragonite; 25 percent pirssonite* crystals 

averaging 3 mm in length disseminated throughout.

.52. 3 . 7 No core.
154

Depth

(feet) nest (feet) Description

52. 5 0. 2 Clay and pirssonite*. Olive-gray (5F 3/2) to black (N 1) 

dense clay, with seams, 0.05 to 1.5 mm thick of disseminated pirssonite* crystals. Clay 50 percent, pirssonite* 

50 percent.

56. 2 3. 7 Clay and gaylussite. Grayish olive-green (5(7 Y 3/2) to 

grayish-black (N 2) to black (N 1) dense finely laminated 

clay with scattered pockets and streaks of disseminated 

anhedral gaylussite up to 12 cm in length. Clay 85 percent, 

gaylussite 15 percent.

56. 3 .1 No core.

58. 3 2. 0 Clay and gaylussite. Black (N 1) to grayish-black (N 2) 

to dark-gray (N 3) dense coarsely laminated clay revealed 

by color differences; 5 percent gaylussite in scattered 

pockets ranging from 1 to 3 cm in length; seam of lightbrown (5 YR 5/6) algae (?)-discolored clay 3 mm wide 

at 58.0 ft.

60. 1 1. 8 Clay. Black (N 1) dense clay.

61. 2 1. 1 No core.

61. 4 .2 Clay and gaylussite*. Black (AT 1) dense clay with 25 percent disseminated crystals of gaylussite averaging 2 mm in 

length.

61. 6 .2 Clay. Black (N 1) dense clay; very few disseminated crystals.

61. 8 .2 Clay and gaylussite. Black (N 1) dense clay with 50 percent 

disseminated gaylussite crystals averaging 2 mm in length.

62. 0 .2 Clay. Black (N 1) dense clay.

62. 1 .1 Gaylussite and clay. Consolidated aggregate of gaylussite 

crystals averaging 5 mm in length with 25 percent interstitial black (AT 1) clay.

62. 9 .8 Clay. Black (N 1) dense clay.

63. 3 .4 Clay and gaylussite. Black (N 1) dense clay with 50 percent 

disseminated gaylussite crystals averaging 2 mm in length.

63. 7 .4 Clay. Black (N 1) dense clay.

64. 4 .7 Clay and gaylussite. Black (N 1) dense clay with 30 percent 

disseminated gaylussite crystals averaging 5 mm in length.

64. 9 .5 Clay. Black (N 1) dense clay with a few thin seams of 

gaylussite silt.

65. 0 .1 Clay and gaylussite. Black (N 1) dense clay with 30 percent 

disseminated gaylussite sand.

65. 1 .1 Trona. Loosely consolidated fibrous trona locally discolored dark gray (N 3) by clay, with pockets of white 

(N 1) massive trona. Trona 95 percent, clay 5 percent.

65. 3 .2 No core.

65. 6 . 3 Trona and clay. Fragments of fibrous trona mixed with 

black (N 1) clay. Probably cuttings, not core. Clay 95 

percent, trona 5 percent.

65. 7 .1 Trona and clay. Well-consolidated seams of white (N 9) 

massive trona with seams of black (N 1) clay. Trona 80 

percent, clay 20 percent.

65. 9 .2 Clay. Black (N 1) dense clay.
CORE LOGS FROM SEARLES LAKE, CALIFORNIA 155

Unit thickness (feet) Description

67. 9 2. 0 Clay and gaylussite. Black (N 1) dense clay with 25 percent 

disseminated gaylussite crystals from 2 to 10 mm in length.

 68. 4 . 5 Clay. Black (N 1) dense clay.

 69. 2 .8 Trona. Well-consolidated white (N 1) massive trona.

 69.4 .2 No core. 

70.0 . 6 Trona. Hard vuggy massive trona discolored dark-gray

(N 3) to grayish-green (10G 4/2) by trace of intermixed

clay. 

72. 0 2. 0 Trona. Well-consolidated white (N- 9) to dark-gray (N 3)

to light-brown (SYR 6/4) trona, discolored by trace of

intermixed clay. ' 

72. 4 . 4 Clay and gaylussite. Black (N 1) dense clay with 5 percent

disseminated gaylussite crystals averaging 1 mm in length.

72. 5 . 1 Clay and gaylussite. Black (N 1) dense clay with 75 percent 

disseminated gaylussite crystals averaging 5 mm in length.

73. 3 . 8 Clay and gaylussite. Black (N 1) dense clay with 35 percent 

disseminated gaylussite crystals 3 to 5 mm in length.

73. 9 . 6 No core.

74. 6 . 7 Clay and gaylussite*. Poorly consolidated soft olive-gray 

(5Y 3/2) to black (N 1) clay with 50 percent disseminated 

gaylussite* crystals from 1 to 2 mm in length, averaging 

10 mm.

75. 3 . 7 Clay and gaylussite. Black (AT 1) dense clay with 25 percent 

disseminated gaylussite crystals from 5 to 10 mm in length.

76. 2 . 9 Clay. Black (N 1) dense clay.

76. 8 . 6 Trona. Greenish-gray (5GY 6/1) to grayish-black (N 2) 

massive trona, discolored by trace of intermixed clay; large 

colorless trona blades averaging 10 mm in length in upper 

0.1 ft.

77. 0 .2 Clay. Black (N 1) dense clay.

77. 8 .8 Trona. White to greenish-gray (5GY 6/1) to grayish-black 

(N 2) dense hard massive trona; trace of fibrous trona in 

lower 0.2 ft.

78. 8 1. 0 No core.

79. 2 . 4 Trona. Colorless to white (N 9) fibrous trona locally discolored grayish black (N 2) to medium gray (N 5) by trace 

of interstitial clay.

79. 6 . 4 Clay. Black (N 1) to light-gray (N 7) to white (N 9) dense 

finely laminated clay; 2 moderate reddish-brown (1012 4/6) 

algae (?)-discolored laminae in lower 0.1 ft about 1 mm wide.

79. 8 . 2 Trona. Well-consolidated moderate reddish-brown (10/2 4/6) 

to dark-gray (N 3) to greenish-gray (5GY 6/1) to light olivegray (5F 6/1) fibrous trona.

SO. 5 .7 Clay. Black (N 1) to grayish-olive (10F 4/2) to light-gray 

(N 7) dense finely laminated clay.

:80. 6 .1 Clay and gaylussite. Black (N 1) to greenish-black (5GY 2/1) 

dense clay with 50 percent disseminated gaylussite crystals 

averaging 5 mm in length.

£0.9 . 3 Clay and gaylussite. Black (N 1) clay with 50 percent 

disseminated gaylussite crystals from 1 to 3 mm in length.
156 GEOLOGIC INVESTIGATIONS IN MOJAVE DESERT REGION

Depth Unit thick-

(feet) ness (feet) Description

81. 8 0. 9 Clay. Black (N 1) dense clay; 3 faint seams averaging 1 mm 

wide of moderate reddish-brown (1012 4/6) algae (?)-discolored clay and 1 contorted seam 5 mm wide of moderate 

reddish-orange (1QR 6/6) algae (?)-discolored clay.

81. 9 .1 Trona. Densely packed aggregate of trona blades averaging 

10 mm in length; core fractured and obscured.

82. 1 .2 Clay. Black (N 1) dense clay.

84. 2 2. 1 No core.

84. 5 .3 Clay. Black (N 1) to grayish-olive (1074/2) to greenish-gray

(5GY 6/1) dense finely laminated clay. 

84. 8 .3 Clay and gaylussite. Black (N 1) dense clay with 50 percent

disseminated gaylussite crystals from 1 to 2 mm in length. 

86. 0 1. 2 Trona. Well-consolidated aggregate of coarse bladed trona

with interstitial soft massive trona and trace of clay.

86. 9 .9 Clay and tychite. Black (N 1) to grayish-olive (10 Y 4/2) to 

medium light-gray (N 6) dense finely laminated clay; a few 

seams 4 mm wide of disseminated tychite octahedrons less 

than 1 mm in diameter. Clay 99 percent, tychite 1 percent.

87. 7 .8 Clay and gaylussite. Black (N 1) dense clay with 50 percent 

disseminated gaylussite crystals averaging 10 mm in 

length.

87. 9 .2 Clay and gaylussite. Black (N 1) dense clay with 50 percent 

disseminated gaylussite sand.

88. 3 . 4 Clay. Black (N 1) dense clay. 

88. 4 .1 No core.

88. 8 .4 Clay and gaylussite. Black (N 1) to grayish-olive (10 Y 4/2) 

clay with seams, from 3 to 4 mm wide, of disseminated 

gaylussite sand.

89. 0 .2 Trona. Well-consolidated medium-gray (N 5) massive trona; 

discolored by trace of intermixed clay.

92. 5 3. 5 Clay and gaylussite. Dark greenish-gray (5(?F 4/1) and 

5G 4/1) to light-gray (N 7) to light-brown (SYR 5/6) to 

dusky yellow (57 6/4) to black (N 1) dense finely laminated 

clay with 20 percent disseminated gaylussite crystals from 

5 to 10 mm in length.

92. 8 .3 No core.

Searles drill hole GS-2

LOCATION: Searles Lake, Calif., about 300 ft east of east J^6 sec. cor., sees. 24 and 

25, T. 25 S., R. 43 E., Mount Diablo base line and meridian.

ELEVATION AT TOP OF HOLE: 1,617 ft.

ELEVATION AT BOTTOM OF HOLE: 1,509.7 ft.

TOTAL DEPTH: 107.3 ft.

DATE OF DRILLING: July 26 to Aug. 6, 1954.

CASING USED: 73 ft of 3-in. pipe.

MINERAL DETERMINATIONS: Minerals identified microscopically are denoted by 

an asterisk (*).

Depth Unit thick-

(feet) ness (feet) Description

0. 1 0. 1 Halite. Well-consolidated porous aggregate of white (N 9) 

to colorless halite crystals averaging 3 mm in length.
CORE LOGS FROM SEARLES LAKE, CALIFORNIA 157

Depth Unit thick- 

(feet) ness (feet) Description

0. 3 0. 2 Halite and clay. Well-consolidated porous aggregate of colorless to white (N 9) halite crystals averaging 3 mm in length, 

with 5 percent interstitial light olive-gray (5 F5/2) to grayisholive (10T 4/2) clay.

.5 .2 Halite and clay. Poorly consolidated porous aggregate of 

halite anhedra with 5 percent interstitial grayish-olive (10Y 

-4/2) clay.

1.0 .5 Halite. Poorly consolidated porous aggregate of subhedral 

halite cubes 3-5 mm in diameter; 2 percent interstitial 

grayish-olive (10F4/2) clay.

1. 2 .2 Clay and halite. Dark greenish-gray (5GY 4/1) clay with 

loose disseminated anhedral halite crystals and rounded 

octahedra up to 5 cm in length. Clay 75 .percent, halite 

25 percent.

2. 4 1. 2 Clay and halite. Greenish-gray (5GY 6/1 to 5G 6/1) clay 

with 50 percent disseminated anhedral to subhedral halite 

crystals showing octahedral faces from 1 to 5 cm in length, 

averaging 25 mm.

3. 0 .6 Borax, halite, and clay. Greenish-gray (5GY 6/1 to 5G 6/1) 

clay with large disseminated subhedral borax crystals up 

to 10 cm, averaging 6 cm; small octahedral and cubic halite 

crystals 3 mm in length are also disseminated in the clay. 

Borax 50 percent, clay 40 percent, halite 10 percent.

3. 3 .3 Clay and hanksite. Unconsolidated black (N 1) soft clay 

with 20 percent disseminated euhedral hanksite crystals 

averaging 5 mm in length.

3. 8 . 5 No core:

4.0 .2 Halite, hanksite, and borax. Unconsolidated aggregate of 

anhedral halite with a few crystals showing octahedral 

faces, averaging 10 mm in length; 30 percent intermixed 

hanksite crystals averaging 10 mm in length; 10 percent 

borax fragments 25 mm in length. Probably cuttings, not 

core.

4. 2 .2 Halite and clay. Well-consolidated anhedral halite with 10' 

percent interstitial black (N 1) to greenish-black (5G 2/1) 

clay.

5. 6 1. 4 Halite and clay. Well-consolidated aggregate of subhedral. 

halite crystals averaging 10 mm in length, with 40 percent, 

interstitial black (N 1) clay.

6. 1 .5 Hanksite and clay. Well-consolidated aggregate of euhedral, 

hanksite crystals averaging 10 mm in length, with 10 percent interstitial black (N 1) clay.

7. 0 . 9 No core.

7. 3 .3 Halite and clay. Well-consolidated anhedral halite crystals;

averaging 10 mm in length, with 50 percent interstitial

black (N 1) clay; a few octahedra. 

7. 5 .2 Halite and borax. Unconsolidated anhedral halite crystals.

averaging 10 mm in length, with 10 percent disseminated

borax crystals up to 50 mm in length, averaging 25 mm.
158 GEOLOGIC INVESTIGATIONS IN MOJAVE DESERT REGION

Depth Unit thick-

(feet) ness (feet) Description

8. 6 1.1 Clay and halite. Well-consolidated grayish-black (N 2) clay 

with 20 percent disseminated anhedral halite crystals 

averaging 20 mm in length.

8. 8 .2 Clay, halite, and borax. Unconsolidated grayish-black (N 2)

soft clay with 25 percent disseminated halite crystals averag-

: ing 10 mm in length and 15 percent euhedral borax crystals

averaging 20 mm in length; a few borax crystals coated

; with layer of pirssonite* and clay* 1 mm thick.

9.3 .5 Halite and clay. Well-consolidated aggregate of halite 

crystals averaging 10 mm in length, with 20 percent interstitial black (N 1) to grayish-black (N 2) clay; prominent 

clay inclusions in halite.

M). 1 .8 Borax, halite, and clay. Poorly consolidated aggregate of 

euhedral borax crystals from 10 to 50 mm in length, averaging 25 mm; 15 percent disseminated halite cubes 5 to 10 mm 

in length with scattered subhedral halite octahedra; 5 percent interstitial grayish-black (N 2) clay.

10. 8 .7 Halite and clay. Well-consolidated grayish-black (N 2) clay 

with 60 percent disseminated anhedral halite crystals 

averaging 12 mm in length; a few halite cubes and subhedral octahedra.

11. 0 . 2 No core.

13. 1 2. 1 Clay, halite, and borax. Poorly consolidated grayish-black 

(N 2) clay with disseminated aggregate of halite cubes and 

cubes modified by octahedron with individual disseminated 

crystals of halite averaging 10 mm in length; 10 percent 

disseminated anhedral borax crystals 50 to 100 mm in 

length; single crystal of hanksite. Clay 50 percent, halite 

= ' 40 percent, borax 10 percent.

13. 2 .1 No core.

14. 0 .8 Trona. Dark-gray (N 3) soft massive trona.

14.6 .6 Halite and clay. Unconsolidated to friable aggregate of 

anhedral halite crystals up to 50 mm in length, averaging 

15 mm, 5 percent interstitial dark gray (N 3) clay.

17. 6 3. 0 No core.

17. 9 . 3 Halite and trona. Dark-gray (N 3) soft massive trona containing disseminated anhedral to subhedral halite crystals 

and aggregates of halite crystals from 2 to 7 cm in length. 

Halite 50 percent, trona 50 percent.

18. 1 . 2 Halite and hanksite. Well-consolidated massive halite with 

40 percent disseminated hanksite crystals from 10 to 25 

mm in length.

18.9 .8 Hanksite, trona, and halite. Unconsolidated mixture of 

soft massive trona, hanksite crystals from 10 to 25 mm in 

length, and anhedral halite crystals up to 50 mm in length, 

averaging 10 mm. Hanksite 60 percent, trona 25 percent, 

halite 15 percent.

19. 2 . 3 Hanksite and halite. Well-consolidated aggregate of euhedral 

hanksite crystals averaging 15 mm in length, with 20 

percent interstitial anhedral halite crystals.

20. 5 1. 3 No core.
159

Depth Unit thick*

(feet) ness (feet) Description

20. 9 0. 4 Hanksite and borax. Well-consolidated to unconsolidated 

hanksite crystals averaging 15 mm in length, with 50 

percent intermixed massive borax.

22. 9 2. 0 Hanksite, borax, and trona. Well-consolidated mixture of 

anhedral to subhedral borax and hanksite crystals with 

streaks and pockets of soft white (N 9) massive trona. 

Hanksite 65 percent, borax 30 percent, trona 5 percent.

23.5 .6 Borax, clay, and trona. Well-consolidated aggregate of 

borax crystals averaging 25 mm in length, with 3 percent 

interstitial olive-black (5V 2/1) clay; 2 percent fibrous trona 

in vugs.

24. 5 1.0 Borax and hanksite. Well-consolidated fractured aggregate 

of anhedral, subhedral, and massive borax; a few disseminated hanksite crystals averaging 10 mm in length. 

Borax 95 percent, hanksite 5 percent.

24. 6 .1 No core.

25. 1 .5 Borax and hanksite. Well-consolidated aggregate of borax 

crystals averaging 10 mm in length, with disseminated 

anhedral to euhedral hanksite crystals averaging 10 mm 

in length. Borax 90 percent, hanksite 10 percent.

25.7 . 6 Borax and halite. Well-consolidated aggregate of borax 

crystals averaging 35 mm in length, with 5 percent disseminated halite crystals; trace of soft massive trona in 

upper 0.1 ft; small amount of black (N 1) clay in interstices 

of borax crystals.

26.2 .5 Halite and borax. Well-consolidated massive halite with, 

scattered vugs containing boYax crystals from 5 to 10 mm 

in length; traces of clay. Halite 95 percent, borax 5 percent.

26. 4 . 2 Hanksite, clay, and borax. Well-consolidated greenish-black 

(5GY 2/1) clay with disseminated hanksite and borax 

crystals averaging 25 mm in length. Hanksite 60 percent,, 

clay 30 percent, borax 10 percent.

28. 0 1. 6 Halite and trona. Medium-gray (N 6) to white (AT 9) granular 

massive halite with narrow streaks, lenses, and pockets 

of dark yellowish-orange (10YR 6/6) fibrous trona. Halite 

80 percent, trona 20 percent.

30. 6 2. 6 No core.

31. 6 1.0 Halite, trona, and clay. Friable vuggy aggregate of subhedral halite crystals averaging 10 mm in length, with 1 

percent interstitial black (N 1) clay; 1 percent interstitial 

soft massive trona.

31.9 .3 Halite, trona, and clay. Well-consolidated aggregate of 

halite crystals with 15 percent interstitial dark greenishgray (5G 4/1) to dark-gray (N 3) to dark yellowish-orange 

(10YR 6/6) soft massive trona; 5 percent black (N 1) clay 

in interstices of halite and mixed with trona. Halite 80 

percent, trona 15 percent, clay 5 percent.

32.6 .7 Halite. Well-consolidated slightly vuggy aggregate of 

grayish-yellow (5Y 8/4) to white (N 9) halite crystals 

averaging 1 mm in length; traces of colorless fibrous trona.
160 GEOLOGIC INVESTIGATIONS IN MOJAVE DESERT REGION

Depth Unit thick-

(feet) ness (feet) Description

32.7, 0.1 Halite, trona, and clay. Well-consolidated aggregate of 

halite crystals with 5 percent interstitial dark greenish 

gray (5G 4/1) to dark-gray (N 3) to dark yellowish-orange 

(10YR 6/6) soft massive trona; black (N 1) clay in interstices of halite and mixed with trona. Halite 90 percent, 

trona 5 percent, clay 5 percent.

33. 3 . 6 Halite. Well-consolidated aggregate of colorless to white 

(N 9) halite crystals averaging 1 mm in length, locally 

stained grayish-yellow (5 Y 8/4).

33. 5 .2 Halite, trona, and clay. Same as unit 32.6 to 32.7 ft.

33. 7 .2 Trona. Unconsolidated white (N 9) soft massive trona.

34. 3 .6 No core.

34. 7 . 4 Halite, hanksite, and clay. Poorly consolidated aggregate 

of white (N 9) halite cubes and anhedra averaging 2 mm 

in length; a few fragments of hanksite about 10 mm in 

length; traces of interstitial black (N 1) clay. May be 

cuttings, not core. Halite 98 percent, hanksite 1 percent, 

clay 1 percent.

34. 9 . 2 Halite and hanksite.. Well-consolidated slightly vuggy aggregate of white (N 9) halite crystals averaging 5 mm in length; 

hanksite crystals from 10 to 50 mm in length at base. 

Halite 90 percent, hanksite 10 percent.

35. 3 . 4 No core.

35. 5 .2 Trona and halite. Unconsolidated greenish-gray (5GY 6/1) 

soft trona mixed with 20 percent halite anhedra averaging 

2 mm in length. Probably cuttings, not core.

56. 0 . 5 Halite. Unconsolidated white (N 9) halite fragments averaging 2 mm in length.

36. 1 . 1 Halite. Well-consolidated aggregate of colorless to white 

(N 9) halite crystals averaging 3 mm in length.

 36. 5 . 4 Hanksite. Well-consolidated light olive-gray (5Y 6/1) to pale 

yellowish-brown (IOYR 6/2) massive hanksite.

 36. 8 . 3 Hanksite. Dense vuggy aggregate of hanksite crystals averaging 10 mm in length.

36. 9 . 1 Halite. Well-consolidated aggregate of colorless to white 

(N 9) halite crystals averaging 10 mm in length.

37. 0 . 1 Trona. Well-consolidated white (N 9) to pale yellowishbrown (10F.R 6/2) compact fibrous trona.

 37. 5 . 5 Hanksite. Well-consolidated massive hanksite and aggregates of hanksite crystals averaging 15 mm in length.

37. 6 .1 Trona, hanksite*, and halite*. White (N 9) soft massive 

trona with scattered disseminated hanksite crystals up to 5 

mm in length; numerous inclusions, 1-2 mm long, of hard 

white (N 9) massive hanksite*. Trona 95 percent, hanksite 3 percent, halite 2 percent.

38. 3 . 7 No core.

38. 5 .2 Halite. Unconsolidated aggregate of white (N 9) halite 

anhedra averaging 4 mm in length.

40. 3 1. 8 Hanksite and halite. Well-consolidated slightly vuggy granular massive hanksite and halite, with vugs containing 

euhedral hanksite crystals; 1 large hanksite crystal 10 cm 

in length. Hanksite 60 percent, halite 40 percent.
CORE LOGS FROM SEARLES LAKE, CALIFORNIA 161

Depth Unit thick-

(feet) ness (feet) Description .

43. 9 3. 6 No core.

44. 1 .2 Halite. Well-consolidated aggregate of colorless to white (N 

9) halite cubes from 2 to 5 mm in length.

44. 4 .3 Hanksite*, halite*, and trona*. Well-consolidated aggregate 

of pale yellowish-brown (10YR 6/2) intermixed granular 

massive hanksite*, halite*, and trona*. Hanksite 35 percent, halite 35 percent, trona 30 percent.

44. 9 . 5 Hanksite and clay. Well-consolidated aggregate of hanksite 

crystals averaging 10 mm in length, with 25 percent interstitial black (N 1) clay.

45. 1 .2 Hanksite and halite. Well-consolidated aggregate of hanksite crystals averaging 2 cm in length, with 50 percent disseminated halite crystals averaging 2 mm in length.

45. 3 .2 Hanksite. Pale yellowish-brown (10 YR 6/2) massive hanksite.

45. 4 .1 Hanksite, halite, and clay. Well-consolidated vuggy aggregate of hanksite crystals averaging 5 mm in length, with 

black to dark yellowish-orange (10 YR 6/6) to dark-gray (W3) 

clay seams containing disseminated halite crystals averaging 2 mm in length. Hanksite 80 percent, clay 10 percent, halite 10 percent.

45. 5 . 1 Halite. Friable aggregate of colorless halite cubes averaging 

2 mm in length.

45. 7 .2 Hanksite. Black (N 1) to olive-gray (5Y 4/1) massive hanksite, discolored by trace of intermixed clay.

45. 8 .1 Hanksite, halite, and clay. Black (N 1) to dark-gray (N 3) 

to dark yellowish-orange (10 YR 6/6) clay with disseminated 

halite and hanksite crystals averaging 10 mm in length. 

Clay 50 percent, hanksite 40 percent, clay 10 percent.

46. 1 . 3 Hanksite. Dense granular aggregate of hanksite crystals 

averaging 4 mm in length.

46. 7 . 6 Hanksite. Well-consolidated vuggy aggregate of hanksite 

crystals averaging 10 mm in length.

47. 3 . 6 Hanksite. Very dense granular aggregate of hanksite crystals 

from 3 to 4 mm in length.

47. 7 .4 Hanksite and halite. Well-consolidated slightly vuggy aggregate of 50 percent halite crystals from 1 to 2 mm in 

length and 50 percent granular massive hanksite.

47. 9 .2 Trona. White (N 9) to very light gray (N 8) soft massive 

trona.

48. 1 .2 No. core.

48. 3 . 2 Halite. Unconsolidated aggregate of halite crystals averaging 

2 mm in length. Probably cuttings, not core.

48.4 .1 Trona and clay. Well-consolidated dark-gray (N 3) soft 

massive trona and black (N 1) clay. Trona 50 percent, 

clay 50 percent.

48. 7 .3 Trona and hanksite. Well-consolidated massive hanksite 

and trona. Hanksite 50 percent, trona 50 percent.

48. 9 .2 Trona and hanksite. Well-consolidated massive trona containing 50 percent disseminated hanksite crystals from 5 to 

10 mm in length. 
162 GEOLOGIC INVESTIGATIONS IN MOJAVE DESERT REGION

Depth Unit thick-

(feet) ness (feet) Description

49. 1 0. 2 Hanksite and trona. Well-consolidated massive hariksite 

with pockets of soft massive trona. Hanksite 90 percent, 

trona 10 percent.

49.3 .2 Halite and hanksite. Unconsolidated aggregate of halite 

crystals averaging 2 mm in length, containing 20 percent 

disseminated hanksite crystals averaging 10 mm in length.

49. 4 .1 Hanksite. Well-consolidated massive hanksite.

49. 5 . 1 Clay. Well-consolidated black (N 1) clay and intermixed 

olive-gray (5F4/1) silt.

49.6 .1 Halite and hanksite. Unconsolidated aggregate of halite 

crystals from 1 to 2 mm in length, containing 10 percent 

disseminated hanksite crystals averaging 10 mm in length.

49. 9 .3 Hanksite. Well-consolidated massive hanksite.

50. 2 .3 Halite and trona. Poorly consolidated aggregate of halite 

crystals from 1 to 2 mm in length, with fragments of white 

(N 9) to light-gray (N 7) massive trona. Halite 50- 

percent, trona 50 percent.

50. 4 .2 Trona. Well-consolidated white (N 9) to light-gray (N 7) 

massive trona.

51. 4 1. 0 No core.

52. 7 1. 3 Trona and hanksite. Well-consolidated white (N 9) massive 

trona with disseminated crystals of hanksite averaging 10- 

mm in length and seams averaging 5 mm wide of massive 

hanksite.. Trona 80 percent, hanksite 20 percent.

54. 3 1. 6 No core.

55. 0 .7 Trona. White (N 9) to very light gray (N 8) soft massive 

trona.

55. 3 .3 Trona and hanksite. White (N 9) to very light gray (N 8) 

hard, bony trona with disseminated hanksite crystalsaveraging 10 mm in length. Trona 80 percent, hanksite 

20 percent.

56. 1 .8 Clay and gaylussite.* Black (N 1) dense laminated clay with 

50 percent disseminated gaylussite* crystals from 5 to 10" 

mm in length.

56. 6 .5 Clay and gaylussite. Black (N 1) to moderate yellowishbrown" (10Y7E 5/4) to grayish yellow-green (5GY 7/2) tovery light gray (N 8) to grayish olive-green (5GY 3/2) densefinely laminated clay with 5 percent disseminated gaylussitecrystals averaging 10 mm in length.

57. 1 .5 Clay and gaylussite. Black (N 1) to grayish olive-green. 

(5GY 3/2) dense finely laminated clay with 50 percent disseminated gaylussite crystals from 5 to 10 mm in length.

58.1 1.0 Clay. Black (N 1) to dusky yellow-green (5GY 5/2) tomoderate olive-brown (5F 4/4) dense laminated clay.

58.4 .3 Clay, aragonite, and gaylussite. Moderate olive-brown-. 

(5F 4/4) to black (N 1) clay coarsely laminated with widely 

spaced seams, averaging 1 mm wide, of light-gray (N 7) toyellowish-gray (5Y 7/2) soft massive finely crystallinearagonite; seam of disseminated gaylussite crystals, 5 mm. 

wide, at base. Clay 92 percent, aragonite 5 percent,, 

gaylussite 3 percent.

59. 3 ' . 9 No core.
163

J)epth Unit thick- 

(feet) nest (feet) Description

59. 7 0. 4 Clay. Black (N 1) to light olive-brown (57 5/6) to duskyyellow (5F 6/4) coarsely laminated clay with a few disseminated gaylussite crystals from 5 to 10 mm in length; 

seam of disseminated gaylussite silt at 59.5 ft.

61. 2 1. 5 Clay and gaylussite. Black (N 1) to grayish-orange (1QYR 

7/4) to very light gray (AT 8) to dark-gray (N 3) dense 

finely laminated clay; scattered clusters and pods of disseminated gaylussite crystals. Clay 98 percent, gaylussite 

2 percent.

 1. 3 , 1 Clay and gaylussite*. Black (N 1) clay with 50 percent disseminated gaylussite* crystals averaging 5 mm in length.

 2. 6 1. 3 Clay and gaylussite. Black (N 1) to greenish-black (5GY 2/1) 

finely laminated clay with pockets of disseminated gaylussite 

crystals averaging 5 mm in length. Clay 95 percent, gaylussite 5 percent.

 3.1 .5 Clay. Black (N 1) to pale yellowish-orange (WYR 8/6) to 

very light gray (N 8) dense coarsely laminated clay. 

63. 2 .1 Clay and gaylussite. Light olive-gray (5Y 5/2) to pale-olive 

(10 Y 6/2) to black (N 1) clay with seams of disseminated 

gaylussite crystals. Clay 40 percent, gaylussite 60 percent.

63. 6 . 4 No core.

64. 8 1. 2 Clay and gaylussite. Black (N 1) to dusky-yellow (57 6/4) 

to yellowish-gray (5F 7/2) to dark yellowish-orange (10 YR 

6/6) to grayish yellow-green (5G Y 7/2) dense finely laminated 

clay; pockets and streaks of disseminated gaylussite crystals 

averaging 5 mm in length. Clay 80 percent, gaylussite 20 

percent.

65. 8 1. 0 Clay and gaylussite. Black (N 1) to light-olive (107 5/4) to 

moderate-yellow (5F 7/6) to grayish-olive (107 4/2) dense 

clay with 30 percent disseminated gaylussite crystals from 

1 to 3 mm in length.

66. 2 .4 Clay. Black (N 1) dense clay.

66. 8 .6 Clay. Black (N 1) to light-olive (107. 5/4) to moderateyellow (57 7/6) to grayish-olive (107 4/2) dense clay with 

indistinct layers discolored moderate reddish-orange (10/2 

6/6) by algae(?).

67. 5 . 7 No core.

67. 8 .3 Clay and pirssonite*. Black (N 1) dense clay with seams of 

disseminated euhedral colorless pirssonite* crystals from 

1 to 2 mm in length. Clay 80 percent, pirssonite 20 percent.

68. 1 .3 Clay and northupite*. Black (N 1) to greenish-black (5GY 

2/1) to grayish olive-green (5 Or 7 3/2) to dark yellowishorange (10 YR 6/6) dense clay; seam at base; 5 mm wide, of 

disseminated northupite* octahedra averaging 1 mm in 

length. Clay 98 percent, northupite 2 percent.

68.. 3 . 2 Clay and pirssonite. Black (N 1) dense clay with 30 percent' 

disseminated pirssonite crystals averaging 1 mm-in length.

68. 5 .2 Trona and borax. Aggregate of trona blades averaging 5 mm 

in length, with disseminated borax crystals averaging 10 mm 

in length. Borax 80 percent, trona 20 percent.
164

Depth Unit thick-

(feet) nets (feet) Description

69. 1 0. 6 Trona and clay. Well-consolidated white (N 9) to light olivegray (5F 6/1) bladed and massive trona; black (N 1) clay 

seam from, 68.7 to 68.8 ft. Trona 85 percent, clay 15 percent.

71. 0 1. 9 Clay and pirssonite. Black (N 1) dense clay with 40 percent 

disseminated pirssonite crystals from 1 to 3 mm in length.

72. 3 1. 3 Trona. Well-consolidated compact fibrous trona, discolored 

white (N 9) to dark-gray (N 3) by intermixed clay. Trona 

98 percent, clay 2 percent.

73.2 .9 Halite, trona, and clay. Well-consolidated slightly vuggy 

aggregate of halite cubes averaging 5 mm in length, with 

fine fibrous trona in pockets; discolored by intermixed black 

(N 1) clay; moderate reddish-orange (IQR 6/6) algae(?) 

discolored clay at 72.7 to 72.9 ft with algal(?) inclusions 

in halite crystals. Halite 80 percent, trona 15 percent, 

clay 5 percent.

73. 9 .7 Trona and clay. White (N 9) to dark-gray (N 3) fine fibrous 

trona at top grading to hard massive trona at base; discolored by 10 percent intermixed clay.

74. 2 .3 Clay. Black (N 1) dense clay.

74.4 .2 Clay and pirssonite. Black (N 1) to olive-black (5F 2/1) 

clay with, seams and pockets of disseminated pirssonite 

crystals, averaging 5 mm in length. Clay 80 percent, 

pirssonite 20 percent.

75. 3 .9 No core.

76. 7 1. 4 Clay and pirssonite. Black (N 1) dense clay with 40 percent 

pirssonite crystals averaging 5 mm in length in seams 1 to 

2 mm wide and disseminated throughout the clay.

77. 1 .4 Clay and pirssonite. Black (N 1) clay with 35 percent disseminated pirssonite sand.

77. 3 .2 Borax and clay. Black (N 1) clay with 80 percent disseminated euhedral borax crystals from 5 to 10 mm in 

length.

77. 4 .1 Trona. Poorly consolidated dark-gray (N 3), fine fibrous 

trona;

78. 0 .6 No core.

78. 4 .4 Trona. Well-consolidated white (N 9) to dark-gray (N 3) 

massive trona.

79. 4 1.0 Halite, trona, and clay. Unconsolidated aggregate of halite 

cubes averaging 5 mm in length, massive trona fragments, 

and black (N 1) clay. Halite 80 percent, trona 15 percent, 

clay 5 percent.

79. 6 .2 Halite and trona. Well-consolidated colorless to white 

(N 9) halite crystals averaging 5 mm in length, with thin 

seam of soft massive trona at top. Halite 95 percent, 

trona 5 percent.

79. 8 .2 Trona. Well-consolidated white (N 9) to medium dark-gray 

(N 4) massive trona.

80. 8 1. 0 No core.

81. 2 .4 Trona. Medium-gray (N 5) soft massive trona.
CORE LOGS FROM SEARLES LAKE, CALIFORNIA 165

Depth Unit thick-

(feet) ness (feet) Description

81. 5 0.3 Halite. Poorly consolidated aggregate of white (N 9) to 

colorless halite cubes averaging 3 mm in length.

82. 2 .7 Halite and trona. Well-cqnsplidated. aggregate of halite 

crystals averaging 3 mm in -length-'an'dt medium-gray (N 5) 

soft massive trona. Halite 50 percent, trona 50 percent.

82.4 .2 Halite. Well-consolidated colorless to white (AT 9) halite 

crystals averaging 3 mm in length.

82. 5 . 1 No core.

82. 9 .4 Trona. Well-consolidated medium-gray (N 5) soft massive 

trona.

83.8 .9 Halite. Well-consolidated colorless to white (N 9) halite 

cubes from 5 to 10 mm in length.

84. 1 . 3 Trona. Well-consolidated grayish-yellow (5Y 8/4) hard 

massive trona.

84. 4 .3 Halite. Well-consolidated white to colorless halite cubes 

2 to 5 mm in length.

84. 6 .2 Trona, halite and hanksite*. Grayish-yellow (5Y 8/4) hard 

slightly vuggy massive trona with colorless halite and hanksite* crystals, averaging 5 mm in length, in vugs. Trona 

94 percent, halite 5 percent, hanksite 1 percent.

84. 9 .3 Halite. Well-consolidated white (N 9) to colorless halite 

, cubes, averaging 3 mm in length.

85. 0 .1 Trona and'halite. -Poorly consolidated white (N 9) to darkgray (N 3) soft massive trona with disseminated halite 

crystals averaging 5 mm in length. Trona 50 percent, 

halite 50 percent.

85. 3 .3 Halite. Well-consolidated aggregate of pale-pink (5RP 8/2) 

halite crystals averaging 3 mm in length.

85. 4 .1 Trona. Poorly consolidated dark-gray (N 3) soft massive 

trona.

85. 7 .3 Halite. Poorly consolidated aggregate of white (N 9) to 

colorless halite cubes, averaging 5 mm. in length, discolored 

by trace of interstitial clay.

86. 1 .4 Trona. Well-consolidated dark greenish-gray (5GY 4/1) soft 

massive trona.

86. 3 .2 Halite. Well-consolidated aggregate of white (N 9) halite 

cubes averaging 3 mm in length.

86.6 .3 Burkeite* and halite. Grayish-yellow (5F 8/4) to dark 

greenish-gray (5GY 6/1) soft massive burkeite* with disseminated halite crystals 5 to 10 mm in length; burkeite 

locally discolored moderate reddish-orange (10/2 6/6) by 

algae(?). Burkeite 80 percent, halite 20 percent.

86. 8 .2 Halite. Poorly consolidated aggregate of white (N 9) to 

colorless halite cubes averaging 5 mm in length.

87. 2 .4 Trona. Well-consolidated dark greenish-gray (5GY 4/1) soft 

massive trona.

87. 9 .7 Halite. Well-consolidated aggregate of white (N 9) to color-

 less'halite'crystals, averaging 5 mm- hv length, discolored

dark-gray (N 3) by trace of interstitial clay; trace of trona.

88. 0 .1 Clay and trona. Black (AT 1) clay seam with disseminated 

trona blades 5 to 10 mm in length. Clay 80 percent, trona 

20 percent.
166 GEOLOGIC INVESTIGATIONS IN MOJAVE DESERT REGION

Depth UnU thick-

(feet) ness (feet) Description

88. 3 0. 3. Trona. Well-consolidated dark greenish-gray (5GY 4/1) to 

white (N 9) hard slightly vuggy massive trona with grayishorange (IQYR 8/6) fibrous trona in vugs.

88. 7 .4 Trona. Pale yellowish-orange (IQYR 8/6) to white (N 9) hard 

dense massive trona.

89. 1 .4 Halite, hanksite, and trona. Well-consolidated aggregate of 

colorless to white (AT 9) halite crystals averaging 5 mm in 

length, with large pocket of intermixed euhedral hanksite 

crystals with prominent basal pinacoid and grayish-orange 

. (10 YR 7/4) fibrous trona. Halite 90 percent, hanksite 5 

percent, trona 5 percent.

.89. 4 . 3 Clay. 'Black (AM) to grayish yellow-green (5GY7/2) to lightgray (N 7) dense finely laminated clay; several laminae discolored light red (5R 6/6) by algae (?).

89. 5 .1 Borax and trona. Seam of euhedral borax crystals, averaging 

10 mm in length, at top with seam of fibrous trona at base. 

Borax 50 percent, trona 50 percent.

89. 7 .2 Trona. Fractured core. Fragments of white (N 9) to grayish-orange (10F.R 7/4) soft massive trona.

90. 3 .6 Burkeite and hanksite. Grayish-orange (10Y".R 7/4) moderately vuggy hard dense massive burkeite; euhedral hanksite 

crystals with prominent basal pinacoid, averaging 5 mm in 

length, in lenticular horizontal vugs, Burkeite 95 percent, 

hanksite 5 percent.

90. 6 .3 Trona. Poorly consolidated. Greenish-gray (5GY 6/1) to 

white (N 9) soft trona.

90. 8 .2 Trona. Well-consolidated white (N 9) to dark-gray (N 3) 

hard massive trona, discolored locally moderate reddishorange (WR 6/6) by algae(?).

91. 3 .5 Clay, borax, and northupite. Black (N 1) to grayish-black 

(N 2) to light-gray (A7 7) to moderate olive-brown (5Y 4/4) 

to grayish-olive (10Y 4/2) dense finely laminated clay; disseminated borax crystals up to 25 mm in length; circular to 

oval nodules, averaging 1 mm in diameter, of white (N 9) 

massive northupite* with minor gaylussite* in layer 10 mm 

wide at 91.0 ft. Clay 95 percent, borax 5 percent.

91. 6 .3 Clay and gaylussite. Black (N 1) to light-olive (10 Y 5/4) to 

moderate olive-brown (5Y 4/4) dense finely laminated clay 

with diseminated gaylussite crystals from less than 1 to 

6 mm in length, averaging 2 mm; a few laminae of moderate 

yellowish-brown (10FR 5/4) silt. Clay 60 percent, gaylussite 40 percent.

92. 3 .7 Clay. Black (AT 1) to pale-olive (10Y 6/2) to grayish-olive

(10Y 4/2) dense finely laminated clay; scattereo silty layers

1 to 5 mm thick; 6 distinct laminae, 1 mm wide, discolored

moderate reddish orange (10J? 6/6) by algae(?) from 91.8 to

: 92.0ft.

93. 3 1.0 Trona. Well-consolidated white (AT 9) to greenish-gray 

(5GY 6/1) hard massive trona with pockets of pale yellowish-orange (10 YR 8/6) to white (N 9) fibrous trona.
CORE LOGS FROM SEARLES LAKE, CALIFORNIA 167

Depth Unit thick-

(feet) ness (feet) Description

93. 7 0. 4 Clay. Black (N 1) to moderate olive-brown (5Y 4/4) dense 

finely laminated clay.

93. 8 .1 Clay and gaylussite. Black (N 1) to moderate olive-brown 

(5Y 4/4) dense finely laminated clay with 40 percent 

disseminated gaylussite crystals averaging 1 mm in length.

94. 1 .3 Clay. Black (N 1) to moderate olive-brown (5Y 4/4) dense 

finely laminated clay.

94. 3 .2 Trona and borax. Coarse aggregate of pale yellowish-orange 

(10 YR 8/6) to white (N 9) fibrous and bladed trona with 

disseminated borax crystals averaging 5 mm in length. 

Trona 80 percent, borax 20 percent.

95. 3 1. 0 No core.

96. 3 1.0 Trona. Coarse vuggy aggregate of fibrous and bladed trona 

with layers and pods of pale yellowish-orange (10 ¥72 8/6) 

to white (N 9) to medium-gray (N 5) massive trona; 

trace of medium dark-gray (N 4) clay.

97. 1 .8 Clay. Grayish-black (N 2) to greenish-black (5GY 2/1) 

dense finely laminated clay with a few thin seams of gaylussite silt.

97. 7 .6 Clay and gaylussite. Black (N 1) to light-brown (5YR 5/6) 

clay with 40 percent disseminated gaylussite crystals from 

less than 1 to 15 mm in length.

98. 3 .6 Clay. Black (N 1) to grayish-black (N 2) to greenish-black 

(5 GY 2/1) to light olive-brown (BY 5/6) dense finely 

laminated clay; scattered seams of disseminated gaylussite 

silt.

98. 7 .4 Trona and clay. Well-consolidated white (N 9) to light 

olive-gray (5Y 6/1) trona with intermixed black (N 1) 

clay. Trona 80 percent, clay 20 percent.

99. 3 .6 Clay and gaylussite. Well-consolidated black (Nl) to lightbrown (SYR 5/6) to light olive-brown (5Y 5/6) clay with 35 

percent disseminated gaylussite crystals averaging 10 mm 

in length.

100. 2 . 9 No core.

100. 8 . 6 Clay and gaylussite. Light-brown (SYR 5/6) to pale-olive 

(10 Y 6/2) to grayish-green (1QGY 5/2) dense finely laminated clay with 30 percent disseminated gaylussite crystals 

up to 35 mm in length, averaging 20 mm.

101. 4 .6 Clay. Black (N 1) to medium dark-gray (N 4) to duskyyellow (5Y 6/4) to pale-olive (10 Y 6/2) dense finely laminated clay.

101. 5 . 1 Clay and gaylussite. Black (N 1) to medium dark-gray 

(N 4) to dusky-yellow (5 Y 6/4) to pale-olive (10 Y 6/2) 

dense finely laminated clay with 40 percent disseminated 

gaylussite crystals from 5 to 10 mm in length.

101. 8 . 3 Clay. Same as in unit 100.8 to 101.4 ft.

101. 9 . 1 Clay and gaylussite. Same as in unit 101.4 to 101.5 ft but 

with 30 percent disseminated gaylussite crystals from 3 to 5 

mm in length.

103. 7 1. 8 Clay and gaylussite. Same as in unit 101.4 to 101.5 ft but 

with 10 percent disseminated gaylussite crystals from 5 to 

10 mm in length. 

491349r 59 3
168 GEOLOGIC INVESTIGATIONS IN MOJAVE DESERT REGION

Depth Unit thick-

(feet) ness (feet) Description

104. 5 0. 8 Clay. Dark yellowish-orange (10 YR 6/6) to grayish-black 

(N 2) to greenish-gray (5GY 6/1) to very light gray (N 8) 

dense finely laminated clay.

104. 6 . 1 Clay and gaylussite. Clay as in unit 103. 7 to 104.5 ft but 

with 50 percent disseminated gaylussite crystals averaging 

5 mm in length.

105. 1 . 5 Clay. Same as in unit 103.7 to 104.5 ft.

105. 3 . 2 Clay and gaylussite. Clay as in unit 103.7 to 104.5 ftTbut

with 50 percent disseminated gaylussite crystals averaging

10 mm in length. 

107. 3 2. 0 Clay. Same clay as in unit 103.7 to 104.5 ft.

Searles drill hole GS-4

LOCATION: Searles Lake, Calif., sec.: 17, T. 26 S., R., 44 E., Mount Diablo base

and meridian, approx. 1,788 ft S. 88° W. of }4 sec. marker for sees. 8 and 17. 

ELEVATION AT TOP OF HOLE: 1,619 ft (approx.). 

ELEVATION AT BOTTOM OP HOLE: 1,522.8 ft. 

TOTAL DEPTH: 96.2ft. 

DATE OF DRILLING: Sept. 10-21, 1954. 

CASING USED: 24.0 ft of 16-in casing from surface; hole refilled with sand from

bottom to 63.3 ft and cemented from 63.3 to 50.5 ft. 

MINERAL DETERMINATIONS: Minerals identified microscopically are denoted by

an asterisk (*); minerals identified by X-ray diffraction methods are denoted

by two asterisks (**).

Depth Unit thick-

(feet) ness (feet) Description

22. 5 22. 5 Overburden mud; not cored. Brown to black (N 1) soft 

moist clay.

23. 7 1. 2 Clay. Black (N 1) to dusky-yellow (57 6/4) clay with a 

few disseminated crystals of pirssonite* and halite.

24. 1 .4 Clay and halite. Black (N 1) clay with 50 percent subhedral 

to anhedral halite crystals averaging 10 mm in length, 

loosely disseminated throughout.

24. 3 .2 Halite. Well-consolidated aggregate of halite cubes averaging 3 mm in length; discolored dusky yellow (50? Y 5/2) to 

medium gray (N 5) by trace of interstitial clay.

24. 8 .5 Clay and halite. Black (N 1) clay with seam, 15 mm wide, 

of halite cubes averaging 2 mm in length, at 24.5 ft. Clay 

90 percent, halite 10 percent.

25. 0 .2 Halite. Well-consolidated slightly vuggy aggregate of halite 

cubes and cubes modified by octahedron, averaging 4 mm in 

length; discolored medium gray (N 5) by trace of interstitial 

clay.

25. 2 .2 Halite and trona. Well-consolidated very vuggy aggregate 

of halite cubes and cubes modified by octahedron, averaging 

10 mm in length, with 10 percent interstitial fibrous trona.

25. 4 .2 Trona and clay. Compact fibrous trona discolored pale olive 

(107 6/2) to grayish yellow (57 8/4) to grayish black (N 2) 

by 10 percent interstitial black (N 1) to grayish-black (N 2) 

clay.
CORE LOGS FROM SEARLES LAKE, CALIFORNIA 169

Depth Unit thick-

(feet) ness (feet) Description

25. 8 0. 4 Halite. Well-consolidated slightly vuggy dense aggregate of 

halite cubes averaging 3 mm in length; discolored greenish 

gray (5GY 6/1) to medium dark gray (N 4) by trace of 

interstitial clay.

26. 0 .2 Trona and clay. Well-consolidated compact fibrous trona

discolored grayish yellow (5F 8/4) to grayish black (N 2)

by 5 percent interstitial clay. 

26. 6 .6 Halite and clay. Well-consolidated slightly vuggy aggregate

of halite cubes averaging 3 mm in length, with thin black.

(N 1) clay streaks. Halite 90 percent, clay 10 percent,

26. 7 .1 Clay. Black (N 1) dense clay.

27. 7 1.0 Halite and clay. Friable vuggy aggregate of halite cubes up 

to 25 mm in diameter, averaging 5 mm, with 10 percent 

interstitial black (N 1) clay.

27. 9 .2 Halite and clay. Slightly vuggy massive halite with pockets 

of grayish-yellow (5F 8/4) fibrous trona; halite discolored 

medium light gray (N 6) by trace of interstitial clay; clay 

seam 15 mm wide, with trace of trona at base. Halite 

75 percent, clay 25 percent.

28. 7 .8 Halite, trona, and clay. Well-consolidated aggregate of 

halite cubes, averaging 10 mm in length, intermixed with 

10 percent fibrous trona and 10 percent black (N 1) clay.

28. 8 .1 Trona and halite. Grayish-green (10(7 F 5/2) massive trona 

with 30 percent disseminated halite cubes and anhedra 

averaging 3 mm in length.

29. 0 .2 Halite. Well-consolidated vuggy aggregate of halite cubes 

averaging 3 mm in length; locally discolored by trace of 

interstitial black (N 1) clay.

30. 5 1. 5 No core.

31. 1 .6 Halite. Well-consolidated aggregate of white (N 9) to 

medium-gray (N 5) halite cubes and cubes modified by 

octahedron, averaging 3 mm in length; discolored by trace 

of interstitial clay.

32. 6 1. 5 Halite and burkeite*. Well-consolidated vuggy aggregate of 

white (N 9) to colorless halite cubes and cubes modified by 

octahedron, with thin streaks and pockets of white (N 9) 

to very pale orange (lOFjR 8/2) massive burkeite*. Halite 

80 percent, burkeite 20 percent.

33. 2 .6 Trona and halite. Well-consolidated vuggy white (N 9) to 

light greenish-gray (5G Y 8/1) massive trona, with disseminated halite crystals averaging 5 mm in length; lenticular vugs contain halite crystals. Trona 65 percent, halite 

35 percent.

33. 8 .6 Halite. Well-consolidated slightly vuggy aggregate of white 

(N 9) to greenish-gray (50 Y 6/1) to colorless halite cubes 

averaging 3 mm in length.

34. 0 .2 Halite* and clay. White (N 9) to light-gray (N 7) dense 

massive halite* with streak of black (N 1) clay, 5 mm wide, 

at base. Halite 90 percent, clay 10 percent.
170 GEOLOGIC INVESTIGATIONS IN MOJAVE DESERT REGION

Depth Unit thick-

(feet) ness ( eet) Description

34. 6 0. 6 Halite, trona, and clay. Well-consolidated slightly vuggy 

aggregate of white (N 9) to colorless halite cubes and 

massive halite alternating with layers of white (N 9) to 

greenish-gray (5GY 6/1) massive trona; vugs contain 

fibrous trona and halite crystals averaging 5 mm in diameter; scattered thin streaks and lenticular pockets of 

black (N 1) to grayish-black (N 2) clay. Halite 50 percent, troca 45 percent, clay 5 percent.

34. 8 .2 No core.

36. 6 1. 8 Trona, halite, and hanksite. Well-consolidated white (N 9) 

to greenish-gray (5GF 6/1) massive trona, with disseminated 

crystals and thin streaks and pockets of halite cubes modified 

by octahedron, averaging 5 mm in length; pockets of 

euhedral hanksite crystals averaging 10 mm in length in 

lower 0.5 ft. Trona 55 percent, halite 40 percent, hanksite 

5 percent.

36.9 .3 Hanksite, trona, and clay. Dense aggregate of euhedral 

hanksite crystals averaging 10 mm in length, with thin 

streaks and pockets of very light gray (N 2) soft massive 

trona; seam of black (N 1) clay, 5 mm wide, at base. 

Hanksite 70 percent, trona 25 percent, clay 5 percent.

 37. 7 .8 Halite. Friable aggregate of white (N 9) to light-gray (N 7) 

halite cubes and anhedra averaging 3 mm in length.

38. 0 .3 Halite and trona. Well-consolidated aggregate of halite cubes 

and cubes modified by octahedron, averaging 5 mm, with 

15 percent interstitial fibrous trona.

38. 2 .2 Hanksite and trona. Vuggy aggregate of euhedral hanksite 

crystals averaging 10 mm in length, with 15 percent interstitial dark greenish-gray (5GY 4/1) to greenish-gray 

(5(rY 6/1) soft massive trona.

38. 4 .2 Halite. Well-consolidated aggregate of white (N 9) to colorless 

 to dark-gray (N 3) halite cubes averaging 3 mm in length.

39. 4 1. 0 No core.

39. 9 .5 Halite*, trona*, hanksite, and clay. Light brownish-gray 

(5YR 6/1) to white (N 9) dense massive intermixed halite* 

and trona* with vuggy seams, 5 mm wide, of black (N 1) to 

grayish-black (N 2) clay, halite cubes averaging 3 mm in 

length and euhedral hanksite crystals averaging 5 mm. 

Halite 80 percent, trona 10 percent, hanksite 5 percent, clay 

5 percent.

40. 6 .7 Halite. Well-consolidated dense aggregate of white (N 9) to 

colorless halite cubes averaging 3 mm in length.

41. 0 .4 Halite and trona. Vuggy aggregate of halite cubes averaging 

3 mm in length, with fibrous trona in pockets and lining 

vugs. Halite 70 percent, trona 30 percent.

41. 4 .4 Hanksite, trona, and clay. Well-consolidated massive hanksite alternating with vuggy seams, 3 mm wide, of fibrous 

trona, black (N 1) to grayish-black (N 2) clay, and hanksite crystals averaging 3 mm in length. Hanksite 60 percent, 

trona 35 percent, clay 5 percent.
CORE LOGS FROM SEARLES LAKE, CALIFORNIA 171

Depth Unit tMck-

(feet) ness (feet) Description

41. 7 0. 3 Trona and hanksite. Well-consolidated dense white (N 9) 

fibrous trona with disseminated hanksite crystals averaging 

5 mm in length. Trona 60 percent, hanksite 40 percent.

42. 1 .4 Trona, hanksite, and clay. Well-consolidated white (N 9) to 

olive-gray (5Y 4/1) dense massive trona containing disseminated euhedral hanksite crystals averaging 5 mm in 

length; with vuggy layers of fibrous trona, black (N 1) clay, 

and hanksite crystals averaging 5 mm in length. Trona 

70 percent, hanksite 25 percent, clay 5 percent.

42. 2 .1 Trona. Light-gray (N 7) to greenish-gray (5GY 6/1) soft 

porous massive trona.

45. 2 3. 0 No core.

46. 2 1.0 Trona. White (N 9) soft porous massive trona.

47. 7 1. 5 No core.

49. 0 1. 3 Trona. White (N 9) soft porous massive trona.

49. 1 .1 Trona. White (N 9) to yellowish-gray (5Y 7/2) dense hard

bony massive trona. 

49. 8 .7 No core.

49. 9 .1 Clay and pirssonite. Dusky-yellow (5Y 6/4) to grayish-olive 

(10F 4/2) to grayish-black (N 2) dense finely laminated 

clay, with 20 percent disseminated pirssonite crystals 

averaging 15 mm in length.

50. 1 .2 Clay and pirssonite. Dark greenish-gray (5(? 4/1) to grayishblack (N 2) to black (N 1) dense faintly laminated clay with 

layer, 5 mm wide, of pirssonite crystals at 50.0 ft. Clay 90 

percent, pirssonite 10 percent.

51. 2 1.1 Clay and pirssonite. Black (N 1) to greenish-black (5(? 2/1) 

dense finely laminated clay with 45 percent pirssonite 

crystals, averaging 20 mm in length, disseminated in layers.

52. 4 1. 2 Clay and pirssonite. Black (N 1) to grayish-olive (10YR 4/2) 

to grayish-green (5(? 5/2) to grayish yellow-green (5GY 7/2) 

dense finely laminated clay with scattered pockets of 

pirssonite crystals, averaging 15 mm in length, in lower 

0.5 ft. Clay 95 percent, pirssonite 5 percent.

53. 8 1. 4 Clay and aragonite. Black (N 1) dense clay, coarsely laminated with widely spaced seams, averaging 1 mm, of light 

greenish-gray (5GY 8/1) to greenish-gray (5GY 6/1) to very 

light gray (N 8) soft massive finely crystalline aragonite; 

laminae contorted in lower 0.6 ft. Clay 95 percent, aragonite 5 percent.

54. 4 .6 Clay and gaylussite. Black (N 1) to very light gray (N 8) to 

grayish-olive (10Y 4/2) to dusky-yellow (5Y 6/4) dense 

finely laminated clay with 25 percent gaylussite crystals, 

averaging 10 mm in length, forming layers of disseminated 

crystals.

55. 4 1.0 Clay and gaylussite. Black (N L) to very light gray (AT 8) to 

grayish-olive (10F 4/2) to dusky-yellow (57 6/4) to dark 

yellowish-orange (10 Y /B6/6) dense coarsely laminated clay 

with scattered pockets of gaylussite crystals averaging 10 

mm in length. Clay 90 percent, gaylussite 10 percent.
172 GEOLOGIC INVESTIGATIONS IN MOJAVE DESERT REGION

Depth Unit thick- 

(feet) ness (feet) Description

56. 9 1. 5 Clay and gaylussite. Black (N 1) to very light gray (N 8) to 

grayish-olive (1QY 4/2) to dusky-yellow (5Y 6/4) to dark 

yellowish-orange (10 YR 6/6) dense finely laminated clay 

with scattered pockets of 5 percent gaylussite crystals 

averaging 5 mm in length.

57. 2 .3 Clay and gaylussite. Black (N 1) to very light gray (N 8) to 

grayish-olive (10F 4/2) to dusky-yellow (5Y 6/4) dense 

finely laminated clay with 20 percent gaylussite crystals 

averaging 10 mm in length, disseminated in layers.

57. 8 .6 Clay, aragonite, and gaylussite. Black (N 1) dense clay, 

coarsely laminated with widely spaced laminae of very light 

gray (N 8) to grayish-olive (10 F 4/2) to dusky-yellow 

(5Y 6/4) soft massive aragonite; layer, 10 mm wide, of disseminated gaylussite crystals, averaging 5 mm in length, at 

57.5 ft. Clay 90 percent, aragonite 5 percent, gaylussite 

5 percent.

58. 3 .5 No core.

58. 5 .2 Clay. Black (N 1) to greenish-black (5GY 2/1 and 5G 2/1) to 

dusky yellow-green (5GY 5/2) to grayish-olive (10Y 4/2) to 

dark yellowish-orange (10F7«! 6/6) dense faintly coarsely 

laminated clay.

58. 8 .3 Clay and aragonite**. Black (N 1) to greenish-black (5GY 

2/1) dense clay, coarsely laminated with widely spaced 

seams, averaging 1 mm, of very light gray (N 8) soft massive 

aragonite**. Clay 95 percent, aragonite 5 percent.

62.3 3.5 Clay and gaylussite. Black (N 1) to greenish-black (5GY 2/1) 

to grayish olive-green (5GY 3/2) to grayish-green (5G 5/2) 

clay with laminae, averaging 10 mm thick, shown by color 

differences; scattered pockets of disseminated gaylussite 

crystals averaging 5 mm in length. Clay 95 percent, 

gaylussite 5 percent.

63. 0 .7 No core.

63. 2 .2 Clay and gaylussite. Black (N 1) dense clay with 50 percent 

disseminated gaylussite crystals averaging 10 mm in length.

63. 5 .3 Clay and gaylussite* sand. Black (N 1) dense clay with 50 

percent disseminated gaylussite* crystals 1 mm or less in 

length.

63. 7 .2 Clay. Black (N 1) to dark greenish-gray (5(7 4/1) to grayish 

olive-green (5GY 3/2) dense clay. .

63. 8 .1 Clay and gaylussite. Black (N 1) clay with 50 percent disseminated gaylussite crystals averaging 1 mm or less in 

length.

64. 0 .2 Clay. Black (N 1) dense clay.

64. 4 .4 Clay and gaylussite. Black (N 1) to dusky-yellow (5F6/4) 

to dark greenish-gray (5G 4/1) dense clay with 40 percent 

disseminated gayiussite crystals averaging 2 mm in length.

64. 6 .2 Clay. Black (N 1) dense clay.

65. 5 .9 Trona and clay. Light-gray (N 7) to white (N 9) dense 

massive trona with streaks and pockets of dark-gray (N 3) 

clay; in lower 0.3 ft, fibrous trona in vugs with a few trona 

blades 5 mm long. Trona 95 percent, clay 5 percent.
CORE LOGS FROM SEARLES LAKE, CALIFORNIA 173

Depth Unit thick-

(feet) ness (feet) Description

65. 9 0. 4 Clay. Black (N 1) to light-gray (N 7) dense faintly laminated 

clay.

67. 1 1. 2 Clay and gaylussite*. Black (N 1) to grayish-black (N 2) clay 

with 50 percent disseminated crystals of gaylussite* averaging 2 mm in length.

67. 3 .2 No core.

69. 4 2. 1 Clay and gaylussite. Black (N 1) to dark greenish-gray (5(7 

4/1) dense clay with 50 percent disseminated gaylussite crystals averaging 5 mm in length.

70. 0 .6 Clay. Black (N 1) dense clay.

71. 0 1.0 Trona. White (N 9) to dark-gray (N 3) dense massive trona,

discolored by trace of clay. 

71. 8 . 8 No core.

74. 5 2. 7 Clay and gaylussite. Black (N 1) clay with 45 percent disseminated gaylussite crystals averaging 10 mm in length.

75. 6 1.1 Clay. Black (N 1) dense clay.

76. 3 .7 No core.

77. 6 1. 3 Trona. Dense aggregate of white (N 9) to colorless bladed 

and fibrous trona, discolored dark gray (N 3) by trace of 

interstitial clay.

78. 8 1. 2 Trona and northupite*. White (N 9) dense massive and 

fibrous trona, locally discolored dark gray (N 3) by trace of 

clay; layer, 10 mm wide, of yellowish-gray (5Y 7/2) massive 

northupite* with intermixed minor trona* at base. Torna 

97 percent, northupite 3 percent.

79. 2 .4 Clay. Black (N 1) dense clay with faint closely spaced very 

light gray (N 8) laminae; pale yellowish-orange (10 YR 8/6) 

silty layers at base less than 1 mm wide; distinct lamina, 

1 mm wide, of moderate reddish-orange (10/2 6/6) algae(?) 

at 79.0 ft.

79. 9 .7 Trona. White (N 9) to very pale orange (10 YR 8/2) massive 

and fibrous trona, discolored dark gray (N 3) by trace of 

intermixed clay in upper 0.1 ft.

80. 8 .9 No core.

81. 6 .8 Trona and clay. White (N 9) to dark-gray (N 3) dense 

massive trona with grayish-black (N 2) clay streaks 2 mm 

wide; irregular wavy seams, about 2 mm wide at 81.2 and 

81.5 ft of moderate reddish-orange (WR 6/6) algae(?); 

layer of densely packed trona* blades 10 mm wide at base. 

Trona 95 percent, clay 5 percent.

82. 2 .6 Clay and northupite. Black (N 1) dense finely laminated 

clay with layers of discrete circular to oval nodules, averaging 1 mm in length, of white (N 9) massive northupite 

from 81.7 to 82.0 ft. Clay 95 percent, northupite 5 percent.

82. 6 .4 Clay and gaylussite. Greenish-black (5GY 2/1) to moderate 

yellowish-brown (10YR 5/4) to grayish olive-green (5GY 

3/2) clay with 40 percent disseminated gaylussite crystals 

averaging 2 mm in length.

83. 1 .5 Clay. Black (N 1) dense clay.

83. 9 .8 Trona and clay. Coarse white (N 9) to colorless bladed 

trona, blades averaging 20 mm in length; with 10 percent 

black (N 1) clay in thin interstitial streaks.
174 GEOLOGIC INVESTIGATIONS IN MOJAVE DESERT REGION

Depth Unit thick-

(feet) ness (feet) Description

84. 2 0. 3 Clay and tychite*. Black (N 1) to greenish-black (5GY 2/1) 

dense clay with 20 percent disseminated colorless octahedra 

of tychite* averaging 1 mm in diameter.

84. 5 .3 Clay and gaylussite. Black (N 1) to greenish-black (5GY 2/1) 

dense clay with 50 percent disseminated gaylussite crystals 

averaging 2 mm in length; a few thin layers of gaylussite 

sand.

" 85. 0 .5 Clay. Black (N 1) dense finely laminated clay with contorted 

laminae.

86. 0 1. 0 No core.

86. 3 .3 Trona. Medium light-gray (N 6) to dark-gray compact 

(N 3) fibrous trona discolored by trace of interstitial clay.

87. 2 .9 Clay. Black (N 1) to greenish-black (5 GY 2/1) to grayishyellow (5Y 8/4) to white dense finely laminated (N 9) clay.

87. 9 .7 Clay and gaylussite. Black (N 1) to olive-gray (5Y 3/2) to 

greenish-black (5GY 2/1) clay with 50 percent disseminated 

gaylussite crystals averaging 10 mm in length.

88. 2 .3 Clay and gaylussite. Black (N 1) to greenish-black (5GY 2/1) 

dense clay with 50 percent disseminated gaylussite sand.

88. 5 .3 Clay. Black (N 1) to grayish-black (N 2) to very light gray 

(N 8) dense finely laminated clay.

88. 9 .4 Clay and gaylussite. Black (N 1) to olive-black (5Y 2/1) to 

olive-gray (5Y 3/2) dense clay with 20 percent disseminated 

gaylussite sand.

89. 0 .1 Trona and clay. Dense massive trona with black (N 1) clay 

streaks. Trona 90 percent, clay 10 percent.

89. 5 .5 Clay. Grayish-black (N 2) to dark greenish-gray (5GY 4/1) 

to medium dark-gray (N 6) to olive-gray (5Y 3/2) dense 

finely laminated clay.

89. 7 .2 Clay and gaylussite. Dense finely laminated clay with 

colors as in unit 89.0 to 89.5 ft; with 10 percent disseminated 

gaylussite crystals, averaging 1 mm in length, in layers 2 to 

3 mm wide.

90.3 .6 Gaylussite and clay. Olive-black (5Y 2/1) to olive-gray 

(5Y 3/2) dense clay with 60 percent disseminated gaylussite 

crystals, averaging 25 mm in length, oriented in horizontal 

layers; fine closely spaced dark yellowish-orange (10YJK6/6) 

to pale yellowish-orange (10Y.R 8/6, clay laminae in lower 

0.1 ft.

90. 6 .3 Clay. Medium dark-gray (N 4) to light-gray (N 7) dense 

finely laminated clay.

90. 9 .3 Clay and gaylussite. Olive-gray (5Y 3/2) to grayish- black, 

(N 2) to moderate yellowish-brown (01 YE 5/4) to grayisholive (10 Y 4/2) dense finely laminated clay with 20 percent 

disseminated gaylussite crystals averaging 15 mm in length.

91. 2 .3 No core.

95. 9 4. 7 Clay. Black (N 1) to grayish-black (N 2) to olive-black 

(5Y 2/1) to grayish-yellow (5Y 8/4) to yellowish-gray 

(5Y 7/2) to white (AT 9) to light-brown (5/2 5/6) dense 

finely laminated clay.

96. 2 .3 No core.
CORE LOGS FROM SEARLES LAKE, CALIFORNIA 175

Searles drill hole GS-7

LOCATION: Searles Lake, Calif., center of sec. 13, R. 43 E., T. 26 S., Mount 

Diablo base line and meridian.

ELEVATION AT TOP OF HOLE: 1,621 ft (approx.).

ELEVATION AT BOTTOM OF HOLE: 1,525.5 ft.

TOTAL DEPTH: 95.5 ft.

DATES DRILLED: Nov. 4-29, 1954.

CASING TJSED: 31.0 ft of 16-in. casing extends from the surface through overburden mud; 70.2 ft of 3-in. pipe extends from the surface into top of lower 

salt brine.

MINERAL DETERMINATIONS: Minerals identified microscopically are denoted by 

an asterisk (*). .

Depth Unit thick-

(feet) ness (feet) Description

18. 0 18. 0 Overburden mud; not cored. Dense tenacious greenish-gray 

(5GY 6/1) to dark greenish-gray (5GY 4/1) to medium darkgray (N 4) clay.

31. 5 13. 5 Overburden mud; not cored. Grayish-black (N2) clay with 

scattered small streaks and pods of dense tenacious dusky 

yellow-green (5GF5/2) to black (N 1) clay.

32. 9 1.4 Clay and pirssonite. Black (N 1) to grayish-black (N 2) clay 

with 10 percent disseminated pirssonite crystals averaging 

1 mm in length.

33. 4 .5 Clay and halite. Black (N 1) clay with 50 percent disseminated halite crystals up to 50 mm in length, averaging 

15 mm.

34. 0 .6 Halite, clay, and trona. Well-consolidated vuggy aggregate 

of clear colorless halite cubes up to 40 mm in length, averaging 10 mm, with greenish-black (5GY 2/1) to dark greenishgray (5GY 4/1) clay and colorless fibrous trona in interstices of halite crystals. Halite 90 percent, clay 5 percent, 

trona 5 percent.

34. 9 .9 No core.

39. 5 4. 6 Trona, halite, and clay. White (N 9) to yellowish-gray 

(5 Y 8/1) porous massive trona with numerous vuggy seams 

and streaks, from 1 to 5 mm wide, containing euhedral 

halite cubes and cubes modified by octahedron, averaging 

3 mm in length, with intermixed grayish-black (N 2) clay 

and fibrous trona in interstices of halite crystals. Trona 

85 percent, halite 10 percent, clay 5 percent.

39. 8 . 3 Halite and clay. Poorly consolidated aggregate of white 

(N 9) to colorless halite cubes averaging 1 mm in length, 

with 1 percent interstitial dark greenish-gray (5GY 4/1) 

clay.

40. 2 .4 No core.

40. 8 . 6 Halite, trona, and clay. Well-consolidated aggregate of colorless halite cubes and cubes modified by octahedron; discolored by interstitial dark greenish-gray (5GY 4/1) clay; 

seam, 20 mm wide, of white (N 9) dense massive trona at 

40.3 ft. Halite 85 percent, trona 10 percent, clay 5 percent.
176

Depth Unit thick- 

(feet) ness (feet) Description

41. 5 0. 7 Trona and halite. White (N 9) to light-gray (N 6) porous 

massive trona with numerous seams, streaks, and disseminated crystals of halite averaging 3 mm in length. Trona 

50 percent, halite 50 percent.

42. 2 .7 No core.

42. 6 .4 Halite and trona. Well-consolidated vuggy aggregate of 

halite cubes and cubes modified by octahedron, averaging 

4 mm in length, with streaks and pockets, up to 25 mm 

wide, of white (N 9) porous massive trona. Halite 50 

percent, trona 50 percent.

42. 8 .2 Halite. Well-consolidated aggregate of halite cubes and cubes 

modified by octahedron, averaging 3 mm in length, with 

trace of interstitial dark greenish-gray (5G Y 4/1 and 5G 4/1) 

clay.

43. 1 .3 Halite and clay. Well-consolidated aggregate of halite crystals averaging 3 mm in length, with 40 percent interstitial 

dark greenish-gray (5GY 4/1 and 5G 4/1) clay.

43. 2 .1 Halite. Well-consolidated aggregate of white (N 9) to colorless halite cubes and cubes modified by octahedron, averaging 3 mm in length.

43. 5 .3 Halite and clay. Poorly consolidated friable aggregate of 

halite cubes and cubes modified by octahedron, averaging

2 mm in length, with 15 percent interstitial dark greenishgray (5GY 4/1 and 5G 4/1) clay.

43. 8 .3 Halite and clay. Unconsolidated aggregate of coarse halite 

sand with 25 percent intermixed dark greenish-gray (5G Y 4/1 

and 5G 4/1) to dark-gray (N 3) to grayish-black (N 2) 

clay. Probably cuttings, not core.

44. 4 .6 Halite, clay, and trona. Well-consolidated vuggy aggregate 

of halite cubes averaging 3 mm in length, with interstitial 

colorless fibrous trona and dark greenish-gray (5GY 4/1 and 

5G 4/1) clay. Halite 85 percent, clay 10 percent, trona 5 

percent.

44. 6 .2 Halite, clay, and trona. Well-consolidated aggregate of 

halite cubes and cubes modified by octahedron, averaging

3 mm in length, with streaks of black (N 1) to grayishblack (N 2) clay, colorless fibrous trona in interstices of 

halite crystals, and pockets of white (N 9) massive trona, 

averaging 15 mm in diameter, disseminated throughout. 

Halite 70 percent, clay 25 percent, trona 5 percent.

44. 7 .1 Trona and clay. White (N 9) soft massive trona with thin 

streak of dark-gray (N 3) to dark greenish-gray (5GY 4/1) 

clay. Trona 95 percent, clay 5 percent.

44. 8 .1 Halite. Well-consolidated aggregate of colorless halite cubes 

averaging 3 mm in length.

45.0 .2 Halite. Poorly consolidated aggregate of halite cubes, 

averaging 3 mm in length, with trace of interstitial dark 

greenish-gray (5GY 4/1) massive trona.

45. 2 .2 Trona. Well-consolidated white (N 9) to light greenish-gray 

(5GY 8/1) to light olive-gray (5Y 6/1) to greenish-gray 

(5GY 6/1) soft massive trona.
CORE LOGS FROM SEARLES LAKE, CALIFORNIA 177

Depth Unit thick-

(feet) ness (feet) Description

45. 6 0. 4 Trona, clay, halite, and hanksite. White (N 9) to dark-gray 

(N 3) vuggy massive trona discolored by thin black (N 1) 

clay streaks; scattered halite cubes and cubes modified by 

octahedron, in vugs; a few disseminated crystals of euhedral 

hanksite, averaging 10 mm in length, at base. Trona 83 

percent, clay 15 percent, halite 1 percent, hanksite 1 percent.

46. 5 .9 Halite. Well-consolidated aggregate of white (N 9) to 

colorless halite cubes and cubes modified by octahedron, 

averaging 3 mm in length, locally discolored dark greenishgray (5GY 4/1) by trace of interstitial clay.

46. 9 .4 Halite and trona. Well-consolidated aggregate of halite 

cubes and cubes modified by octahedron, averaging 3 mm 

in length, with 10 percent interstitial greenish-black 

(56?F 2/1) to dark greenish-gray (50?F 4/1) fibrous trona 

discolored by trace of interstitial clay.

48. 1 1. 2 Trona. Well-consolidated vuggy aggregate of white (N 9) 

to light greenish-gray (56? 8/1) to colorless fibrous trona 

with intermixed dark greenish-gray (56? F 4/1) massive 

trona.

48.4 .3 Trona. Well-consolidated white (N 9) to greenish-gray 

(56?F 6/1) .porous massive trona.

51. 8 3. 4 No core.

52. 0 .2 Trona. Fragments of well-consolidated white (N 9) to dark 

greenish-gray (56?F 4/1) soft porous massive trona. Probably cuttings, not core.

52. 1 .1 Borax* and clay. Seam, 10 mm wide, of black (N 1) dense 

clay underlain by seam, 20 mm wide, of colorless massive 

borax.* Borax 67 percent, clay 33 percent.

53. 6 1. 5 Clay and pirssonite. Grayish-green (106?F 5/2) to dark 

greenish-gray (56? F 4/1) to black (N 1) dense faintly 

finely laminated clay with numerous seams of disseminated 

pirssonite crystals up to 15 mm in length, averaging 5 mm. 

Clay 70 percent, pirssonite 30 percent.

54. 6 1.0 Clay, pirssonite, and borax. Dusky yellow-green (56?F 5/2) 

to grayish-green (106?F 5/2) to dark greenish-gray (56?F 4/1 

and 56?F 4/1) to grayish-yellow (5F 8/4) to olive-gray 

(5F 3/2) dense finely laminated clay with seam, 10 to 15 mm 

wide, of massive borax crosscutting laminae at steep angle 

from 53.6 to 54.6 ft; 40 percent disseminated euhedral 

pirssonite crystals in lower 0.4 ft. Clay 80 percent, 

pirssonite 15 percent, borax 5 percent.

58. 5 2. 9 No core.

59. 2 .7 Clay and aragonite. Black (N 1) to greenish-black (56?F 2/1) 

to dark greenish-gray (56? F 4/1) dense clay coarsely laminated with widely spaced seams, averaging 1 mm in 

width, of very light gray (N 8) to white (N 9) soft massive 

finely crystalline aragonite. Clay 95 percent, aragonite 

5 percent.

59. 3 .1 Clay and gaylussite. Black (N 1) to greenish-black (56? F 2/1) 

faintly finely laminated clay with 40 percent disseminated 

euhedral gaylussite crystals from 3 to 10 mm in length.
178 GEOLOGIC INVESTIGATIONS IN MOJAVE DESERT REGION

Depth Unit thick-

(feet) ness (feet) Description

60. 6 1. 3 Clay and gaylussite. Black (N 1) to grayish-black (N 2) 

to greenish-black (5GY 2/1) to dark greenish-gray (5GY 

2/1) to grayish-yellow (5Y 8/4) to very light gray (N 8) 

to white (N 9) finely laminated clay with a few pockets, 

25-50 mm in diameter, of disseminated gaylussite crystals 

averaging 10 mm in length. Clay 90 percent, g&ylussite 

10 percent.

60. 8 .2 Clay and gaylussite. Black (N 1) to greenish-black (5GY 

2/1) dense clay with 50 percent disseminated gaylussite 

crystals averaging 5 mm in length.

62. 2 1. 4 Clay. Black (N 1) to grayish-black (N 2) to greenish-black 

(5GY 2/1) to dark greenish-gray (5GY 2/1) to grayishyellow (5Y 8/4) to very light gray (AT" 8) to white (N 9) 

dense finely laminated clay.

63. 0 .8 No core.

63. 7 .7 Clay and gaylussite. Black (N 1) to grayish-black (N 2) to 

greenish-black (5GY 2/1) to grayish-yellow (5F 8/4) to 

grayish-olive (10 F 4/2) to white (N 9) dense finely laminated 

clay with a few pockets of disseminated gaylussite crystals 

averaging 10 mm in length. Clay 98 percent, gaylussite 2 

percent.

64. 3 .6 Clay and gaylussite. Black (N 1) to greenish-black (5GY 

2/1) to dark-gray (N 3) dense clay with scattered pockets of 

disseminated gaylussite crystals averaging 10 mm in length; 

scattered thin streaks less than 1 mm wide and spots of 

moderate reddish-brown (10R 4/6) algae(?). Clay 95 percent, gaylussite 5 percent.

66.5 2.2 Clay. Grayish-black (N 2) to dark-gray (N 3) to dark 

greenish-gray (5GY 4/1 and 5G 4/1) to dusky yellow-green 

(5GY 5/2) to grayish olive-green (5GY 3/2) dense faintly 

coarsely laminated clay with laminae revealed by color 

differences; faint lamina discolored moderate reddish-orange 

(10# 6/6) by algae(?) at 65.0 ft.

66. 8 .3 Clay and gaylussite. Black (N 1) to grayish-black (N 2) 

dense clay with 50 percent disseminated gaylussite crystals 

averaging 20 mm in length.

67. 2 .4 Clay and gaylussite. Black (N 1) to grayish-black (N 2) to 

greenish-black (5(?F 2/1) dense clay with 40 percent disseminated gaylussite crystals averaging 1 mm in length; 

moderate reddish-orange (10 R 6/6) algae (?) discolored 

streaks and spots throughout.

67. 4 .2 Clay and gaylussite. Grayish-black (N 2) to greenish-black 

(5YR 2/1) to moderate olive-brown (57 4/4) to light olivebrown (5F 5/6) clay with 10 percent disseminated 

gaylussite crystals averaging 10 mm in length.

67. 9 .5 Clay. Black (N 1) to grayish-black (N 2) to grayish-yellow 

(5F 8/4) to medium light-gray (N 6) to white (N 9) dense 

moderately coarsely laminated clay.

68. 1 .2 No core.

69. 5 1. 4 Clay and gaylussite. Black (N 1) to grayish-black (N 2) to 

greenish-black (5GF 2/1) dense clay with 40' percent disseminated gaylussite crystals averaging 1 mm in length.
CORE LOGS FROM SEARLES LAKE, CALIFORNIA 179

Depth Unit thick-

(feet) ness (feet) Description

69. 6 0. 1 Trona. White (N 9) to light-gray (N 7) soft porous massive 

trona with scattered streaks and spots, averaging 1 mm in 

width, discolored moderate reddish-orange (10/2 6/6) by 

algae(?).

70. 0 .4 Trona and clay. White (N 9) soft massive trona with seams, 

1-3 mm wide, of grayish-black (N 2) clay. Trona 95 percent, 

clay 5 percent.

70. 1 .1 Trona and clay. Densely packed aggregate of coarse trona 

blades with 5 percent interstitial black (N 1) to greenish^ 

black (5GY 2/1) clay.

71. 3 1. 2 Clay and gaylussite. Black (N 1) to greenish-black (5GY 

2/1) to moderate olive-brown (5F 4/4) clay with 10 percent 

disseminated gaylussite crystals averaging 2 mm in length.

73. 0 1. 7 Clay and gaylussite. Black (N 1) to grayish-black (N 2) to 

greenish-black (5GY 2/1) dense clay with 35 percent disseminated gaylussite crystals averaging 5 mm in length.

73. 3 .3 No core.

73. 5 .2 Clay and gaylussite. Black (N 1) to grayish-black (N 2) to 

greenish-black (5GY 2/1) dense clay with 50 percent disseminated gaylussite crystals averaging 10 mm in length.

73. 7 . 2 Clay and trona. Black (N 1) to grayish-black (N 2) dense 

clay with a few }4-in. lenticular pockets of white (N 9) to 

light greenish-gray (5GY 8/1) massive trona. Clay 95 

percent, trona 5 percent.

75. 3 1. 6 Trona. White (N 9) to medium-gray (N 5) to yellowish-gray 

(5F 7/2) to grayish olive-green (5GY 3/2) compact fibrous 

trona discolored by trace of clay; a few thin seams of white 

(N 9) massive trona.

75. 8 . 5 Trona. White (N 9) to greenish-gray (5GY 6/1) to dark 

greenish-gray (5GY 4/1) porous massive trona with scattered 

large pockets of coarse bladed trona.

76. 3 .5 Clay and gaylussite. Black (N 1) to grayish-black (N 2) 

dense clay with disseminated fine gaylussite sand and silt. 

Clay 90 percent, gaylussite 10 percent.

77. 9 1. 6 Clay and gaylussite. Black (N 1) to grayish-black (N 2) to 

greenish-black (5GY 2/1) to olive-gray (5Y 3/2) clay with 

40 percent disseminated gaylussite crystals averaging 10 mm 

in length.

79. 6 1. 7 No core.

80. 9 1. 3 Clay and gaylussite. Greenish-black (5GY 2/1) to black 

(N 1) clay with 40 percent disseminated gaylussite crystals 

averaging 10 mm in length.

81. 2 .3 Clay and gaylussite. Black (N 1) dense clay with 40 percent 

disseminated gaylussite crystals averaging 1 mm in length.

81. 5 .3 Clay. Black (N 1) dense clay with a few disseminated gaylussite crystals 1-3 mm in length.

82. 2 . 7 Trona. White (N 9) to dark-gray (N 3) to dark greenish-gray

(5GY 4/1) compact fibrous trona discolored by trace of

interstitial clay. 

82. 4 . 2 Clay and trona. Black (N 1) to grayish-black (AT 2) clay with

thin irregular seams of white (N 9) massive trona. Clay 70

percent, trona 30 percent.
180 GEOLOGIC INVESTIGATIONS IN MOJAVE DESERT REGION

Depth Unit thick-

(feet) ness (feel) Description

83. 1 0. 7 Trona a.nd clay. White (N 9) to greenish-gray (5GY 6/1) 

porous massive trona with thin seams, 1-3 mm wide, of 

intermixed dark-gray (N 3) clay and fibrous trona. Trona 

98 percent, clay 2 percent.

83. 6 .5 Clay. Black (N 1) to grayish-black (N 2) to grayish-yellow 

(5Y 8/4) faintly laminated clay with a few seams, 1 mm 

wide, discolored light-brown (SYR 5/6) by algae(?).

83.8 .2 Trona. White (N 9) to dark-gray (N 3) porous massive 

trona discolored by trace of intermixed clay.

84. 2 .4 Trona. White (N 9) hard bony massive trona with irregular 

discolorations of moderate reddish-orange (10.R 6/6) algae(?).

85. 3 1. 1 No core.

85. 6 .3 Trona. White (N 9) to dark greenish-gray (5GY 4/1) to

dark-gray (N 3) porous massive trona discolored by trace

of intermixed clay.

85. 9 .3 Trona and clay. White (AT9) to pale yellowish-brown (10YR 

6/2) to grayish-orange (lOYjR 7/4) to colorless massive and 

bladed trona in seams, 10-30 mm wide, alternating with 

seams of black (N 1) to grayish-black (N 2) to yellowish-gray 

(5Y 7/2) clay; distinct seam of moderate reddish-orange 

(WR 6/6) to grayish-orange (1QYR 7/4) algae(?)-discolored clay at top. Trona 60 percent, clay 40 percent.

86. 0 .1 Trona. Coarse aggregate of colorless trona blades averaging

15 mm in length. 

86. 4 .4 Clay and northupite. Black (N 1) to grayish-black (N 2)

dense clay with layers of disseminated discrete oval to

circular nodules, averaging 1 mm in diameter, of white

(N 9) massive northupite. Clay 98 percent, northupite 2

percent. 

86.5 . 1 Clay and gaylussite. Black (N 1) to greenish-black (5GY

2/10) clay with 50 percent disseminated gaylussite crystals

averaging 5 mm in length.

86. 9 .4 Clay. Black (N 1) dense faintly finely laminated clay with 

a few seams, 1 mm wide, of fine gaylussite sand.

87. 1 .2 Clay and trona. Black (N 1) to medium bluish-gray (5B 5/1)

dense clay with 30 percent disseminated trona blades

averaging 5 mm in length. 

87. 7 . 6 Trona. White (N 9) to colorless trona blades averaging 5

mm in length; discolored dark greenish-gray (5GY 4/1) by

trace of interstitial clay.

87. 9 .2 Clay and northupite. Black (2V 1) to grayish-black (N 2) 

dense clay with irregular seam, 3-4 mm wide, of pale yellowish-orange (10 YR 8/6) massive northupite at base. Clay 

95 percent, northupite 5 percent.

88. 4 .5 Clay and northupite. Black (N 1) faintly finely laminated 

clay with seams of disseminated oval to circular nodules, 

averaging 1 mm in diameter, of white (N 9) massive northupite in upper 0.2 ft. Clay 99 percent, northupite 1 percent.

88. 6 .2 Clay and gaylussite. Black (JV 1) to greenish-black (5GY 2/1) 

dense clay with 50 percent disseminated gaylussite crystals 

averaging 1 mm in length.
181

Depth Unit thick- 

(feet) ness (feet) Description

88. 9 0. 3 Clay and trona. Black (AT 1) to grayish-black (N 2) to very 

light gray (N 8) dense faintly laminated clay with thin layer 

of disseminated trona blades averaging 5 mm in length at 

base. Clay 99 percent, trona 1 percent.

89. 5 .6 Trona. White (N 9) to grayish-black (N 2) compact fibrous 

trona with scattered irregular pockets and streaks of white 

(N 9) massive trona.

90. 2 .7 Clay. Black (N 1) to grayish-black (N 2) to greenish-black 

(5GY 2/1) to light olive-gray (5Y 6/1) to dark greenish-gray 

(5GY 4/1) faintly finely laminated clay.

90. 8 .6 No core.

91. 2 .4 Clay. Black (N 1) to grayish-black (N 2) to greenish-black 

(5GY 2/1) to very light gray (N 7) to grayish-yellow (5F 

8/4) faintly finely laminated clay.

91. 7 .5 Clay and gaylussite. Greenish-black (5GY 2/1) to grayishblack (N 2) dense clay with 50 percent disseminated gaylussite crystals averaging 10 mm in length.

92. 0 .3 Clay and gaylussite. Black (N 1) to grayish-black (N 2) clay 

with 50 percent disseminated gaylussite sand.

93. 6 1. 6 Clay and gaylussite. Grayish-black (N 2) to greenish-black 

(5GY 2/1) with clay with 10 percent disseminated gaylussite 

sand.

93. 7 .1 Clay. Grayish-black (N 2) to dark greenish-gray (5GY 4/1) 

dense finely laminated clay.

95. 5 1. 8 Clay and gaylussite. Dark greenish-gray (5GY 4/1) to black 

(N 1) to grayish-black (N 2) to greenish-gray (5GY 6/1 and 

5(7 6/1) to grayish-yellow (5 Y 8/4) finely laminated clay 

with 40 percent disseminated gaylussite crystals averaging 

20 mm in length.

Searles drill hole GS-9

LOCATION: Searles Lake, Calif., about 20 ft east of % sec. marker for sec. 5, T26 S., and sec. 32, T. 25 S., R. 43 E., Mount Diablo base line and meridian.

ELEVATION AT TOP OF HOLE: 1,618 ft.

ELEVATION AT BOTTOM OF HOLE: 1,514.5 ft.

TOTAL DEPTH: 103.5 ft.

DATES DKILLED: Dec. -14-^28, 1954.

CASING USED: 36.5 ft of 16-in. casing from surface; 69.7 ft of 3-in. pipe extends 

from surface to top of lower salt brine.

MINERAL DETERMINATIONS: Minerals identified microscopically are denoted by 

an asterisk (*).

Depth Unit thick-

(feet) ness (feet) Description

37. 2 37. 2 .Clay. Overburden mud, not cored. Pale-olive (107 6/2) to 

dusky yellow-green (5GY 5/2) to greenish gray (5GY 6/1) 

to black (N 1). clay.

37.6 0.4 Clay and pirssonite*. Black (N 1) to grayish-black (N 2) 

clay with 50 percent disseminated subhedral pirssonite* 

crystals averaging 1 mm in length.

37.7 .1 Clay and pirssonite. Well-consolidated black (N 1) to 

grayish-black (N 2) clay with 25 percent disseminated 

pirssonite crystals averaging 5 mm in length.
182 GEOLOGIC INVESTIGATIONS IN MOJAVE DESERT REGION

Depth Unit thick- 

(feet) ness (feet) Description

38. 2 0. 5 Clay, pirssonite, and trona. Well-consolidated dense black 

(N 1) to grayish-black (N 2) clay with disseminated fine 

pirssonite sand; irregular seam, 5 10mm wide, of white (N 9) 

densely packed fibrous trona at base. Clay 75 percent, 

pirssonite 20 percent, trona 5 percent.

38. 5 .3 Trona and clay. Core fractured. Fragments of massivewhite (N 9) trona to densely packed white (N 9) fibrous, 

trona discolored black (N 1) to greenish-black (5GY 2/1) by 

irregular thin seams of clay. Trona 95 percent, clay 5 

percent.

39. 6 1. 1 No core.

40. 0 .4 Trona, halite, and clay. Poorly consolidated mixture of 

halite cubes less than_l mm in length, discolored by 5 percent 

interstitial grayish-black (N 2) to dark greenish-gray (5GY 

5/1) clay; mixture contains 50 percent rounded fragments,, 

averaging 2 in. across, of densely packed grayish-black 

(N 2) to light greenish-gray (5GY 8/1) to dark greenish-gray 

(5GY 4/1) fibrous trona discolored by trace of interstitial 

clay. Probably cuttings, not core. Trona 50 percent,, 

halite 45 percent, clay 5 percent.

40. 3 .3 Hanksite and trona. Well-consolidated vuggy light olivegray (5Y 6/1) to white (Ar 9) to colorless granular massive 

hanksite with a few embedded hanksite crystals averaging; 

5 mm in length; scattered Yz-in. pockets of white (N 9) 

massive trona. Hanksite 95 percent, trona 5 percent.

40. 5 .2 Trona and hanksite. Well-consolidated white (N 9) tomedium-gray (N 5) to greenish-gray (5GY 6/1) hard massive 

trona with irregular seams, averaging 5 mm in width, of 

densely packed colorless hanksite crystals averaging 3 mm 

in length; trace of grayish-black (N 2) clay with hanksite. 

Trona 80 percent, hanksite 20 percent.

40. 7 .2 Halite, trona, and hanksite. Well-consolidated slightly vuggy 

aggregate of white (N 9) to colorless halite cubes, averaging: 

2 mm in length, with 20 percent interstitial white (N 9} 

hard massive trona; scattered pockets and disseminated! 

crystals of colorless hanksite averaging 5 mm in length. 

Halite 75 percent, trona 20 percent, hanksite 5 percent.

41. 2 . 5 Halite and hanksite. Core fractured. Fragments of denselypacked smoky hanksite crystals, averaging 5 mm in length 

with fragments of densely packed white (N 9) to colorless, 

halite cubes averaging 2 mm in length. Halite 50 percent,, 

hanksite 50 percent.

41. 6 .4 Hanksite and trona. Well-consolidated vuggy aggregate of 

densely packed smoky to colorless hanksite crystals from 

2 to 20 mm in length, with irregular seams and pockets of 

white (N 9) to colorless massive and fibrous trona. Hanksite 

80 percent, trona 20 percent.

45. 7 4. 1 No core.

46. 2 .5 Hanksite and trona. Vuggy aggregate of smoky hanksite 

crystals averaging 10 mm in length and granular massive 

hanksite with interstitial grayish-yellow (57 8/4) to colorless fibrous trona. Hanksite 90 percent, trona 10 percent..
CORE LOGS FROM SEARLES LAKE, CALIFORNIA 183

Depth Unit thick- 

(feet) ness (feet) Description

46. 9 0. 7 Hanksite and trona. Well-consolidated dense aggregate of 

smoky hanksite crystals averaging 10 mm in length, with 

seam, 15 mm wide, of dark-gray (2V 3) to dark greenish-gray 

(5G 4/1) massive trona at base. Hanksite 93 percent, 

trona 7 percent.

47. 5 .6 Hanksite and clay. Friable aggregate of hanksite crystals 

averaging 25 mm in length, with 10 percent interstitial 

grayish-black (N 2) clay.

49. 3 1. 8 No core.

51. 6 2. 3 Trona and clay. Well-consolidated white (TV 9) compact 

fibrous trona with irregular wavy clay seam, 10 mm wide, 

of black (N 1) to brownish-gray (5YR 4/1) clay at 50.0 ft; 

several seams, 1-3 mm wide, of fibrous trona discolored 

by trace of intermixed clay at 51.0 ft; scattered vuggy 

horizontal pockets and seams of white (TV 9) to pale yellowish-brown (10F.R 6/2) massive trona with fibrous trona from 

50.6 ft to base. Trona 98 percent, clay 2 percent.

53. 3 1. 7 No core.

55. 8 2. 5 Trona. White (N 9) to medium-gray (TV 5) soft massive 

trona with seam of dark-gray (N 3) trona discolored by a 

trace of intermixed clay at 54.4 to 54.5 ft.

56. 5 .7 No core.

57. 4 .9 Trona. White (TV 9) soft massive trona with a few seams, 

1-2 mm wide, of medium-gray (TV 5) trona discolored by 

trace of clay; wavy seams of white (TV 9) to yellowish-gray 

(5F 7/2) hard bony massive trona in lower 0.2 ft.

58. 3 . 9 No core.

58. 9 .6 Clay and gaylussite. Grayish-black (TV 2) to grayish-green 

(5G 5/2) to grayish olive-green (5F 3/2) to grayish-yellow 

(5-y 8/4) to greenish-black (5GY 2/1) clay with 30 percent 

disseminated gaylussite crystals averaging 5 mm in length.

60. 8 1. 9 Clay and gaylussite. Grayish olive-green (5GY 3/2) to paleolive (107 6/2) to olive-gray (10 Y 4/2) to. greenish-black 

(5GY 2/1 and 5G 2/1) faintly finely laminated clay with 

25 percent disseminated gaylussite crystals averaging 5 mm 

in length.

61. 6 .8 Clay and aragonite*. Grayish-black (TV 2) to greenish-black 

(5GY 2/1 and 5.G 2/1) clay with widely spaced seams, up to 

1 mm wide, of light greenish-gray (5GY 8/1) to very light 

gray (TV 8) soft massive finely crystalline aragonite*; 

laminae contorted in lower 0.2 ft. Clay 95 percent, aragonite 5 percent.

62. 2 .6 Clay. Grayish-black (TV 2) to greenish-black (5GY 2/1 and 

5G 2/1) to light greenish-gray (5GY 8/1) to grayish-olive 

(10 Y 4/2) to grayish-yellow (5 F 8/4) to very light gray (TV 8) 

finely laminated clay.

63. 0 .8 Clay and gaylussite. Olive-black (5 Y 2/1) to olive-gray 

(5F 3/2) to grayish-black (TV 2) to grayish-yellow (5Y 8/4) 

clay, locally finely laminated, with 30 percent disseminated 

anhedral gaylussite crystals up to 20 mm in length, averaging 5 mm. 

491349 59 4
184

Depth Unit thick-

(feet) neat (feet) Description

63. 8 0. 8 No core.

65. 3 1. 5 Clay and gaylussite. Grayish-black (N 2) to greenish-black 

(5(7 F 2/1 and 5(7 2/1) to dusky yellow-green (5(7 F 5/2) to 

greenish-gray (5(7 6/1 and 5(?F 6/1) to grayish-yellow 

(5F 8/4) to very light gray (N 8) finely laminated clay 

with seams, 15 mm wide, of 90 percent gaylussite crystals 

averaging 5 mm in length at 63.9, 64.1, 64.8, and 65.0 ft; 

a few 1- to 2-in. pockets of gaylussite crystals; laminae 

slightly contorted at base. Clay 90 percent, gaylussite 

10 percent.

65. 8 .5 No core.

66. 2 .4 Clay and gaylussite. Black (N 1) to grayish-black (N 2) to 

greenish-black (5(7 F 2/1) to grayish olive-green (5(7 F 3/2) 

to pale yellowish-green (10(7 F 7/2) to dark yellowish-orange 

(WYR 6/6) to very light gray (N 8) finely laminated clay 

with pockets of gaylussite crystals averaging 15 mm in 

length. Clay 90 percent, gaylussite 10 percent.

67. 0 .8 Clay and gaylussite. Black (N 1) to grayish-black (N 2) to 

greenish-black (5(7 F 2/1 and 5(7 2/1) to grayish olive-green 

(5(7 Y 3/2) to dark greenish-gray (5(7 4/1) coarsely laminated 

clay; laminae from 10 to 25 mm wide revealed by color 

differences; with 1 percent disseminated gaylussite crystals 

averaging 10 mm in length; faint spots and irregular 

laminae of moderate reddish-brown (WR 4/6) algae?- 

discolored clay throughout.

68. 0 1.0 Clay and gaylussite. Black (N 1) to grayish-black (N 2) to 

greenish-black (5(7 Y 2/1 and 5(7 2/1) to dark greenish-gray 

(5(7 4/1) clay with 20 percent disseminated gaylussite 

crystals averaging 10 mm in length.

68. 5 .5 Clay. Black (N 1) to grayish-black {N 2) to dusky yellowgreen (5(7 Y 5/2) to grayish olive-green (5(7 Y 3/2) coarsely 

laminated clay revealed by color differences.

68. 7 .2 Clay and gaylussite. Black (N 1) clay with 50 percent disseminated gaylussite crystals averaging 3 mm in length.

69. 5 .8 Clay and gaylussite. Grayish-black (N 2) to dusky yellowgreen (5(7 F 5/2) to greenish-black (5(7 F 2/1 and 5(7 2/1) 

clay with 50 percent disseminated gaylussite sand.

69.7 .2 Clay. Grayish olive-green (5(7 Y 3/2) clay.

69. 9 .2 Clay and gaylussite. Black (N 1) clay with 50 percent disseminated gaylussite crystals averaging 1 mm in length.

70. 7 .8 Trona, clay and borax. Dense hard massive white (N 9) 

trona with 1- to 2-in. pockets of fibrous trona intermixed 

with blades of trona and a few borax crystals 10 mm long; 

pockets discolored greenish-black (5(7 Y 2/1) by 5 percent 

clay. Trona 94 percent, clay 5 percent, borax 1 percent.

72. 6 1. 9 No core.

72. 8 .2 Trona and clay. Well-consolidated vuggy aggregate of trona 

blades averaging 15 mm in length, with 5 percent interstitial greenish-black (5(7 Y 2/1) clay.
CORE LOGS FROM SEARLES LAKE, CALIFORNIA 185

Depth Unit thick-

(feet) ness (feet) Description

74. 4 1. 6 Clay and pirssonite. Black (N 1) to grayish-black (N 2) to 

greenish-black (5GY 2/1) clay with 40 percent disseminated 

euhedral to subhedral pirssonite crystals averaging 3 mm 

in length.

77. 5 3. 1 Trona. White (N 9) to medium dark-gray (N 4) to dark 

greenish gray (5GT4/1) to yellowish-gray (5F8/1) compact 

fibrous trona with irregular pockets and streaks of massive 

trona.

77. 8 .3 No core.

79. 1 1. 3 Trona and halite. White (N 9) to greenish-gray (5GY 6/1) 

to dark greenish-gray (5GY 4/1) massive vuggy trona with 

prominent 10- to 20-mm bands of moderate reddish-brown 

(10E 4/6) algae?-discolorations in trona at top and at 78.7 

ft; scattered pockets and irregular streaks of halite cubes 

modified by octahedron averaging 4 mm in length, some 

halite cubes with inclusions of moderate reddish-brown 

(1072 4/6) algae?; a few vugs containing fibrous trona 

associated with halite. Trona 85 percent, halite 15 percent.

80.3 1.2 Clay and pirssonite. Olive-gray (5Y 3/2) to light olivebrown (5Y 5/6) to grayish olive-green (5GY 3/2) clay with 

40 percent disseminated crystals averaging 10 mm in 

length.

81. 3 1. 0 Clay and pirssonite. Black (N 1) to grayish-black (N 2) 

clay with 40 percent disseminated pirssonite sand.

81. 4 .1 Trona, clay, and borax. Densely packed aggregate of trona 

blades with 5 percent interstitial black (N 1) clay; scattered 

Yz-in. pockets of grayish-yellow (5K 8/4) fibrous trona; 

embedded borax crystals, up to 50 mm in length, at top. 

Trona 90 percent, clay 5 percent, borax 5 percent.

81. 6 .2 Trona. White (N 9) to greenish-gray (5GY 6/1) massive, 

vuggy trona with numerous pockets of white (N 9) to 

grayish-yellow (5 Y 8/4) fibrous trona.

83. 3 1. 7 No core.

83.6 .3 Trona. and clay. Well-consolidated dark-gray (N 3) to 

greenish-black (5GY 2/1) massive trona discolored by 5 

percent intermixed clay; numerous pockets of white (N 9) 

to grayish-yellow (5F 8/4) fibrous trona.

83.8 .2 Trona and clay. Poorly consolidated aggregate of trona 

blades averaging 5 mm in length, with 5 percent interstitial 

dark greenish-gray (5GY 4/1) clay.

85. 4 1. 6 Halite. Well-consolidated aggregate of white (N 9) to colorless 

halite cubes modified by octahedron, averaging 3 mm in 

length.

87. 5 2. 1 No core.

8a 5 1. 0 Trona. White (N 9) to greenish-gray (5GY 6/1) to dark 

greenish-gray (5GY 4/1) soft massive trona with irregular 

streaks and spots of moderate reddish-brown (1QR 4/6) 

algae? throughout.

88. 9 .4 Clay and northupite*. Black (N 1) to greenish-black (5GY 

2/1 and 5G 2/1) faintly finely laminated clay with 1 percent 

disseminated nodules, averaging 1 mm in diameter, of white 

(N 9) massive northupite containing minor gaylussite*.
186 GEOLOGIC INVESTIGATIONS IN MOJAVE DESERT REGION

Depth Unit thick-

(feet) ness (feet) Description

89. 3 0. 4 Clay and gaylussite. Greenish-black (5GY 2/1 and 5G 2/l> 

to grayish olive-green (5GY 3/2) to olive-gray (5F 3/2) 

clay with 50 percent disseminated gaylussite crystalsaveraging 5 mm in length.

89. 6 .3 Clay and gaylussite. Greenish-black (5GY 2/1) to very light, 

gray {N 8) faintly finely laminated clay with a few laminaeof gaylussite silt. Clay 95 percent, gaylussite 5 percent.

89. 8 .2 Clay. Black (N 1) to grayish-black (N 2) to medium bluishgray (5B 5/1) clay with irregular streaks of moderatereddish-orange (10jR 6/6) algae?-discolored clay.

90. 9 1.1 Trona and clay. White to pale greenish-yellow (10 Y 8/2) 

dense hard massive trona with pockets containing 60 percent fibrous trona and 40 percent black (N 1) clay in upper 

0.2 ft. Trona 97 percent, clay 3 percent.

91. 4 .5 Clay. Black (AT" 1) to greenish-black (5GY 2/1 and 5G 2/1) 

to dusky yellow-green (5GY 5/2) to very light gray (N 8) 

faintly finely laminated clay with a few laminae of gaylussitesilt.

91. 7 .3 Clay and gaylussite. Black (N 1) to greenish-black (5GY 

2/1) clay with 50 percent disseminated gaylussite crystals 

averaging 1 mm in length.

92. 1 .4 Clay and gaylussite. Black (N 1) to greenish-black (5GY 

2/1) to medium bluish-gray (5.3 5/1) to very light gray 

(N 8) faintly finely laminated clay with common laminaeof gaylussite silt. Clay 95 percent, gaylussite 5 percent.

92. 3 .2 Trona. Dense slightly vuggy aggregate of white (N 9) to 

grayish-yellow (5Y 8/4) to colorless trona blades averaging. 

10 mm in length; trace of interstitial clay. .

93. 3 1. 0 No core.

94.3 1.0 Trdna. Well-consolidated compact aggregate of white (AT 9) 

to colorless trona blades averaging 10 mm in length, with 

scattered pockets of interstitial black (N 1) clay in lower 

0.4 ft.

95. 1 .8 Trona and northupite. White (N 9) to yellowish-gray- 

(5F 8/1) dense hard massive trona with % in. pockets, vugs,, 

and irregular seams of colorless fibrous trona; 2 seams, 

7 mm wide, of very pale orange (10YR 8/2) to grayishorange (IQYR 7/4) soft massive northupite with 50 percent, 

intermixed fibrous trona from 94.8 to 94.9 ft. Trona 97 

percent, northupite 3 percent.

95. 2 .1 Trona and clay. Well-consolidated aggregate of trona blades 

averaging 5 mm in length, with 50 percent interstitial, 

greenish-black (5GY 2/1 and 5G 2/1) to medium bluishgray (5B 5/1) clay.

95. 5 .3 Clay and trona. Black (N 1) to greenish-black (5GY 2/1) 

clay with 20 percent disseminated trona blades averaging, 

10 mm in length.
CORE LOGS FROM SEARLES LAKE, CALIFORNIA 187

JDepth Unit thick- 

(feet) ness (feet) Description

96. 2 0. 7 Clay and northupite. Black (N 1) to greenish-black (5GY 

2/1) to dusky yellow-green (5GY 5/2) to grayish olive-green 

(5GY 3/2) to very light gray (N 8) to white (N 9) finely 

laminated clay with 1 percent disseminated white (N 9) 

massive northupite nodules, averaging 1 mm in diameter, 

in upper 0.2 ft.

. -96. 8 .6 Clay and gaylussite. Black (N 1) to olive-black (5Y 2/1) to 

grayish olive-green (5GY 3/2) to dusky-yellow (5Y 6/4) 

clay with 40 percent disseminated gaylussite crystals 

averaging 10 mm in length.

97. 0 .2 Clay and gaylussite. Black (N 1) to olive-black (5Y 2/1) to 

greenish-black (5GY 2/1) clay with 50 percent disseminated 

gaylussite crystals averaging 1 mm in length.

97. 9 . 9 Clay. Well-corsolidated dusky yellow-green (5GT 5/2) to 

grayish olive-green (5GY 3/2) to grayish-yellow (5F 8/4) 

to grayish-black (N 2) to very light gray (N 8) finely 

laminated clay.

9a 3 .4 No core.

9& 9 .6 Clay and nahcolite*. Black (N 1) to greenish-black (5GY 

2/1) to medium bluish-gray (5J5 5/1) with irregular stringers 

and ^-in. lenticular pockets of white (N 9) massive pulverulent nahcolite*. Clay 65 percent, nahcolite 35 percent.

39.1 .2 Clay. Brownish-black (5 YR 2/1) to greenish-black (5GY 2/1)

to dusky yellow-green (5GY 5/2) finely laminated clay.

103. 1 4. 0 Clay and gaylussite. Olive-gray (5Y 3/2) to moderate yellowish-brown (WYR 5/4) to dusky-yellow (5F 6/4) to 

brownish-black (SYR 2/1) to greemsh-black (5GY 2/1 and 

5G 2/1) to medium bluish-gray (5J3 5/1) finely laminated 

clay with 35 percent disseminated gaylussite crystals 

averaging 10 mm in length. 

103.5 . 4 No Core.

Searles drill hole GS-10

LOCATION: Searles Lake, Calif., about 190 feet east of east 1/16 sec. cor., sec. 33, 

T. 25 S., and sec. 4, T. 26 S., R. 43 E., Mount Diablo base line and meridian.

ELEVATION AT TOP OF HOLE: 1,618 ft.

ELEVATION AT BOTTOM OF HOLE: 1,498.1 ft.

TOTAL DEPTH: 119.9 ft.

DATES DRILLED: Dec. 29, 1954, to Jan. 13, 1955.

CASING USED: 32.2 ft of 16-in. casing; 83.9 ft of 3-in. pipe.

MINERAL DETERMINATIONS: Minerals identified microscopically are denoted by 

an asterisk (*).

Depth Unit thick-

(feet) ness (feet) Description

7.2 7.2 Overburden mud, not cored. Moderate yellowish-brown 

(IQYR 5/4) clay.

18. 5 11. 3 Overburden mud, not cored. Dusky yellow-green (5GTT 

5/2) clay.

32. 4 13. 9 Overburden mud, not cored. Black (N 1) clay.

32. 8 .4 Clay and pirssonite. Black (N 1) clay with 40 percent disseminated pirssonite crystals averaging 5 mm in length.
188 GEOLOGIC INVESTIGATIONS IN MOJAVE DESERT REGION

Depth Unit thick-

(feet) ness (feet) Description

32. 9 0. 1 Halite and clay. Well-consolidated aggregate of halite cubes 

and anhedra, averaging 5 mm in length, with 5 percent 

interstitial black (N 1) clay.

33. 7 .8 Clay and pirssonite. Well-consolidated black (N 1) clay with 

40 percent disseminated pirssonite crystals averaging 10 mm 

in length.

33. 8 .1 Halite and clay. Well-consolidated aggregate of halite cubes 

and anhedra, averaging 3 mm in length, with 5 percent 

interstitial black (N 1) clay.

34. 4 .6 Clay and pirssonite. Black (N 1) clay with 10 percent disseminated pirssonite crystals averaging 2 mm in length and 

pockets of pirssonite crystals.

34. 7 .3 Halite and clay. Well-consolidated aggregate of halite cubes 

averaging 3 mm in length, with 5 percent interstitial black 

(N 1) clay.

35. 3 .6 Clay and pirssonite. Well-consolidated black (N 1) clay with 

50 percent disseminated pirssonite crystals averaging 5 mm 

in length.

35. 4 .1 Halite and clay. Well-consolidated aggregate of halite cubes 

and anhedra, averaging 3 mm in length, with 5 percent 

interstitial black (N 1) clay.

35. 7 .3 Clay and pirssonite*. Black (N 1) clay with 20 percent disseminated pirssonite* sand.

35. 9 .2 Halite and clay. Well-consolidated aggregate of halite cubes 

averaging 3 mm in length, with 5 percent interstitial black 

(N 1) clay.

36. 3 .4 Clay and pirssonite. Black (N 1) clay with 20 percent disseminated pirssonite sand.

36. 5 .2 Halite and clay. Well-consolidated aggregate of halite cubes 

averaging 2 mm in length, with 15 percent interstitial black 

(N 1) to greenish-black (5GT 2/1 and 5(7 2/1) clay.

36. 7 .2 Halite and trona. Well-consolidated aggregate of halite crystals averaging 2 mm in length, with 40 percent interstitial 

dark greenish-gray (5GY 4/1 and 5G 4/1) massive trona.

36. 9 .2 Trona and halite. Well-consolidated slightly vuggy aggregate 

of white (N 9) massive trona with 40 percent halite crystals 

disseminated throughout and concentrated in vuggy pockets.

37. 6 .7 Halite and trona. Well-consolidated vuggy aggregate of 

halite cubes averaging 3 mm in length, with 25 percent 

greenish-gray (5GY 6/1) to dark greenish-gray (5(? 4/1) massive trona in lenticular pockets and irregular seams, averaging 10 mm in width; trace of interstitial greenish-black 

(5GY 2/1) to greenish-gray (50Y 6/1) clay.

38. 0 .4 No core.

39. 0 1.0 Clay and pirssonite*. Well-consolidated black (N 1) clay with 

40 percent disseminated pirssonite* crystals averaging 2 mm 

in length.

39. 1 .1 Halite and trona. Well-consolidated aggregate of halite cubes 

and cubes modified by octahedron, averaging 2 mm in length, 

with 50 percent intermixed dark greenish-gray (5GY 4/1 

and 5(7 4/1) massive trona.
CORE LOGS FROM SEARLES LAKE, CALIFORNIA 189

Depth Unit thick-

(feet) ness (feet) Description

39. 2 0. 1 Trona. White (N 9) soft massive trona.

39.4 .2 Halite and trona. Well-consolidated aggregate of halite 

cubes modified by octahedron, averaging 4 mm in length, 

with 1 percent interstitial dark greenish-gray (5GY 4/1 and 

5G4/1) massive trona.

39. 6 .2 Halite and trona. Poorly consolidated aggregate of halite 

cubes modified by octahedron, averaging 4 mm in length, 

with 1 percent interstitial dark greenish-gray (5YG 4/1 and 

5G 4/1) massive trona.

40. 4 .8 Clay and pirssonite. Black (N 1) clay with 40 percent disseminated pirssonite crystals averaging 2 mm in length.

40. 8 .4 Halite. Well-consolidated dense aggregate of white (N 9) to 

colorless halite crystals averaging 4 mm in length.

41. 0 .2 Clay and pirssonite.* Poorly consolidated soft black (N 1) 

clay with 30 percent black (N 1) crystal fragments of pirssonite* disseminated throughout.

42. 6 1. 6 No core.

43. 1 .5 Halite and trona. . Friable aggregate of halite cubes and 

cubes modified by octahedron, averaging 4 mm in length, 

with 30 percent dark greenish-gray (5Cr 4/1) fibrous trona 

in irregular streaks.

43. 7 .6 Halite and trona. Well-consolidated slightly vuggy aggregate 

of halite cubes and cubes modified by octahedron, averaging 

2 mm in length, with intermixed irregular streaks of white 

(N 9) massive trona and streaks of dark greenish-gray 

(5(2 4/1) fibrous trona. Halite 50 percent, trona 50 percent.

44. 0 .3 Trona, halite, and clay. Poorly consolidated mixture of 

fragments consisting of aggregates of dark greenish-gray 

(5G 4/1) fibrous trona with disseminated halite crystals 

averaging 3 mm in length; pockets and streaks of white 

(N 9) massive trona throughout; core discolored by 5 

percent intermixed greenish-black (5GY 2/1 and 5(22/1) 

clay. Trona 75 percent, halite 20 percent, clay 5 percent.

44. 6 .6 Trona and halite. White (N 9) to yellowish-gray (5Y 8/1) 

dense hard slightly vuggy massive trona with disseminated 

crystals and irregular streaks of colorless halite. Trona 

60 percent, halite 40 percent.

45. 3 .7 No core.

45.4 .1 Hanksite. Densely packed aggregate of dark-gray (N 3)

anhedral hanksite crystals averaging 10 mm in length. 

45. 7 .3 Halite and trona. Well-consolidated slightly vuggy aggregate

of halite cubes with 30 percent interstitial white (N 9)

massive trona.

45. 8 .1 Halite and clay. Well-consolidated aggregate of halite cubes 

averaging 3 mm in length, with 5 percent interstitial black 

(N 1) to greenish-black (5GY 2/1) clay.

46. 1 .3 Trona and halite. Well-consolidated white (N 9) vuggy 

massive trona with disseminated halite crystals throughout; 

halite cubes modified by octahedron, averaging 3 mm in 

length, lining narrow horizontal lenticular vugs. Trona 60 

percent, halite 40 percent.
190 GEOLOGIC INVESTIGATIONS IN MOJAVE DESERT REGION

Depth Unit thick-

(feet) ness (feet) Description

46. 3 0. 2 Trona, halite, and clay. Well-consolidated white (N 9) to 

dark greenish-gray (5GY 4/1) vuggy massive trona with 

numerous narrow lenticular vugs lined with halite cubes 

averaging 2 mm in length; irregular streaks of black (N 1) 

clay throughout. Trona 80 percent, halite 10 percent, clay 

10 percent.

47. 0 .7 Halite. Well-consolidated aggregate of halite cubes and 

cubes modified by octahedron, averaging 2 mm in length; 

discolored by trace of greenish-gray (5GY 6/1) clay.

47. 5 .5 Trona and halite. Fractured core. White (N 9) hard vuggy 

massive trona with disseminated halite crystals and irregular streaks of halite crystals averaging 2 mm in length. 

Trona 60 percent, halite 40 percent.

47. 7 .2 Halite and trona. Well-consolidated aggregate of halite 

cubes averaging 3 mm in length, with scattered #-in pockets 

of white (N 9) massive trona. Halite 98 percent, trona 2 

percent.

48. 4 . 7 Trona and halite. Well-consolidated white (N 9) vuggy 

massive trona with 50 percent disseminated halite crystals 

averaging 2 mm in length.

48. 5 . 1 Halite. Well-consolidated aggregate of halite crystals averaging 2 mm in length; discolored by trace of interstitial 

greenish-gray (5GY 6/1) clay.

48. 6 .1 Clay and hanksite. Black (N 1) clay with large disseminated 

hanksite crystals averaging 30 mm in length. Clay 50 percent, hanksite 50 percent.

48. 7 . 1 Halite and trona. Well-consolidated aggregate of halite crystals averaging 2 mm in length, with seams, 1-2 mm wide, 

of white (N 9) massive trona. Halite 80 percent, trona 20 

percent.

49. 9 1. 2 No core.

50. 2 .3 Hanksite. Fractured core. Fragments of hard dense granular massive colorless to faint smoky hanksite.

50. 6 .4 Hanksite. Hard dense massive colorless to smoky 'hanksite.

51. 0 . 4 Trona and halite. White (N 9) massive vuggy trona with 

disseminated halite crystals averaging 4 mm in length; 

numerous horizontal lenticular vugs lined with euhedral 

halite cubes modified by octahedron, averaging 4 mm in 

length. Trona 60 percent, halite 40 percent.

51. 3 .3 Halite and trona. Core fractured. Well-consolidated aggregate of halite cubes modified by octahedron, with seams of 

white (N 9) massive trona. Halite 50 percent, trona 50 

percent.

51. 4 .1 Hanksite. Hard dense massive colorless hanksite.

52. 8 1. 4 No core.

53. 0 .2 Trona and halite. Well-consolidated white (N 9) to dark 

greenish-gray (5GY 4/1) slightly vuggy massive trona with 

pockets of euhedral halite cubes modified by octahedron, 

averaging 3 mm in length. Trona 90 percent, halite 10 

percent.

53. 3 .3 Hanksite. Dense hard massive smoky hanksite.
CORE LOGS FROM SEARLES LAKE, CALIFORNIA 191

Depth Unit thick-

(feet) ness (feet) Description

53. 8 0. 5 Hanksite, trona, and halite. Fractured core. Fragments of 

colorless to brownish-smoky granular massive hanksite 

containing pockets and thin seams of white (N 9) to dark 

greenish-gray (5GY 4/1) massive trona; fragments of granular massive hanksite at base, containing seam of halite 

cubes averaging 3 mm in length. Hanksite 78 percent, 

trona 20 percent, halite 2 percent.

54. 2 . 4 No core.

54. 8 .6 Hanksite, halite, and trona. Fractured core. Fragments of 

colorless to smoky granular massive hanksite with %-in. 

pockets of halite cubes averaging 3 mm and pockets up to 

several inches long of dark greenish-gray (5GY 4/1) massive 

trona. Hanksite 70 percent, halite 20 percent, trona 10 

percent.

55. 1 .3 Hanksite. Massive dense hard smoky hanksite.

55. 5 .4 Halite and trona. Well-consolidated white (N 9) to colorless 

halite cubes averaging 3 mm in length, with 20 percent interstitial white (W 9) to dark greenish-gray (5GY 4/1) massive trona.

55. 6 .1 Trona. Well-consolidated white (N 9) to yellowish-gray (5Y 

8/1) dense compact massive trona.

56. 9 1. 3 No core.

59. 0 2. 1 Hanksite, trona, and clay. Well-consolidated vuggy aggregate of euhedral hanksite crystals up to 60 mm in length, 

averaging 30 mm; interstitial dark greenish-gray (5GY 4/1) 

massive trona in lower 0.1 ft; scattered pockets of black 

(N 1) clay and grayish-yellow (5F 8/4) fibrous trona in interstices of hanksite crystals in lower 1.0 ft. Hanksite 95 

percent, trona 4 percent, clay 1 percent.

59. 3 .3 Trona. Greenish-gray (5GY 6/1) to dark greenish-gray (5(7 

4/1) vuggy massive trona with numerous thin horizontal 

lenticular vuggy seams lined with colorless fibrous trona.

59. 8 .5 Trona. Well-consolidated greenish-gray (5GY 6/1) to dark 

greenish-gray (5GY 4/1) massive trona.

60. 3 .5 Hanksite and trona. Dense hard massive brownish smoky 

hanksite with 1- to 2-in. pockets of white (N 9) to colorless 

fibrous trona. Hanksite 90 percent, trona 10 percent.

65. 1 4. 8 No core.

65. 7 .6 Trona and hanksite. Well-consolidated white (N 9) to dark 

greenish-gray (5GF4/1) to light olive-gray (5F6/1) slightly 

vuggy massive trona with seams, 5 mm wide, of massive 

smoky hanksite. Trona 80 percent, hanksite 20 percent.

66. 0 .3 Trona. Fractured core. Fragments of white (N 9) to yellowish-gray (5Y 7/2) soft massive trona. 

66. 2 .2 No core.

68. 5 2. 3 Trona. White (N 9) to light greenish-gray (5GY 8/1) soft 

massive trona.

69. 1 .6 No core.

70. 3 1. 2 Trona. White (N 9) soft massive trona.

71. 1 .8 No core.
192 GEOLOGIC INVESTIGATIONS IN MOJAVE DESERT REGION

Depth Unit thick-

(feet) ness (feet) Description

71.5 0.4 Clay and pirssonite. Grayish-green (WGY 5/2) and (10(? 4/2) 

to dusky yellow-green (5GY 5/2) to moderate-yellow (57 

7/6) to black (N 1) finely laminated clay with seam, 10 mm 

wide, of black (N 1) clay containing 50 percent disseminated 

pirssonite crystals averaging 1 mm in length at base. Clay 

96 percent, pirssonite 4 percent.

72.3 .8 Clay and gaylussite*. Olive-gray (57 3/2) to olive-black 

(572/1) to grayish-green OOG75/2) clay,, locally faintly 

finely laminated, with 35 percent disseminated gaylussite* 

crystals averaging 10 mm in length.

73. 0 .7 Clay and gaylussite. Grayish-green (10(77 5/2) to olive-black 

(57 2/1) to medium bluish-gray (5B 5/1) to very light gray 

(N 8) finely laminated clay with 1- to 2-in. pockets and disseminated crystals of gaylussite averaging 15 mm in length. 

Clay 90 percent, gaylussite 10 percent.

73. 9 .9 Clay and aragonite. Black (N 1) to greenish-black (5GY 2/1) 

to grayish-green (10G7 5/2) clay coarsely laminated with 

widely spaced laminae, up to 1 mm wide, of moderate 

olive-brown (5 7 4/4) to very light gray soft finely crystalline 

massive (N 8) aragonite. Clay 95 percent, aragonite 5 

percent.

74. 5 .6 Clay and aragonite. Black (N 1) to greenish-black (5G7 2/1) 

clay coarsely laminated with widely spaced laminae, up to 

1 mm wide, of soft finely crystalline massive aragonite. 

Clay 95 percent, aragonite 5 percent.

75. 1 .6 Clay and gaylussite*. Black (N 1) to olive-black (57 2/1) 

to olive-gray (57 3/2) to grayish-yellow (57 8/4) to grayishgreen (10G7 5/2) to very light gray (N 8) finely laminated 

clay with seam, 15 mm wide, of 50 percent disseminated 

gaylussite* crystals averaging 5 mm in length at 75.0 ft. 

Clay 96 percent, gaylussite 4 percent.

75. 2 .1 No core.

77.2 2.0 Clay and gaylussite. Black (N 1) to dark greenish-gray 

. (5G7 4/1 and 5G 4/1) to grayish-yellow (57 8/4) to dark 

yellowish-orange (10 YR 6/6) to moderate olive-brown 

(57 4/4) to very light gray (N 8) to white (N 9) dense finely 

laminated clay with scattered pockets of disseminated gaylussite* crystals averaging 5 mm in length. Clay 98 percent, gaylussite 2 percent.

77. 8 .6 No core.

78. 3 . 5 . Clay. Pale-olive (107 6/2) to dusky yellow-green (5GY 5/2) 

to olive-gray (57 3/2) to grayish-yellow (57 8/4) to light 

olive-brown (57 5/6) to pale greenish-yellow (107 8/2) to 

dark yellowish-orange (IOYR 6/6) to medium bluish-gray 

(55 5/1) to white (N 9) dense finely laminated clay.

79. 1 .8 Clay and gaylussite*. Black (N 1) to dusky yellow-green 

(5(r7 5/2) to medium bluish-gray (55 5)1) to very light 

gray (N 8) to white (N 9) finely laminated clay with 50 

percent anhedral gaylussite* crystals and irregular intergrown gaylussite and clay masses up to 2 in. in length.
CORE LOGS FROM SEARLES LAKE, CALIFORNIA 193

Depth Unit thick-

(feet) ness ( feef) Description

81. 2 2.1 Clay and gaylussite. Pale-olive (10 Y 6/2) to dusky-yellow 

(5Y 6/4) to medium bluish-gray (5J5 5/1) to olive-gray 

(5Y 3/2) coarsely laminated clay revealed by color differences with 40 percent disseminated anhedral gaylussite 

crystals; a few laminae, 1 mm wide, of moderate reddishorange (10/B 6/6) algae(?)-discolored clay.

81. 7 .5 Clay and pirssonite. Black (N 1) to greenish-black (5GY 2/1) 

clay with 40 percent disseminated euhedral pirssonite 

crystals averaging 5 mm in length.

82. 0 .3 No core.

83. 1 1.1 Clay and pirssonite. Black (N 1) to greenish-black (5GY 2/1) 

clay with 40 percent disseminated euhedral pirssonite crystals averaging 5 mm in length.

84. 0 . 9 Trona and clay. Compact vuggy aggregate of colorless trona 

blades averaging 10 mm, with irregular pockets and streaks 

of greenish-gray (5 GY 6/1) massive trona; 5 percent interstitial greenish-black (5GY 2/1) to dark greenish-gray 

(5GY 4/1) clay; a few moderate reddish-brown (10.R 4/2) 

irregular algae(?)-discolored streaks in clay.

84. 3 . 3 Trona and borax. Dense slightly vuggy aggregate of colorless 

trona blades averaging 10 mm in length, with 10 percent 

disseminated subhedral to euhedral borax crystals averaging 5 mm in length.

84. 9 .6 Clay, pirssonite, and borax. Black (N 1) clay with 30 percent disseminated coarse pirssonite sand and 5 percent disseminated euhedral borax crystals averaging 5 mm in length.

85. 5 .6 Clay and pirssonite. Black (N 1) to dusky yellow-green 

(5GY 5/2) clay with 50 percent disseminated euhedraJ 

pirssonite crystals averaging 2 mm in length.

.85. 7 . 2 No core.

86. 4 .7 Clay and pirssonite. Black (N 1) to greenish-black (5GY 2/1) 

clay with 35 percent disseminated euhedral pirssonite crystals averaging 5 mm in length.

87. 0 .6 Trona. Well-consolidated compact aggregate of white (N 9) 

to dark greenish-gray (5GY 4/1) fibrous trona.

90. 0 3. 0 Trona and halite. Well-consolidated white (N 9) to greenishgray (5GY 6/1) to dark greenish-gray (5GY 4/1) vuggy 

massive trona with disseminated crystals and lenticular 

pockets of halite cubes and cubes modified by octahedron, 

up to 10 mm in length, averaging 3 mm; vugs lined with 

halite crystals containing interstitial fine fibrous trona; 

irregular moderate reddish-orange (10R 6/6) algae(?) discolorations in hah'te crystals and in massive trona at 87.8 

ft, and in massive trona at 88.5 and 89.6 ft. Trona 80 

percent, halite 20 percent.

90. 3 .3 No core.

92. 4 2. 1 Clay and pirssonite. Black (N 1) to greenish-black (5GY 

2/1) clay with 40 percent disseminated euhedral pirssonite 

crystals averaging 5 mm in length.
194 GEOLOGIC INVESTIGATIONS IN MOJAVE DESERT REGION

Depth Unit thick-

(feet) ness (feet) Description

93. 1 0. 7 Trona, clay, and pirssonite. White (AT 9) to grayish-green 

(IQGY 5/2) massive trona with irregular seams of intermixed black (N 1) to greenish-black (5GY 2/1) clay and 

fibrous trona; pockets of white (N 9) to colorless fibrous 

trona; scattered euhedral prismatic borax crystals, 5 mm 

long, disseminated in a trona-clay seam in upper 0.1 ft; 

black (N 1) clay seam, 10 mm wide, at 92.9 ft, containing 

25 percent disseminated euhedral pirssonite crystals 

averaging 2 mm in length. Trona 95 percent, clay 4 percent, pirssonite 1 percent.

93. 7 .6 Halite and trona. Friable aggregate of white (N 9) to colorless halite cubes and cubes modified by octahedron, averaging 3 mm, with seam, 10 mm wide, of white (N 9) grayishgreen (10GT 5/2) massive trona at 93.4 ft. Halite 95 

percent, trona 5 percent.

93.9 .2 Halite and trona. Well-consolidated aggregate of halite 

cubes and cubes modified by octahedron, averaging 3 mm 

in length, with 30 percent interstitial white (N 9) massive 

trona in pockets and irregular seams.

94. 1 .2 Burkeite*, trona*, and borax*. Hard dense very slightly 

vuggy massive yellowish-gray (5Y 7/2) intermixed burkeite* 

and trona* with minor borax*. Burkeite 70 percent, trona 

25 percent, borax 5 percent.

94. 6 .5 Halite, trona, and clay. Fractured core. Fragments of 

dusky yellow-green (5GY 5/2) to colorless fibrous trona 

with irregular seams of interstitial black (N 1) clay; fragments consisting of aggregates of halite cubes and cubes 

modified by octahedron, averaging 5 mm in length. Halite 

50 percent, trona 48 percent, clay 2 percent.

94. 8 .2 Trona. White (N 9) to grayish-green (10GY 5/2) to grayish 

olive-green (5GY 3/2) dense hard massive trona discolored 

by trace of clay.

95. 8 1. 0 No core.

96. 1 .3 Trona. Poorly consolidated white (N 9) to dark greenish-gray 

(5GY 4/1) soft massive trona. Probably cuttings, not core.

96.3 .2 Burkeite*. Pale yellowish-orange (10YR 8/6) dense hard 

massive burkeite*.

96. 6 .3 Halite. Friable aggregate of white (N 9) to colorless halite 

cubes and cubes modified by octahedron, averaging 3 mm 

in length.

97.0 .4 Trona and burkeite. White (N 9) to light greenish-gray 

(5GY 8/1) dense massive trona with 1- to 3-in. pockets 

of pale yellowish-orange (1QYR 8/6) dense hard massive 

burkeite. Trona 80 percent, burkeite 20 percent.

97.4 .4 Halite and trona. Well-consolidated aggregate of white 

(N 9) to colorless halite cubes and cubes modified by 

octahedron, averaging 3 mm in length, with a few 1-in. 

pockets of white (N 9) massive trona. Halite 98 percent, 

trona 2 percent.

97. 5 .1 Trona. Well-consolidated white (N 9) soft massive trona.
CORE LOGS FROM SEARLES LAKE, CALIFORNIA 195

Depth Unit thick-

(feet) ness (feet) Description

97. 9 0. 4 Halite. Well-consolidated aggregate of white (N 9) to colorless 

halite cubes and cubes modified by octahedron, averaging 

3 mm in length.

98. 1 .2 Halite and trona. Well-consolidated aggregate of halite 

cubes and cubes modified by octahedron, averaging 3 mm 

in length, with 20 percent interstitial white (N 9) to greenish-gray (5GY 6/1) soft massive trona.

98.5 .4 Trona, halite, and clay. White (N 9) to greenish-gray 

(5GY 6/1) soft massive trona with seam, 10 mm wide, of 

white (N 9) to colorless halite crystals in upper 0.1 ft and 

irregular thin black (N 1) clay streaks in lower 0.2 ft. 

Trona 90 percent, halite 8 percent, clay 2 percent.

98. 9 .4 Halite. Well-consolidated aggregate of white (N 9) to colorless halite cubes and cubes modified by octahedron, averaging 3 mm in length.

99. 2 .3 Trona and halite. White (N 9) to greenish-gray (5GY 6/1) 

soft massive trona with numerous seams of white (N 9) 

to colorless halite cubes and cubes modified by octahedron, 

averaging 2 mm in length; numerous streaks, less than 1 

mm wide, of moderate reddish-orange (10.R 6/6) algae(?) 

discolorations in trona and as inclusions in halite crystals. 

Halite 50 percent, trona 50 percent.

99. 5 .3 Halite and burkeite. Well-consolidated aggregate of white 

(N 9) to colorless halite cubes and cubes modified by octahedron, averaging 3 mm in length, with seam, 10 mm wide, 

of pale yellowish-orange (lOY/E 8/6) hard dense massive 

burkeite at base. Halite 90 percent, burkeite 10 percent.

100. 1 .6 Halite and trona. Fractured core. Poorly consolidated 

fragments of white (N 9) to colorless halite cubes and cubes 

modified by octahedron, with 10 percent interstitial white 

(N 9) to greenish-gray (5GY 6/1) soft massive trona.

100. 6 . 5 No core.

100. 8 . 2 Halite and trona. Well-consolidated aggregate of halite cubes 

averaging 2 mm in length, with 5 percent interstitial white 

(N 9) soft massive trona.

101.0 .2 Burkeite. Pale yellowish-orange (IQYR 8/6) hard dense 

massive burkeite.

101. 2 . 2 Trona and halite. White (N 9) to greenish-gray (5GY 6/1) 

soft massive trona with 1- to 2-in. pockets of colorless 

halite cubes modified by octahedron, averaging 3 mm in 

length; irregular streaks of trona discolored medium-gray 

(N 5) by trace of clay. Trona 85 percent, halite 15 percent.

101. 5 . 3 Halite, trona, and burkeite. Well-consolidated aggregate of 

white (N 9) to colorless halite cubes and cubes modified by 

octahedron, averaging 3 mm in length, with thin seams, 

1-3 mm wide, of white (N 9) soft massive trona; pockets, 

1 in. long, of pale yellowish-orange (10Y.R 8/6) hard massive burkeite at 101.4 ft. Halite 90 percent, trona 5 percent, 

burkeite 5 percent.
196 GEOLOGIC INVESTIGATIONS IN MOJAVE DESERT REGION

Depth Unit thick-

(feet) ness (feet) Description

101. 6 0. 1 Trona and northupite*. White (N 9) to dark-gray (N 3) 

dense hard massive trona with seam, 3 mm wide, of grayishorange (lOYjR 7/4) soft massive northupite* containing 

minor intermixed gaylussite* at base. Trona 90 percent, 

northupite 10 percent.

102.0 . 4 Clay and borax. Black (N 1) to greenish-black (5GY 2(1). 

to grayish-yellow green (5GY 3/2) to very light gray (N 8) 

dense finely laminated clay with seam, 15 mm wide, of 40 

percent disseminated euhedral prismatic borax crystals 

averaging 5 mm in length at 101.9 ft; seam, 1 mm wide, of 

60 percent disseminated gaylussite crystals at base; & 

seams, 1 mm wide, of moderate reddish-orange (10 R 6/6) 

algae (?)-discolored clay from 101.6 to 101.7 ft. Clay 95 

percent, borax 5 percent.

102. 2 . 2 Trona and halite. White (N 9) to light greenish-gray (5GY 

8/1) hard massive trona with 5 percent halite crystals in 

scattered pockets, 1 in. long.

102. 4 .2 Trona and halite. Fractured core. White (N 9) to light 

greenish-gray (5GY 8/1) massive trona with pockets of 

halite crystals averaging 3 mm in length. Trona 90 percent, halite 10 percent.

102. 5 . 1 Burkeite. Greyish-orange (10 YR 7/4) hard dense massive 

burkeite.

102. 7 . 2 Burkeite and trona. Fractured core. Fragments of grayishorange (10 YR 7/4) hard dense massive burkeite with interstitial dark greenish-gray (5GY 4/1) soft massive trona 

containing distinct irregular seams, 1 mm wide, of lightbrown (5YR 6/4) algae (?) discolored trona. Burkeite 80 

percent, trona 20 percent.

104. 8 2. 1 No core.

105. 3 . 5 Clay, borax, and northupite. Black (N 1) to greenish-black 

(5GY 2/1) to light greenish-gray (5GY 8/1) to very light 

gray (N 8) finely laminated clay with seams of disseminated 

round to oval nodules, averaging 1 mm in diameter, of 

white (N 9) massive northupite; seam, 15 mm wide, of 50 

percent disseminated euhedral borax crystals, averaging 

15 mm in length, in black (N 1) clay at top. Clay 90 percent, borax 5 percent, northupite 5 percent.

105. 5 . 2 Clay and gaylussite. Greenish-black (5GY 2/1) to black 

(N 1) clay with 50 percent disseminated gaylussite crystals 

averaging 10 mm in length.

105. 6 . 1 Clay and gaylussite. Black (N 1) clay with 50 percent disseminated clear colorless euhedral gaylussite crystals averaging 2 mm in length.

106. 0 . 4 Clay and northupite*. Black (N 1) to grayish-black (N 2> 

to greenish-black (5GY 2/1) to very light gray (N 8) faintly 

finely laminated clay with 2 distinct seams, 1 mm wide,, 

of grayish-orange (10YR 7/4) massive northupite* containing minor intermixed gaylussite* in lower 0.1 ft. Clay 

98 percent, northupite 2 percent.
CORE LOGS FROM SEARLES LAKE, CALIFORNIA 197

Depth Unit thick-

(feet) ness (feet) Description

106. 5 0. 5 Trona and clay. Densely packed aggregate of radiating 

trona blades averaging 25 mm in length, with 25 percent 

interstitial black (N 1) clay; a few euhedral borax crystals, 

averaging 10 mm in length, at top.

107. 0 . 5 Hanksite and trona. Well-consolidated vuggy aggregate of 

euhedral hanksite crystals with prominent basal pinacoid 

up to 35 mm in length, averaging 20 mm, associated with 

interstitial colorless trona blades averaging 20 mm in 

length. Hanksite 65 percent, trona 35 percent.

107. 3 . 3 Trona, hanksite, and clay. White (N 9) to greenish-gray 

(5GY 6/1) vuggy massive trona, with numerous pockets of 

bladed trona; large vug at base containing hanksite crystals 

showing prominent basal pinacoid up to 35 mm in length, 

with interstitial black (N 1) clay. Trona 80 percent, hanksite 15 percent, clay 5 percent.

107. 8 . 5 No core.

108. 0 . 2 Clay. Greenish-black (5GY 2/1) to very light gray (N 8)

faintly finely laminated clay. 

108. 2 .2 Clay and gaylussite. Greenish-black (5GY 2/1) clay with 50

percent disseminated clear colorless euhedral gaylussite

crystals averaging 1 mm in length. 

108. 4 . 2 Clay. Black (N 1) to dark-gray (N 3) to greenish-black

(5GY 2/1) to very light gray (N 8) faintly finely laminated

clay.

108. 5 . 1 Trona*. Dark greenish-gray (5GY 4/1 and 5G 4/1) dense 

hard massive trona* with vugs of trona blades averaging 

5 mm in length; seam, 10 mm wide, of coarse colorless to 

white (N 9) trona blades, averaging 20 mm in length, at 

top.

109. 5 1. 0 Trona. Vuggy aggregate of colorless trona blades averaging 

10 mm in length, with pockets of white (N 9) massive trona 

and local interstitial dark greenish-gray (5G 4/1) massive 

trona.

109. 6 . 1 Trona*. Aggregate of colorless trona blades containing 

pockets of white (N 9) massive trona; interstitial very pale 

orange (IQYR 8/2) soft massive trona*.

109. 8 . 2 Trona. Dense hard massive trona with seam, 10 mm wide, 

of colorless trona blades averaging 5 mm in length at top109. 9 . 1 Clay. Black (N 1) to greenish-black (5GY 2/1) to very light 

gray (N 8) faintly finely laminated clay.

110. 0 .1 Thenardite*. Vuggy aggregate of tabular thenardite* crystals averaging 10 mm in length.

110. 1 .1 Clay. Black (N 1) to dusky yellow-green (5GY 5/2) to very 

light gray (N 8) faintly finely laminated clay.

110. 3 .2 Clay and gaylussite. Black (N 1) to greenish-black (5GY 

2/1) clay with 50 percent disseminated gaylussite crystals 

averaging 1 mm in length.
198 GEOLOGIC INVESTIGATIONS IN MOJAVE DESERT REGION

Depth Unit thick-

(feet) ness (feet) Description

110. 9 0. 6 Clay. Black (N 1) to greenish-gray (5GY 6/1) to dusky 

yellow-green (5GY 5/2) to very light gray (N 8) finely 

laminated clay.

111. 0 .1 Clay and gaylussite. Greenish-black (5GY 2/1) clay with 50 

percent disseminated gaylussite sand.

111. 1 .1 Trona and clay. Hard dense aggregate of trona blades with 

50 percent interstitial greenish-black (5GY 2/1) clay.

111. 3 .2 Trona. Dark greenish-gray (5GY 4/1) hard dense massive 

trona.

111. 7 .4 Well-consolidated aggregate of colorless trona blades discolored by 2 percent interstitial greenish-black (5GY 2/1) 

clay; interstitial pockets of white (N 9) soft to hard massive 

trona.

113. 8 1. 7 No core.

114.5 .7 Trona*. Well-consolidated aggregate of colorless trona blades 

averaging 10 mm in length with pockets of dark greenishgray (5GY 4/1) massive trona; local interstitial very pale 

orange (WYR 8/2) soft massive trona* at 109.5 to 109.6 

ft.

115. 1 .6 Clay and trona. Black (N 1) to grayish olive-green (5GY 

3/2) to greenish-black (5GY 2/1) to very light gray (N 8) 

finely laminated clay with seams, 5 mm wide, of colorless 

trona blades averaging 3 mm in length at 114.6 ft. Clay 

97 percent, trona 3 percent.

116. 9 1. 8 Clay and gaylussite. Black (N 1) to olive-gray (5F 3/2) clay 

with 50 percent disseminated euhedral colorless gaylussite 

crystals up to 40 mm in length, averaging 10 mm.

117. 3 .4 Clay and gaylussite. Grayish-yellow (5Y 8/4) to dark 

yellowish-orange (10 YR 6/6) to medium bluish-gray (5B 

5/1) to olive-gray (5Y 3/2) finely laminated clay with 5 

percent disseminated gaylussite crystals averaging 3 mm 

in length.

118. 2 .9 Clay and gaylussite. Olive-gray (57 3/2) to medium bluishgray (5B 5/1) to dusky yellowish-brown (WYR 2/2) finely 

laminated clay with 35 percent disseminated euhedral 

gaylussite crystals from 1 to 30 mm in length, averaging 

10 mm.

118. 5 .3 Clay and gaylussite. Dark yellowish-orange (IQYR 6/6) to 

medium bluish-gray (55 5/1) to olive-gray (5F 3/2) to 

very light gray (N 8) finely laminated clay with 2 percent 

disseminated anhedral gaylussite crystals averaging 10 mm 

in length.

118. 7 .2 Clay and gaylussite. Olive-gray (5F 3/2) to moderate olivebrown (5Y 4/4) to pale yellowish-orange (10 YR 8/6) 

coarsely laminated clay with 40 percent disseminated 

euhedral gaylussite crystals averaging 15 mm in length.

119. 9 1. 2 No core.
CORE LOGS FROM SEARLES LAKE, CALIFORNIA 199

Searles drill hole GS-11

LOCATION: Searles Lake, Calif., approx. 12 ft east of common cor., sees. 25 and 

36, R. 43 E., and sees. 30 and 31, R. 44 E., T. 25 S., Mount Diablo base line 

and meridian.

ELEVATION AT TOP OF HOLE: 1,616 ft.

ELEVATION AT BOTTOM OF HOLE: 1,491.2 ft.

TOTAL DEPTH: 124.8 ft.

DATES DRILLED: Dec. 13, 1954, to Jan. 24, 1955.

CASING USED: 85.5 ft. of 3-in. pipe.

MINERAL DETERMINATIONS: Minerals identified microscopically are denoted by 

an asterisk (*).

Depth Unit thick-

(feet) ness (feet) Description

1.0 1.0 Halite. Not cored; friable aggregate of colorless cubes and 

cubes modified by octahedron, averaging 5 mm in length.

1. 4 .4 Halite. Unconsolidated aggregate of colorless halite cubes 

and cubes modified by octahedron, up to 40 mm in length, 

averaging 4 mm; halite discolored dusky yellow-green 

(5GY 5/2) by trace of interstitial clay. Probably cuttings, 

not core.

1. 7 .3 Halite and clay. Consolidated aggregate of colorless halite 

cubes and cubes modified by octahedron, averaging 3 mm 

in length, with 20 percent interstitial dusky yellow-green 

(5 GY 5/2) clay.

1. 9 .2 Halite and clay. Poorly consolidated aggregate of halite 

cubes and cubes modified by octahedron, averaging 3 mm 

in length, with 5 percent interstitial dusky yellow-green 

clay.

2. 6 ..7 No core.

3. 1 .5 Halite and clay. Unconsolidated aggregate of halite cubes 

and cubes modified by octahedron, averaging 3 mm in 

length, with 5 percent interstitial dusky yellow-green 

(5GY 5/2) clay. Probably cuttings, not core.

3.3 .2 Halite and clay. Well-consolidated aggregate of halite 

cubes and cubes modified by octahedron, up to 20 mm 

in length; averaging 4 mm; with 5 percent interstitial dusky 

yellow-green (5GY 5/2) clay.

3. 5 .2 Clay and halite. Grayish-green (5 Or 5/2) to greenish-gray 

(5 Or 6/1) clay with 30 percent disseminated halite cubes 

and cubes modified by octahedron, up to 20 mm in length.

3.9 .4 Hanksite and clay. Dense aggregate of hanksite crystals 

averaging 25 mm in length, with 5 percent interstitial 

dusky yellow-green (5GY 5/2) clay; a few hanksite crystals 

showing basal pinacoid.

4.0 .1 Clay. Greenish-black (5GY 2/1 and 5G 2/1) to grayishblack (N 2) clay.

4. 5 .5 No core.

4. 9 .4 Halite and clay. Poorly consolidated aggregate of halite 

anhedra and subhedra, averaging 25 mm in length, with 

50 percent interstitial grayish-green (lOOrF 5/2) clay. 

Probably cuttings, not core. 

491349 59 5
200 GEOLOGIC INVESTIGATIONS IN MOJAVE DESERT REGION

Depth Unit thick- 

(feef) ness (feet) Description

5. 8 0. 9 Clay and halite. Grayish-green (WGY 5/2) to dusky yellowgreen (5GY 5/2) dense tenacious clay with irregular layers 

and streaks of grayish-black (N 2) clay; 10 percent loose 

disseminated halite anhedra and subhedra averaging 25 

mm in length.

5. 9 . 1 No core.

6. 2 .3 Clay and halite. Grayish-green (10GF 5/2) tenacious clay 

with 50 percent loose disseminated halite crystals averaging 

3 mm in length. Probably cuttings, not core.

6. 9 .7 Clay and halite. Grayish-green (10GT 5/2) to grayish-black 

(N 2) dense clay with 50 percent disseminated glassy halite 

crystals in aggegates up to 4 in. long.

7. 0 . 1 No core.

7. 2 .2 Clay. Grayish-green (10GY 5/2) to grayish-black (N 2) 

clay.

7. 5 . . 3 Halite and clay. Well-consolidated aggregate of halite 

anhedra averaging 20 mm in length, with 10 percent 

inerstitial grayish-green (10GT 5/2) to grayish-black 

(N 2) clay.

7. 8 .3 Clay and halite. Grayish-green (OGY 5/2) clay with irregular 

streaks and pockets of grayish-black (N 2) clay; 20 percent 

disseminated halite crystals averaging 15 mm in length.

8.0 .2 Halite and clay. Well-consolidated aggregate of halite 

crystals averaging 15 mm in length, with 10 percent interstitial grayish-green (10GY 5/2) to grayish-black (N 2) clay.

8. 9 .9 Clay and halite. Greenish-black (5GY 2/1 and 5G 2/1) to 

grayish-black (N 2) dense clay with 5 percent disseminated 

halite crystals averaging 20 mm in length.

9. 7 .8 Clay. Greenish-black (5GY 2/1 and 5G 2/1) to grayish-black 

(N 2) dense clay.

9. 9 .2 Halite and clay. Well-consolidated aggregate of halite 

anhedra averaging 25 mm in length, with 5 percent interstitial greenish-black (5GY 2/1 and 5G 2/1) clay.

10. 2 .3 Clay. Greenish-black (5GY 2/1 and 5G 2/1) to grayishblack (N 2) dense tenacious clay.

10.3 .1 Halite and clay. Well-consolidated aggregate of halite 

anhedra averaging 20 mm in length, with 5 percent interstitial greenish-black (5GY 2/1 and 5(7 2/1) clay.

10. 6 .3 Clay. Greenish-black (5GY 2/1 and 5G 2/1) to grayish-black 

(N 2) dense clay.

10. 7 .1 Halite and clay. Well consolidated aggregate of halite 

crystals averaging 20 mm in length with 10 percent interstitial greenish-black (5GY 2/1 and 5G 2/1) to grayish-black 

(N 2) clay.

10. 9 .2 Clay. Greenish-black (5GY 2/1) to grayish-black (AT 2) clay.

11. 0 .1 Halite and hanksite. Unconsolidated mixture of halite 

crystals and hanksite crystals averaging 20 mm in length; 

a few hanksite crystals with basal pinacoid present. Halite 

50 percent, hanksite 50 percent. Probably cuttings, not 

core.
CORE. LOGS FROM SEARLES LAKE, CALIFORNIA 201

Depth Unit thick- 

(feet) ness (feet) Description

11. 4 0. 4 Clay. Greenish-black (5GY 2/1 and 5G 2/1) to grayish-black 

(N 2) dense clay.

12. 4 1.0 Halite and clay. Well-consolidated aggregate of halite 

crystals averaging 10 mm in length, with 20 percent interstitial greenish-black (5GY 2/1 and 5(? 2/1) to grayish-black 

(N 2) clay.

12. 8 . 4 No core.

13. 9 1.1 Clay and halite. Greenish-black (5GY 2/1 and 5G 2/1) to 

grayish-black (N 2) dense clay with 50 percent disseminated 

halite crystals averaging 10 mm in length.

14. 3 .4 Clay and halite. Poorly consolidated grayish-green (lOGY" 

5/2 to greenish-black (5GY 2/1 and 5G 2/1) clay with 

50 percent disseminated halite cubes averaging 2 mm in 

length.

15. 2 .9 No core.

16. 1 .9 Halite and clay. Well-consolidated aggregate of halite 

crystals averaging 5 mm in length, with 5 percent interstitial greenish-black (5GY 2/1 and 5G 2/1) clay.

16. 3 .2 Clay. Greenish-black (5GY 2/1 and 5G 2/1) dense clay.

16.4 .1 Halite and clay. Well-consolidated aggregate of halite 

crystals averaging 5 mm in length, with 5- percent interstitial greenish-black (5GY 2/1 and 5G 2/1) clay.

17. 1 . 7 No core.

17. 9 .8 Halite and clay. Well-consolidated aggregate of halite 

crystals averaging 5 mm in length, with 5 percent interstitial greenish-black (5GY 2/1 and 5G 2/1) clay.

18. 1 . 2 No core.

19. 1 1.0 Halite and clay. Well-consolidated aggregate of halite 

crystals averaging 3 mm in length, with 5 percent interstitial greenish-black (5GY 2/1 and 5G 2/1) clay.

20. 1 1.0 Halite and clay. Poorly consolidated friable aggregate of 

halite crystals averaging 3 mm in length, with 5 percent 

interstitial greenish-black (5GY 2/1 and 5G 2/1) clay; seam, 

10 mm wide, of grayish-black (N 2) clay at base.

20.8 .7 Halite, trona, and clay. Poorly consolidated mixture of 

medium dark-gray (N 4) to dark greenish-gray (5GY 4/1) 

massive trona with disseminated halite crystals averaging 

10 mm in length; intermixed grayish-black (N 2) to greenishblack (5GY 2/1 and 5G 2/1) clay. Halite 50 percent, 

trona 30 percent, and clay 20 percent. May be cuttings, 

not core.

21. 4 .6 Trona and halite. Well-consolidated massive medium darkgray (,W 4) to dark greenish-gray (5GY 4/1) trona with 

10 percent disseminated halite crystals averaging 2 mm 

in length.

21. 6 . 2 No core.

21. 9 .3 Halite and clay. Unconsolidated aggregate of halite cubes 

averaging 1 mm in length, with 10 percent intermixed 

grayish-red (N 2) to greenish-black (50 Y 2/1 and 5(? 2/1) 

clay. Probably cuttings, not core.
202 GEOLOGIC INVESTIGATIONS IN MOJAVE DESERT REGION

Depth Unit thick- 

(feet) ness (feet) Description

22. 5 0. 6 Halite and clay. Well-consolidated aggregate of halite 

crystals averaging 5 mm in length, with 10 percent interstitial grayish-black (N 2) to greenish-black (5GY 2/1 and 

5G 2/1) clay.

22. 6 .1 No core.

23. 3 .7 Trona and halite. Dark greenish-gray (5GF4/1) soft massive 

trona with 50 percent halite cubes, averaging 1 mm in 

length, disseminated throughout; scattered 1- to 2-in. 

pockets of white (N 9) dense hard massive trona discolored 

by black (N 1) clay streaks.

23.8 .5 Trona and hanksite. Core fractured. Well-consolidated 

white (N 9) hard dense massive trona with scattered 

}4-in. pockets of fibrous trona; irregular greenish-black 

(5GY 2/1) to grayish-black (N 2) seams of dense granular 

massive hanksite with trace of intermixed clay. Trona 

90 percent, hanksite 10 percent.

24. 1 .3 No core.

24. 5 .4 Trona and halite. Unconsolidated greenish-gray (5GY 4/1) 

soft massive trona with 40 percent disseminated halite 

sand. Probably cuttings, not core.

24. 8 .3 Hanksite. Well-consolidated slightly vuggy hard granular 

massive hanksite.

24. 9 .1 No core.

25. 7 .8 Trona and halite. Unconsolidated dark greenish-gray (5GY 

4/1) soft massive trona with 40 percent disseminated halite 

cubes averaging 1 mm in length. Probably cuttings, not 

core.

26. 7 1.0 Halite and clay. Poorly consolidated mixture of halite 

crystals averaging 3 mm in length, with 5 percent intermixed black (N 1) to greenish-black (5GY 2/1 and 5G 2/1) 

clay, a few fragments of hanksite crystals or densely packed 

hanksite crystal aggregates. May be cuttings, not core.

27. 4 .7 No core.

28. 0 .6 Hanksite and clay. Granular massive hanksite with scattered 

lenticular pockets of fibrous trona; irregular seams of 

greenish-black (5GY 2/1) clay; densely packed aggregates 

consisting of hanksite crystals, up to 30 mm in length, in 

upper 0.1 ft, with 10 percent interstitial greenish-black 

(5GY 2/1 and 5(? 2/1) clay. Hanksite 95 percent, clay 

5 percent.

28. 8 . 8 Hanksite, clay, and borax. Granular massive hanksite and 

densely packed hanksite crystal aggregates containing 

interstitial black (N 1) to greenish-black (5GY 2/1 and 

5G 2/1) clay; a few disseminated borax crystals up to 1-in. 

long. Hanksite 90 percent, clay 10 percent.

30. 7 1. 9 No core.

32. 6 1. 9 Trona and halite. Poorly consolidated mixture of dark 

greenish-gray (5GY 4/1) soft massive trona with 10 percent 

disseminated halite crystals averaging 1 mm in length; 

scattered fragments of white (N 9) hard massive trona and 

a few rounded aggregates of densely packed hanksite 

crystals. May be cuttings, not core.
CORE LOGS FROM SEARLES LAKE, CALIFORNIA- 203

Depth Unit thick-

(feet) ness (feet) Description

32. 8 0. 2 Hanksite. Densely packed aggregate of white (N 9) colorless 

hanksite crystals.

33. 7 .9 No core.

33. 9 .2 Hanksite. Densely packed aggregate of white (N 9) to 

colorless hanksite crystals.

34. 3 .4 Hanksite and clay. Aggregate of large hanksite crystals up 

to 5 in. long, with 10 percent interstitial black (N 1) to 

greenish-black (5GY 2/1 and 5G 2/1) clay.

35. 7 1. 4 Clay and hanksite. Black (N 1) to greenish-black (5GY 2/1 

and 5G 2/1) clay with 25 percent disseminated euhedral 

hanksite crystals averaging 25 mm in length.

35. 8 .1 No core.

36. 2 .4 Trona. Core fractured. Dark greenish-gray (5GY 4/1) soft 

massive trona with a few disseminated hanksite crystals.

36. 6 .4 Hanksite. Well-consolidated, densely packed aggregate of 

white (N 9) to colorless hanksite crystals.

38. 4 1. 8 Hanksite, halite, and clay. Fractured core. Fragments of 

densely packed white (N 9) to colorless hanksite crystals 

with interstitial seams of grayish-black (N 2) to greenishblack (5GY 2/1) clay; scattered pockets of halite and 

fibrous trona. Hanksite 90 percent, halite 5 percent, clay 

5 percent.

38. 5 .1 No core.

39. 2 .7 Trona and halite. Unconsolidated mixture of dark greenishgray (5GY 4/1) soft massive trona with intermixed colorless 

halite sand; a few hanksite crystals 25-30 mm long. Trona 

50 percent, halite 50 percent. Probably cuttings, not core.

39. 5 .3 Trona* and halite*. Well-consolidated aggregate of white 

(N 9) to colorless hard massive intermixed trona* and 

halite*. Trona 60 percent, halite 40 percent.

39. 9, .4 Hanksite, clay, and sulfohalite. Dense granular aggregate of 

smoky hanksite crystals with 5 percent interstitial greenishblack (5GY 2/1) clay; seam, 10 mm wide, of 10 percent 

disseminated sulfohalite octahedra, averaging 5 mm in 

length, at base. Hanksite 95 percent, clay 5 percent.

41. 3 1. 4 Hanksite. Dense granular slightly vuggy aggregate of colorless hanksite crystals with irregular streaks, 10 mm wide, 

of granular massive smoky hanksite; trace of colorless 

fibrous trona in vugs.

41. 4 .1 No core.

42. 0 .6 Trona. Unconsolidated dark greenish-gray (5GY 4/1) soft 

massive trona. May be cuttings, not core.

43. 7 1. 7 Halite and clay. Core fractured. Poorly consolidated friable 

aggregate of colorless halite crystals averaging 3 mm in 

length, with irregular pockets and seams of interstitial 

black (N 1) clay. Halite 85 percent, clay 15 percent.

44. 7 1. 0 Trona and hanksite. Greenish-gray (5GY 6/1) to dark 

greenish-gray (5GY 4/1) soft massive trona* with disseminated euhedral hanksite crystals up to 70 mm in length. 

Trona 95 percent, hanksite 5 percent.

45. 3 .6 Hanksite. Well-consolidated dense granular slightly vuggy 

aggregate of white (N 9) to colorless hanksite crystals.
204 GEOLOGIC INVESTIGATIONS IN MOJAVE DESERT REGION

Depth Unit thick-

(feet) ness (feet) Description

46.0 0. 7 Hanksite and clay. Well-consolidated dense aggregate of 

smoky hanksite crystals with 5 percent interstitial greenishblack (5GY 2/1) clay.

46. 6 .6 Hanksite. Dense granular slightly vuggy aggregate of white 

(N 9) to colorless hanksite.

46. 8 .2 Hanksite and clay. Dense granular aggregate of white 

(N 9) to colorless hanksite with 5 percent interstitial 

greenish-black (5GY 2/1) clay.

47. 6 .8 No core.

47. 7 .1 Hanksite. Dense granular slightly vuggy aggregate of white 

(N 9) to colorless hanksite; trace of trona.

48. 1 .4 Hanksite. Dense granular aggregate of white (N 9) to 

colorless to smoky hanksite; 2 percent greenish-gray (5GY 

6/1) massive trona in thin seams and pockets in lower 0.1 

ft with a few pockets of colorless halite cubes averaging 3 

mm in length.

48. 3 .2 Trona. Poorly consolidated white (N 9) to dark greenishgray (5GY 4/1) soft massive trona. May be cuttings, not 

core.

48.8 .5 Trona and hanksite. Well-consolidated white (N 9) to 

colorless vuggy massive trona with irregular streaks of 

granular massive smoky hanksite; vugs occur as narrow 

horizontal seams. Trona 90 percent, hanksite 10 percent.

49. 0 .2 Halite and trona. Unconsolidated mixture of fragments consisting of aggregates of halite cubes averaging 3 mm in 

length, with intermixed seams and interstitial white (N 9) 

to dark greenish-gray (5GY 4/1) massive trona. Halite 

75 percent, trona 25 percent.

49. 8 .8 Halite and trona. Well-consolidated white (N 9) to dark 

greenish-gray (5GY 4/1) massive trona with narrow seams 

of halite cubes and cubes modified by octahedron and 

disseminated halite cubes, averaging 3 mm in length. 

Halite 50 percent, trona 50 percent.

50. 0 .2 Halite. Well-consolidated aggregate of white (N 9) to colorless halite cubes and cubes modified by octahedron, averaging 3 mm in length.

50. 1 .1 No core.

50. 5 .4 Trona and halite. White (N 9) to greenish-gray (5GY 6/1 

and 5(? 6/1) massive trona with irregular seams and disseminated crystals of halite averaging 3 mm in length. 

Trona 75 percent, halite 25 percent.

50. 7 .2 No core.

50. 8 .1 Trona. Well-consolidated dark greenish-gray (5GY 4/1) soft 

massive trona.

51. 3 .5 Halite and hanksite. Well-consolidated aggregate of halite 

cubes and cubes modified by octahedron, averaging 2 mm 

in length, with large pockets, 4-5 in. long, of granular 

massive smoky hanksite. Halite 60 percent, hanksite 40 

percent.
CORE LOGS FROM SEARLES LAKE, CALIFORNIA 205

Depth Unit thick-

(feet) ness (feet) Description

51. 8 0. 5 Trona and halite. Well-consolidated white (N 9) to very 

pale orange (10F/B 8/2) massive trona with vuggy seams, 

averaging 3 mm in width, lined with halite cubes and cubes 

modified by octahedron, averaging 3 mm in length. Trona 

90 percent, halite 10 percent.

52. 1 .3 Halite. Well-consolidated aggregate of halite cubes and 

cubes modified by octahedron, averaging 3 mm in length.

52. 6 .5 Trona and halite. White (N 9) to very pale orange (10 YR 

8/2) massive trona with numerous vuggy seams, averaging 

1 to 3 mm in width, lined with halite cubes and cubes 

modified by octahedron. Trona 80 percent, halite 20 

percent.

53. 1 .5 Halite, burkeite*, borax*, and trona*. Well-consolidated 

aggregate of halite cubes and cubes modified by octahedron, 

averaging 4 mm in length, with irregular seams and interstitial fillings of white (N 9) to very pale orange (1QYR 8/2) 

massive intermixed burkeite*, halite*, and borax*, with 

minor trona*; trace of greenish-black (5GY 2/1) clay in 

interstices of halite in lower 0.2 ft. Halite 80 percent, 

burkeite 20 percent. Borax and trona estimated less than 

1 percent.

55. 6 2. 5 No core.

56.0 .4 Trona. Unconsolidated greenish-gray (5GY 6/1) to dark 

greenish-gray (5GY 4/1) soft massive trona. Probably 

cuttings, not core.

56. 1 . 1 Burkeite* and hanksite. Well-consolidated very pale orange 

(lOYTi; 8/2) to grayish-orange (IQYR 7/4) vuggy massive 

burkeite*; vugs lined with colorless hanksite crystals averaging 5 mm in length, with trace of dark greenish-gray 

(5GY 4/1) hard massive trona. Burkeite 95 percent, hanksite 5 percent.

56. 9 .8 Halite and trona. Well-consolidated aggregate of white (N 9) 

to colorless halite cubes and cubes modified by octahedron, 

with 1 percent interstitial white (N 9) to dark greenish-gray 

(5GY 4/1) massive trona.

57. 0 .1 Hanksite. Well-consolidated white (N 9) to brownish smoky 

hard dense granular massive hanksite.

58. 3 1. 3 No core.

59. 0 .7 Burkeite and hanksite. Well-consolidated very pale orange 

(WYR 8/2) to grayish-orange (WYR 7/4) hard massive 

burkeite with irregular seams, averaging 10 mm wide and 

pockets averaging 1 in. long, of colorless hanksite crystals 

5 mm in length. Burkeite 85 percent, hanksite 15 percent.

59. 8 .8 Halite, burkeite, and hanksite. Well-consolidated white 

(N 9) to very pale orange (10YR 8/2) hard massive burkeite 

with irregular seams averaging 5 mm in width and disseminated crystals of halite averaging 3 mm in length; 1-in. 

pockets of smoky hanksite crystals, averaging 10 mm in 

length, in lower 0.2 ft. Halite 50 percent, burkeite 45 

percent, hanksite 5 percent.
206 GEOLOGIC INVESTIGATIONS IN MOJAVE DESERT REGION

Depth Unit thick-

(feet) ness (feet) Description

60. 7 0. 9 Halite. Well-consolidated aggregate of halite cubes and cubes 

modified by octahedron, averaging 3 mm in length, with 

trace of interstitial grayish-green (5G 5/2) soft massive trona.

61. 0 .3 No core.

61. 2 .2 Hanksite and trona. Dark smoky dense hard granular 

massive hanksite with seam, 5 mm wide, of white (N 9) 

massive trona at top. Hanksite 92 percent, trona 8 percent.

61. 6 .4 Halite. Well-consolidated aggregate of white (N 9) to colorless halite cubes and cubes modified by octahedron, averaging 2 mm in length,

62. 0 .4 Hanksite and clay. Dark smoky dense hard granular massive 

hanksite with irregular thin streaks, averaging 2 mm in 

width, of black (N 1) clay. Hanksite 95 percent, clay 5 

percent.

63. 0 1.0 Halite and trona. Well-consolidated aggregate of white (N 9) 

to colorless halite cubes up to 10 mm in length, averaging 

3 mm, with 10 percent interstitial light greenish-gray 

(5GY 8/1) to greenish-gray (5GY 6/1) massive trona.

63. 5 .5 Trona and halite. Well-consolidated slightly vuggy white 

(N 9) massive trona with seam, 10 mm wide, of halite cubes 

and cubes modified by octahedron, averaging 5 mm in 

length, at 63.3 ft; scattered 1-in. lenticular pockets and 

vugs, containing halite cubes and cubes modified by octahedron, averaging 3 mm in length. Trona 90 percent, 

halite 10 percent.

63. 8 .3 Trona and halite. Fractured core. Large fragments of wellconsolidated yellowish-gray (5Y 8/1) massive trona with 50 

percent disseminated halite crystals averaging 2 mm in 

length.

64. 2 .4 Trona and clay. White (N 9) to light-gray (N 7) dense massive trona with irregular thin streaks and seams of oliveblack (5Y 2/1) to olive-gray (5F 3/2) clay. Trona 95 percent, clay 5 percent.

64. 8 .6 Halite and trona. Well-consolidated aggregate of halite cubes 

averaging 3 mm in length, with 5 percent interstitial colorless fibrous trona.

65. 5 .7 No core.

66. 1 .6 Trona and hanksite. Well-consolidated white (N 9) to 

yellowish-gray (5Y 7/2) dense hard massive trona with 2-in. 

pockets of smoky granular massive hanksite. Trona 90 

percent, hanksite 10 percent.

66. 3 .2 Trona* and halite*. Dense hard aggregate of white (N 9) 

massive trona* with 50 percent disseminated halite* cubes 

averaging 3 mm in length.

67. 2 .9 No core.

67. 8 .6 Trona and halite. Well-consolidated white (N 9) to dark 

greenish-gray (5G 4/1) soft massive trona with 50 percent 

disseminated halite crystals averaging 3 mm in length.
CORE LOGS FROM SEARLES LAKE, CALIFORNIA 207

Depth Unit thick-

(feet) ness (feet) Description

67. 9 0. 1 Trona. Well-consolidated pale yellowish-brown (10YR 6/2) 

massive trona.

68. 0 .1 Trona. Well-consolidated slightly vuggy aggregate of greenish-gray (5C? 6/1) to dark greenish-gray (5G 4/1) compact 

fine fibrous trona.

68. 6 .6 Trona. Fractured core. Large fragments of light olive-gray 

(5V 6/1) to greenish-gray (5GY 6/1) soft massive trona.

71. 4 2. 8 No core.

72. 5 1.1 Trona. Well-consolidated white (N 9) to light-gray (N 7) to 

greenish-gray (5GY 6/1) slightly vuggy massive trona.

72. 7 .2 Borax*, clay, and pirssonite. Well-consolidated granular aggregate of white (N 9) to colorless borax* crystals averaging 

3 mm in length, with seam at base, 10 mm wide, of black 

(N 1) to greenish-black (5GY 2/1) clay containing 30 percent 

disseminated euhedral pirssonite crystals and 20 percent 

disseminated borax* crystals. Borax 87 percent, clay 8 

percent, pirssonite 5 percent.

73. 0 .3 Clay. Medium bluish-gray (55 5/1) to dark greenish-gray 

(5G 4/1) to dark yellowish-orange (10YR 6/6) to brownishblack (5YR 2/1) dense finely laminated clay.

73. 2 .2 Clay and pirssonite*. Olive-gray (5Y 3/2) to black (N 1) to 

light-brown (5YR 5/6) clay with 30 percent disseminated 

anhedral pirssonite* crystals averaging 10 mm in length.

73. 4 . 2 Clay and pirssonite. Greenish-black (5GY 2/1) to dusky 

yellowish-green (1QGY 3/2) to grayish olive-green(5(?y 3/2) 

to dusky yellow-green (5GY 5/2) faintly finely laminated 

clay with numerous thin seams, less than 1 mm wide, of 

anhedral pirssonite. Clay 90 percent, pirssonite 10 percent.

73. 8 . 4 Clay. Dusky yellow-green (5GY 5/2) to grayish olive-green 

(5GY 3/2) to olive-gray (5Y 3/2) to grayish-yellow (5Y 

8/4) to grayish-green (5G 5/2) to grayish-black (N 2) dense 

finely laminated clay.

74. 2 If .4 Clay and gaylussite. Olive gray (5Y 3/2) to dusky yellowgreen (5G Y 5/2) to very light gray (N 8) dense finely laminated clay With 40 percent disseminated gaylussite crystals 

averaging 15 mm in length.

74. 4 .2 Clay. Black (N 1) to greenish-black (5GY 2/1) to grayish 

olive-green (5GY 3/2) to olive-gray (5Y 3/2) to very light 

gray (N 8) finely laminated clay.

75. 4 1.0 Clay. Grayish olive-green (5GY 3/2) to greenish-black (5GY 

2/1) to olive-gray (5F 3/2) to brownish-black (5YR 2/1) to 

light greenish-gray (5GY 8/1) dense finely laminated clay.

75. 8 . 4 Clay ard aragonite. Greenish-black (5GY 2/1) to grayish 

olive-green (5GY 3/2) to moderate olive-brown (5F 4/4) 

coarsely laminated clay with widely spaced laminae, averaging 1 mm wide, of light greenish-gray (5GY 8/1) to very 

light gray (N 8) soft massive finely crystalline aragonite. 

Clay 95 percent, aragonite 5 percent.
208 GEOLOGIC INVESTIGATIONS IN MOJAVE DESERT REGION

Depth Unit thick-

(feet) ness (feet) Description

77. 1 1. 3 Clay. Grayish-black (N 2) to dusky yellow-green (5GY 5/2) 

to dusky-brown (5YR 2/2) to dark yellowish-orange (10FE 

6/6) to medium bluish-gray (5B 5/1) to very light gray 

(N 8) finely laminated clay.

77. 7 .6 No core.

78. 1 .4 Clay. Medium bluish-gray (5B 5/1) to greenish-gray (5G 6/1) 

to dark yellowish-orange (1QYR 6/6) to very light-gray 

(2V 8) dense finely laminated clay.

78. 2 .1 Clay and gaylussite. Black (N 1) to greenish-black (5(7 F 2/1) 

clay with numerous seams, 1 mm wide, of anhedral gaylussite. Clay 50 percent, gaylussite 50 percent.

78. 5 .3 Clay. Medium bluish-gray (5B 5/1) to greenish-gray (5G 6/1) 

to dark yellowish-orange (lOFjR 6/6) to grayish-black (TV 2) 

to very light gray (N 8) dense finely laminated clay; laminae 

contorted in lower 0.1 ft.

78. 9 .4 Clay and gaylussite. Greenish-gray (5(?F 6/1) to dark-gray 

(TV 3) to dark yellowish-orange (1QYR 6/6) to dusky yellowgreen (5GF 5/2) to moderate olive-brown (5F 4/4) to very 

light gray (TV 8) dense finely laminated clay with a few 

pockets of anhedral gaylussite crystals. Clay 99 percent, 

gaylussite 1 percent.

79. 5 .6 Clay and gaylussite. Black (TV 1) to greenish-black (5GY 2/1) 

clay with numerous seams, 1 mm wide, of light greenishgray (5(7 F 8/1) anhedral gaylussite. Clay 90 percent, 

gaylussite 10 percent.

80. 1 .6 Clay, gaylussite, and borax*. Greenish-gray (5GY 6/1) to 

dark greenish-gray (5(?F 4/1) to light olive-brown (5F.5/6) 

to greenish-black (5(7 F 2/1) to very light gray (TV 8) clay 

with numerous seams, averaging 1 mm in width, of light 

greenish-gray (5F 8/1) anhedral gaylussite; clay is finely 

laminated in lower 0.2 ft with seam, 15 mm wide, of massive 

borax at 80.0 ft. Clay 82 percent, gaylussite 10 percent, 

borax 8 percent.

81. 2 1.1 Clay and gaylussite. Greenish-black (5GY 2/1) to black (TV 1) 

to medium bluish-gray (5J5 5/1) to grayish-yellow (5F 8/4) 

coarsely laminated clay with laminae revealed by color differences; scattered pockets of anhedral gaylussite crystals. 

Clay 99 percent, gaylussite 1 percent.

81. 5 .3 Clay. Black (TV 1) to grayish-black (TV 2) to greenish-gray 

(5(7 6/1) coarsely laminated clay; laminae revealed by color 

differences.

82. 1 .6 Clay and gaylussite. Black (TV 1) to grayish-black (TV 2) clay 

with 10 percent disseminated fine gaylussite sand and silt. 

82. 5 .4 No core.

82. 8 .3 Clay and gaylussite.* Black (TV 1) to grayish-black (TV 2) 

clay with 10 percent disseminated gaylussite* silt.

83. 3 i 5 Clay and pirssonite. Black (TV 1) to greenish-black (5(7F 2/1) 

clay with 50 percent disseminated clear euhedral pirssonite 

crystals averaging 2 mm in length.

83. 5 .2 Clay. Dusky yellow-green (5(?F 5/2) to grayish-green (5(? 

5/2) clay.
CORE LOGS FROM SEARLES LAKE, CALIFORNIA 209

Depth Unit thick-

(feet) ness (feet) Description

84. 5 1.0 Halite, trona*, clay, and pirssonite. Well-consolidated aggregate of white (N 9) to colorless halite crystals averaging 

3 mm in length, with 25 percent interstitial colorless fibrous 

trona and scattered pockets of white (N 9) massive trona*; 

irregular black (N 1) clay streaks and traces of interstitial 

black (N 1) clay, with clay in streaks containing 30 percent 

clear colorless euhedral pirssonite crystals averaging 1 mm 

in length and irregular spots and streaks, 1-5 mm long, of 

moderate reddish-brown (10ft 4/6) algae?-discolored clay. 

Halite 60 percent, trona 30 percent, clay 7 percent, pirssonite 

3 percent.

87. 5 3. 0 No core.

88. 2 .7 Clay and pirssonite. Fractured core. Fragments of black 

(N 1) to greenish-black (5GY 2/1) clay with 40 percent disseminated euhedral pirssonite crystals averaging 2 mm in 

length.

88. 9 .7 Clay, gaylussite*, and borax. Black (N 1) to greenish-black 

(5GY 2/1) clay with 40 percent disseminated gaylussite* 

crystals from 1 to 10 mm in length; scattered subhedral 

borax crystals, averaging 20 mm in length, at base. Clay 

59 percent, gaylussite 40 percent, borax 1 percent.

89. 2 . 3 Trona and clay. White (N 9) compact fibrous trona locally 

discolored dark-gray (N 3) by 5 percent intermixed clay.

90. 6 1. 4 Halite, trona, and clay. Well-consolidated aggregate of colorless halite cubes modified by octahedron, averaging 3 mm 

in length, with 30 percent white (N 9) massive to fine 

fibrous trona in pockets and interstices of halite crystals; 

locally discolored by 1 percent intermixe'd grayish-black 

(N 2) clay.

91. 2 .6 Trona and halite. Well-consolidated white (N 9) massive 

slightly vuggy trona with 40 percent disseminated halite 

cubes and cubes modified by octahedron, averaging 3 mm 

in length.

91. 5 .3 Halite. Friable aggregate of colorless halite cubes modified 

by octahedron, averaging 5 mm in length. "

92. 0 .5 No core.

93. 0 1.0 Halite, trona, and clay. Unconsolidated mixture of dark 

greenish-gray (50?Y 4/1) halite sand, clay, and trona. Halite 

85 percent, trona 10 percent, clay 5 percent. Probably 

cuttings, not core.

93. 2 .2 Trona and halite. Well-consolidated white" (N 9) to dark 

greenish-gray (5GY 4/1) massive trona with 10 percent disseminated halite cubes modified by octahedron, averaging 

3 mm in length.

94. 2 1.0 Clay and pirssonite. Black (N 1) to greenish-4black (5GY 2/1) 

clay with 35 percent disseminated euhedral' pirssonite crystals averaging 5 mm in length.

94. 9 .7 Clay and gaylussite. Black (N 1) to greenish-black (5GY 2/1) 

clay with 50 percent disseminated anhedral pirssonite 

crystals.
210 GEOLOGIC INVESTIGATIONS IN MOJAVE DESERT REGION

Depth Unit thick-

(feet) ness (feet) Description

95. 2 0. 3 Clay, pirssonite, and borax. Black (N 1) clay with 40 percent 

disseminated euhedral pirssonite crystals averaging 1 mm 

in length; seam, 20 mm wide, of granular aggregate of borax 

crystals, averaging 5 mm in length, at base. Clay 50 percent, pirssonite 30 percent, borax 20 percent.

95. 4 .2 Trona and clay. Fractured core. Fragments of white (N 9) 

massive trona with pockets of fibrous trona, locally discolored dark gray (N 3) to grayish black (N 2) by streaks 

of intermixed clay. Trona 95 percent, clay 5 percent.

95. 6 .2 Halite. Friable aggregate of colorless halite cubes modified 

by octahedron, averaging 5 mm in length, with trace of 

interstitial black (N 1) clay.

95. 7 .1 Clay and pirssonite. Black (N 1) clay with 50 percent disseminated euhedral pirssonite crystals averaging 1 mm in 

length.

95. 8 .1 Trona and clay. Well-consolidated aggregate of colorless 

fibrous trona with 5 percent interstitial black (N 1) clay.

96. 2 .4 Halite, trona, and clay. Well-consolidated aggregate of colorless halite cubes and cubes modified by octahedron, averaging 5 mm in length, with 2 percent interstitial grayishblack (N 2) clay; pockets of white (N 9) to dark-gray (N 3) 

massive trona in upper 0.1 ft. Halite 88 percent, trona 10 

percent, clay 2 percent.

96. 7 .5 Trona and clay. White (N 9) to dark-gray (N 3) massive 

trona discolored by irregular streaks of grayish-black (N 2) 

clay; pockets of fibrous trona. Trona 98 percent, clay 2 

percent.

97. 2 .5 Halite, burkeite, and clay. Friable aggregate of halite cubes 

modified by octahedron, averaging 5 mm in length, with 2 

percent interstitial grayish-black (/V 2) clay; very irregular 

seam, varying from 25 to 75 mm in width, of very pale 

orange (1077? 8/2) to grayish-yellow (5F8/4) dense massive 

burkeite at base. Halite 68 percent, burkeite 30 percent, 

clay 2 percent.

97. 6 .4 Halite, trona and clay. Well-consolidated aggregate of colorless halite cubes modified by octahedron, with interstitial 

fibrous trona mixed with grayish-black (2V 2) clay; irregular 

pockets and seams of white (N 9) massive trona. Halite 

88 percent, trona 10 percent, clay 2 percent.

97. 7 .1 Trona. White '(N 9) hard massive trona.

98. 0 .3 Trona, halite, and clay. Fractured core. Fragments of white 

(N 9) massive trona associated with unconsolidated halite 

sand containing intermixed dark greenish-gray (5GY 4/1) 

clay. Trona 50 percent, halite 40 percent, clay 10 percent.

100. 0 2. 0 No core.

100. 6 . . 6 Halite. Well-consolidated aggregate of white (N 9) to colorless halite cubes and cubes modified by octahedron, averaging 3 mm in length.

V
211

Depth Unit thick-

(feet) ness (feet) Description

101. 2 0. 6 Halite and burkeite. Well-consolidated slightly vuggy aggregate of white (N 9) to colorless halite cubes and cubes 

modified by octahedron, averaging 3 mm in length, with 

irregular lenticular discontinuous seam of grayish-yellow 

(5F 8/4) to very pale orange (1QYR 7/2) hard massive 

burkeite and scattered 10- to 20-mm pockets of similar 

burkeite. Halite 85 percent, burkeite 15 percent.

101. 4 . 2 Trona and halite. White (N 9) dense massive trona with 40 

percent disseminated colorless halite crystals averaging 2 

mm in length.

102. 0 .6 Halite and trona. Well-consolidated aggregate of colorless 

halite cubes and cubes modified by octahedron, averaging 

3 mm in length, with 10 percent interstitial white (N 9) 

massive and fibrous trona.

102. 4 .4 Burkeite. Fractured core. Fragments of grayish-yellow 

(5 Y 8/4) dense hard massive burkeite.

103. 0 .6 Halite. Well-consolidated aggregate of colorless halite cubes 

and cubes modified by octahedron, averaging 3 mm in 

length.

103. 1 . 1 Halite, trona, and clay. Well-consolidated aggregate of colorless halite cubes and cubes modified by octahedron, averaging 3 mm in length, with 20 percent white (N 9) to colorless massive and fibrous trona in irregular pockets; 5 percent 

interstitial dark greenish-gray (5GY 4/1) clay.

104. 8 1. 7 No core.

105. 7 . 9 Halite, burkeite, clay, and sulfohalite. Friable aggregate of 

of colorless subhedral halite cubes and cubes modified by 

octahedron, with irregular seam, 20 mm wide, of intermixed 

colorless halite and grayish-yellow (5F 8/4) burkeite at 

105.3 ft; thin seam, 5 mm wide, of black (N 1) clay with 

trace of intermixed colorless fibrous trona at base; single 

sulfohalite octahedron, 3 mm in diameter, intergrown with 

halite. Halite 96 percent, burkeite 3 percent, clay 1 percent.

105. 8 . 1 Clay and trona. Black (AT 1) to greenish-black (5GY 2/1) 

clay with numerous very dusky red (10jR 2/2) algae? discolorations in clay; with 50 percent disseminated trona 

blades averaging 5 mm in length.

106. 0 . 2 Trona, burkeite, and clay. Wavy seams of white (N 9) to 

grayish-green (10GY 5/2) dense massive trona with thin 

irregular wavy seams, 1 mm wide, of greenish-black (5GY 

2/1) trona discolored by trace of intermixed clay; pockets, 

25 mm wide, of grayish-yellow (5 Y 8/4) dense hard massive 

burkeite at base. Trona 97 percent, burkoite 2 percent, 

clay 1 percent.

106. 1 .1 Halite. Well-consolidated aggregate of colorless halite subhedra averaging 2 mm in length,' with trace of interstitial 

colorless fibrous trona.

106. 3 . 2 Trona. White (N 9) hard dense massive trona.

106. 4 . 1 Burkeite. Irregular seam, averaging 0.1 ft in width, of 

grayish-orange (10 YR 7/4) to very pale orange (10 YR 8/2) 

dense hard massive burkeite.
212 GEOLOGIC INVESTIGATIONS IN MOJAVE DESERT REGION

Depth Unit thick-

(feet) ness (feet) Description

107. 0 0. 6 Halite and trona. Well-consolidated aggregate of colorless 

halite cubes and cubes modified by octahedron, averaging 

3 mm in length, with seams and streaks of white (N 9) 

massive trona. Halite 70 percent, trona 30 percent.

107.3 .3 Clay. Grayish-black (N 2) to grayish-yellow (57 8/4) to 

dusky-red (5R 3/4) to very light gray (N 8) dense finely 

laminated clay.

107. 9 . 6 Burkeite and clay. Very pale orange (10 YR 8/2) dense hard 

massive vuggy burkeite with irregular pockets of moist 

tenacious black (N I) clay. Burkeite 95 percent, clay 5 

percent.

109. 7 1. 8 No core.

110. 1 .4 Clay. Black (N 1) to greenish-black (5GY 2/1) to moderate 

yellow-green (5GY 7/4) faintly finely laminated clay.

110. 4 .3 Clay and gaylussite. Greenish-black (5GY 2/1) clay with 

50 percent disseminated clear colorless euhedral gaylussite 

crystals averaging 5 mm in length.

111. 0 .6 Clay and northupite*. Black (N 1) to greenish-black (5GY 2/ 

1) to blackish-red (5R 2/2) to very light gray (N 8) dense 

faintly finely laminated clay with distinct laminae, 1-2 mm 

wide, of grayish-orange (IOYR 7/4) massive northupite* 

containing minor intermixed gaylussite* at 110.7 and 110.8 

ft. Clay 98 percent, northupite 2 percent.

111. 1 .1 Trona. Very coarse aggregate of colorless trona blades 

averaging 20 mm in length.

111. 7 .6 Trona and clay. White (N 9) to greenish-gray (5GY 6/1) 

massive trona with pockets, 10-50 mm wide, of colorless 

fibrous trona intermixed with 10 percent greenish-black 

(5GY 2/1) clay. Trona 98 percent, clay 2 percent.

113. 4 1. 7 No core.

114. 9 1. 5 Trona. Compact aggregate of colorless trona blades averaging 5 mm in length, with numerous %-in. pockets of white 

(N 9) to dark greenish-gray (5GY 4/1) massive trona; 10 

percent interstitial greenish-black (5GY 2/1) to dark greenish-gray (5GY 4/1) clay seams, from 114.6 to 114.7 ft, containing 50 percent intermixed grayish-orange (IQYR 7/4) 

soft massive northupite.

115. 2 . 3 Clay. Greenish-black (5GY 2/1) to black (N 1) to grayishyellow (5 Y 8/4) to very light gray (N 8) dense finely laminated clay.

115. 5 . 3 Clay and gaylussite. Greenish-black (5GY 2/1) clay with 

50 percent disseminated gaylussite crystals averaging 5 mm 

in length.

115. 8 . 3 Clay and gaylussite. Greenish-black (5GY 2/1) to olivegray (5Y 3/2) clay with 40 percent disseminated gaylussite 

sand.

116. 4 . 6 Clay. Grayish-black (N 2) to greenish-black (5GY 2/1) to 

dusky yellow-green (5GY 3/2) to moderate olive-brown 

(5 Y 4/4) to very light gray (N 8) dense finely laminated clay.
CORE LOGS FROM SEARLES LAKE, CALIFORNIA 213

Depth Unit thick-

(feet) ness (feet) Description

116. 7 0. 3 Trona* and clay. Very densely packed hard coarse aggregate 

of trona* blades averaging 40 mm in length, with 5 percent 

interstitial black (N 1) clay.

116. 8 .1 Trona. White (N 9) dense hard massive trona.

117. 7 .9 Trona, northupite, and clay. White (N 9) to light greenishgray (5GF 8/1) massive trona with seams, 2-3 mm wide, of 

colorless fibrous trona and seams of similar width of dark 

greenish-gray (5GY 4/1) to olive-black (5Y 2/1) clay in 

lower 0.3 ft; seam, 5 mm wide, of grayish-orange (10FJR 7/4) 

massive northupite at 117.4 ft. Trona 96 percent, clay 2 

percent, northupite 2 percent.

118.9 1.2 Trona. Well-consolidated porous aggregate of colorless trona 

blades averaging 10 mm in length, with pockets and irregular streaks of white (N 9) massive trona; trace of interstitial greenish-gray (5GY 6/1) clay.

119. 5 .6 Trona and clay. Fractured core. Fragments of densely 

packed colorless trona blades with 5 percent interstitial 

greenish-black (5GY 2/1) clay; fragments of black (AT l) to 

greenish-black (5GY 2/1) clay. Trona 60 percent, clay 

40 percent.

120. 8 1. 3 No core.

120. 9 . 1 Clay. Black (N 1) to greenish-black (5GF 2/1) to brownishblack (SYR 2/1) to grayish-green (5G 5/2) to grayish-yellow 

(5F 8/4) dense finely laminated clay.

121.6 .7 Clay and gaylussite. Olive-gray (5F 3/2) to .grayish-green 

(10GF 5/2) clay with 40 percent disseminated gaylussite 

crystals averaging 10 mm in length.

121. 7 , 1 Clay. Grayish-green (10GF 5/2) to olive-gray (5F 3/2) to 

grayish-yellow (57 8/4) to dusky yellow-green (5GF 5/2) 

finely laminated clay.

122. 7 1. 0 Clay and gaylussite. Olive-gray (3F 3/2) to black (N 1) to 

greenish-black (5GY 2/1) to brownish-black (SYR 2/1) 

clay with 40 percent disseminated gaylussite crystals 

averaging 10 mm in length.

122. 9 . 2 Clay and gaylussite. Grayish-green (10GF 5/2) to olivegray (5F 3/2) to grayish-yellow (5F 8/4) to dusky yellowgreen (5GY 5/2) finely laminated clay with 10 percent disseminated gaylussite crystals averaging 15 mm in length.

123.7 .8 Clay and gaylussite.' Olive-gray (5F 3/2) to greenish-gray 

(5(7 6/1) to grayish-black (N 2) clay with 30 percent disseminated gaylussite crystals averaging 10 mm in length.

124. 8 1. 1 Clay. Dark yellowish-orange (10YR 6/6) to light bluishgray (5B 7/1) to dark greenish-gray (5GF 4/1) to dusky 

yellow-green (5GY 5/2) to grayish-yellow (5F 8/4) to 

grayish-black (N 2) to very light gray (N 8) finely laminated 

clay.
214 GEOLOGIC INVESTIGATIONS IN MOJAVE DESERT REGION"

Searles drill hole GS-12

LOCATION: Searles Lake, Calif., at 1/4 sec. marker for sees. 2 and 3, R. 43 E., T.

26 S., Mount Diablo base line and meridian. 

ELEVATION AT TOP OF HOLE: 1,618 ft. 

ELEVATION AT BOTTOM OP HOLE: 1,491.4 ft. 

TOTAL DEPTH: 126.6 ft. 

DATES DBILLED: Jan. 14 to Feb. 2, 1955. 

CASING USED: 26.0 ft of 16-in. casing; 87.7 ft of 3-in. pipe. 

MINERAL DETERMINATIONS: Minerals identified microscopically are denoted by

an asterisk (*).

Depth Unit thick-

(feef) ness (feet) Description

8. 5 8. 5 Clay. Overburden mud, not cored. Moderate yellowishbrown (10 YR 5/4) clay.

15. 0 6. 5 Clay. Overburden mud, not cored. Dusky yellow-green 

(5GY 5/2) clay.

24. 5 9. 5 Clay. Overburden mud, not cored. Black (N 1) clay.

25. 5 1.0 Clay and pirssonite*. Black (N 1) dense clay with irregular 

pockets and streaks of dusky yellow-green (5GY 5/2) clay; 

numerous seams of disseminated euhedral pirssonite* 

crystals averaging 3 mm in length. Clay 95 percent, 

pirssonite 5 percent.

26. 0 .5 Clay and pirssonite. Black (N 1) clay with 50 percent 

disseminated euhedral pirssonite* crystals averaging 5 mm 

in length.

26. 3 .3 Clay and pirssonite*. Black (N 1) clay with 35 percent disseminated subhedral pirssonite* crystals averaging 3 mm 

in length.

26. 9 .3 Clay and pirssonite. Black (N 1) clay with 10 percent disseminated fine pirssonite sand.

27. 5 .6 Halite and clay. Moderately well consolidated aggregate of 

colorless halite cubes and cubes modified by octahedron, 

averaging 5 mm in length, with 10 percent interstitial black 

(N 1) to dusky yellow-green (5GY 5/2) clay.

29. 1 1. 6 No core.

29. 7 .6 Clay and pirssonite. Black (N 1) clay with 50 percent disseminated subhedral to anhedral pirssonite crystals averaging 10 mm in length.

30. 3 .6 Clay and pirssonite. Black (N. 1) clay with 50 percent disseminated pirssonite sand.

30. 6 .3 Halite, clay, and pirssonite. Well-consolidated aggregate of 

halite cubes and cubes modified by octahedron, averaging 

3 mm in length, with interstitial black (N 1) clay containing 

50 percent disseminated pirssonite sand. Halite 70 percent, clay 15 percent, pirssonite 15 percent.

31.2 .6 Halite and clay. Well-consolidated aggregate of halite 

cubes and cubes modified by octahedron, up to 20 mm in 

length, averaging 3 mm, with 5 percent interstitial black 

(N 1) to dusky yellow-green (5GY 5/2) clay.

31. 3 .1 Clay and pirssonite*. Black (N 1) clay with 50 percent 

disseminated pirssonite* sand.
CORE LOGS FROM SEARLES LAKE, CALIFORNIA 215

Depth Unit thick- 

(feet) ness (feet) Description

31. 6 0. 3 Halite and clay. Fractured core. Fragments consisting of 

aggregates of halite cubes and cubes modified by octahedron, 

averaging 3 mm in length, with 5 percent interstitial black 

(N 1) clay.

32. 0 .4 Halite and clay. Well-consolidated aggregate of halite cubes 

and cubes modified by octahedron, averaging 3 mm in 

length, with 10 percent interstitial black (N 1) clay.

32. 1 .1 Halite. Unconsolidated aggregate of subhedral to anhedral 

halite crystals averaging 30 mm in length.

33. 3 1. 2 No core.

33. 8 .5 Halite and trona. Well-consolidated vuggy aggregate of 

halite cubes and cubes modified by octahedron, averaging 

3 mm in length, with 30 percent interstitial white (N 9) to 

colorless massive and fibrous trona.

33. 9 .1 Halite. Colorless halite anhedra averaging 30 mm in length.

34.0 .1 Halite and trona. Well-consolidated aggregate of white 

(N 9) to colorless halite cubes and cubes modified by 

octahedron, averaging 3 mm in length, with 15 percent 

interstitial colorless to grayish-yellow (5 Y 8/4) fibrous trona.

35. 1 1.1 Halite. Well-consolidated aggregate of white (N 9) to 

colorless halite cubes and cubes modified by octahedron, 

with a few irregular thin seams of interstitial black (N 1) 

clay.

35.8 .7 Halite and trona. Well-consolidated vuggy aggregate of 

halite cubes and cubes modified by octahedron, with 25 

percent interstitial white (N 9) to dark greenish-gray 

(5GY 4/1) massive trona.

36. 1 .3 Trona and halite. Well-consolidated dense aggregate of 

white (N 9) hard massive trona with 50 percent disseminated 

halite cubes averaging 3 mm in length.

36. 4 .3 Halite and clay. Well-consolidated aggregate of halite 

cubes and cubes modified by octahedron, averaging 3 mm 

in length, with 5 percent interstitial black (N 1) clay.

36. 7 .3 Halite and trona. Well-consolidated slightly vuggy aggregate of halite cubes with 30 percent interstitial white 

(N 9) hard massive trona.

37.3 .6 Halite and trona. Fractured core. Unconsolidated halite 

sand and halite cubes 5-10 mm in length; fragments, 

several inches in length, consisting of halite cubes and cubes 

modified by octahedron, averaging 3 mm in length, with 

10 percent interstitial white (N 9) massive trona.

38. 8 1. 5 No core.

39. 0 .2 Trona. White (N 9) to very pale orange (10 YR 8/2) dense 

hard massive trona.

39. 5 .5 Trona and halite. White (N 9) to greenish-gray (5GY 6/1) 

to very pale orange (10FJR 8/2) dense hard massive trona 

with seams, 10-30 mm in width, of coarse glassy anhedral 

halite. Trona 65 percent, halite 35 percent.

40. 3 .8 Halite and trona. Dense granular aggregate of colorless 

halite crystals averaging 3 mm in length, with 10 percent 

interstitial white (N 9) to very pale orange (IQYR 8/2) to 

greenish-gray (5(7 Y 6/1) hard massive trona.

491,3,49 59 6
216 GEOLOGIC INVESTIGATIONS IN MOJAVE DESERT REGION

Depth Unit thick- 

(feet) ness (feet) Description

41.4 1.1 Halite and trona. Well-consolidated vuggy aggregate of 

colorless halite cubes and cubes modified by octahedron, 

averaging 3 mm in length, with white.(AT 9) to dark greenishgray (5GY 4/1) to greenish-black (5GY 2/1) massive trona 

in irregular pockets and seams and in interstices of halite 

crystals; trona locally discolored by trace of intermixed 

clay. Halite 85 percent, trona 15 percent.

41. 6 .2 Trona and halite. White (N 9) to very pale orange (10YR 

8/2) dense hard slightly vuggy massive trona with 25 percent disseminated halite cubes averaging 3 mm in length.

41. 7 .1 Halite and trona. Well-consolidated aggregate of colorless 

halite cubes and cubes modified by octahedron, averaging 

3 mm in length, with 5 percent white (N 9) to dark greenishgray (5(?Y 4/1) massive trona in irregular pockets and in 

interstices of halite.

42. 0 .3 Halite and trona. Densely packed very slightly vuggy granular aggregate of halite crystals with 30 percent interstitial 

white (N 9) hard massive trona.

. 42. 9 .9 Halite and trona. Well-consolidated slightly vuggy aggregate 

of colorless halite cubes and cubes modified by octahedron, 

averaging 3 mm in length, with 40 percent interstitial white 

(N 9) to greenish-gray (5GY 6/1) to dark greenish-gray 

(5GY 4/1) massive trona.

43. 3 .4 Clay, pirssonite, and trona. Black (N 1) clay with 40 percent disseminated euhedral to subhedral pirssonite sand; 

10 percent disseminated flat rounded fragments of white (N 

9) bony massive trona.

43. 4 .1 Trona and halite. White (N 9) dense hard massive trona 

with 50 percent disseminated colorless halite crystals.

45. 4 2. 0 No core.

46. 1 .7 Halite and trona. Well-consolidated densely packed granular aggregate of halite crystals with 30 percent interstitial 

white (N 9) massive trona; numerous horizontal lenticular 

vugs 2-3 mm wide and 20-50 mm long.

46. 3 .2 Clay, pirssonite, and hanksite. Black (N 1) clay with 25 

percent disseminated fine pirssonite sand; scattered loose 

singly terminated euhedral hanksite crystals, 10-40 mm 

long, containing black clay inclusions. Clay 70 percent, 

pirssonite 25 percent, hanksite 5 percent.

46. 9 .6 Halite and trona. Well-consolidated slightly vuggy aggregate 

of halite cubes averaging 3 mm in length, with 20 percent 

interstitial white (N 9) to dark greenish-gray (5GF 4/1) 

massive trona; trace of interstitial black (N Jf) clay.

47. 6 .7 Halite and trona. Dense granular slightly vuggy aggregate 

of colorless halite cubes averaging 3 mm in length, with 40 

percent interstitial white (N ff) hard massive trona.

48. 8 1. 2 No core.

49.0 .2 Halite and trona. Well-consolidated dense aggregate of 

colorless halite cubes averaging 3 mm in length, with 10 

percent interstitial white (N 9) massive trona; seam, 10 

mm wide, of white (N 9) soft massive trona at top. Halite 

73 percent, trona 27 percent.
^ CORE LOGS FROM SEARLES LAKE, CALIFORNIA 217

V Depth Unit thick- 

' (feet) ness (feet) Description

49. 5 0. 5 Trona and halite. White (N 9) to greenish-gray (5GY 6/1) 

to dark greenish-gray (5GY 4/1) to greenish-black (5GY

1 2/1) soft vuggy massive trona with grayish-yellow (5Y 8/4)

to colorless fibrous trona lining vugs; scattered pockets and

 » disseminated cubes and cubes modified by octahedron of

colorless halite averaging 3 mm in length. Trona 85 per1 cent, halite 15 percent.

49. 6 .1 Halite and trona. Well-consolidated aggregate of colorless 

halite cubes averaging 3 mm in length, with 10 percent 

interstitial grayish-yellow (57 8/4) to colorless fibrous 

trona.

+ 49. 8 .2 Halite and trona. Densely packed granular aggregate of

halite crystals with 10 percent interstitial white (N 9)

 \ massive trona.

50. 1 .3 Halite and trona. Well-consolidated vuggy aggregate of 

colorless halite cubes and cubes modified by octahedron,

j averaging 3 mm in length, with 10 percent greenish-gray

(5GY 6/1) to dark greenish-gray (5(7 4/1) massive trona in 

irregular seams and in interstices of halite.

50. 7 .6 Halite. Well-consolidated moderately friable aggregate of 

J white (N 9) to colorless halite cubes and cubes modified

by octahedron, averaging 2 mm in length, with trace of 

interstitial grayish-yellow (5Y 8/4) to colorless fibrous trona.

51. 2 , 5 Halite, trona, and clay. Well-consolidated aggregate of 

' halite cubes and cubes modified by octahedron, averaging

3 mm in length, with 15 percent interstitial greenish-gray 

(5GY 6/1) to dark greenish-gray (5GY 4/1) massive trona; 

seams of intermixed black (N 1) clay. Halite 75 percent, 

trona 15 percent, clay 10 percent.

52. 2 1. 0 Trona and halite. Well-consolidated vuggy thin alternating 

seams, 1-4 mm wide, of white (N 9) massive trona, with 

seams of colorless halite cubes and cubes modified by 

octahedron, averaging 2 mm in length; horizontal vugs

, 1-3 mm wide and up to 50 mm long. Trona 60 percent,

halite 40 percent.

 52.6 .4 Halite. Fractured core. Fragments consisting of well- 

\ consolidated aggregates of colorless halite cubes averaging

3 mm in length. 

/ 53.3 , 7 No core.

54. 0 .7 Trona and halite. Well-consolidated vuggy white (N 9) 

to greenish-gray (5GY 6/1) massive trona with 50 percent 

disseminated colorless halite cubes and cubes modified by 

octahedron, averaging 3 mm in length; trace of black (N 1) 

clay in lower 0.1 ft.

54. 1 .1 Halite and trona. Well-consolidated aggregate of colorless 

halite cubes and cubes modified by octahedron, averaging 

2 mm in length, with 5 percent interstitial white (N 9) to 

greenish-gray (5GY 6/1) massive trona.
218 GEOLOGIC INVESTIGATIONS IN MOJAVE DESERT REGION

Depth Unit thick-

(feet) ness (feet) Description

. 55.5 1.4 Trona and halite. Well- consolidated vuggy alternating seams*- 

1-10 mm wide, of white (N 9) to grayish-yellow (5V 8/4) 

massive trona with vuggy seams lined with colorless halite 

cubes and cubes modified by octahedron, up to 10 mm in, 

length, averaging 2 mm. Trona 75 percent, halite 25 percent.

56. 1 .6 Halite and trona. Fractured core. Fragments consisting of 

well-consolidated aggregates of halite cubes and cubes, 

modified by octahedron, averaging 3 mm in length, with 

10 percent interstitial white (AT 9) to greenish-gray (5GF6/1) 

massive trona.

56. 5 .4 No core.

57. 1 .6 Trona and halite. White (N 9) to light greenish-gray 

(5GY 8/1) soft vuggy massive trona with colorless halite 

cubes and octahedra, averaging 3 mm in length, in irregular 

streaks, as disseminated crystals, and lining vugs. Core 

fractured in lower 0.3 ft. Trona 60 percent, halite 40 

percent.

57. 8 .7 Halite and trona. Poorly consolidated friable aggregate of 

colorless halite cubes and cubes modified by octahedron, 

averaging 3 mm in length, with 5 percent interstitial white 

(N 9) to light greenish-gray (5GY 8/1) massive trona.

58. 0 .2 Trona and halite. Moderately friable white (N 9) massive 

trona with 20 percent disseminated halite cubes averaging 

3 mm in length.

58. 3 .3 Halite and trona. Friable aggregate of colorless halite cubes 

and cubes modified by octahedron, averaging 4 mm in 

length; 5 percent interstitial white (N 9) massive and colorless fibrous trona.

60. 7 2. 4 No core.

61. 0 .3 Halite and trona. Poorly consolidated colorless halite sand 

with 10 percent interstitial white (N 9) soft massive trona. 

Probably cuttings, not core.

61. 2 .2 Trona. Well-consolidated white (N 9) soft massive trona.

61. 5 .3 Halite. Core fractured. Friable aggregate of colorless halite 

cubes averaging 2 mm in length.

61. 9 .4 Halite and trona. Poorly consolidated mixture of colorless 

halite cubes averaging 3 mm in length, with 10 percent 

interstitial white (N 9) to light greenish-gray (5GY 8/1) 

soft massive trona.

62. 9 /I. 0 No core.

63. 9 1.0 Trona, halite, and hanksite. Poorly consolidated white (N 9) 

soft massive trona with intermixed halite sand; fragments of 

colorless to smoky granular massive hanksite at base. 

Probably cuttings not core. Trona 65 percent, halite 25 

percent, hanksite 10 percent.

65. 1 1. 2 Hanksite. Densely packed granular slightly vuggy aggregate 

of dark smoky hanksite crystals with euhedral hanksite 

crystals, 5-15 mm in length, lining vugs; trace of greenishblack (5GY 2/1) clay and colorless to grayish-yellow (5F8/4) 

fibrous trona in scattered vugs.
CORE LOGS FROM SEARLES LAKE, CALIFORNIA 219

J)epth Unit thick- 

(feet) ness (feet) Description

68. 0 2. 9 No core.

 68. 5 . 5 Hanksite, trona, and sulfohalite. Densely packed granular 

vuggy aggregate of colorless to dark smoky hanksite crystals 

with euhedral to subhedral hanksite crystals, up to 50 mm 

in length, in vugs; 1- to 2-in. pockets of white (N 9) to light 

greenish-gray (5GY 8/1) massive trona and %- to 1-in. 

pockets of colorless to grayish-yellow (5Y 8/4) fibrous 

trona; single sulfohalite octahedron, 6 mm in diameter, in 

1 vug. Hanksite 95 percent, trona 5 percent.

'69. 4 . 9 Hanksite and trona. Densely packed granular vuggy aggregate of colorless to dark smoky hanksite crystals with 25 

percent white (NQ) to dark greenish-gray (5GF4/1) massive 

trona in irregular streaks 1-10 mm wide.

>69. 7 . 3 Trona and halite. Compact aggregate of colorless to grayishyellow (5Y 8/4) fibrous trona with 10 percent disseminated 

halite cubes averaging 3 mm in length; numerous interstitial 

streaks and pockets of greenish-gray (5GY 6/1) to white 

(N 9) massive trona.

'70. 0 . 3 Hanksite. Dense granular massive smoky hanksite.

70. 3 .3 Halite and trona. Well-consolidated aggregate of halite 

cubes averaging 3 mm in length, with 40 percent interstitial 

greenish-gray (5GY 6/1) to white (N 9) massive trona.

70. 8 . 5 Trona. White (N 9) soft massive trona.

74. 2 3. 4 No core.

75. 7 1. 5 Trona. White (N 9) soft massive trona.

75. 9 . 2 Trona. White (N 9) to dusky yellow-green (5GY 5/2) soft 

massive trona.

76. 1 . 2 Trona and hanksite. White (N 9) soft massive vuggy trona 

with pockets and lenticular streaks of granular massive 

smoky to colorless hanksite; )^-in. vugs lined with grayishyellow (5F 8/4) fine fibrous trona; a few subhedral borax 

crystals 10 mm long and vugs containing fine fibrous trona 

scattered along base. Trona 70 percent, hanksite 30 

percent.

76. 3 . 2 Borax. Vuggy aggregate of colorless euhedral borax crystals 

averaging 10 mm in length with trace of interstitial grayishyellow (5F8/4) to grayish-black (N 2) clay.

76. 6 . . 3 Clay. Dark greenish-gray (5(? 4/1) to dusky yellow-green 

(5GY 5/2) to olive-gray (5F 3/2) to dark yellowish-orange 

(IQYR 6/6) faintly finely laminated clay with a few thin 

lamina of anhedral gaylussite averaging 1 mm thick.

77. 1 . 5 Clay and gaylussite*. Black (N 1) to dark greenish-gray 

(5(? 4/1) to greenish-black (5GY 2/1) to dusky yellow-green 

(5GY 5/2) very faintly finely laminated clay with 25 percent 

disseminated anhedral gaylussite* crystals averaging 10 

mm in length, locally in radiating clusters.

77. 4 .3 Clay and gaylussite. Greenish-black (5(7F 2/1 and 5G 2/1) 

to grayish-black (N 2) to dark-gray (AT 3) to grayish yellowgreen (5GY 7/2) to brownish-black (5YR 2/1) faintly finely 

laminated clay with 20 percent disseminated gaylussite 

crystals averaging 10 mm in length.
220 GEOLOGIC INVESTIGATIONS IN MOJAVE DESERT REGION

Depth Unit thick-

(feet) ness (feet) Description

77. 7 0. 3 Clay. Grayish-black (N 2) to dark greenish-gray (5G 4/1) 

to greenish-gray. (5G 6/1) to yellowish-gray (5Y 8/1) densefinely laminated clay with a few seams, 1 mm wide, of 

anhedral gaylussite and scattered disseminated gaylussite 

crystals.

78. 0 .3 Clay and gaylussite. Grayish-black (N 2) to brownish-black 

(5YR 2/1) to greenish-black (5G 2/1) clay with 35 percent, 

disseminated anhedral gaylussite crystals averaging 15 mm 

in length, seams of anhedral gaylussite, and local radiating, 

clusters of anhedral gaylussite crystals up to 50 mm in 

length.

80. 0 2. 0 Clay and aragonite*. Black (N 1) to yellowish-gray (5Y 7/2) 

to greenish-gray (5GY 6/1) coarsely laminated clay with 

widely spaced laminae, averaging 1 mm wide, of grayish 

yellow-green (5GY 7/2) to light greenish-gray (5GY 8/1) 

soft massive finely crystalline aragonite*.

82. 1 2. 1 Clay and gaylussite. Grayish-black (N 2) to greenish-black 

(5GY 2/1) to grayish-yellow (5Y 8/4) to dark greenish-gray 

(5GY 4/1 and 5G 4/1) to greenish-gray (5GY 6/1) to very 

light gray (N 8) dense finely laminated clay, with scattered 

1- to 2-in. pockets of anhedral gaylussite crystals; laminae 

coarser in lower 0.5 feet. Clay 99 percent, gaylussite 1 

percent.

82. 8 .7 No core.

82. 9 .1 Clay and gaylussite. Black (N 1) to brownish-black (5YR 

2/1) to very light gray (N 8) to grayish-yellow (5F 8/4) to 

moderate-yellow (5 Y 7/6) clay with 50 percent disseminated 

anhedral gaylussite crystals.

83.2 .3 Clay. Black (AT 1) to brownish-black (5 YR 2/1) to very light 

gray (N 8) to grayish-yellow (5F 7/4) to moderate-yellow 

(5F 7/6) coarsely laminated clay revealed by color differences.

83. 5 .3 Clay and gaylussite. Black (N 1) to greenish-black (5(?F 2/1) 

to dusky yellow-green (5GY 5/2) to moderate-yellow (5F 

7/6) to very light gray (N 8) coarsely laminated clay revealed by color differences with 40 percent disseminated 

gaylussite crystals.

83.9 .4 Clay. Grayish-black (AT 2) to greenish-black (5GY 2/1) to 

greenish-gray (5G 6/1) to dark greenish-gray (5G 4/1) to 

grayish olive-green (5GY 3/2) faintly finely laminated clay 

with faint irregular laminae, 1 mm or less in thickness, 

discolored moderate reddish-brown (10.B 4/6) by algae(?).

85. 3 1. 4 Clay and gaylussite. Grayish black (N 2) to light-olive 

(10 Y 5/4) to light-gray (N 7) coarsely laminated clay 

revealed by color differences, with 5 percent disseminated 

gaylussite in scattered pockets; distinct moderate reddishbrown (10R 4/6) algae (?) discolored seams at 83.9 and 84.2 

ft.
CORE LOGS FROM SEARLES LAKE, CALIFORNIA 221

Depth Unit thick- 

(feet) ness (feet) . Description

86.9 1.6 Clay and gaylussite. Dusky yellow-green (5GY 3/2) to grayish 

olive-green (5GT 3/2) to grayish-black (N 2) to light-gray 

(N 7) coarsely laminated clay revealed by color differences, 

with 25 percent disseminated gaylussite crystals averaging 

5 mm in length; distinct laminae discolored moderate 

reddish-brown (1QR 4/6) by algae(?).

/ 87.4 .5 Borax and clay. Dense aggregate of anhedral to euhedral

borax crystals averaging 15 mm in length, with trace of

\ interstitial grayish-yellow (5Y 8/4) clay in upper 0.3 ft;

5 percent interstitial black (N 1) to grayish-black (N 2) 

4 clay in lower 0.2 ft. Borax 99 percent, clay 1 percent.

87.6 .2 Trona, clay, and borax. Fractured core. Fragments consisting of vuggy aggregates of trona* blades averaging 

15 mm in length, containing minor intergrown pirssonite* 

with 5 percent interstitial dark greenish-gray (5GY 4/1) to 

grayish-yellow (5Y 8/4) clay; 5 percent intermixed subhedral 

borax crystals averaging 5 mm in length.

* 88. 1 .5 No core.

89. 6 1. 5 Trona. White (N 9) to dark greenish-gray (5GY 4/1) soft 

J\ massive to fine fibrous trona with scattered 1-in. streaks and

spots discolored moderate reddish-brown (10/2 4/6) by 

algae (?).

89.8 .2 Halite and trona. Well-consolidated aggregate of white 

(N 9) to colorless halite cubes and cubes modified by 

octahedron, averaging 3 mm in length, with 1 percent 

interstitial white (N 9) to greenish-gray (5 G Y 6/1) massive

* trona.

90.2 .4 Trona, pirssonite, and clay. Well-consolidated slightly

4 vuggy aggregate of white (N 9) to colorless fibrous trona

with pockets of white (N 9) to greenish-gray (5GY 6/1) 

massive trona; irregular wavy seam, 10 mm wide, of black 

(N 1) clay with 10 percent disseminated pirssonite crystals,

 > averaging 2 mm in length, at 89.9 ft. Trona 92 percent, 

^ clay 7 percent, pirssonite 1 percent.

90. 5 .3 Trona and clay. White (N 9) dense hard massive vuggy

-j trona with 1 percent black (N 1) greenish-black (5GY 2/1)

clay in irregular streaks. 

' 90. 9 .4 Clay and pirssonite. Black (N 1) to moderate olive-brown

(5F 4/4) clay with 35 percent disseminated euhedral 

1 pirssonite crystals averaging 2 mm in length.

91. 8 .9 No core.

93. 2 1. 4 Clay and pirssonite. Black (N 1) to moderate olive-brown

(5Y 4/4) to medium light-gray (N 6) clay with 40 percent

disseminated euhedral pirssonite crystals averaging 4 mm 

i in length.

93. 8 . 6 Trona. White (N 9) to colorless aggregate of fine fibrous

trona with seam, 10 mm wide, of grayish-yellow (5F 8/4)

fibrous trona at top.
222 GEOLOGIC INVESTIGATIONS IN MOJAVE DESERT REGION

Depth Unit thick-

( feet) ness (feet) Description

94. 1 0.3 Halite and trona. Well-consolidated aggregate of white 

(N 9) to colorless halite cubes and cubes modified by 

octahedron, averaging 3 mm in length, with 40 percent 

interstitial white (N 9) to greenish-gray (5GY 6/1) massive 

trona.

94. 9 .8 No core.

 95. 6 . 7 Halite and trona. Well-consolidated aggregate of halite 

cubes and cubes modified by octahedron, averaging 3 mm 

in length, with 30 percent interstitial white (N 9) to dark 

greenish-gray (5G! Y'4/1) to grayish-yellow (5Y" 8/4) massive 

trona.

 .96. 1 . 5 Trona and halite. Well-consolidated white (N 9) to dark 

greenish-gray (5GY 4/1) to light-brown (SYR 6/4) massive 

trona with 25 percent disseminated colorless halite cubes 

modified by octahedron, averaging 3 mm in length.

'96. 4 .3 Trona. Fractured core. Fragments of well-consolidated 

white (N 9) to dark greenish-gray (5GY 4/1) massive vuggy 

trona.

 97. 2 . 8 Halite and trona. Well-consolidated aggregate of colorless 

halite cubes modified by octahedron, averaging 3 mm in 

length, with 20 percent white (N 9) to greenish gray 

(5GY 6/1) massive trona in interstices and pockets; moderate reddish-orange (10 R 6/6) algae (?) discolorations, 

1-3 mm wide, in massive trona at top.

'98. 0 .8 Trona. Well-consolidated white (N 9) to greenish-gray 

(5GY 6/1) massive trona with dusky-red (5R 3/4) algae (?) 

discoloration, 10 mm wide, in trona at 97.5 ft; a few irregular seams, 1-2 mm wide, of black (N 1) clay; scattered 

pockets of colorless halite anhedra averaging 3 mm in 

length.

100. 2 2. 2 No core.

101. 6 1. 4 Clay and pirssonite. Black (N 1) to grayish olive-green 

(5GY 3/2) to dusky-yellow (5Y 6/4) to grayish-green 

(5G 5/2) to light olive-brown (5Y 5/6) clay with 40 percent 

disseminated euhedral pirssonite crystals averaging 5 mm 

in length.

101. 8 . 2 Clay, pirssonite, and trona. Black (N 1) clay with 40 percent 

disseminated euhedral pirssonite crystals averaging 1 mm in 

length; 5 percent disseminated rounded nodules, up to 60 

mm in length, averaging 20 mm, of grayish-yellow (5Y 8/4) 

hard dense massive trona*.

101. 9 . 1 Halite. Well-consolidated aggregate of white (N 9) to colorless halite cubes and cubes modified by octahedron, averaging 3 mm in length.

102. 1 . 2 Burkeite. Irregular vuggy seam, averaging 0.15 ft in width, 

of grayish-yellow (5 Y 8/4) hard dense massive burkeite.

102. 3 . 2 Trona. White (N 9) to yellowish-gray (5 Y 8/1) dense massive 

trona.
CORE LOGS FROM SEARLES LAKE, CALIFORNIA 223

Depth Unit thickQfeet) ness (feet) Description

102. 4 0. 1 Halite, trona, and clay. Well-consolidated aggregate of white 

(N 9) to colorless halite cubes and cubes modified by 

octahedron, averaging 4 mm in length, with 1 percent interstitial grayish-black (N 2) clay and 1 percent interstitial 

white (N 9) massive trona.

102. 8 .4 Halite and trona. Well-consolidated aggregate of white 

(N 9) to colorless halite cubes and cubes modified by octahedron, averaging 3 mm in length, with seam, 10 mm wide, 

of light greenish-gray (5GY 8/1) to greenish-gray (5GY 6/1) 

massive trona at 102.6 ft. Halite 92 percent, trona 8 percent.

103. 0 . 2 Burkeite and halite. Irregular seam of grayish-yellow (5Y 

8/4) dense hard massive vuggy burkeite with halite cubes 

modified by octahedron, averaging 5 mm in length in vugs. 

Burkeite 99 percent, halite 1 percent.

103. 1 . 1 Halite. Well-consolidated aggregate of halite cubes modified 

by octahedron, averaging 4 mm in length.

103. 8 . 7 Trona. Well-consolidated white (N 9) to medium-gray (AT 5) 

to colorless massive to fibrous trona with a few disseminated 

halite crystals.

103. 9 . 1 Halite and trona. Well-consolidated white (N 9) massive 

trona with pockets of halite cubes modified by octahedron, 

averaging 4 mm in length. Trona 50 percent, halite 50 

percent.

104. 0 . 1 Trona. White (N 9) to medium-gray (N 5) dense massive 

trona.

104. 6 . 6 Trona, burkeite, and halite. White (N 9) to. yellowish-gray 

(5Y 8/1) massive vuggy trona with irregular seams and 

pockets of pale yellowish-orange (10 Y.R 8/6) to dark yellowish-orange (10 YR 6/6) hard massive burkeite; scattered' 

pockets of halite cubes modified by octahedron, averaging 

5 mm in length. Trona 60 percent, burkeite 39 percent, 

halite 1 percent.

104. 7 .1 Trona and clay. White (A7 9) soft massive trona with seam,. 

1 mm wide, of black (N 1) clay at base. Trona 97 percent, 

clay 3 percent.

105. 0 . 3 Halite. Well-consolidated aggregate of colorless halite cubesand cubes modified by octahedron, averaging 3 mm in 

length, with trace of interstitial colorless fibrous trona.

105. 4 . 4 Halite and trona. Poorly consolidated aggregate of colorlesshalite cubes and cubes modified by octahedron, averaging 

3 mm in length, with 5 percent interstitial white (N 9) togreenish-gray (5(?y 6/1) massive trona.

106. 6 1. 2 No core.

106.8 .2 Trona. White (N 9) to moderate orange-pink (SYR 8/4) 

massive trona with pockets of colorless fibrous trona.

107. 8 1.0 Halite. Friable aggregate of white (N 9) to colorless halite 

cubes and cubes modified by octahedron, averaging 3 mm 

in length; seam, 10 mm wide, of halite with 20 percent interstitial white (N 9) to greenish-gray (5G Y 6/1) to colorless, 

massive, fibrous, and bladed trona containing 10 percent 

intermixed grayish-black (N 2) clay at 107.6 ft.
224 GEOLOGIC INVESTIGATIONS IN MOJAVE DESERT REGION

Depth Unit thick-

(feet) ness (feet) Description

108. 0 0. 2 Halite and trona. Well-consolidated aggregate of colorless 

halite cubes with 25 percent interstitial colorless fibrous 

trona.

108. 3 . 3 Trona, burkeite, and halite. White (N 9) to light greenishgray (5GY 8/1) massive trona with pockets of colorless 

fibrous trona and pockets of colorless halite cubes and cubes 

modified by octahedron, averaging 3 mm in length; irregular 

vuggy lenticular pockets, averaging 3 in. in length, of moderate yellowish-brown (10YR 5/4) dense hard massive burkeite in lower 0.1 ft. Trona 75 percent, burkeite 20 percent, 

halite 5 percent.

108. 6 .3 Halite, burkeite, and trona. Well-consolidated aggregate of 

colorless halite cubes and cubes modified by octahedron, 

averaging 3 mm in length, with 5 percent interstitial colorless fibrous trona and irregular vuggy pockets of moderate 

yellowish-brown (WYR 5/4) dense hard massive burkeite 

at base. Halite 80 percent, burkeite 15 percent, trona 5 

percent.

109. 3 . 7 Halite, trona, burkeite. Well-consolidated vuggy aggregate of 

colorless halite cubes and cubes modified by octahedron, 

averaging 3 mm in length, with 5 percent fibrous and bladed 

trona in interstices and in vugs; local moderate orange-pink 

(5YR 8/4) algae discolorations in 1-in. pockets with trona; 

scattered ^-in. pockets of grayish-orange (1QYR 7/4) dense 

hard massive burkeite in upper 0.3 ft. Halite 94 percent, 

trona 5 percent, burkeite 1 percent.

109. 4 .1 Burkeite and halite. Fractured core. Fragments of grayishorange (1QYR 7/4) to pale-olive (10 Y 6/2) dense hard vuggy 

massive burkeite with pockets of colorless halite cubes averaging 4 mm in length. Burkeite 60 percent, halite 40 

percent.

110. 0 . 6 No core.

110. 1 . 1 Trona. White (N 9) to medium dark-gray (N 4) massive 

trona with a few disseminated colorless halite crystals.

110. 5 .4 Halite and trona. Well-consolidated aggregate of colorless 

halite cubes modified by octahedron, averaging 2 mm in 

length, with seam, 20 mm wide, of white (N 9) to medium 

dark-gray (N 4) massive trona at top. Halite 78 percent, 

trona 22 percent.

110. 8 .3 Burkeite and trona. Grayish-orange (10 YR 7/4) dense hard 

vuggy massive burkeite with seams, 15 mm wide, of white 

(N 9) massive trona at top and base. Burkeite 67 percent, 

trona 33 percent.

111. 0 .2 Halite and trona. Well-consolidated aggregate of colorless 

halite cubes and cubes modified by octahedron, averaging 

3 mm in length, with pockets of colorless massive trona. 

Halite 90 percent, trona 10 percent.

111. 2 .2 Trona, burkeite and halite. White (N 9) to medium darkgray (N 4) slightly vuggy massive trona with 10 percent 

disseminated halite crystals; seam, 10 mm wide, of pale 

yellowish-orange (10YR 8/6) massive burkeite at base. 

Trona 75 percent, burkeite 15 percent, halite 10 percent.
CORE LOGS FROM SEARLES LAKE, CALIFORNIA 225

Depth Unit thick- 

(feet) ness (feet) Description

111. 4 0. 2 Clay. Grayish-black (N 2) to dusky-red (5R 3/4) to very 

light-gray (N 8) finely laminated clay.

111. 5 . 1 Clay, gaylussite, and borax. Greenish-black (5GY 2/1) clay 

with 30 percent disseminated fine gaylussite sand and 10 

percent disseminated euhedral prismatic borax crystals averaging 20 mm in length.

111. 7 .2 Trona and clay. White (N 9) to yellowish-gray (5Y 7/2) to 

dark greenish-gray (5GY 4/1) seams of fine fibrous and massive trona with a few seams, 1-2 mm wide, .of black (N 1) 

clay; moderate reddish-brown (IQR 4/6) algae (?) discolorations in trona in upper 20 mm. Trona 99 percent, clay 1 

percent.

111. 9 .2 Trona and burkeite. White (N 9) massive trona with lenticular pockets of grayish-orange (10 YR 7/4) dense hard vuggy 

massive burkeite. Trona 75 percent, burkeite 25 percent.

112. 5 .6 Burkeite. Grayish-orange (10YR 7/4) hard vuggy massive 

burkeite; core fractured in lower 0.2 ft.

112. 9 .4 Clay and northupite. Grayish-black (N 2) to greenish-black 

(5GY 2/1) to dusky yellow-green (5GY 5/2) to very lightgray (N 8) finely laminated clay with disseminated oval to 

round nodules, averaging 1 mm in length, of white (N 9) 

massive northupite arranged in layers. Clay 99 percent, 

northupite 1 percent.

113. 0 .1 Clay. Clay as described in preceding unit; no northupite.

113. 1 .1 Clay and gaylussite. Black (N 1) to greenish-black (5GY 2/1) 

clay with 25 percent disseminated euhedral gaylussite crystals averaging 2 mm in length; numerous seams, less than 1 

mm wide, of moderate greenish-yellow (10 Y 7/4) to grayishyellow (5F 8/4) gaylussite silt. Clay 85 percent, gaylussite 

15 percent.

113. 4 .3 Clay and gaylussite. Black (N 1) to greenish-black (5GY 2/1) 

to light greenish-gray (5GY 8/1) locally faintly finely laminated clay with seams of disseminated colorless euhedral 

gaylussite crystals from 1 to 4 mm in length. Clay 60 percent, gaylussite 40 percent.

113. 6 . 2 Clay and borax. Fractured core. Dusky yellow-green (50? Y 

5/2) to greenish-gray (5GY 6/1 and 5G 6/1) to light bluishgray (5B 7/1) faintly finely laminated clay with seam, 20 

mm wide, of massive borax; scattered nodules, averaging 

5 mm in diameter, of white (N 9) massive northupite. Clay 

70 percent, borax 30 percent.

114. 3 . 7 No core.

114.6 .3 Clay. Black (N 1) to grayish-yellow (5Y 8/4) to mediumgray (N 5) finely laminated clay.

114. 8 .2 Trona, northupite, and clay. Colorless to smoky dense hard 

granular trona; seam, 10 mm wide, at top, containing trona 

blades averaging 5 mm in length, with 75 percent interstitial black (N 1) clay; seam, 15 mm wide, at base of black 

(N 1) clay with 10 percent disseminated trona needles and 

distinct seams of grayish-orange (10 YR 7/4) northupite. 

Trona 75 percent, northupite 15 percent, clay 10 percent.
226 GEOLOGIC INVESTIGATIONS IN MOJAVE DESERT REGION

Depth Unit thick-

(feet) nest (feet) Description

115.0 0.2 Clay. Medium bluish-gray (5B 5/1) to dark greenish-gray 

(5GY 4/1) to dark-gray (N 3) finely laminated clay with 

wavy laminae and a few fine laminae of moderate reddishbrown (10/2 4/6) algae (?)-discolored clay; scattered nodules, 

15 mm long, of very pale orange (1QYR 8/2) massive 

northupite.

115. 1 .1 'Trona. Coarse vuggy bladed trona, blades averaging 20 mm 

in length.

115. 3 .2 Trona. Fractured core. Fragments of coarse bladed trona, 

blades averaging 10 mm in length.

115. 6 .3 Clay and northupite. Grayish-black (N 2) to greenish-black 

(5(77 2/1) to dusky yellow-green (50Y 5/2) to pale-olive 

(10 Y 6/2) finely laminated clay with disseminated oval to 

round white (N 9) massive northupite nodules, averaging 

1 mm in diameter, arranged in layers in lower 0.1 ft. Clay 

95 percent, northupite 5 percent.

115. 7 . 1 Clay and gaylussite. Greenish-black (5GY 2/1) clay with 

50 percent disseminated gaylussite silt.

116. 0 .3 Clay. Finely laminated clay as in previous interval.

116. 9 .9 Trona and clay. White (N 9) to medium-gray (N 5) compact 

massive trona with numerous pockets of colorless to light 

greenish-gray (5GY 8/1) fibrous and bladed trona, blades 

averaging 5 mm in length; 5 percent intermixed grayishblack (N 2) clay in interstices of trona blades in lower 0.2 ft.

117. 1 .2 Clay, northupite, and sulfohalite*. Grayish-black (N 2) to 

dark-gray (N 3) to dusky yellow-green (5GY 5/2) faintly 

finely laminated clay with disseminated oval to circular 

nodules, averaging less than 1 mm in diameter, of white 

(N 9) massive northupite arranged in layers; scattered 

amber-colored anhedral to subhedral sulfohalite* crystals 

averaging 5 mm in diameter. Clay 95 percent, northupite 

5 percent.

117. 5 .4 Clay and gaylussite*. Grayish-black (N 2) to medium darkgray (N 4) to grayish-yellow (5Y 8/4) to very light gray 

(N 8) finely laminated clay with 25 percent disseminated 

gaylussite* silt.

118. 0 .5 Clay and gaylussite. Grayish-black (N 2) to grayish-yellow 

(5F 8/4) clay with 50 percent disseminated gaylussite 

crystals averaging 15 mm in length.

119. 3 1. 3 No core.

119. 6 .3 Clay and gaylussite. Moderate yellowish-brown (IOYR 5/4) 

to grayish-black (N 2) clay with 40 percent disseminated 

euhedral gaylussite crystals averaging 10 mm in length; a 

few seams, 1 mm wide, of fine gaylussite silt.

120. 0 . 4 Clay and gaylussite. Grayish-black (N 2) to greenish-black 

(5GY 2/1) to moderate yellowish-brown (1QYR 5/4) clay with 

40 percent disseminated euhedral clear gaylussite crystals 

averaging 1 mm in length.

120.4 .4 Clay. Grayish-black (N 2) to grayish-yellow (5Y 8/4) to 

dusky yellow-green (5GY 5/2) to very light gray (N 8) 

finely laminated clay.
CORE LOGS FROM SEARLES LAKE, CALIFORNIA 227

Depth Unit thick-

(feet) ness (feet) Description

120. 6 0. 2 Clay and gaylussite. Grayish-black (N 2) clay with 50 percent disseminated gaylussite silt.

120. 8 .2 Trona and clay. Aggregate of coarse trona blades averaging 

20 mm in length, with 5 percent interstitial grayish-black. 

(N 2) to greenish-black (5GY 2/1) clay.

121. 5 . 7 Trona and northupite. White (N 9) to light greenish-gray 

(5GY 8/1) to medium-gray (N 5) porous massive trona with 

seams, 10 mm wide, of colorless fibrous trona at 121.2 and 

121.5 ft; seam, 15 mm wide, of massive trona discolored very 

pale orange (107/2 8/2) to grayish-orange (1QYR 7/4) by 

30 percent interstitial massive northupite at 121.4 ft. 

Trona 98 percent, northupite 2 percent.

121. 9 . 4 Trona. Well-consolidated aggregate of coarse colorless trona 

blades averaging 10 mm in length, with numerous ^-in. 

pockets and irregular streaks of white (N 9) to colorless 

massive trona; trace of interstitial greenish-gray (5GY 6/1) 

clay.

122.0 .1 Trona and clay. Grayish-black (N 2) to yellowish-gray 

(5Y 8/1) clay with 50 percent disseminated trona blades 

averaging 10 mm in length.

123. 5 1. 5 No core.

123.7 .2 Clay. Grayish-black (N 2) to brownish-black (5YR 2/1) to 

grayish-yellow (5Y 8/4) to medium bluish-gray (55.7/1) 

to very light gray (N 8) finely laminated clay.

126. 6 2. 9 Clay and gaylussite. Dark greenish-gray (5GY 4/1) to 

moderate olive-brown (5Y 4/4) to dusky yellow-green (5GY 

5/2) to grayish-black (N 2) clay, locally finely laminated, 

with 45 percent disseminated euhedral gaylussite crystals 

averaging 10 mm in length.

Searles drill hole GS-14

LOCATION: Searles Lake, Calif., at common cor., sees. 25, 26, 35, and 36, R. 43 EM

T. 25 S., Mourt Diablo base line and meridian. 

ELEVATION AT TOP OP HOLE: 1,616 ft. 

ELEVATION AT BOTTOM OP HOLE: 1,490.6 ft. 

TOTAL DEPTH: 125.4.ft. 

DATES DKILLED: Feb. 3-18, 1955. 

CASING USED: 85.5 ft of 3-in. pipe. 

MINERAL DETERMINATIONS: Minerals identified microscopically are denoted by

an asterisk (*).

Depth Unit thickMeet) ness (feet) Description

0. 8 0. 8 Halite and clay. Friable aggregate of colorless halite cubes 

and cubes modified by octahedron, averaging 10 mm in 

length, with 5 percent interstitial pale-olive (10Y 6/2) to 

dusky-yellow (5Y 6/4) clay.

1. 7 .9 Halite and clay. Poorly consolidated aggregate of colorless 

halite cubes and cubes modified by octahedron, averaging 

10 mm in length, with 5 percent interstitial dusky yellowgreen (5GY 5/2) to pale-olive (10 F 6/2) clay.

2. 1 . 4 No core.
228 GEOLOGIC INVESTIGATIONS IN MOJAVE DESERT REGION

Depth Unit thick- 

(feet) ness (feet) Description . 

2. 4 0. 3 Halite and clay. Friable aggregate of halite cubes and cubes 

modified by octahedron, averaging 10 mm in length, with 

5 percent interstitial dusky yellow-green (5GY 5/2) clay.

3. 2 .8 Halite and clay. Poorly consolidated aggregate of colorless 

halite cubes and cubes modified by octahedron, averaging 

10 mm in length, with 5 percent interstitial dusky yellowgreen (5GY 5/2) clay.

4. 0 .8 Clay and halite. . Well-consolidated dusky yellow-green 

(5GY 5/2) clay with 50 percent disseminated colorless 

halite cubes modified by octahedron, averaging 10 mm in 

length.

4. 3 . 3 No core.

6. 0 1. 7 Clay, hanksite*, and halite. Dusky yellow-green (5GY 5/2) 

to dark greenish-gray (5GY 4/1) soft moist clay with 10 

percent disseminated halite cubes modified by octahedron, 

averaging 10 mm in length; 60 percent disseminated subhedral to euhedral hanksite* crystals up to 80 mm in 

length, averaging 60 mm, in lower 0.8 ft. Clay 60 percent, 

hanksite 30 percent, halite 10 percent.

7.9 1. 9 Halite. Poorly consolidated aggregate of halite cubes and 

cubes modified by octahedron, averaging 5 mm in length, 

with trace of interstitial dusky yellow-green (5GY 5/2) clay. 

9.2 1.3 Clay and halite. Grayish-green (1QGY 5/2) clay with 25 

percent disseminated colorless halite cubes modified by 

octahedron and anhedra, averaging 10 mm in length.

10. 3 1.1 Halite and clay. Poorly consolidated aggregate of colorless 

halite cubes modified by octahedron, averaging 5 mm in 

length, with 2 percent interstitial grayish-green (10 Or F 5/2) 

clay.

10. 6 .3 Halite and clay. Fractured core. Vuggy granular aggregate 

of halite with 10 percent interstitial greenish-gray (lOOrF 5/2) 

clay.

11.0 .4 Halite and clay. Well-consolidated aggregate of halite 

anhedra with 10 percent interstitial grayish-green (WGY 

5/2) to grayish-black (N 2) clay.

13. 7 2. 7 No core.

14. 0 .3 Halite and clay. Fractured core. Fragments of anhedral to 

subhedral halite crystal aggregates with 2 percent interstitial grayish-green (WGY 5/2) to dark greenish-gray 

(5(3 4/1) clay.

14.6 .6 Clay and halite. Well-consolidated grayish-green (100? F 

5/2) to greenish-black (50? F 2/1) clay with 40 percent disseminated colorless halite cubes modified by octahedron, 

averaging 3 mm in length.

14.9 .3 Halite. Poorly consolidated mixture of halite sand and disseminated halite anhedra and subhedra averaging 10 mm in 

length; trace of dusky yellow-green (5GY 5/2) clay. Probably cuttings, not core.

15. 8 . 9 No core.
CORE LOGS FROM SEARLES LAKE, CALIFORNIA 229.

Depth Unit thick- 

(feet) ness (feet) Description

17. 3 1. 5 Halite and clay. Poorly consolidated aggregate of colorless 

halite cubes averaging 2 mm in length, with trace of dusky 

yellow-green (bGY 5/2) clay; large fragments, 4-5 in. long, 

consisting of aggregates of colorless halite cubes modified 

by octahedron with 2 percent interstitial dusky yellowgreen (5GY 5/2) to grayish-green (IOGY 5/2) clay.

18.1 . 8 No core.

18. 6 .5 Halite and clay. Well-consolidated aggregate of halite cubes 

modified by octahedron, anhedra, and subhedra, averaging 

10 mm in length, with 15 percent interstitial grayish-green 

. (1QGY 5/2) to dusky-green (50 3/2) clay.

19.2 .6 Hanksite, clay, and halite. Poorly consolidated mixture of 

yellowish euhedral to subhedral hanksite crystals up to 

80 mm in length, averaging 20 mm, and colorless halite 

cubes modified by octahedron and anhedra, averaging 15 

mm in length, with 20 percent interstitial grayish olivegreen (5GY 3/2) clay. Hanksite, 70 percent, clay 20 percent, halite 10 percent.

20. 0 . 8 Halite and hanksite. Poorly consolidated aggregate of colorless to white (N 9) halite cubes averaging 2 mm in length, 

with a few colorless euhedral hanksite crystals 2 mm long.

20. 2 .2 No core.

21.2 1.0 Halite and hanksite. TJnconsolidated aggregate of colorless 

halite sand, discolored dusky yellow-green (5GY 5/2) by 

trace of clay, with disseminated fragments of dense granular 

massive yellowish hanksite and large subhedral hanksite 

crystals. Probably cuttings, not core. Halite 80 percent, 

hanksite 20 percent.

21.7 .5 Halite, hanksite, and clay. Core fractured. Well-coneolidated vuggy aggregate of halite cubes modified by octahedron, averaging 5 mm in length, with 10 percent disseminated subhedral yellowish smoky hanksite crystals 

averaging 20 mm in length; 10 percent interstitial dusky 

yellow-green (5GY 5/2) clay.

21. 9 .2 Hanksite. Unconsolidated loose crystals of yellowish subhedral to euhedral hanksite averaging 25 mm in length, 

with a few dark yellowish-orange (IOYR 6/6) hanksite 

crystals.

22. 2 .3 Halite* and trona*. Dense granular aggregate of grayishorange (1QYR 7/4) intermixed halite* and trona* with large 

pocket of colorless halite cubes modified by octahedron, 

averaging 5 mm in length. Halite 75 percent, trona 25 

percent.

25. 3 3. 1 No core.

25. 5 .2 Halite. Unconsolidated halite sand discolored dusky yellowgreen (5GY 5/2) by trace of interstitial clay. Probably 

cuttings, not core.

25. 8 .3 Hanksite. Unconsolidated loose crystals of euhedral to 

anhedral smoky hanksite with numerous dark yellowishorange (IOYR 6/6) algae(?) inclusions.
230 GEOLOGIC INVESTIGATIONS IN MOJAVE DESERT REGION

Depth Unit thick-

(feet) ness (feet) Description

26. 2 0. 4 Halite. Well-consolidated aggregate of colorless halite cubes 

modified by octahedron, averaging 3 mm in length.

26. 4 .2 Halite, borax, and trona. Fractured core. Fragments consisting of aggregates of halite cubes modified by octahedron, 

averaging 3 mm in length; single large subhedral borax 

crystal, 3 in. long, with surficial fibrous trona at base of 

crystal; loose disseminated borax crystals averaging 20 mm 

in length throughout. Halite 80 percent, borax 20 percent.

26.9 .5 Halite and clay. Well-consolidated aggregate of colorless 

halite anhedra and cubes modified by octahedron, averaging 

3 mm in length, with 2 percent interstitial dusky yellowgreen (5(rF 5/2) to grayish-green (10GY 5/2) clay.

27. 1 .2 Trona* and borax. Unconsolidated loose irregular vuggy 

fragments of very pale orange (1QYR 8/2) massive to 

fibrous trona* with disseminated subhedral colorless borax 

crystals averaging 20 mm in length; loose subhedral borax 

crystals up to 60 mm in length. Trona 90 percent, borax 

10 percent.

27. 5 .4 Hanksite, borax, trona, and halite. Well-consolidated vuggy 

irregular seams of very pale orange (10F.R 8/2) massive 

trona with irregular seams of tabular colorless borax 

crystals, averaging 20 mm in length, between trona seams; 

very pale orange (10 YR 8/2) euhedral hanksite crystals, 

averaging 20 mm in length, disseminated throughout or 

collected in irregular seams; irregular seam of colorless 

halite cubes and anhedra, averaging 2 mm in length, at 

base. Hanksite 40 percent, borax 25 percent, trona 25 

percent, halite 10 percent.

27. 6 .1 Halite and trona. Well-consolidated aggregate of halite 

cubes and cubes modified by octahedron, averaging 2 mm 

in length, with 5 percent interstitial pale-olive (10 Y 5/2) 

massive trona.

28. 2 .6 Halite and trona. Dense granular aggregate of grayishorange (10 YR 7/4) to very pale orange (1QYR 8/2) intermixed halite and trona; scattered subhedral borax crystals, 

25 mm in length, at top. Halite 50 percent, trona 50 

percent.

28.3 .1 Halite and clay. Well-consolidated aggregate of halite 

cubes, averaging 3 mm in length, with 5 percent interstitial 

dusky yellow-green (5GY 5/2).

29. 3 1. 0 No core.

29. 6 .3 Hanksite, halite, and clay. Well-consolidated aggregate of 

large subhedral or rounded smoky hanksite crystals up to 

90 mm in length, averaging 45 mm, with 5 percent interstitial dusky yellow-green (5GY 5/2) to grayish yellowgreen (5GY 3/2) clay containing 50 percent disseminated 

colorless halite cubes and cubes modified by octahedron, 

averaging 2 mm in length; a few pockets of white (N 9) to 

colorless trona blades averaging 5 mm in length. Hanksite 

95 percent, clay 3 percent, halite 2 percent.
CORE LOGS FROM SEARLES LAKE, CALIFORNIA 231

Depth Unifthick-

(feef) ness (feet) Description

30. 1 0.5 Trona and borax. Well-consolidated slightly vuggy very 

pale orange (10YR 8/2) to grayish-orange (10 YR 7/4) 

massive trona, with seams, averaging 10 mm in width, of 

colorless anhedral borax containing trace of interstitial 

grayish olive-green (5(? Y 3/2) clay; a few halite cubes modified by octahedron, averaging 2 mm in length, in lenticular 

horizontal vugs in upper 0.1 ft. Trona 70 percent, borax 

30 percent.

30.2 .1 Halite. Well-consolidated vuggy aggregate of colorless 

halite cubes modified by octahedron, averaging 3 mm in 

length.

30. 6 .4 Halite and trona. Densely packed granular aggregate of 

colorless halite, with 20 percent interstitial white (N 9) to 

very pale orange (10Y75! 8/2) massive trona; a few disseminated subhedral anhedral borax crystals averaging 2 mm 

at base.

30.9 .3 Clay, pirssonnite, and hanksite. Grayish-black (N 2) to 

dusky yellow-green (5GY 5/2) coarsely laminated clay; 

seam, 20 mm wide, of grayish-black (N 2) clay containing 

30 percent disseminated pirssonite* sand at 40.0 ft; embedded subhedral hanksite crystals, averaging 50 mm in 

length, at top of section; laminae and irregular streaks,

1 mm wide, of moderate reddish-brown (10.R 4/6) algae(?) 

chiefly in upper 0.2 ft. Clay 88 percent, pirssonite 7 percent, hanksite 5 percent.

31. 1 .2 Hanksite. Well-consolidated granular aggregate of subhedral colorless hanksite crystals with large euhedral colorless hanksite crystals, averaging 50 mm in length, embedded 

in clay at top.

31. 4 .3 Hanksite and trona. Dense granular aggregate of colorless 

hanksite with 30 percent interstitial very pale orange 

(iOYR 8/2) massive trona.

32. 0 .6 Hanksite and trona. Dense granular aggregate of colorless 

hanksite, with 5 percent interstitial white (N 9) massive 

trona.

32. 8 .8 Halite and clay. Well-consolidated aggregate of colorless 

halite cubes and cubes modified by octahedron, averaging

2 mm in length, with trace of interstitial dusky yellowgreen (5GY 5/2) clay; seam, 20 mm wide, of' grayish-black 

(N2) to dusky yellow-green (5GY 5/2) clay at base. Halite 

92 percent, clay 8 percent.

33. 8 1. 0 No core.

34. 1 .3 Halite and clay. Friable aggregate of colorless halite cubes 

and cubes modified by octahedron, averaging 2 mm in 

length, with 5 percent interstitial greenish-black (5GY 2/1) 

to dark greenish-gray (5GY 4/1) clay.

34.4 .3 Hanksite, halite, and clay. Fractured core. Fragments 

consisting of aggregates of euhedral to subhedral smoky 

hanksite crystals averaging 50 mm in length, with interstitial halite cubes modified by octahedron, averaging 2 mm 

in length, intermixed with dark greenish-gray (5GY 4/1) 

clay. Hanksite 85 percent, halite 10 percent, clay 5 

percent. 

491349 59 7
232 GEOLOGIC -INVESTIGATIONS IN MOJAVE DESERT 'REGION

Depth Unit thick- 

(feet) nets (feet) Description

34. 6 0. 2 Hanksite ; and trona. Well-consolidated granular aggregate 

of colorless to smoky hanksite, with 5 percent interstitial 

white (N 9) massive trona.

34. 7 .1 Borax and trona. Vuggy .aggregate of euhedral borax crystals 

from 10-50 mm in length, with 10 percent interstitial 

white (N 9) massive trona; a few pockets of fibrous trona.

35. 4 .7 Hanksite and trona. Well-consolidated dense granular aggregate of colorless to smoky hanksite, with 5 percent interstitial 

white (N 9) massive .trona.

35. 7 . 3 Halite and hanksite. Poorly consolidated mixture of colorless 

halite cubes and cubes modified by octahedron, averaging 

3 mm in length, with scattered loose :subhedral hanksite 

crystals averaging 30 mm in length; trace of interstitial 

white (N 9) massive trona and dark greenish-gray (5GF4/1) 

clay. Halite 90 percent, hanksite 10 percent.

36. 0 .3 Halite. Well-consolidated aggregate of colorless halite cubes 

and cubes modified by octahedron, averaging 2 mm in 

length.

36.3 .3 Halite. Well-consolidated granular aggregate of colorless 

halite with trace of interstitial olive-gray (5V 4/1 clay.

36. 8 . 5 No core.

37.5 .7 Hanksite, clay, sulfohalite, and borax. Well-consolidated 

granular aggregate of smoky hanksite with 5 percent interstitial dusky yellow-green (5GY 5/2) to grayish olive-green 

(5(7 F 3/2) clay; euhedral hanksite crystals, averaging 20 mm 

in length, at top, with scattered 'sulfohalite octahedrons 

averaging 5 mm in length, and a few subhedral borax 

crystals averaging 20 mm in length; pocket, 2 in. long, of 

halite cubes modified by octahedron, in lower 0.2 ft.

37. 7 i 2 Halite, trona, and hanksite. Friable aggregate if halite cubes 

and cubes modified by octahedron, averaging 3 mm in 

length, with interstitial white (N 9) massive trona; a few 

disseminated smoky hanksite crystals up .to 70 onm in 

length; trace of olive-gray (5V 3/2) clay. Halite 90 percent, 

trona 5 percent, and hanksite 5 percent.

38.0 .3 .Hanksite and trona. Well-consolidated granular grayishorange (IQYR 7/4) aggregate of hanksite with 5 percent 

interstitial white (N 9) massive trona.

38.1 ; 1 Borax and trona. Well-consolidated aggregate of colorless 

subhedral borax crystals averaging 20 mm in length, with 

25 percent interstitial white (N 9) massive trona; trace of 

dusky yellow-green (5GY 5/2) clay.

.38. 4 .3 Hanksite, halite, and clay. Dense granular dark smoky hanksite with 10 percent interstitial greenish-black (50Y 2/1) 

to dusky yellow-green (5GY 5/2) clay; pockets of colorless 

halite cubes and cubes modified by octahedron; thin clay 

seams, 20 .mm wide, at top, with disseminated euhedral 

hanksite crystals averaging 20 mm in length. Hanksite 75 

.percent, halite 15 percent, clay 10 percent.
233

Depth Unit thick- (feet) ness (feet) Description

38. 7 0. 3 Trona and halite. Fractured core. Fragments showing 

vuggy seams of very pale orange (IQYR 8/2) massive trona 

containing disseminated colorless halite cubes and cubes 

modified by octahedron, averaging 3 mm in length. Trona. 

90 percent, halite 10 percent.

38. 9 . 2 Trona and halite. Dense granular slightly vuggy aggregate 

of very pale orange (10 YR 8/2) massive trona with 50 percent disseminated halite crystals averaging 3 mm in length; 

a few sulfohalite octahedra at base.

-40. 4 1. 5 No core.

41. 7 1. 3 Trona and halite. Well-consolidated white (N9) to very pale 

orange (10 YR 8/2) to grayish-orange (10 YR 7/4) massive 

trona with irregular seams and disseminated crystals of 

colorless halite. Trona 60 percent, halite 40 percent.

41. 8 . 1 Halite* and trona*. Well-consolidated granular aggregate of 

colorless halite* crystals averaging 5 mm in length, with 

interstitial massive trona*. Halite 75 percent, trona 25 

percent.

41. 9 . 1 Hanksite and trona. Fractured core. Fragments consisting 

of smoky euhedral to subhedral hanksite crystals averaging 

20 mm in length, with 5 percent interstitial white (N 9) 

massive trona.

42. 4 .5 Trona and halite. Well-consolidated slightly vuggy white 

(AT9) to very pale orange (IQYR 8/2) massive trona with 50- 

percent disseminated colorless halite crystals averaging 2 

mm in length.

43. 1 .7 Halite and trona. Poorly consolidated aggregate of colorless 

halite cubes averaging 3 mm in length, with 25 percent 

interstitial yellowish-gray (5Y 7/2) to pale olive (1QY 6/2) 

massive trona.

43. 3 . 2 Halite and trona. Well-consolidated aggregate of colorless 

halite cubes and cubes modified by octahedron, averaging 

3 mm in length, with 5 percent interstitial white (N9) to 

yellowish-gray (5Y 8/1) massive trona.

43. 8 .5 Trona. Well-consolidated white (W9) to very pale orange 

(IQYR 8/2) slightly vuggy massive trona with a few small 

%-in. pockets of colorless fibrous trona.

44. 0 . 2 No core.

44. 3 . 3 Trona and clay. Irregular vuggy seams 3-5 mm wide and 

pockets of colorless bladed trona with interstitial dusky 

yellow-green (5GY 5/2) to grayish olive-green (5GY 3/2) 

clay); scattered halite cubes averaging 3 mm in length. 

Trona 90 percent, clay 10 percent-.

44. 8 .5 Halite. Well-consolidated aggregate of colorless halite cubes 

averaging 3 mm in length.

45. 1 . 3 Trona, hanksite, and halite. Massive to fibrous trona discolored grayish-olive (1QY. 4/2) to grayish-yellow (5Y 8/4) 

by trace of intermixed clay; with irregular seams and 

pockets of smoky hanksite and colorless halite cubes 

averaging 3 mm in length. Trona 60 percent, hanksite 30 

percent, halite 10 percent.
234 GEOLOGIC INVESTIGATIONS IN MOJAVE DESERT REGION

Depth Unit thick-

(/««<) ness (feet) Description

45. 9 0. 8 Trona, hanksite, and clay. White (AT" 9) to pale-olive (10Y 6/2) 

to very pale orange (10 KB 8/2) massive trona with seams, 

averaging 5 mm in width, of smoky hanksite and horizontal 

streaks, 1 in. long, of smoky hanksite; seam, 20 mm wide, 

of grayish-olive (10F 4/2) to grayish-yellow (5Y 8/4) clay 

containing scattered euhedral hanksite crystals and a few 

sulfohalite octaheda at 46.2 ft. Trona 85 percent, hanksite 

10 percent, clay 5 percent.

46. 8 .9 Halite and trona. Dense granular slightly vuggy aggregate 

of colorless halite crystals averaging 2 mm in length, with 

35 percent interstitial very pale orange (10 YR 8/2) massive 

trona; scattered horizontal vugs 3-5 mm wide. 

47.8 1.0 No core. 

 48. 1 .3 Hanksite. Dense granular aggregate of smoky hanksite with

a few streaks, 1 in. long, of white (N 9) massive trona.

48. 5 .4 Trona and halite. White (N 9) to yellowish-gray (5F 7/2) 

to very pale orange (WYR 8/2) vuggy massive trona with 

30 percent disseminated halite cubes averaging 2 mm in 

length; long horizontal vugs 1-2 mm wide.

48.7 .2 Halite and trona. Fractured core. Poorly consolidated

vuggy aggregate of halite cubes and cubes modified by

octahedron, averaging 4 mm in length, with 25 percent

' interstitial white (N 9) massive trona; trace of greenish-

' black (5GY 2/1) clay.

.49.1. .4 Halite and trona. Fractured core. Vuggy aggregate of 

colorless halite cubes and cubes modified by octahedron, 

averaging 3 mm in length, with 10 percent interstitial 

pale-olive (10Y 6/2) massive trona.

 49. 4 .3 Halite and trona. Dense granular slightly vuggy aggregate 

of halite with 15 percent interstitial white (N 9) to grayishyellow (5Y 8/4) massive trona; trace of smoky hanksite 

at base.

, 49. 6 .2 Hanksite, trona, and halite. Fractured core. Poorly con-

' '' solidated fragments consisting of smoky hanksite seams

averaging 10 mm in width, with seams of pale-olive (10Y

6/2) to pale greenish-yellow (10Y 8/2) massive trona con-

: : taining disseminated colorless halite cubes and cubes

modified by octahedron, averaging 3 mm in length. Hanks-

> ite 50 percent, trona 35 percent, and halite 15 percent.

49. 9 .3 Halite. Well-consolidated aggregate of colorless halite cubes 

averaging 3 mm in length, with trace of interstitial white 

(N 9) to grayish-yellow (5F 8/4) massive trona.

50. 2 .3 Halite and trona. Well-consolidated aggregate of colorless 

halite cubes and cubes modified by octahedron, averaging 

3 mm in length, with 50 percent interstitial white (N 9) to 

pale-olive (10 Y 6/2) massive trona.
CORE LOGS FROM SEARLES LAKE, CALIFORNIA

Depth Unit tMck- (feet) ness (feet) Description

50. 6 0. 4 Trona and halite. Well-consolidated slightly vuggy white 

(N 9) to very pale orange (10 YR 7/4) massive trona with 

10 percent disseminated colorless halite cubes and cubes 

modified by octahedron, averaging 2 mm in length; trace 

of grayish-olive (10 Y 4/2) clay; scattered ^-in. pockets of 

fibrous trona discolored grayish-yellow (5Y" 8/4) by trace 

of clay.

51. 7 1.1 Halite and trona. Well-consolidated slightly vuggy dense 

granular aggregate of halite cubes averaging 3 mm in length, 

with 50 percent interstitial white (N 9) to very pale orange 

(10 YR 8/2) massive trona.

51. 9 .2 Halite and trona. Well-consolidated aggregate of colorless 

halite cubes and cubes modified by octahedron, averaging

2 mm in length, with 30 percent interstitial white (N 9) 

to dusky-yellow (5Y 6/4) to grayish-olive (10 Y 4/2) massive 

trona discolored by traces of clay.

52. 3 .4 Halite and trona. Well-consolidated aggregate of colorless 

halite cubes and cubes modified by octahedron, averaging

3 mm in length, with 50 percent white (N 9) to very pale 

orange (10 YR 8/2) massive trona in interstices and seams.

52. 6 .3 Halite. Well-consolidated aggregate of colorless halite cubes 

modified by octahedron, averaging 3 mm in length.

54. 3 1. 7 Trona and halite. White (N 9) to very pale orange (IQYR 

8/2) massive trona in vuggy thin seams averaging 1-3 mm 

in width, with alternating seams and disseminated crystals 

of colorless halite cubes and cubes modified by octahedron, 

averaging 2 mm in length. Trona 60 percent, halite 40 

percent.

54. 4 .1 No core.

54. 8 .4 Trona. White (N 9) soft massive trona.

55. 8 1.0 Halite and trona. Well-consolidated aggregate of colorless 

halite cubes and cubes modified by octahedron, averaging 

3 mm in length, with 15 percent interstitial very pale 

orange (IQYR 8/2) massive trona; trace of aphthitalite 

(glaserite).

56. 4 .6 No core.

56. 9 .5 Halite and trona. Friable aggregate of colorless halite cubes 

and cubes modified by octahedron, averaging 3 mm in 

length, with 1- to 2-in. pockets of white (N 9) to very 

pale orange (10 YR 8/2) massive trona. Halite 98 percent, 

trona 2 percent.

59. 2 2. 3 Trona and halite. White (N 9) to very pale orange (IQYR 

8/2) vuggy massive trona with friable seams (averaging 

5 mm in width), pockets, and disseminated crystals of 

colorless halite cubes and cubes modified by octahedron, 

averaging 3 mm in length. Trona 60 percent, halite 40 

percent.

59. 9 . 7 Halite. Well-consolidated friable aggregate of colorless halite 

cubes and cubes modified by octahedron, averaging 3 mm 

in length.
236 GEOLOGIC INVESTIGATIONS IN MOJAVE DESERT REGION

Depth Unit thick-

(feet) nest (feet) Description

60. 2 0. 3 Halite and trona. Well-consolidated slightly vuggy aggregate 

of halite cubes and cubes modified by octahedron, averaging 

2 mm in length, with 15 percent interstitial white (AT 9) 

massive trona.

61.2 1.0 No core.

61. 3 .1 Trona and halite. White (N 9) to light greenish-gray (5GY 

8/1) soft massive trona with 5 percent disseminated colorless 

halite cubes and cubes modified by octahedron, averaging 

5 mm in length.

61. 4 . 1 Halite. Well-consolidated aggregate of colorless halite cubes 

and cubes modified by octahedron, averaging 3 mm in 

length, with trace of interstitial white (N 9) trona.

 61. 6 . 2 Trona and halite. White (N 9) dense massive trona with 

scattered streaks, 1-2 mm wide, of colorless halite. Trona 

99 percent, halite 1 percent.

61. 8 .2 Trona, halite, and clay. White (N 9) to very pale orange 

(IQYR 8/2) to light olive-gray (5K 5/2) massive trona with 

irregular pockets of colorless halite cubes and cubes modified 

by octahedron, averaging 2 mm in length; a few thin seams 

of black (N 1) to grayish-yellow (5F 8/4) interstitial clay. 

Trona 69 percent, halite 30 percent, clay 1 percent.

62. 2 .4 Halite and trona. Well-consolidated aggregate of colorless 

halite cubes and cubes modified by octahedron, averaging 

2 mm in length, with 20 percent interstitial white (N 9) 

to colorless massive and fibrous trona.

6&6 .4 Trona and clay. White (N 9) to yellowish-gray (5F 8/1) 

massive trona with irregular streaks, 1-5 mm wide, of 

greenish-black (5GY 2/1) clay; a few disseminated colorless 

halite cubes averaging 3 mm in length and scattered sulfohalite octahedra up to 15 mm in length, averaging 3 mm. 

Trona 98 percent, clay 2 percent.

62. 8 .2 Hanksite and clay. Euhedral to subhedral hanksite crystals 

averaging 30 mm in length, with 5 percent interstitial 

greenish-black (5(?F 2/1) clay.

64. 4 1. 6 Halite and trona. Friable aggregate of colorless halite cubes 

and cubes modified by octahedron, averaging 3 mm in 

length, with 10 percent interstitial white {N 9) massive 

trona; a few sulfohalite octahedra disseminated throughout.

65. 2 .8 Trona and halite. Core fractured. White (N 9) massive 

trona with 5 percent disseminated halite cubes, cubes 

modified by octahedron, and octahedra, averaging 2 mm in 

length.

65. 3 .1 No core.

67. 6 2.3 Trona. Core fractured in lower 1.3 ft. Poorly consolidated 

white (N 9) soft massive trona, with fragments of white 

(N 9) massive trona in lower 1.3 ft; seam of smoky anhedral 

hanksite, averaging 5 mm in width, at 66.5 ft; a few disseminated colorless halite cubes modified by octahedron, 

from 66.3 to 66.5 ft.

69. 5 1. 9 No core.
CORE LOGS FROM SEARLES LAKE, CALIFORNIA 237

Depth Unit thick-

(/erf) ness (feet) Description

70. 0 0. 5 Trona. Poorly consolidated white (N 9) soft massive trona. 

May be cuttings, not core.

71. 3 1. 3 Trona. Well-consolidated white (N 9) soft massive trona; 

seams; 5 mm wide, of dusky-yellow (5Y 6/4) massive trona 

at 71.2 and 7T.3 ft, probably discolored by intermixed clay; 

single colorless euhedral hanksite crystal 20 mm in length 

at 70.9 ft.

71. 8 .5 Trona. Fractured core. Fragments consisting of alternating 

seams, averaging 5 mm in width, of white (N 9) massive 

trona> locally discolored yellowish-gray (5Y 7/2) to pale-olive 

(10 Y 6/2); a few fragments show wavy seams of trona.

72. 3 .5 No core.

72. 5 .2 Trona and borax. Seams of white (N 9) massive trona with 

alternating seams of irregular width, from 5-20 mm wide, 

of colorless subhedral borax crystals, averaging 3 mm in 

length, containing trace of grayish-yellow (5Y 8/4) interstitial fibrous trona; trona discolored dark yellowish-brown 

(10 YR 4/2) to grayish-black (N 2) by trace of clay in lower 

0.1 ft. Trona 60 percent, borax 40 percent'.

72. 8 .3 Clay. Core fractured. Greenish-gray (5G 6/1) to olive-gray 

(5Y 4/1) to dusky yellow-green (5GY 5/2) to dusky-yellow 

(5F 6/4) to moderate olive-brown (5Y 4/4) finely laminated 

clay.

73.7 .9 Clay and pirssonite.* Olive-gray (5F 3/2) to grayish-black 

(N 2) to grayish-yellow (5Y 8/4) to greenish-black (5GY 

2/1) finely laminated clay with 20 percent disseminated 

anhedral pirssonite* crystals and thin seams, 1 mm wide or 

less, of pirssonite.

74. 1 . 4 Clay. Grayish-black (N 2) to grayish-green (WGY 5/2 and 

5G 5/2) to olive-gray (51 3/2) to grayish-yellow (5F 8/4) 

finely laminated clay with a few disseminated anhedral 

gaylussite crystals.

74.6 .5 Clay and gaylussite. Grayish-black (N 2.) to olives-gray 

(5Y 3/2) to dusky yellow-green (5GY 5/2) to grayish yellowgreen (5GY 7/2) finely laminated clay with 20 percent disseminated anhedral gaylussite crystals and thin seams, 1 

mm or less in width, of anhedral gaylussite.

76. 2 1, 6 Clay. Greenish-black (5GY 2/1) to grayish-black (AT 2) to 

grayish-green (5GY 6/1) to pale greenish-yellow (10 Y 8/2) 

to grayish-olive (10F 4/2) to light greenish-gray (5GY 8/1) 

coarsely laminated clay.

76. 5 . 3 Clay. Grayish-black (N 2) to greenish-black (5GY 2/1) to 

pale greenish-yellow (10 Y 8/2) to pale yellowish-orange 

(1QYR 8/6) finely laminated clay with seam, 1 mm wide, of 

gaylussite sand at 76.3 ft; a few disseminated anhedral 

gaylussite* crystals averaging 10 mm in length.

76. 6 .1 No core.

77. 7 1. 1 Clay. Core badly fractured. Fragments of greenish-black 

(5GY 2/1) to grayish-yellow (5F 8/1) to grayish-black (AT 2) 

to very light gray (N 7) clay, coarsely laminated in some 

fragments.
238 GEOLOGIC INVESTIGATIONS IN MOJAVE DESERT REGION

Depth Unit thiek-

(feet) nets (feet) Description

78.4 0.7 .Clay. Grayish-black (N 2) to greenish-black (5(7r~2/l) to 

grayish-yellow (5 Y 8/4) to pale yellowish-orange (10 YR 8/6) 

to grayish-green (5(7 5/2) finely laminated clay.

78. 9 .5 Clay. Grayish-black (N 2) to greenish-black (5GY 2/1) to 

dusky yellow-green (5GY 5/2) to pale yellowish-orange 

(1QYR 8/6) to very light gray (N 7) finely laminated clay; 

laminae faulted and contorted along steep angle fault.

79. 9 1.0 Clay and aragonite. Grayish-black (N 2) to greenish-black 

(5GY 2/1) to grayish-yellow (5F 8/1) to grayish-olive (10Y 

4/2) clay, coarsely laminated with widely spaced laminae 

of pale yellowish-orange (IOYR 8/6) to very light gray (N 8) 

soft massive finely crystalline aragonite. Clay 95 percent, 

aragonite 5 percent.

80. 2 .3 Clay and gaylussite. Black (N 1) to grayish-black (N 2) 

to greenish-black (5(7 F 2/1) clay with 60 percent disseminated anhedral gaylussite crystals averaging 5 mm in 

length.

80. 7 .5 Clay and gaylussite.* Greenish-black (5(?Y 2/1) to dusky, 

yellow-green (5GY 5/2) to blackish-red (512 5/2) to grayishgreen (10(7 4/2 and 100? 5/2) coarsely laminated clay, 

laminae revealed by color differences, with 60 percent anhedral gaylussite* crystals disseminated in black (N 1) 

clay at 80.5 to 80.6 ft; thin seam, 2 mm wide, of euhedral 

gaylussite crystals, averaging 1 mm in length, at 80.6 ft. 

Clay 88 percent, gaylussite 12 percent.

81. 3 .6 Clay and gaylussite. Grayish-black (N 2) to grayish-green 

(10(7 4/2) faintly coarsely laminated clay, laminae revealed 

by faint color differences, with 50 percent disseminated 

euhedral gaylussite crystals from 1 to 5 mm in length; 

numerous moderate reddish-orange (10/2 6/6) algae(?) 

streaks throughout.

82.1 .8 Clay and gaylussite. Grayish-black (N 2) to grayish-green 

(10(7 4/2) coarsely laminated clay with numerous moderate 

reddish-orange (10/2 6/6) algae(?) streaks, less than 1 mm 

wide, throughout grayish-black (N 2) clay in lower 0.4 ft; 

seams, 10 mm wide, of 50 percent disseminated euhedral 

gaylussite crystals at 81.8 and 81.9 ft. Clay 96 percent, 

gaylussite 4 percent.

82. 2 .1 No core.

83. 7 1. 5 Clay and gaylussite. Black (N 1) to greenish-black (5(7 Y 2/1) 

to dusky yellow-green (5GY 5/2) coarsely laminated clay, 

laminae revealed by color differences, with 30 percent disseminated euhedral gaylussite crystals averaging 1 mm in length; 

distinct seams, 1 mm wide, of moderate reddish-brown 

(WR 4/6) algae(?) at 82.8, 83.0, and 83.5 ft, and additional 

vague blackish-red (5R 2/2) algal (?) discolorations throughout.
CORE LOGS FROM SEARLES LAKE, CALIFORNIA 239

Depth Unit thick-

(feet) ness (feet) Description

85. 9 2. 2 Trona. White (N 9) to light greenish-gray (5GY 8/1) to 

dark greenish-gray (5GY 4/1) soft porous massive and fine 

fibrous trona with numerous vuggy pockets lined with 

colorless fibrous trona containing traces of interstitial 

grayish-yellow (5Y 8/4) clay; irregular pocket of colorless 

trona blades averaging 10 mm in length in upper 0.1 ft; 

scattered pockets of very pale orange (1QYR 8/2) massive 

trona in lower 0.6 ft which is dominantly fibrous trona; 

seam, 10 mm wide, of black (N 1) clay with 50 percent 

disseminated euhedral pirssonite crystals averaging 1 mm 

in length and thin irregular seams, less than 1 mm wide, of 

moderate reddish-brown (1QR 4/6) algae(?) at 85.7 ft.

86. 3 .4 Clay, trona, and pirssonite. Greenish-black (50 Y 2/1) clay 

with a few disseminated trona blades averaging 10 mm in 

length and euhedral pirssonite crystals averaging 10 mm 

in length.

88. 2 1. 9 No core.

88.4 .2 Clay and pirssonite. Black (N 1) clay with 25 percent 

disseminated pirssonite sand.

89. 9 1. 5 Trona and clay. White (N 9) to yellowish-gray (5F 8/1) 

compact fine fibrous trona with scattered 1-in. pockets of 

medium light-gray (N 6) massive trona and numerous 

irregular streaks and pockets of interstitial medium darkgray (N 4) to dark-gray (N 3) clay. Trona 98 percent, 

clay 2 percent.

91. 0 1. 1 Trona, halite, and clay. White (N 9) dense hard massive 

trona with irregular pockets and streaks of colorless halite 

cubes modified by octahedron, averaging 5 mm in length; 

fine fibrous trona in interstices of halite crystals discolored 

by interstitial greenish-black (5GY 2/1) clay in upper 

0.6 ft. Trona 94 percent, halite 5 percent, and clay 1 

percent.

91. 2 .2 Halite. Friable aggregate of colorless halite cubes modified 

by octahedron, averaging 3 mm in length, with inclusions 

of moderate reddish-orange (10R 6/6) algae(?).

91. 7 .5 Trona and halite. White (N 9) to grayish-yellow (5Y 8/4) 

dense hard slightly vuggy massive trona with 15 percent 

disseminated colorless halite crystals and trace of dark 

greenish-gray (5G Y 4/1) clay in irregular seams and pockets.

91. 8 .1 Trona. Very light gray (N 7) to greenish-gray (5GY 6/1) 

massive sugary-tex tured trona w ith dis tinct seams discolored 

moderate reddish-orange (10R 6/6) by algae (?) at base.

92. 2 .4 Halite and trona. Well-consolidated aggregate of colorless 

halite cubes modified by octahedron, with 20 percent 

interstitial white (N 9) massive trona.

92. 5 .3 No core.
240 GEOLOGIC INVESTIGATIONS IN MOJAVE DESERT REGION

Depth Unit thick-

(feet) ness (feet) Description

92. 8 ^0. 3 Trona and halite. Well-consolidated white (N 9) to greenishgray (5GY 6/1) massive trona with irregular streaks and 

pockets of colorless halite cubes modified by octahedron, 

averaging 3 mm in length; distinct seams, 2 mm wide, of 

trona discolored moderate reddish-brown (1QR 4/6) by 

ajgae(?) at 92.5 and 92.7 ft. Trona 75 percent, halite 25 

percent.

:94. 4 1. 6 Clay, pirssonite, and borax. Greenish-black (5 GY 2/1) clay 

with 40 percent disseminated euhedral to subhedral pirssonite crystals averaging 10 mm in length; a few disseminated euhedral borax crystals, averaging 20 mm in length, 

in greenish-black clay at 93.8 ft.

94. 6 .2 Clay, pirssonite, and borax. Black (N 1) clay with 39 

percent disseminated pirssonite sand; seam, 15 mm wide of 

50 percent disseminated euhedral borax crystals averaging 

20 mm in length at base. Clay 65 percent, pirssonite 23 

percent, borax 12 percei.t.

95. 0 .4 Trona. Well-consolidated aggregate of colorless trona blades 

averaging 10 mm in length, with trace of interstitial dark 

greenish-gray (5GF4/1) clay.

95. 4 .4 Trona. Fine colorless fibrous trona with trace of interstitial 

dark greenish-gray (5(?F4/1) clay.

95. 6 .2 Halite. Well-consolidated aggregate of colorless halite cubes 

and cubes modified by octahedron, averaging 3 mm in 

length, with trace of interstitial white (N 9) massive trona.

95. 8 .2 Trona and clay. White (N 9) to light greenish-gray (5GY 8/1) 

massive trona with irregular streaks of intermixed grayishblack (N 2) clay. Trona 98 percent, clay 2 percent.

97. 1 1. 3 No core.

97. 7 . 6 Halite and trona. Well-consolidated aggregate of colorless 

halite cubes and cubes modified by octahedron, averaging 

4 mm in length, with irregular streaks and pockets of fine 

fibrous trona discolored greenish-black (5 GY 2/1) to dark 

greenish-gray (5GY 4/1) by trace of interstitial clay. Halite 

90 percent, trona 10 percent.

97.8 .1 Clay and pirssonite. Black (N 1) clay with 40 percent 

disseminated pirssonite crystals averaging 1 mm in length.

98. 1 .3 Trona and halite. White (N 9) -to greenish-black (5GY 2/1) 

massive and fine fibrous trona discolored by trace of 

interstitial clay; scattered pockets of colorless halite cubes 

modified by octahedron, averaging 2 mm in length. Trona 

99 percent, halite 1 percent.

99.0 .9 Halite. Friable aggregate of colorless halite cubes and 

cubes modified by octahedron, averaging 5 mm in length; 

trace of interstitial white (N 9) massive trona in lower 0.1 

ft.

99. 2 .2 Trona. Well-consolidated vuggy aggregate of colorless trona 

blades averaging 5 mm in length, with 1-rin. pockets of 

medium-gray (N 5) massive trona discolored by trace of 

intermixed clay; a few disseminated halite cubes modified 

by octahedron, averaging 5 mm in length.
CORE LOGS FROM SEARLES LAKE, CALIFORNIA 241

Depth Unit thick- (feet) nets (feet) Description

99. 3 0. 1 Clay, pirssonite, and hanksite. Black (N 1) clay with 25 

percent disseminated pirssonite sand; a few disseminated 

white (N 9) opague octahedra of sulfohalite* with minor 

intermixed gaylussite* at top; 10 percent disseminated 

colorless trona blades, averaging 10 mm in length, throughout; disseminated euhedral hanksite crystals, averaging 25 

25 mm in length, at base. Clay 55 percent, pirssonite 25 

percent, hanksite 10 percent, trona 10 percent.

99. 4 . 1 Trona. Well-consolidated white (N 9) to light-gray (N 7) 

massive trona.

99. 7 .3 Halite and trona. Well-consolidated aggregate of colorless 

halite cubes and cubes modified by octahedron, averaging 

3 mm in length, with 25 percent interstitial yellowish gray 

(5V 8/1) massive trona.

100:2 .5 Trona and borax. Well-consolidated aggregate of trona 

blades averaging 10 mm in length, with 25 percent interstitial white (N 9) to light greenish-gray (5GY 8/1) massive 

trona; 35 percent disseminated subhedral borax crystals, 

averaging 20 mm in length, in lower 0.3 ft. Trona #0 percent, borax 20 percent.

101. 8 1. 6 No core.

102. 1 . 3 Burkeite. Grayish-yellow (5Y 8/4) to pale yellowish-orange 

(10 YR 8/6) dense hard massive burkeite. 

102. 3 . 2 Halite. Friable aggregate of colorless halite cubes and cubes 

modified by octahedron, averaging 3 mm in length.

102. 5 . 2 Trona. Well-consolidated white (N 9) to light greenish-gray 

(5GY 8/1) to medium light-gray (N 6) massive trona.

102. 8 . 3 Halite. Friable aggregate of colorless halite cubes and cubes; 

modified by octahedron, averaging 3 mm in length.

103. 2 . 4 No core.

104. 3 1. 1 Halite and clay. Friable aggregate of colorless halite cubes' 

and cubes modified by octahedron, averaging 3 mm in 

length, with seam, 5 mm wide, of greenish-black (5GY 2/1) 

clay at 103.9 ft; trace of interstitial white (N 9) to colorless 

massive and fibrous trona in lower 0.5 ft. Halite 99 percent, clay 1 percent.

104! 5 .2 Burkeite and trona. Vuggy aggregate of grayish-yellow 

(5Y 8/4) to pale yellowish-orange (10YR 8/6) hard massive 

burkeite in lenticular pockets with interstitial white (N 9) 

to greenish-gray (5GY 6/1) massive trona containing intermixed colorless trona blades averaging 10 mm in length. 

Burkeite 50 percent, trona 50 percent.

104. 7 . 2 Halite. Friable aggregate of colorless halite cubes and cubes 

modified by octahedron, averaging 3 mm in length.

104. 9 . 2 Burkeite. Grayish-orange (10 YR 7/4) massive hard slightly 

vuggy burkeite.

105. 1 . 2 Trona and clay. Medium light-gray (N 6) massive trona 

with pockets of colorless fibrous trona; irregular streaks, 

1 mm wide, of grayish-black (N 2) clay and traces of interstitial clay throughout. Trona 99 percent, clay 1 percent.
242

Depth Unit thick-

(feet) nes8(fee() Description

A05. 3 0. 2 Burkeite, trona, halite, and borax. Core badly fractured. 

Fragments consisting of (a) grayish-orange (10172 7/4) 

hard massive burkeite, (b) aggregates of colorless halite 

cubes and cubes modified by octahedron, averaging 3 mm 

in length, (c) halite crystal aggregates with pockets of 

burkeite, (d) scattered subhedral borax crystals associated 

with halite; greenish-gray (5GY 6/1) massive trona intermixed with fragments. Burkeite 50 percent, trona 30 percent, halite 19 percent, borax 1 percent.

105. 6 . 3 No core.

105. 9 . 3 Trona and halite. White (N 9) to greenish-gray (5GY 6/1) 

soft massive trona with 10 percent disseminated colorless 

halite cubes, cubes modified by octahedron, and anhedra, 

averaging 3 mm in length; a few grayish-yellow (5Y 8/4) 

rounded nodules of massive burkeite averaging 10 mm in 

length. Probably cuttings, not core.

106.0 .1 Burkeite*. Vuggy seam of grayish-yellow (5Y 8/4) hard 

massive burkeite*.

106. 5 . 5 Halite and trona. Well-consolidated aggregate of colorless 

halite cubes and cubes modified by octahedron, averaging 

3 mm in length, with 5 percent interstitial white (N 9) 

to greenish-gray (5GY6/1) massive trona.

106. 6 .1. Clay and trona. Greenish-black (5GY 2/1) to grayish-black 

(N 2) to blackish-red (5R 2/2) to dark reddish-brown 

(10/2 3/4) clay, locally discolored by intermixed algae(?), 

with irregular seam, 10-20 mm wide, of white (N 9) massive trona at base. Clay 50 percent, trona 50 percent.

106. 7 . 1 Trona. White (N 9) to dark greenish-gray (5G 4/1) to 

greenish-black (5GY 2/1) massive trona, discolored by 

trace of intermixed clay.

106. 9 ; 2 Burkeite*, halite, trona, and borax. Pockets of grayishyellow (5Y 8/4) massive burkeite* with intermixed interstitial colorless halite cubes modified by octahedron, averaging 10 mm in length, and colorless trona blades and fibrous 

trona locally discolored moderate orange-pink (5YR 8/4) 

by algae (?); a few euhedral borax crystals, averaging 5 mm 

in length, disseminated in pockets with burkeite*. Burkeite 

60 percent, halite 25 percent, trona 15 percent.

107. 2 . 3 Halite. Moderately friable aggregate of colorless to faintly 

tinted grayish orange-pink (10 YR 8/2) halite cubes and 

cubes modified by octahedron, averaging 2 mm in length, 

with trace of interstitial colorless fibrous trona.

107. 3 . 1 Trona. White (N 9) massive sugary-textured trona.

107.4 .1 Burkeite. Grayish-yellow (5Y 8/4) hard dense massive 

burkeite.

107. 7 . 3 Trona, burkeite, and halite. White (N 9) to light greenishgray (5GY 8/1) massive trona with vuggy seams, averaging 

5 mm in width, lined with colorless fibrous trona containing minor interstitial grayish-orange (10 YR 7/4) massive trona, and euhedral colorless halite cubes modified by 

octahedron, averaging 4 mm in length; irregular streaks
CORE LOGS FROM SEARLES LAKE, CALIFORNIA 243

Depth Unit thick-

(feef) ness (feet) Description

and pockets of grayish-orange (10 YR 7/4) to moderate 

yellowish-brown (1QYR 5/4) massive burkeite; trace of 

greenish-black (5GY 2/1) clay in irregular streak at 107.6 

ft; scattered euhedral borax crystals, averaging 16 mm in 

length, at base. Trona 75 percent, burkeite 20 percent, 

halite 5 percent.

108. 3 0. 6 Clay and gaylussite. Greenish-black (5GY 2/1) to grayishblack (N 2) to grayish-yellow (5Y 8/4) to very light gray 

(N 7) finely laminated clay with 15 percent disseminated 

gaylussite silt; a few laminae, less than 1 mm wide, discolored moderate reddish-brown (10R 4/6) by algae(?).

108. 5 . 2 Trona and sulfohalite*. White (N 9) to grayish-yellow (5Y 

8/4) fine fibrous trona intermixed with colorless trona 

blades averaging 10 mm in length; fine fibrous trona locally 

discolored moderate orange-pink (1QR 7/4) by algae(?); 

disseminated rounded nodules, averaging 2 mm in length, 

of grayish-orange (10 YR 7/4) sulfohalite* 10 mm from top.

108.7 . 2 Burkeite. Fractured core. Fragments of grayish-orange 

(1QYR 7/4) hard dense massive burkeite.

109. 4 . 7 No core.

109. 9 . 5 Clay and gaylussite. Greenish-black (5GY 2/1) to grayisholive (10 Y 4/2) to pale-olive (10 Y 6/2) to grayish-yellow 

(5Y 8/4) finely laminated clay with 10 percent disseminated 

gaylussite silt.

110. 1 .2 Clay and gaylussite. Greenish-black (5GY 2/1) to grayishblack (N 2) to moderate-brown (SYR 4/4) clay with disseminated euhedral gaylussite crystals averaging 10 mm in 

length and seams, 1-2 mm wide, of disseminated colorless 

euhedral gaylussite sand. Clay 50 percent, gaylussite 50 

percent.

110. 5 .4 Clay and gaylussite. Greenish-black (5GY 2/1) to grayishblack (N 2) to pale-olive (10F 6/2) to grayish-yellow (5Y 

8/4) finely laminated clay with 15 percent disseminated 

gaylussite sand.

110. 7 .2 Clay. Grayish-black (N 2) to greenish-black (5GY 2/1) clay 

with numerous laminae, less than 1 mm in width, of discolored moderate reddish-brown (1012 4/6) by algae(?).

111. 0 .3 Trona. Densely packed aggregate of colorless trona blades, 

averaging 20 mm in length, discolored grayish-black (N 2) 

by trace of interstitial clay.

112. 2 1. 2 Trona. Well-consolidated aggregate of colorless to grayishyellow (5Y 8/4) fibrous trona with pockets and irregular 

seams of white (N 9) to medium-gray (N 5) massive trona; 

local traces of interstitial black (N 1) clay.

112. 7 .5 Clay and northupite. Greenish-black (5GY 2/1) to paleolive (10 Y 6/2) to very light gray (N 7) finely laminated 

clay with 5 percent disseminated nodules, averaging 1 mm 

in length, of white (N 9) massive northupite.

112. 8 . 1 Clay and gaylussite. Greenish-black (5GY 2/1) clay with 40 

percent disseminated euhedral gaylussite crystals averaging 

1 mm in length.
244 GEOLOGIC INVESTIGATIONS IN MOJAVE DESERT REGION

Depth Unit thick-

(feet) ness (feet) Description

113. 1 0. 3 Clay and gaylussite. Greenish-black (5GY 2/1) clay with 25 

percent disseminated gaylussite silt.

113. 2 .1 Trona. Well-consolidated aggregate of colorless trona blades 

averaging 5 mm in length, locally discolored grayish-yellow 

(5 Y 8/4) by trace of interstitial clay.

113. 4 . 2 No core.

113.9 .5 Trona. Fractured core. Fragments consisting of aggregates 

of white (N 9) to colorless trona blades averaging 5 mm in 

length.

;114. 4 . 5 Clay. Grayish-black (N 2) to greenish-black (5GY 2/1) to 

light olive-gray (5 Y 5/2) to grayish-yellow (5 Y 8/4) to very 

light gray (N 8) finely laminated clay.

314. 8 .4 Clay and gaylussite. Grayish-black (N 2) to greenish-black 

(5GY 2/1) to olive-gray (5Y 3/2) to moderate yellowishbrown (10 YR 5/4) clay with 40 percent disseminated euhedral gaylussite crystals averaging 5 mm in length.

115. 4 .3 Clay. Grayish-black (N 2) to medium-gray (N 5) to lightgray (N 7) to grayish-yellow (5Y 8/4) finely laminated clay.

115. 6 .2 Clay and gaylussite. Greenish-black (5GY 2/1) to grayishblack (N 2) to grayish-olive (107 4/2) faintly finely laminated clay with 25 percent disseminated gaylussite silt.

117. 4 1. 8 Trona. White (AT 9) to medium light-gray (N 6) to darkgray (N 3) seams of massive trona with seams and irregular 

pockets of colorless to grayish-yellow (5Y 8/4) trona blades 

averaging 10 mm in length; 50 percent interstitial grayishblack (N 2) clay in upper 0.1 ft containing small streaks, 

1-5 mm long, of moderate reddish-brown (WR 4/6) algae (?) 

discolorations.

118. 2 . 8 No core.

119. 0 .8 Trona. White (N 9) to medium light-gray (N 6) massive 

trona seams with seams and irregular pockets of colorless 

trona blades averaging 10 mm in length; trace of greenishblack (5GF2/1) clay.

119. 1 .1 Trona and clay. Densely packed hard aggregate of trona 

blades averaging 5 mm in length, with 5 percent interstitial 

greenish-black (5GY 2/1) clay.

120. 1 . 9 No core.

123. 0 3. 0 Clay and gaylussite. Light olive-gray (5Y 5/2) to olive-gray 

(5Y 3/2) to dusky yellow-green (5GY 5/2) clay with 40 percent disseminated euhedral gaylussite crystals from 2 to 30 

mm in length, averaging 10 mm.

125. 1 2. 1 Clay and gaylussite. Light olive-gray (5Y 5/2) to olive-gray 

(5 Y 3/2) to dark greenish-gray (5(? 4/1) clay with 40 percent disseminated gaylussite crystals averaging 15 mm in 

length.

124. 4 . 3 No core.
CORE LOGS FROM SEARLES LAKE;, CALIFORNIA. 245

Searles drill hole GS-16

LOCATION: Searles Lake, Calif., at common cor., sees. 26, 27, 34, and 35, T. 25 S.,

R., 43 E., Mount Diablo base line and meridian. 

ELEVATION AT TOP OF HOLE: 1,616ft. 

ELEVATION AT BOTTOM OF HOLE: 1,486 ft. 

TOTAL DEPTH: 130.0 ft. 

DATES DRILLED: March 14-28, 1955. 

CASING USED: 84.0 ft of 3-in. pipe. 

MINERAL DETERMINATIONS: Minerals identified microscopically are denoted by

an asterisk (*); minerals identified by X-ray diffraction methods are denoted

by two asterisks (**).

Depth Unit thlck-

(feet) ness (feet) Description

0. 5 0. 5 Halite and clay. Friable vuggy aggregate of colorless halite 

cubes modified by octahedron and subhedra, averaging 10 

mm in length, with 5 percent interstitial dusky yellow-green 

(50? F 5/2) clay.

2. 1 1. 6 Halite and clay. Unconsolidated mixture of colorless halite 

cubes modified by octahedron and subhedra, averaging 5 

mm in length, with 5 percent interstitial dusky yellow-green 

(50? r 5/2) clay.

2. 2 . 1 No core.

4. 3 2. 1 Halite and clay. Unconsolidated mixture of colorless halite 

cubes, cubes modified by octahedron, and subhedra, up to 

15 mm in length, averaging 5 mm, with 5 percent interstitial 

dusky yellow-green (5GY 5/2) clay.

6. 3 2. 0 Halite, hanksite, and clay. Unconsolidated mixture of colorless halite cubes, cubes modified by octahedron, and subhedra, averaging 3 mm in length, with 15 percent interstitial 

dusky yellow-green (50? Y" 5/2) clay; numerous disseminated 

subhedral smoky hanksite crystals up to 75 mm in length, 

averaging 40 mm. Probably cuttings, not core. Halite 

70 percent, hanksite 29 percent, clay 1 percent.

6. 4 . 1 No core.

8. 3 1. 9 Halite and clay. Unconsolidated mixture of colorless halite 

cubes, cubes modified by octahedron, and subhedra, averaging 3 mm in length, with 20 percent intermixed halite sand 

and 1 percent intermixed dusky yellow-green (5GY 5/2) 

clay; scattered anhedral rounded smoky hanksite crystals 

averaging 20 mm in length. Probably cuttings, not core.

8. 4 . 1 No core.

8. 9 .5 Halite. Unconsolidated halite sand discolored dusky yellow 

green (50?F 5/2) by intermixed clay; 10 percent disseminated 

colorless halite cubes and subhedra, averaging 2 mm1 in 

length.

9. 8-' .9 Halite and clay. Unconsolidated mixture of colorless halite 

cubes, cubes modified by octahedron, and subhedra, averaging 5 mm in length, with 5 percent interstitial dusky yellowgreen (50? F 5/2). clay; a few loose disseminated subhedral 

hanksite crystals averaging 40 mm in length.

9. 9 .1 No core.
246 GEOLOGIC INVESTIGATIONS IN MOJAVE DESERT REGION

Depth Unit thick-

(fed) nets (.feet) Description

10. 5 0. 6 Halite and clay. Unconsolidated mixture of colorless halite 

cubes modified by octahedron and subhedra, averaging 5 

mm in length, with 10 percent interstitial dusky yellowgreen (5G Y 5/2) clay.

10. 9 .4 Clay and halite. Soft tenacious dusky yellow-green (5GY 5/2) 

clay with 40 percent disseminated colorless halite cubes 

modified by octahedron and subhedra, up to 20 mm in 

length, averaging 5 mm.

11. 0 . 1 No core.

11. 8 .8 Halite and hanksite. Unconsolidated mixture of colorless 

halite cubes and cubes modified by octahedron, up to 10 

mm in length, averaging 2 mm, with 10 percent loose disseminated subhedral to euhedral yellowish hanksite crystals 

up to 30 mm in length, averaging 15 mm; trace of interstitial 

dusky yellow-green (5GY 5/2) clay.

11. 9 . 1 No core.

12. 7 .8 Clay, hanksite, and pirssonite. Poorly consolidated dusky 

yellow-green (5GY 5/2) clay with 20 percent disseminated 

crystals euhedral colorless to light-yellowish hanksite crystals averaging 5 mm in length; a few colorless halite cubes 

modified by octahedron or subhedra, averaging 3 mm in 

length; fragments of dusky yellow-green (5GY 5/2) and 

grayish-black (N 2) clay with 20 percent disseminated 

euhedral pirssonite crystals, averaging 1 mm in length, in 

grayish-black (N 2) clay seams. Clay 78 percent, hanksite 

20 percent, pirssonite 2 percent.

13. 7 1.0 Halite, clay, and pirssonite. Friable aggregate of colorless 

halite cubes modified by octahedron, subhedja, and anhedra, averaging 10 mm in length, with seams of intermixed 

dusky yellow-green (5GY 5/2) to grayish-black (N 2) clay 

with 10 percent disseminated euhedral pirssonite silt and 

fine sand. Halite 89 percent, clay 10 percent, pirssonite 1 

percent.

13. 8 .1 No core.

14. 1 .3 Halite and clay. Moderately friable aggregate of colorless 

halite cubes modified by octahedron and subhedra, up to 

20 mm in length, averaging 5 mm, with 1 percent interstitial 

dusky yellow-green (5G Y 5/2) clay.

15. 0 .9 Halite and clay. Unconsolidated aggregate of colorless halite 

cubes modified by octahedron and subhedra, up to 20 mm 

in length, averaging 5 mm, with 5 percent interstitial dusky 

yellow-green (5GY 5/2) clay.

15. 7 .7 Halite and clay. Friable aggregate of colorless halite cubes 

modified by octahedron and subhedra, averaging 5 mm in 

length, with 3 percent dusky yellow-green (5GY 5/2) clay in 

interstices and thin seams with intermixed halite.

15. 8 . 1 No core.

16. 2 .4 Halite. Core fractured. Friable aggregate of colorless halite 

cubes modified by octahedron and subhedra, averaging 4 

mm in length, with trace of interstitial dusky yellow-green 

(5GY 5/2) clay.
CORE LOGS FROM SEARLES LAKE, CALIFORNIA '247

Depth Unit thick-

(feet) ness (feet) Description

17.0 0. 8 Halite. Unconsolidated mixture of colorless halite cubes 

modified by octahedron and subhedra, up to 40 mm in 

length, averaging 4 mm, with 10 percent interstitial fine 

halite sand discolored dusky yellow-green (5GY 5/2) by 

trace of intermixed clay.

17. 2 .2 Halite and clay. Core fractured. Friable aggregate of colorless halite cubes modified by octahedron and subhedra, 

averaging 5 mm in length, with 1 percent interstitial dusky 

yellow-green (5GF5/2) clay.

17. 5 .3 No core.

18.4 .9 Halite. Unconsolidated dusky yellow-green (6GY 5/2) to 

white (N 9) fine halite sand with 5 percent disseminated 

colorless halite cubes modified by octahedron and subhedra, 

averaging 5 mm in length. Probably cuttings, not core.

20. 1 1. 7 Hanksite and halite. Unconsolidated mixture of colorless to 

light-yellowish euhedral to subhedral hanksite crystals from 

I to 40 mm in length, averaging 3 mm, with numerous inclusions of dark yellowish-orange (10YR 6/6) algae(?); 1 

percent colorless halite cubes modified by octahedron, 

averaging 5 mm in length, disseminated throughout.

21. 4 1. 3 No core.

22. 5 1.1 Hanksite and halite. Unconsolidated mixture of euhedral 

to subhedral colorless to yellowish hanksite crystals averaging 5 mm in length; with 1 percent disseminated colorless 

halite cubes and cubes modified by octahedron, averaging 

3 mm in length; 5 percent interstitial halite sand discolored 

(5GY 7/2) grayish yellow green by trace of interstitial clay.

22.9 .4 Hanksite. Well-consolidated slightly vuggy aggregate of 

euhedral yellowish hanksite crystals to 20 mm in length, 

averaging 5 mm, with scattered colorless halite cubes 

modified by octahedron from 3 to 20 mm in length.

25. 3 2. 4 No core.

25. 8 .5 Hanksite and halite. Unconsolidated mixture of euhedral 

to anhedral yellowish hanksite crystals up to 80 mm in 

length, averaging 30 mm, with common inclusions of dark 

yellowish-orange (10 YR 6/6) algae (?); 10 percent interstitial white (N 9) to colorless halite sand (probably cuttings, 

not core); trace of dusky yellow-green (5GY 5/2) clay in 

interstices of hanksite crystals; single euhedral colorless 

borax crystal 25 mm in length.

26.3 .5 Halite and trona. Dense granular aggregate of colorless 

halite crystals with 10 percent interstitial white (N 9) to 

very pale orange (10FIE 8/2) massive trona; scattered 

pinpoint inclusions of pale yellowish-orange (10YR 8/6) 

algae (?) in halite; trace of interstitial colorless bladed 

trona, blades averaging 10 mm in length, in lower 0,1 ft.

26. 5 .2 Halite, clay, and trona. Dense granular aggregate of colorless halite crystals with 5 percent interstitial pale greenishyellow (1QYR 8/2) clay; numerous small pockets of colorless 

fibrous trona in interstices of halite in lower 0.1 ft. Halite 

93 percent, clay 5 percent, trona 2 percent. 

 8
248 GEOLOGIC INVESTIGATIONS IN MOJAVE DESERT REGION

Depth Unit thick-

(feet) ness (feet) Description

26. 7 0. 2 Borax and clay. Dense aggregate of subhedral to anhedral 

borax crystals averaging 20 mm in length, with irregular 

seam, varying from 5 to 20 mm in width, of dusky yellowgreen (5GY 5/2) to grayish olive-green (5GY 3/2) clay at 

top. Borax 80 percent, clay 20 percent.

26. 8 .1 Trona and halite. Compact massive very pale orange 

(WYR 8/2) trona with a few embedded colorless halite 

subhedra averaging 10 mm in length; discontinuous seam, 

1 mm wide, of intermixed dark yellowish-orange (1QYR 

6/6) algae(?) at base. ' Trona 99 percent, halite 1 percent.

27.3 .5 Halite. Granular aggregate of colorless halite crystals 

averaging 3 mm in length, with numerous pinpoint inclusions of dark yellowish-orange (1QYR 6/6) algae(?); trace 

of interstitial dusky yellow-green (5GY 5/2) clay.

27. 4 .1 Trona and halite. Very pale orange (10YR 8/2) compact 

massive trona with pinpoint inclusions of dark yellowishorange (IOYR 6/6) algae(?); 20 percent disseminated 

colorless halite cubes and cubes modified by octahedron, 

averaging 3 mm in length.

29. 6 2. 2 No core.

29. 9 .3 Halite and clay. Well-consolidated granular aggregate of 

colorless halite cubes and cubes modified by octahedron, 

averaging 3 mm in length, with 2 percent interstitial 

grayish olive-green (5GY 3/2) clay.

30. 4 .5 Halite and trona. Well-consolidated vuggy seams, averaging 

5 mm in width, of colorless subhedral halite cubes modified 

by octahedron, white (N 9) massive trona, and intermixed 

colorless halite and white (N 9) massive trona; trace of 

intermixed grayish olive-green (5GY 3/2) clay with halite 

containing pinhead inclusions of algae(?) at 30.0 ft; vague 

seam, % mm wide, of dark yellowish-orange (1QYR 6/6) 

algae(?) at 29.65 ft. Halite 60 percent, trona 40 percent.

30.9 .5 Halite and trona. Dense granular aggregate of colorless 

halite crystals, averaging 3 mm in length, with 10 percent 

interstitial very pale orange (IQYR 8/2) massive trona.

31.0 . 1 Halite, trona, and clay. Well-consolidated aggregate of 

colorless halite cubes modified by octahedron, averaging 

3 mm in length, with seams, 5 mm wide, of dark greenishgray (5GY 4/1) massive trona containing intermixed 

grayish-olive (10 Y 4/2) clay at top and base; pinpoint 

inclusions of dark yellowish-orange (1QYR 6/6) algae(?) 

in halite and trona. Halite 50 percent, trona 40 percent, 

clay 10 percent.

31.1 .1 Halite and trona. Dense granular aggregate of colorless 

halite crystals with 5 percent interstitial white (N 9) to 

very pale orange (10YR 8/2) massive trona.

31. 4 .3 Halite and clay. Friable slightly vuggy aggregate of colorless 

halite cubes modified by octahedron and subhedra, averaging 5 mm in length, with seam, 5 mm wide, of grayish-olive 

(10 Y 4/2) clay at 31.2 ft and irregular seam, 5 to 20 mm 

wide, of grayish-olive (10 Y 4/2) to dusky yellow-green
249

.Depth Unit thick- 

(feet) ness (feet) Description

(5GY 5/2) to greenish-black (5GY 2/1) clay at base; a few 

disseminated sulfohalite octahedra, averaging 3 mm in 

length, in clay seams. Halite 75 percent, clay 25 percent. 

.32. 0 0. 6 Halite and clay. Unconsolidated mixture of colorless halite 

cubes, cubes modified by octahedron, and subhedra, up to 

10 mm in length, averaging 2 mm, with 2 percent intermixed dusky yellow-green (5GY 5/2) to grayish olive-green 

(50 r 3/2) clay.

33. 8 1. 8 No core.

34. 1 .3 Halite and borax. Unconsolidated mixture of colorless 

halite sand with intermixed halite cubes modified by 

octahedron, averaging 3 mm in length, disseminated 

colorless subhedral borax crystals averaging 25 mm in 

length, and a few sulfohalite octahedra averaging 5 mm 

in length. Probably cuttings, not core. Halite 80 percent, 

borax 20 percent.

34.9 .8 Halite and trona. Well-consolidated moderately vuggy 

aggregate of colorless halite cubes modified by octahedron, 

averaging 3 mm in length, with 10 percent interstitial 

pale greenish-yellow (10 y 8/2) to very pale orange (10 YR 

8/2) massive trona.

35. 1 .2 Borax and halite. Well-consolidated aggregate of densely 

packed subhedral colorless to pale yellowish-borax crystals 

averaging 20 mm in length, with disseminated intermixed 

colorless halite cubes modified by octahedron, averaging 

5 mm in length, along base. Borax 98 percent, halite 2 

percent.

35. 4 .3 Halite and borax. Well-consolidated aggregate of colorless 

halite cubes modified by octahedron, averaging 5 mm in 

length, with a few disseminated subhedral borax crystals, 

averaging 20 mm in length, at top; trace of trona blades, 

averaging 5 mm in length, at base. Halite 99 percent, 

borax 1 percent.

35. 5 .1 Clay. Grayish-olive (10y 4/2) to grayish olive-green (50 y 

3/2) clay with pinhead discolorations of dark yellowishorange (10YR 6/6) algae(?).

35. 6 . 1 Halite and clay. Well-consolidated aggregate of colorless 

halite cubes and cubes modified by octahedron, averaging 

3 mm in length; seam, 15 mm wide, of grayish-olive (10y 

4/2) to grayish olive-green (5GT 3/2) clay at base, containing a few disseminated sulfohalite octahedra averaging 5 

mm in length. Halite 50 percent, clay 50 percent.

35. 9 .3 Halite. Friable aggregate of colorless halite cubes modified 

by octahedron, averaging 5 mm in length;, trace of intermixed grayish-olive (10 y 4/2) to grayish olive-green 

(50y 3/2) clay in lower 15 mm.

36i 1 .2 Halite and trona. Well-consolidated slightly vuggy granular 

aggregate of colorless halite crystals averaging 3 mm in 

length, with 10 percent interstitial very pale orange (1QYR 

8/2) to pale greenish-yellow (10y '8/2) massive trona; 

scattered halite cubes modified by octahedron; in vugs.
250 GEOLOGIC INVESTIGATIONS*"IN MOJAVE ;DESERT EEGION

Depth Untt thick-

(feet) ness (feet) Description

36. 3 0. 2 Hanksite and clay. Fractured core. Densely packed aggregate of subhedral to euhedral hanksite crystals showing 

prominent basal pinacoids with 5 percent interstitial 

grayish olive-green (5GY 3/2) clay; a few loose sulfohalite 

octahedra up to 18 mm on edge; scattered loose subhedral 

borax crystals.

36. 4 .1 Halite and trona. Friable aggregate of colorless halite cubes 

modified by octahedron, averaging 3 mm in length, with 2 

percent interstitial pale-olive (10 Y 6/2) massive trona.

37. 3 .9 Halite, trona, and clay. Well-consolidated slightly vuggy 

granular aggregate of colorless halite crystals averaging 3 

mm in length, with 10 percent interstitial white (N 9) to 

very pale orange (10 YR 8/2) massive trona; lenticular horizontal vugs, averaging 3 mm in width, lined with halite 

cubes modified by octahedron, averaging 2 mm in length, 

from 36.7 to 36.9 ft; seam, 10-15 mm wide, of grayish 

olive-green (5GY 3/2) clay at base, containing 5 percent 

disseminated sulfohalite octahedra from 2 to 10 mm in 

length. Halite 85 percent, trona 10 percent, clay 5 percent.

37. 6 .3 Halite. Friable aggregate of colorless halite cubes and subhedra, averaging 5 mm in length.

38. 9 .8 Trona and halite. Well-consolidated slightly vuggy very 

pale orange (IQYR 8/2) to grayish-orange (IQYR 7/4) 

massive trona with horizontal seams and streaks 1-2 mm 

wide, of colorless halite; seam, 10 mm wide, of intermixed 

colorless trona blades averaging 5 mm in length, with light 

greenish-gray (5GY 8/1) massive trona at 38.2 ft. Trona 

90 percent, halite 10 percent.

39.0 .1 Borax and trona. Densely packed aggregate of colorless 

anhedral borax crystals averaging 20 mm in length, with 

2 percent very pale orange (IQYR 8/2) massive trona in 

%-in. pockets and thin streaks.

39. 1 .1 Trona. Very pale orange (10F.R 8/2) to grayish-orange 

(IQYR 8/4) compact massive trona.

40.0 .9 Halite and trona. Well-consolidated moderately vuggy 

aggregate of colorless halite cubes modified by octahedron, 

averaging 3 mm in length, with 10 percent interstitial very 

pale orange (IQYR 8/2) to light greenish-gray (5GY 8/1) 

massive trona.

40. 3 .3 Trona and hanksite. Well-consolidated white (N 9) to light 

olive-gray (5Y 6/1) massive hard trona with 1 percent 

subhedral hanksite crystals averaging 20 mm in length at 

base.

40.6 .3 Halite and trona. Well-consolidated moderately vuggy 

aggregate of colorless halite cubes modified by octahedron, 

averaging 2 mm in length, with 20 percent interstitial white 

(N 9) to very pale orange (IQYR 8/2) to pale greenish-yellow 

(10Y" 8/2) to light-gray (N 7) massive trona; lenticular 

horizontal seams, 2-3 mm wide, lined with halite cubes 

modified by octahedron.

41. 9 1. 3 No core.
CORE LOGS FROM SEARLES LAKE, CALIFORNIA 251

Depth Unit thick- 

(feet) ness (feet) Description

42. 4 0. 5 Halite, trona, and clay. Well-consolidated slightly friable 

aggregate of colorless halite cubes and subhedra, averaging 

3 mm in length, with 2 percent interstitial white (N 9) to 

very pale orange (WYR 8/2) to pale greenish-yellow (10Y 

8/2) massive trona; seam, averaging 5 mm in width, of 

grayish olive-green (5GY 3/2) clay at 42.3 ft.

42. 8 .4 Trona, halite, and borax. Vuggy aggregate of white (AT 9) 

to dusky-yellow (5Y 6/4) massive trona with intermixed 

colorless fine fibrous trona; 5 percent disseminated colorless 

halite cubes and cubes modified by octahedron, averaging 

2 mm in length; scattered streaks and pockets, up to 40 

mm in length, of colorless anhedral borax. Trona 90 

percent, halite 5 percent, borax 5 percent.

43. 5 .7 Halite and trona. Well-consolidated granular aggregate of 

colorless halite cubes with 10 per cent interstitial white (AT 9) 

to grayish-orange (10YR 7/4) massive trona.

43.6 .1 Clay, pirssonite, and trona. Greenish-black (5GY 2/1) to 

grayish-black (N 2) to olive-gray (5Y 3/2) clay with 30 

percent disseminated fine euhedral to subhedral pirssonite 

sand; seam, 5 mm wide, of fine colorless fibrous trona at 

base; disseminated flat rounded pebbles, averaging 10 mm 

in length, of white (N 9) hard massive trona in lower 15 

mm; a few sulfohalite octahedra averaging 5 mm in length; 

clay contains distinct moderate reddish-brown (10/2 4/6) 

algae (?) discolored laminae and pinpoint spots of dark 

yellowish-orange (10YR 6/6) algae(?) throughout. Clay 

65 percent, pirssonite 30 percent, trona 5 percent.

43. 8 . 2 Halite. Friable aggregate of colorless halite cubes and cubes 

modified by octahedron, averaging 2 mm in length.

44. 1 .3 Halite, hanksite, and clay. Well-consolidated aggregate of 

colorless halite cubes and anhedra, averaging 4 mm in 

length, with 5 percent grayish olive-green (50 Y 3/2) clay 

in streaks and pockets; 15 percent disseminated anhedral 

smoky hanksite crystals from 10 to 40 mm in length.

45. 8 1. 7 No core.

46. 1 .3 Hanksite, halite and clay. Well-consolidated aggregate of 

smoky subhedral hanksite crystals up to 50 mm in length, 

with interstitial colorless halite cubes and cubes modified 

by octahedron, averaging 2 mm in length, and grayish 

olive-green (5GY 3/2) to olive-gray (5F 3/2) clay containing 

pinpoint spots of moderate reddish-brown (10/2 4/6) algae. 

Hanksite 60 percent, halite 35 percent, clay 5 percent.

46. 4 .3 Trona and hanksite. Poorly consolidated core. Fragments 

of round very pale orange (10 YR 8/2) hard massive trona 

with soft light olive-gray (5F6/1) massive trona; disseminated subhedral to euhedral colorless to smoky hanksite 

crystals from 10 to 50 mm in length; single sulfohalite 

octahedron, 8 mm in length, noted. Trona 80 percent, 

hanksite 20 percent.
252 GEOLOGIC INVESTIGATIONS IN MOJAVE DESERT REGION

Depth Unit thick-

(feet) ness (feet) Description

46. 6 0.2 Halite and trona. Well-consolidated aggregate of colorless-- 

halite crystals averaging 3 mm in length, with 40 percentinterstitial white (N 9) to very pale orange (10F.R 8/2) 

massive trona; single sulfohalite octahedron at top.

46. 8 .2 Trona, hanksite, and clay. White (N 9) to light greenishgray (5GY 8/1) slightly vuggy massive trona with lenticular 

horizontal vugs and pockets of fine colorless fibrous tronaintermixed with olive-gray ,(5F 3/2) clay containing scattered pinpoint spots of moderate reddish-brown (10R 4/6) 

algae (?); euhedral smoky hanksite crystals, averaging 15- 

mm in length, disseminated throughout but chiefly confined to base. Trona 60 percent, hanksite 39 percent, clay 

1 percent.

47. 3 .5 No core.

48. 1 .8 Halite and trona. Well-consolidated vuggy aggregate of 

colorless halite cubes averaging 3 mm in length, with 40' 

percent interstitial white (N 9) to very pale orange (1QYR 

8/2) massive trona; horizontal lenticular vugs, up to 5 mm 

in width, lined with colorless to white (N 9) halite cubes;: 

trace of intermixed greenish-black (5GY 2/1) clay in lenticlar horizontal pocket at 47.7 ft.

48.3 .2 Trona and halite. Fractured core. Very pale orange- 

(10 YR 8/2) to grayish-yellow (5F 8/4) to pale greenishyellow (10 Y 8/2) massive trona with 20 percent disseminated 

colorless halite crystals averaging 2 mm in length; a few 

narrow horizontal lenticular vugs.

48. 6 .3 Trona and halite. Well-consolidated very pale orange 

(10 YR 8/2) to pale greenish-yellow (10 Y 8/2) massive trona 

with 40 percent disseminated colorless halite crystals; a few 

sulfohalite octahedra at base, with trace of intermixed 

grayish-olive (10 Y 4/2) clay.

49. 1 .5 Halite and trona. Well-consolidated aggregate of colorlesa 

halite cubes averaging 3 mm in length, with seam, 5 mm 

wide, of grayish-yellow (5F 8/4) to pale greenish-yellow 

(10F 8/2) massive trona at 48.9 ft; trace of interstitial 

white (N 9) to grayish-yellow (5F 8/4) trona in lower 0.2 

ft. Halite 97 percent, trona 3 percent.

49. 6 .5 Halite, hanksite, borax, and clay. Well-consolidated aggregate of colorless halite cubes and cubes modified by octahedron, averaging 3 mm in length, with seam of anhedral 

colorless borax crystals, averaging 20 mm in length, at top; 

1 percent interstitial grayish olive-green (5GY 3/2) clay in 

upper 0.3 ft; large disseminated anhedral to subhedral 

smoky hanksite crystals up to 60 mm in length. Halite 57 

percent, hanksite 29 percent, borax 13 percent, clay 1 

percent.

50. 1 .5 Halite, trona, and hanksite. Well-consolidated vuggy aggregate of colorless halite cubes modified by octahedron and 

cubes, averaging 3 mm in length, with 35 percent interstitial 

white (N 9) to grayish-yellow (5F 8/4) massive trona containing traces of fine colorless fibrous trona; large colorless 

halite cubes modified by octahedron, averaging 10 mm in
253

Depth Unit thick- 

(feet) ness (ftei) Description

length, at base, with anhedral to subhedral smoky hanksite 

in lower 0.1 ft. Halite 62 percent, trona 35 percent, hanksite 

3 percent.

50.3 0.2 Halite and trona. Fractured core. Fragments of wellconsolidated vuggy aggregates of colorless halite cubes 

modified by octahedron, up to 10 mm in length, averaging 

5 mm, with 1 percent interstitial white (N 9) to very pale 

orange (10YR 8/2) massive trona.

51. 3 1. 0 No core.

51. 5 .2 Halite and trona. Fractured core. Fragments of well-consolidated aggregates of colorless halite cubes modified by 

octahedron and anhedra, averaging 2 mm in length, with 

5 percent interstitial white (N 9) to very pale orange 

(10YR 8/2) massive trona.

52. 1 .6 Halite and trona. Well-consolidated vuggy aggregate of 

colorless halite cubes modified by octahedron, up to 20 mm 

in length, averaging 5 mm, with 20 percent white (N 9) to 

very pale orange (WYR 8/2) to grayish-yellow (5F8/4) 

massive trona in seams and interstices.

52. 4 .3 Trona and halite. Poorly consolidated core. Grayish-yellow 

(5F 8/4) to very pale orange (WYR 8/2) massive soft vuggy 

trona with 20 percent disseminated colorless halite cubes 

modified by octahedron and subhedra, averaging 5 mm in 

length.

52.6 .2 Trona and halite. Well-consolidated very pale orange 

(WYR 8/2) to moderate orange-pink (5YR 8/4) soft massive 

trona with 20 percent colorless halite cubes and subhedra^ 

averaging 2 mm in length, in seams 1 to 5 mm wide.

53. 1 .5 No core.

53. 5 .4 Halite and trona. Well-consolidated slightly vuggy aggregate of colorless halite cubes modified by octahedron and 

subhedra, averaging 2 mm in length, with 10 percent interstitial white (N 9) to very pale orange (WYR 8/2) massive 

trona; trace of colorless aphthitalite (glaserite) blades, 

averaging 5 mm in length, in Irin. pockets; a few narrow 

lenticular horizontal vugs 1 to 2 mm wide.

53. 6 .1 Halite and trona. Well-consolidated aggregate of colorless 

halite cubes modified by octahedron and cubes, with 10 

percent interstitial white (N 9) to grayish-orange (WYR 

7/4) massive trona.

53. 7 .1 Halite and aphthitalite. Vuggy aggregate of intermixed colorless 

halite cubes modified by octahedron, averaging 5 mm in 

length, with colorless aphthitalite (glaserite) blades averaging 10 mm in length. Halite 75 percent, aphthitalite 25 

percent.

54. 2 .5 Trona and halite. Fractured core. Fragments of well-consolidated slightly vuggy massive very pale orange (WYR 8/2) 

to yellowish-gray (5Y 7/2) trona with scattered pockets,, 

averaging 25 mm in length, of colorless halite cubes modified 

by octahedron, averaging 3 mm in length; trace of colorlessaphthitalite (glaserite) blades, averaging 2 mm in length,, 

lining vugs. Trona 98 percent, halite 2 percent.
254 GEOLOGIC INVESTIGATIONS IN MOJAVE DESERT EEGION

Depth Unit thick- 

(feet) ness (feet) Description

55.4 1.2 Trona and halite. Well-consolidated very pale orange 

(WYR 8/2) to grayish-orange (10/2 7/4) to white (N 9) 

massive trona with 40 percent colorless halite cubes modified by octahedron and subhedra, averaging 3 mm in length, 

in horizontal seams, up to 10 mm wide, and disseminated 

throughout.

55. 8 . 4 Halite and trona. Well-consolidated moderately friable aggregate of colorless halite cubes averaging 3 mm in length, 

with 5 percent interstitial white (N 9) to pale greenishyellow (lOF 8/2) massive trona.

56. 1 .3 Halite and trona. Fractured and poorly consolidated core. 

Colorless to white (N 8) halite sand with fragments of wellconsolidated aggregates of colorless halite cubes modified 

by octahedron, averaging 3 mm in length, containing 5 percent interstitial white (N 9) massive trona; trace of grayish 

olive-green (5GY 3/2) clay in thin seam 5 mm wide, fragments consisting of aggregates of subhedral colorless halite 

crystals averaging 20 mm in length. Probably cuttings, 

not core.

56. 4 .3 Trona and halite. Well-consolidated white (N 9) to very 

pale orange (10Y7J! 8/2) to moderate orange-pink (5YR 8/4) 

massive trona with 10 percent disseminated colorless halite 

cubes modified by octahedron, averaging 2 mm in length, 

in slightly vuggy seams 1 to 5 mm wide.

56. 8 .4 Halite and trona. Well-consolidated slightly vuggy aggregate of colorless halite cubes modified by octahedron, averaging 3 mm in length, with 10 percent interstitial white 

(N 9) to very pale orange (10 YR 8/2) massive trona.

57. 1 .3 Trona and halite. Well-consolidated white (N 9) to very pale 

orange (10 YR 8/2) slightly vuggy massive trona with 40 

percent disseminated colorless halite cubes modified by 

octahedron, averaging 3 mm in length; vugs contain colorless halite cubes modified by octahedron up to 9 mm in 

length.

58. 2 1. 1 No core.

58. 7 .5 Halite and trona. Well-consolidated aggregate of colorless 

halite cubes modified by octahedron, averaging 3 mm in 

length, with trace of interstitial white (N 9) massive trona; 

seam, 5 mm wide, of very pale orange (IQYR 8/2) to pale 

greenish-yellow (10 Y 8/2) massive trona at top. Halite 

97 percent, trona 3 percent.

58.8 .1 Trona and halite. White (N 9) to pale greenish-yellow 

(10 Y 8/2) massive trona with 10 percent disseminated 

colorless halite cubes and cubes modified by octahedron, 

averaging 5 mm in length.

59. 2 . 4 Halite. Well-consolidated dense aggregate of colorless halite 

crystals, averaging 3 mm in length, with trace of interstitial 

very pale orange (IQYR 8/2) massive trona.

59. 8 .6 Halite and trona. Well-consolidated aggregate of colorless 

halite crystals, averaging 2 mm in length, with 10 percent 

interstitial very pale orange (WYR 8/2) massive trona.

0
CORE LOGS FROM SEARLES LAKE, CALIFORNIA 255

Depth Unit thick-

(feet) ness (/erf) Description

59. 9 0.1 Halite and trona. Fractured core. Fragments of well-consolidated aggregates of colorless halite cubes modified by 

octahedron, averaging 5 mm in length, with 15 percent 

interstitial very pale orange (WYR 8/2) massive trona.

60. 0 .1 Trona. Irregular seam, varying from 10 to 40 mm in width, 

. of very pale orange (lOyJS 8/2) compact massive trona.

60. 2 .2 Trona and halite. Well-consolidated white (N 9) to yellowishgray (5F 7/2) to grayish-yellow (57 8/4) massive trona, 

with seam of 10 percent disseminated colorless halite cubes 

and cubes modified by octahedron, averaging 2 mm in 

length, in lower 0.1 ft; trace of olive-gray (5Y 3/2) clay in 

thin irregular discontinuous seams or streaks, 2 mm wide, 

throughout.

61. 1 .9 No core.

62. 0 .9 Halite, trona, and clay. Well-consolidated aggregate of colorless halite cubes averaging 2 mm in length, with 5 percent 

interstitial colorless fibrous trona; seam, 5 mm wide, of 90 

percent colorless to light-gray (N 7) massive trona at 61.6 

ft; trace of grayish-black (N 2) to grayish olive-green (5GY 

3/2) clay in wavy seams 2 mm wide. Halite 93 percent, 

trona 7 percent.

62. 3 .3 Halite and trona. Poorly consolidated aggregate of halite 

cubes modified by octahedron, averaging 3 mm in length, 

with 5 percent interstitial white (N 9) massive trona; fragments of white (N 9) to yellowish-gray (5Y 8/1) massive 

trona containing traces of intermixed greenish-black 

(5GY 2/1) clay. Halite 80 percent, trona 20 percent.

62. 7 .4 Trona. Well-consolidated compact white (N 9) to very pale 

orange (10 YR 8/2) fine fibrous trona.

63. 0 .3 Trona. Yellowish-gray (5Y 8/1) soft massive trona discolored 

light olive-gray (5Y 3/2) by trace of intermixed clay in 

lower 0.1 ft; a few 1-in. pockets of white (N 9) to colorless 

fine fibrous trona in lower 0.1 ft.

64. 0 1.0 No core.

64. 6 .6 Trona. Poorly consolidated soft light greenish-gray (50? Y 8/1) 

to yellowish-gray (5Y 8/1) massive trona; loose fragments 

of well-consolidated dense vuggy light olive-gray (5Y 3/2) 

massive trona, with vugs lined with colorless fibrous trona.

64 8 .2 Trona. Yellowish-gray (5 Y 8/1) soft massive trona.

64 9 .1 Halite and trona. Irregular seam, up to 0.2 ft wide, of wellconsolidated halite crystals with 50 percent interstitial 

yellowish-gray (5Y 8/1) massive trona.

65.6 .7 Trona. Fractured core. Fragments of yellowish-gray (5 Y 7/2) 

to very pale orange (1QYR 8/2) to moderate yellowish-brown 

(1QYR 5/4) soft massive trona with seams and included 

fragments of well-consolidated white (N 9) to moderate 

yellowish-brown (10YR 5/4) dense hard massive trona.

65. 7 .1 Trona. Well-consolidated white (N 9) massive trona with 

seam, 10 mm wide, of pale yellowish-brown (10YR 6/2) 

massive trona.

67. 6 1. 9 No core.
256

Depth Unit thick-

(feet) ness (feet) Description

68. 4 0. 8 Trona. Poorly consolidated white (N 9) to light greenishgray (5GY 8/1) to yellowish-gray (5F 8/1) soft massive 

trona. May be cuttings, not core.

69. 2 .8 No core.

69.7 .5 Trona. Well-consolidated white (N 9) to yellowish-gray 

(5Y 8/1) to dark greenish-gray (50Y 4/1) compact massive 

trona; trace of moderate olive-brown (5F 4/4) to grayisholive (10F 4/2) clay in thin streak, 1 mm wide, in upper 

0.1 ft; a few discontinuous lenticular horizontal seams, 

2 mm wide, filled with colorless subhedral halite crystals 

in lower 0.2 ft.

69. 9 .2 Trona. Fractured core. Grayish-black (N 2) to dark gray 

(N 3) to dusky yellow (5F 6/4) to very pale orange (10 YR 

8/2) dense hard massive trona.

70. 2 . 3 Trona and borax. Dark gray (N 3) to yellowish-gray (5F 

8/1) vuggy massive trona with discontinuous seams and 

pockets of anhedral to subhedral colorless borax. Trona 

75 percent, borax 25 percent.

70. 4 . 2 Trona. White (N 9) soft massive trona with very faint seams, 

2 to 3 mm wide, of very pale orange (10 YR 8/2) trona 

revealed by color differences; seam, 5 mm wide, of grayishblack (N 2) dense hard massive trona at base.

70. 6 .2 Borax and trona. Well-consolidated densely packed aggregates of colorless to smoky anhedral to subhedral borax 

crystals averaging 20 mm in length, with discontinuous 

seam, 5 mm wide, of yellowish-gray (5F 8/1) massive trona 

at 70.5 ft; trace of intermixed greenish-black (5GF 2/1) 

clay in lower 0.1 ft. Borax 96 percent, trona 4 percent.

70. 9 . 3 Clay and gaylussite. Grayish-black (AT 2) to greenish-black 

(5GY 2/1) clay with 30 percent disseminated anhedral to 

subhedral gaylussite crystals averaging 5 mm in length.

71. 1 .2 Clay and gaylussite. Grayish-black (N 2) to olive-gray 

(5F 3/2) to dusky yellow-green (5GY 5/2) to grayish olivegreen (5GY 3/2) to grayish-yellow (5F 8/4) to light olivebrown (5F 5/6) faintly finely laminated clay with seams 

up to 5 mm wide and irregular streaks in upper 0.1 ft containing disseminated euhedral gaylussite sand with lesser 

amounts of intermixed euhedral gaylussite crystals 1 to 2 

mm in length. Clay 80 percent, gaylussite 20 percent.

71. 7 .6 Clay. Grayish-green (50? 5/2) to dusky yellow-green (5GY 

5/2) to grayish olive-green (5GF 3/2) to grayish-black 

(N 2) to light olive-brown (5F 5/6) finely laminated clay; 

seam, 5 mm wide, of 20 percent intermixed euhedral 

gaylussite sand at 71.2 ft.

71.9 .2 Clay and gaylussite. Olive-gray (5F 3/2) to grayish olivegreen (50rF 3/2) to grayish-black (N 2) clay with 50 percent 

disseminated anhedral gaylussite crystals; locally finely 

laminated grayish-yellow (5 F 8/4) to moderate orange-pink 

(5F.R 8/4) to pale greenish-yellow (10F 8/2) to grayisholive (10 F 4/2) to very light gray (N 8) clay without gaylussite crystals. Clay 75 percent, gaylussite 25 percent.
CORE LOGS FROM SEARLES LAKE, CALIFORNIA 257

.Depth Unit thick- 

(feet) ness (feet) Description

73. 5 1. 6 Clay. Greenish-black (50Y 2/1) to grayish-black (N 2) to 

dusky yellow-green (5GF 5/2) to olive-gray (5F 3/2) to 

greenish-yellow (10F 8/2) to light olive-brown (5Y 5/6) 

to very light gray (A*" 8) finely laminated clay.

74. 2 . 7 Clay. Black (N 1) to greenish-black (5GY 2/1) to grayish 

olive-green (5GY 3/2) to olive-gray (5F 3/2) coarsely laminated clay revealed by color differences.

 75. 3 1.1 Clay and aragohite**. Grayish-black (N 2) to greenish-black 

(5GT 2/1) to grayish olive-green (5GF 3/2) clay coarsely 

laminated with laminae, 1 to 2 mm wide, of very light gray 

(N 8) to light greenish-gray (5(7 8/1) finely crystalline massive aragonite**. Clay 95 percent, aragonite 5 percent.

75. 8 .5 Clay. Fractured core. Fragments of black (N 1) to greenishblack (5GY 2/1) to grayish-yellow (5F 8/4) to dusky yellowgreen (5GY 5/2) to very light gray (N 8) fine to coarsely 

laminated clay. Probably cuttings, not core.

77.0 1.2 Clay. Greenish-black (5GY 2/1) to grayish-black (N 2) to 

brownish-black (5YR 2/1) to dusky yellow-green (5GY 

5/2) to pale olive (10 Y 6/2) to grayish-yellow (57 8/4) to 

pale yellowish-orange (WYR 8/6) to very light gray (N 8) 

finely laminated clay.

77. 7 .7 Clay. Dusky yellow-green (5GT 5/2) to grayish-olive (10 Y 

4/2) to grayish-black (N 2) to grayish-yellow (5F 8/4) to 

pale greenish-yellow (10F 8/2) to pale yellowish-orange 

(10 YR 8/6) finely laminated clay.

78. 0 .3 Clay and aragonite**. Greenish-black (5GY 2/1) to grayishblack (AT 2) clay with grayish-yellow (5F 8/4) to pale 

greenish-yellow (10F 8/2) to light greenish-gray (5(7 8/1) 

laminae, averaging 1 mm wide, of soft massive finely 

crystalline aragonite**. Clay 95 percent, aragonite 5 

percent.

78. 1 .1 Clay. Greenish-black (5GY 2/1) to grayish-black (N 2) to 

grayish-yellow (5F 8/4) to pale olive (10F 6/2) to very 

light gray (N 8) finely laminated clay, with laminae wavy 

and crenulated.

78. 3 .2 Clay. Grayish-black (N 2) to dark yellowish-orange (10F.R 

6/6) to pale olive (10F 6/2) to dusky yellow-green (5GY 

5/2) to grayish-yellow (5 F 8/4) finely laminated clay.

78. 5 .2 Clay and aragonite. Grayish-black (N 2) to greenish-black 

(5GY 2/1) clay with light greenish-gray (5GY 8/1) to 

grayish-yellow (5F 8/4) laminae, averaging 1 mm wide 

of soft massive finely crystalline aragonite. Clay 95 

percent, aragonite 5 percent.

78. 7 .2 Clay and gaylussite. Grayish-black (N 2) to greenish-black 

(5GY 2/1) to olive-black (5F 2/1) to pale greenish-yellow 

(10F 8/2) to dusky yellow-green (5(?F 5/2) to dark yellowish-orange (lOFfl 6/6) to grayish-yellow (5F 8/4) moderately coarsely laminated clay; 1 pocket, 25 mm in length, 

of disseminated subhedral dark brittle gaylussite crystals. 

Clay 95 percent, gaylussite 5 percent.
258 GEOLOGIC INVESTIGATIONS IN MOJAVE DESERT REGION

Depth Unit thick- 

(feet) ness (feet) Description

79. 1 0. 4 Clay. Grayish olive-green (50Y 3/2) to dusky yellow-green 

(5GT 5/2) to grayish-olive (10 Y 4/2) to light bluish-gray 

(5B 7/1) to medium bluish-gray (5J3 5/1) coarsely laminated 

clay, laminae revealed by color differences, with irregular 

small streaks, less than 1 mm long, of moderate reddishorange (10R 6/6) algae (?) confined to bluish clay seams at 

78.9 and 79.1 ft.

79. 2 .1 Clay. Grayish-black (N 2) clay with spots and thin streaks 

of moderate reddish-brown (10R 4/6) algae (?)-discolored 

clay.

79. 4 .2 Clay and gaylussite. Grayish-black (N 2) clay with algae(?)- 

discolorations as above, with seam, 5 mm wide, of dusky 

yellow-green (5GY 5/2) clay at base; 50 percent disseminated 

subhedral gaylussite crystals averaging 5 mm in length.

80. 3 .9 Clay and gaylussite. Graylish-black (N 2) to dusky yellowgreen (5GY 5/2) to grayish olive-green (5GY 3/2) to medium 

bluish-gray (5B 5/1) coarsely laminated clay revealed by 

color differences, with 30 percent disseminated euhedral 

gaylussite crystals, averaging 1 mm in length, in lower 

0.5 ft; a few seams of disseminated subhedral to anhedral 

gaylussite crystals, averaging 3 mm in length, in upper 0.4 

ft; moderate reddish-brown (10R 4/6) algae(?) discolorations in clay in upper 10 mm, in seam, 1 mm wide, at 80.1 

ft, and vague discolorations in lower 0.1 ft. Clay 70 percent, 

gaylussite 30 percent.

80. 6 .3 Clay. Grayish-black (N 2) to greenish-gray (5 Or 6/1) coarsely 

laminated clay revealed by color differences.

81.0 .4 Clay and gaylussite. Grayish-black (N 2) clay with 10 

percent disseminated very fine gaylussite silt; seam, 10 

mm wide, of 50 percent disseminated euhedral gaylussite 

crystals, averaging 1 mm in length, at 80.8 ft; moderate 

reddish-brown (10 R 4/6) algae (?) discolorations locally 

present. Clay 86 percent, gaylussite 14 percent.

81. 1 .1 Clay. Grayish-black (N 2) to dusky yellow-green (5GY 5/2) 

clay.

81. 3 .2 Trona and borax. Well-consolidated white (N 9) to light 

greenish-gray (5G 8/1) dense massive trona with disseminated colorless trona blades averaging 10 mm in length; 

euhedral to subhedral colorless borax crystals from 2 to 10 

mm in length, averaging 5 mm, at top. Trona 98 percent, 

borax 2 percent.

81.4 .1 Halite and trona. Well-consolidated dense aggregate of 

colorless halite crystals with 20 percent interstitial white 

(N 9) massive trona conspicuously discolored moderate 

reddish-brown (IOR 4/6) to light-brown (5YR 5/6) by 

intermixed algae(?).

82.1 .7 Clay, gaylussite, and borax. Black (JV 1) to moderate olivebrown (5F 4/4) to greenish-black (5GY 2/1) coarsely laminated clay, revealed by color differences, with 40 percent
CORE LOGS FROM SEARLES LAKE, CALIFORNIA 259

Depth Unit thick-

(feet) ness (feet) Description

disseminated euhedral gaylussite crystals averaging 1 mm 

in length; 5 percent disseminated euhedral borax crystals 

up to 20 mm in length; numerous seams and discolorations 

of moderate reddish-brown (IOR 4/6) algae(?) in lower 0.5 ft.

82. 4 0. 3 Clay and borax. Greenish-black (5GY 2/1) to grayish-black 

(N 2) to grayish olive-green (50 Y 3/2) fiaintly coarsely 

laminated clay, revealed by color differences, with disseminated yellowish euhedral borax crystals from 5 to 20 

mm in length, averaging 10 mm. Clay 75 percent, borax 

25 percent.

82. 6 .2 Clay and pirssonite. Black (N 1) clay with 40 percent disseminated euhedral pirssonite crystals averaging 1 mm in 

length.

82. 8 .2 Clay, borax, and pirssonite. Black (N 1) to greenish-black 

(5GY 2/1) to medium bluish-gray (5(7 5/1) clay with 10 

percent disseminated euhedral pirssonite crystals averaging 

% mm in length; 35 percent disseminated euhedral borax 

crystals up to 30 mm in length, averaging 10 mm; some 

inclusions of moderate reddish-brown (10.R 4/6) algae(?) in 

borax, clay, and pirssonite.

83. 5 .7 Trona. Well-consolidated yellowigh-gray (5F 8/1) to very 

pale orange (10y.R 8/2) to greenish-gray (5GY 6/1) massive 

trona with numerous intermixed pockets and streaks of 

colorless to grayish-yellow (5Y 8/4) fibrous trona associated with a few sulfohalite octaheclra averaging 3 mm 

in length.

83. 7 . 2 No core.

84. 7 1.0 Trona. Well-consolidated slightly vuggy yellowish-gray 

(5Y 8/1) to greenish-gray (5GY 6/1) massive trona with 

numerous irregular pockets and streaks of colorless to 

yellowish-gray (5Y 8/1) fibrous trona.

85. 2 .5 Trona. Fractured core. Fragments of medium-gray (N 5) 

to yellowish-gray (5 Y 8/1) vuggy massive trona with numerous irregular pockets and streaks of colorless to yellowishgray (3Y 8/1) fibrous and bladed trona, blades averaging 

5 mm in length; a few sulfohalite octahedra, averaging 2 mm 

in length, in vugs, with fibrous and bladed trona. Traces of 

moderate reddish-orange (10J? 6/6) algae(?).

85. 9 .7 Trona and halite. Well-consolidated very light gray (N 8) 

to yellowish-gray (5Y 8/1) vuggy massive trona with 40 

percent disseminated colorless halite cubes modified by 

octahedron and subhedra, averaging 2 mm in length; trace 

of colorless to grayish-yellow (5 Y 8/4) fine fibrous trona in 

lenticular horizontal vugs with halite cubes modified by 

octahedron.

86. 0 .1 Halite. Well-consolidated aggregate of colorless halite cubes 

modified by octahedron, up to 20 mm in length, averaging 

10 mm.

86. 8 .8 No core.
GEOLOGIC INVESTIGATIONS IN MOJAVE DESERT REGION

Depth Unit thick-

(feet) ness (feet) Description

87. 7 0. 9 Halite and trona. Moderately friable vuggy aggregate of 

colorless halite cubes modified by octahedron, averaging 

3 mm in length, with 1 percent colorless to grayish-yellow 

(5 Y 8/4) fibrous trona in j^-in. pockets disseminated throughout; trace of medium-gray (N 5) clay intermixed with trona 

in seam, 5 mm wide at 87.2 ft.

87. 8 . 1 Trona and halite. Well-consolidated soft white (N 9) massive 

trona with 25 percent disseminated colorless halite crystals.

88. 3 . 5 Halite and trona. Well-consolidated aggregate of colorless 

halite cubes modified by octahedron, averaging 3 mm in 

length, with trace of interstitial fine colorless fibrous trona; 

seam, 5 mm wide, of fine colorless fibrous trona with distinct 

local discolorations of light-brown (SYR 5/6) algae (?) at 

88.2 ft; local traces of intermixed grayish-black (N 2) clay. 

Halite 97 percent, trona 3 percent.

88. 5 .2 Trona, clay, pirssonite, and halite. Well-consolidated vuggy 

aggregate of colorless to grayish-yellow (5Y 8/4) trona 

blades, averaging 10 mm in length, with J^-in. pockets of 

medium-gray (N 5) massive trona; Beam, 10 mm wide, of 

black (N 1) to grayish-olive (10 Y 4/2) clay containing 40 

percent disseminated euhedral pirssonite crystals, averaging 

1 mm in length, at top; clay also containing local discolorations of moderate reddish-brown (10.R 4/6) algae(?); 

scattered colorless halite cubes modified by octahedron, 

averaging 5 mm in length, at base of clay seam. Trona 82 

percent, clay 10 percent, pirssonite 7 percent, halite 1 

percent.

88. 6 .1 Halite. Well-consolidated aggregate of colorless halite cubes 

and cubes modified by octahedron, averaging 3 mm in 

length, with scattered %-in. pockets of fine colorless fibrous 

trona.

88. 8 .2 Trona and halite. Well-consolidated white (N 9) to yellowish-gray (5Y 8/1) to grayish-yellow (5F 8/4) soft vuggy 

massive trona with 20 percent disseminated colorless halite 

cubes modified by octahedron, averaging 3 mm in length.

89.1 .3 Clay and pirssonite. WeuVconsolidated black (N 1) to 

grayish-black (N 2) clay, locally faintly finely laminated, 

with seam, 10-20 mm wide, of 50 percent disseminated 

euhedral pirssonite crystals averaging 1.5 mm in length at 

top. Clay 92 percent, pirssonite 8 percent.

90. 4 1. 3 Clay and pirssonite. Well-consolidated black (N 1) to dark 

yellowish-orange (10 YR 6/6) to moderate olive-brown (5F 

4/4) clay with 30 percent disseminated euhedral pirssonite 

crystals averaging 5 mm in length; distinct moderate 

reddish-brown (10/2 4/6) algae(?) discolored seam 5 mm 

wide at base.

90. 9 .5 Clay and pirssonite. Poorly consolidated and fractured core. 

Black (N 1) to dark yellowish-orange (1QYR 6/6) to moderate olive-brown (5 Y 4/4) clay with 30 percent disseminated 

euhedral pirssonite crystals averaging 5 mm in length.

91. 4 .5 No core.
GORE LOGS FROM SEARLES LAKE, CALIFORNIA 261

Depth Unit tMck-

(feet) nesa (feet) Description

91. 6 0. 2 Clay and pirssonite. Well-consolidated bUick (N 1) clay with 

20 percent disseminated euhedral pirssonite silt and fine 

sand.

92. 3 . 7 Trona and clay. Well-consolidated colorless to white (N 9) 

to grayish-yellow (5F 8/4) fine fibrous trona discolored 

dark^gray (N 3) by 2 percent intermixed clay.

92. 6 .3 No core.

93. 1 .5 Halite and trona. Well-consolidated slightly vuggy aggregate of colorless halite cubes modified by octahedron, 

averaging 3 mm in length, with 10 percent interstitial 

white (N 9) to yellowish-gray (5Y 8/1) massive trona; 

core fractured in upper 0.1 ft.

93. 3 .2 Trona and halite. Well-rconsolidated medium light-gray (N 6) 

to medium-gray (N 5) massive trona with seams, 5 mm 

wide, of disseminated colorless halite cubes modified by 

octahedron and subhedra, averaging 2 mm in length. 

Trona 75 percent, halite 25 percent.

93. 6 .3 Halite and trona. Well-consolidated slightly friable aggregate 

of colorless halite cubes modified by octahedron averaging 

2 mm in length, with 5 percent interstitial white (N 9) to 

medium light-gray (N 6) massive trona.

94.6 1.0 Trona and halite. Well-consolidated moderately vuggy 

white (N 9) to medium-gray (N 5) massive trona with 

seams, pockets, and irregular streaks, averaging 5 mm In 

width, of colorless halite cubes modified by octahedron 

averaging 5 mm in length; vague seams of light-brown 

(5YR 5/6) intermixed algae (?) in lower 0.1 ft. Trona 90 

percent, halite 10 percent.

95. 1 .5 Halite and trona. Well-consolidated aggregate of colorless 

halite cubes modified by octahedron averaging 3 mm in 

length, with 30 percent interstitial white (N 9) to light 

olive-gray (5F 6/1) massive trona; scattered J^-in. pockets 

of white (N 9) to colorless fine fibrous trona in lower 0.2 ft.

95. 2 .1 Trona. Well-consolidated light-gray (N 7) to dark greenishgray (50 Y 4/1) massive trona with vague irregular seams 

of intermixed moderate reddish-brown (10/2 4/6) algae(?).

95. 7 .5 Halite and trona. Well-consolidated aggregate of colorless 

halite cubes modified by octahedron averaging 2 mm in 

length, with 30 percent interstitial white (N 9) to yellowishgray (5Y 8/1) massive trona.

96.0 .3. Trona and halite. Well-consolidated medium light-gray (N 6) 

to yellowish-gray (5F 8/1) to pale-olive (lOF 6/2) massiv« 

trona, with seam of disseminated intermixed colorless halite 

cubes modified by octahedron averaging, 3 mm in length 

at 96.1 ft, and.a. few. disseminated halite crystals to base; 

distinct discolorations, 5 mm wide, of intermixed moderate 

reddish-brown (10R 4/6) algae(?) at 96.1 ft. Trona 90 

percent, halite 10 percent.
262 GEOLOGIC INVESTIGATIONS IN MOJAVE DESERT REGION

Depth Unit thick-

(feet) ness (feet) Description

96.2 0. 2 Trona. Well-consolidated white (N 9) to yellowish-gray 

(5F 8/1) soft fine fibrous trona with Yz-io.. pockets of medium 

dark-gray (N 4) massive trona; moderate orange-pink 

(SYR 8/4) to grayish-orange (10 YR 7/4) algae(?) discolorations.

96. 5 .3 Trona. Poorly consolidated and fractured core. Fragments 

of white (N 9) to greenish-gray (50 Y 6/1) to medium 

dark-gray (N 4) soft massive to fine fibrous trona; trace of 

intermixed grayish-black (N 2) clay; local light-brown 

(SYR 6/4) algae(?) discolorations.

97. 1 .6 No core.

97.3 .2 Clay, pirssonite, and borax. Black (N 1) to light olivebrown (5F 5/6) to pale-olive (10 Y 6/2) clay with 30 percent 

disseminated euhedral pirssonite crystals averaging 7 mm 

in length, with 10 percent disseminated subhedral to 

euhedral borax crystals 15-40 mm in length.

99. 4 2. 1 Clay, pirssonite, and borax. Black (N 1) to light olivebrown 5Y" 5/6) to dusky yellow-green (5GY 5/2) clay with 

30 percent disseminated euhedral pirssonite crystals averaging 10 mm in length; a few disseminated euhedral to subhedral borax crystals, averaging 15 mm in length, in lower 

0.2 ft; closely spaced pliable thin seams of organic? matter 

from 99.1 to 99.2 ft. Clay 69 percent, pirssonite 30 percent, 

borax 1 percent.

99. 6 .2 Clay and pirssonite. Well-consolidated black (N 1) clay 

with 40 percent disseminated euhedral pirssonite sand.

99. 7 .1 Borax. Friable aggregate of euhedrai to subhedral borax 

crystals up to 15 mm in length, averaging 4 mm.

100. 1 . 4 Halite, clay, and trona. Friable aggregate of colorless halite 

cubes modified by octahedron, averaging 2 mm in length, 

with 1 percent interstitial grayish-yellow (5Y 8/4) massive 

trona; seam, 5 mm wide, of interstitial black (N 1) clay 

at top. Halite 97 percent, clay 2 percent, trona 1 percent.

100. 3 . 2 Halite and trona. Friable aggregate of colorless halite cubes 

modified by octahedron, averaging 2 mm in length, with 

irregular streaks and pockets of colorless to grayish-yellow 

(5Y 8/4) to dark-gray (AT 3) fine fibrous trona, locally 

mixed with white (N 9) massive trona. Halite 95 percent, 

trona 5 percent.

100. 6 . 3 Trona. Well-consolidated white (N 9) to dark-gray (N 3) 

massive trona with seam, 10 mm wide, of colorless to 

grayish-yellow (5Y 8/4) fibrous trona at 100.4 ft, locally 

intermixed with grayish-black (N 2) clay.

100.7 .1 Trona. Well-consolidated colorless to grayish-yellow (5 Y 8/4) 

fibrous trona, locally discolored dark-gray (N 3) by trace 

of intermixed clay.

101. 1 .4 Halite. Poorly consolidated and fractured core. Friable 

aggregate of colorless halite cubes and cubes modified by 

octahedron, averaging 5 mm in length, with trace of interstitial white (N 9) to grayish-yellow (5F 8/4) massive trona; 

trace of grayish-black (N 2) clay locally in thin streaks.
CORE LOGS FROM SEARLES LAKE, CALIFORNIA 263

I''...''- '. ; ' ' '

Depth Unit tMck- 

(feet) ness (feet) Description 

101. 9 0. 8 No core.

102. 3 . 4 Halite. Friable aggregate of colorless halite cubes and subhedra, averaging 3 mm in length, with trace of interstitial 

colorless fibrous trona.

102. 7 . 4 Trona and clay. Well-consolidated white (N 9) to yellowishgray (5Y 8/1) to dark greenish-gray (50Y 4/1) massive 

trona with irregular seam at top, averaging -5 mm in width, 

of grayish-black (N 2) clay containing 10 percent disseminated euhedral pirssonite crystals averaging 3 mm in 

length; thin seams, 1 mm wide, of intermixed grayish-black 

(AT 2) clay in trona in upper 0.1 ft. Trona 95 percent, 

clay 5 percent.

103. 3 .6 Halite and trona. Friable aggregate of colorless halite cubes 

and subhedra averaging 2 mm in length; seam, 10 mm wide, 

of white (AT 9) to pale-olive (10 Y 6/2) massive trona with 

disseminated colorless trona blades averaging 10 mm in 

length, at 103.1 ft. Halite 94 percent, trona 6 percent.

103.6 .3 Burkeite, trona, and halite. Dusky-yellow (5Y 6/4) vuggy 

dense hard massive burkeite with pockets containing colorless trona blades averaging 10 mm in length and a few colorless halite cubes modified by octahedron, up to 20 mm in 

length, averaging 7 mm; trace of intermixed dark-gray (N 3) 

clay with trona blades in lower 0.2 ft. Burkeite 84 percent, 

trona 15 percent, halite 1 percent.

103. 7 .1 Trona, clay, and pirssonite. Aggregate of trona blades averaging 5 mm in length, with seam, 10 mm wide, at top of black 

(N 1) clay containing '30 percent disseminated euhedral 

pirssonite crystals averaging % mm in length, clay locally 

discolored moderate reddish-brown (WYR 4/6) by algae(?). 

Trona 67 percent, clay 23 percent, pirssonite 10 percent.

104. 2 .2 Trona, burkeite, and halite. Well-consolidated white (N 9) 

to medium light-gray (N 6) to colorless slightly vuggy 

fibrous trona with irregular pockets and streaks of grayish 

yellow (5Y 8/4) hard dense massive burkeite; a few disseminated colorless halite cubes modified by octahedron, averaging 5 mm in length. Trona 94 percent, burkeite 5 percent, 

halite 1 percent.

104. 4 . 2 Halite and trona. Well-consolidated vuggy aggregate of colorless halite cubes modified by octahedron, from 2 to 30 mm in 

length, averaging 10 mm, intermixed with coarse colorless 

trona blades averaging 10 mm in length and fine colorless 

grayish-yellow (57 8/4) fibrous trona. Halite 50 percent, 

trona 50 percent.

104. 5 .1 Trona and halite. Well-consolidated white (N 9) to light-gray 

(N 7) dense massive trona with irregular seam, up to 10 mm 

in width at base, of intermixed colorless trona blades and 

halite cubes modified by octahedron. Trona 99 percent, 

halite 1 percent.

104. 9 . 4 Burkeite. Well-consolidated grayish-orange (10Y7J! 7/4) dense 

hard slightly vuggy massive burkeite with trace of colorless 

fine fibrous trona present in vugs in lower 0.2 ft. 

491349 59, 9
264 GEOLOGIC INVESTIGATIONS IN MOJAVE DESERT REGION

Depth Unit thick*

(feet) ness (/eel) Description

105. 3 0. 4 Burkeite and trona. Fractured core. Fragments of grayishorange (1QYR 6/6) dense hard massive burkeite with small 

vugs and pockets of white (N 9) to very pale orange (10YR 

8/2) massive trona. Burkeite 98 percent, trona 2 percent.

105. 6 . 3 No core.

105. 7 .1 Trona and halite. Well-consolidated aggregate of white (N 9) 

massive trona with 30 percent disseminated colorless halite 

cubes modified by octahedron and subhedra averaging, 2 

mm in length; trace of disseminated trona blades averaging 

5 mm in length at base.

105.9 .2 Burkeite. Well-consolidated dense hard massive grayishorange (10 KR 7/4) to yellowish-gray (5GY 6/1) dense hard 

massive burkeite.

106. 3 . 4 Halite, trona, and burkeite. Poorly consolidated core. Fragments of white (N 9) to light-gray (N 7) soft massive trona 

with 10 percent disseminated colorless halite subhedra averaging 2 mm in length; loose disseminated fragments of 

grayish-orange (WYR 7/4) hard dense massive burkeite in 

colorless halite sand. Probably cuttings, noc core. Halite 

60 percent, trona 35 percent, burkeite 5 percent.

106. 6 . 3 Trona, burkeite, and halite. Well-consolidated white (N 9) to 

light-gray (N 7) massive trona with seam, 10 mm wide, of 

fine trona blades averaging 3 mm in length at top; irregular 

streaks of colorless halite crystals, averaging 1 mm in length, 

intermixed with massive white (N 9) trona at 106.4 ft; 

irregular seam, up to 20 mm wide, of lenticular pockets of 

grayish-orange (1QYR 7/4) dense hard massive burkeite at 

106.4 to 106.5 ft. Trona 87 percent, burkeite 12 percent, 

halite 1 percent.

106. 8 . 2 Burkeite and trona. Well-consolidated grayish-orange (10Y/2 

7/4) dense hard massive burkeite with scattered lenticular 

vuggy pockets of very pale orange (10 YR 8/2) massive trona 

containing traces of intermixed colorless fibrous trona. 

Burkeite 95 percent, trona 5 percent.

106. 9 . 1 Trona and halite. Well-consolidated white (N 9) to mediumgray (N 5) massive trona with 30 percent disseminated colorless halice crystals in lower 1.0 mm.

107. 2 . 3 Borax and trona. Well-consolidated aggregate of colorless to 

smoky borax crystals up to 20 mm in length, averaging 10 

mm; 15 percent interstitial white (AT9) sugary-textured massive trona intermixed with minor colorless to grayishyellow (5 Y 8/4) fibrous and bladed trona, blades averaging 

5 mm in length. Borax 80 percent, trona 20 percent.

107. 3 .1 No core.

108. 4 1.1 Halite and trona. Friable aggregate of colorless halite cubes 

modified by octahedron and subhedra, averaging 2 mm in 

length, with 10 percent interstitial white (N 9) to moderate 

yellowish-brown (1QYR 5/4) to medium-gray (N 5) massive 

trona; trace of grayish-black (N 2) to dusky-brown (5YR 

2/2) clay in lower 0.1 ft.

109. 2 . 8 Burkeite, trona, and halite. Well-consolidated grayish-orange 

(1QYR 7/4) dense hard vuggy massive burkeite with seams
CORE LOGS FROM SEARLES LAKE, CALIFORNIA 265

Depth Unit thick- (feet) ness (feet) Description

and pockets of intermixed white (N 9) dense massive trona; 

vugs lined with grayish-orange (1QYR 7/4) superficially 

stained colorless fibrous trona; colorless halite cubes modified 

by octahedron and subhedra, averaging 2 mm in length, 

intermixed with trona at 108.9 to 109.1 ft. Burkeite 80 

percent, trona 15 percent, halite 5 percent.

109. 5 0. 3 Clay, trona, and borax. Black (N 1) to grayish-black (N 2) 

to dark-gray (N 3) to very light gray (N 8) faintly finely 

laminated clay with distinct moderate reddish-orange (10/2 

6/6) algae(?) discolorations in upper 15 mm; seam, 10 mm wide, 

of 80 percenCdiBseminated euhedral prismatic borax crystals 

averaging 5 mm in length, at 109.3 ft; seam, 15 mm wide, 

of white (N 9) very fine fibrous trona locally discolored 

moderate reddish-brown (10.R 4/6) by algae(?) at base. 

Clay 74 percent, trona 17 percent, borax 9 percent.

111. 3 1. 8 No core.

111. 5 .2 Burkeite. Fractured core. Fragments of grayish-orange 

(10 YR 7/4) dense hard massive burkeite.

111. 8 .3 Burkeite. Well-consolidated grayish-orange (10 YR 7/4) 

moderately vuggy dense hard massive burkeite; trace 

of grayish-black (N 2) clay locally in a few vugs.

112.0 .2 Burkeite. Fractured core. Fragments of yellowish-gray 

(5Y 7/2) to grayish-yellow (5F 8/4) dense hard massive 

burkeite.

112. 1 .1 Clay and borax. Well-consolidated grayish-black (N 2) to 

greenish-black (50Y 2/1) clay with 75 percent disseminated 

euhedral borax crystals, averaging 15 mm in length, in lower 

15 mm; trace of light-brown (SYR 6/4) trona discolored by 

algae(?) in upper 15 mm. Clay 63 percent, borax 37 

percent.

112. 2 .1 Clay and northupite. Greenish-black (5GY 2/1) to grayishblack (N 2) to dusky yellow-green (5GY 5/2) to very 

light gray (N 8) faintly finely laminated clay with disseminated round to oval nodules from 0.05 to 1 mm in 

length, averaging 0.25 mm, of white (N 9) to grayishyellow (5F 8/4) massive northupite arranged in layers. 

Clay 95 percent, northupite 5 percent.

112. 4 .2 Trona and halite. Poorly consolidated dusky yellow-green 

(5GY 5/2) to dark greenish-gray (50Y 4/1) soft massive 

trona with intermixed colorless halite sand; a few disseminated colorless trona blades averaging 5 mm in length. 

May be cuttings, not core. Trona 80 percent, halite 20 

percent.

112. 8 . 4 Clay, gaylussite, and northupite. Greenish-black (5GY 2/1) 

to grayish-black (N 2) to very light gray (N 8) finely 

laminated clay with disseminated oval nodules of white 

(N 9) to grayish-yellow (57 8/4) massive northupite, up 

to 3 mm in length, arranged in layers; a few seams, 1-2 mm 

wide, of euhedral gaylussite silt; ripple or eddy marks at 

base of clay at 112.5 ft. Clay 96 percent, gaylussite 3 

percent, northupite 1 percent.
266 GEOLOGIC INVESTIGATIONS IN MOJAVE DESERT REGION

Depth Unit thick-

(feet) ness (feet) Description

. 113.0 0.2 Clay, gaylussite*, and borax. Greenish-black (5GT 2/1) 

'. to grayish-black (AT 2) to dusky yellow-green (5GY 5/2) 

to grayish-yellow (5F 8/4) to very light gray (N 8) finely 

laminated clay with numerous seams, 1 mm wide, and 

disseminated crystals of colorless gaylussite* silt; seam, 10 

mm wide, of 80 percent disseminated subhedral borax 

crystals, up to 30 mm in length, at 112.9 ft; 40 percent 

disseminated euhedral gaylussite crystals, averaging 2 

mm in length, in lower 15 mm; scattered disseminated 

nodules, averaging 2 mm in length, of white (N 9) massive 

northupite. Clay 72 percent, gaylussite 15 percent, 

borax 13 percent.

113. 8 . 8 No core.

114. 1 .3 Clay, northupite, and gaylussite. Grayish-black (N 2) to 

greenish-black (5GY 2/1) to light gray (N 7) faintly finely 

laminated clay; scattered nodules, averaging 5 mm in 

length, of white (N 9) to grayish-yellow.(5 Y 8/4) massive 

northupite; a few seams of disseminated intermixed gay-

. . lussite silt; fine faint laminae of moderate reddish-brown 

' . (IQR 4/6) algae(?) in lower 20 mm. Clay 98 percent, 

northupite 1 percent, gaylussite 1 percent.

114. 2 .1 Trona. Well-consolidated white (AT 9) to dark-gray (N 3) 

dense massive trona; seam 10 mm ,wide, of trona blades, 

averaging 10 mm in length, at topi

. 114. 5 .3 Clay, trona, and northupite. Black (N 1) to grayish-black 

(N 2) clay with 20 percent disseminated colorless trona 

blades averaging 20 mm in length, chiefly confined to lower 

0.2 ft; wavy seams, 1 mm.wide, of white (N 9) and moderate 

orange-pink (5 YR 8/4) massive northupite in upper 20 mm. 

Clay 77 percent, trona 20 percent, northupite 3 percent.

114.8 .3 Trona. Well-consolidated dense aggregate of dark-gray 

(N 3) to colorless trona blades averaging 26 mm in length.

114. 9 . 1 Trona. Well-consolidated aggregate of colorless to superficially stained grayish-yellow (5F 8/4) trona blades 

averaging 5 mm in length.

115.1 .2 Trona. Well-consolidated slightly vuggy very light gray 

(N 8) to medium-gray (N 5) massive trona with thin 

streaks of colorless trona blades, averaging 5 mm in length, 

in lower 0.1 ft; trace of greenish-black (5GF 2/1) clay in 

vugs.

115. 2 .1 Northupite*, clay, and trona. Irregular seam of yellowishgray (5F 7/2) to grayish-yellow (5F 8/4) soft massive 

northupite* containing 5 percent disseminated colorless 

trona blades, averaging 5 mm in length, with irregular 

seams, 1-5 mm wide, of black (N 1) clay, locally discolored 

blackish-red (5R 2/2) by intermixed algae(?). Northupite 

85 percent, clay 10 percent, trona 5 percent.

115. 3 .1 Clay and gaylussite. Grayish-black (N 2) to greenish-black 

(5GF 2/1) to dusky yellow-green (5GF 5/2) faintly finely 

laminated clay with 10 percent disseminated very fine 

gaylussite silt.
CORE LOGS FROM SEARLES LAKE, CALIFORNIA 267

Depth Unit thick-

(feet) ness (feet) Description

115. 5 0. 2 Clay and gaylussite. Grayish-black (N 2) to greenish-black

(5GY 2/1) clay with 35 percent disseminated euhedral

colorless fine to coarse gaylussite sand. 

115.8 .3 Clay. Grayish-black (N 2) to greenish-black (5(?Y 2/1) to

light-gray (N 7) very finely laminated clay with a few

pockets of very fine gaylussite silt.

117. 8 2. 0 No core.

118. 1 .3 Clay and trona. Black (N 1) to grayish-black (N 2) clay 

With irregular pockets and streaks of trona blades averaging 

3 mm in length. Clay 90 percent, trona 10 percent.

119. 0 .9 Trona, burkeite, northupite, and clay. Well-consolidated 

aggregate of white (N 9) to medium dark-gray (N 4) 

massive trona with lenticular horizontal streaks of colorless 

to grayish-yellow (5F 8/4) fibrous trona, locally containing 

1 to 5 percent interstitial black (N 1) to greenish-black 

(5GY 2/1) clay; seams, 5 mm wide, of yellowish-gray 

(5Y 8/1) massive northupite containing 10 percent disseminated colorless trona needles, averaging 5 mm in 

length, at 118.6 and 118.8 ft; large lenticular pocket, 30 

mm wide, of pale yellowish-brown (1QYR 6/2) dense hard 

massive burkeite at base. Trona 90 percent, burkeite 5 

percent, northupite 4 percent, clay 1 percent.

119. 3 . 3 Clay and gaylussite. Black (N 1) to greenish-black (50 Y 2/1) 

to very light gray (N 8) finely laminated clay with 10 

percent disseminated gaylussite silt; a few disseminated 

oval to round nodules, averaging 0.25 mm in length, of 

white (N 9) massive northupite in upper 10 mm; several 

contorted laminae at 119.1 ft.

119. 7 .4 Clay and gaylussite. Black (N 1) to grayish olive-green 

(50Y 3/2) to light olive-brown (57 5/6) to grayish-olive 

(10 Y 4/2) clay with 35 percent disseminated euhedral to 

subhedral gaylussite crystals from 1 to 10 mm in length, 

averaging 5 mm.

119. 8 .1 No core.

120. 2 . 4 Clay and gaylussite. Grayish-black (N 2) to greenish-black 

(50Y 2/1) to grayish olive-green (5GY 3/2) to very light 

gray (N 8) finely laminated clay with seams 5-10 mm wide, 

of 30 percent disseminated euhedral gaylussite sand in 

upper 0.2 ft. Clay 96 percent, gaylussite 4 percent.

120. 4 . 2 Clay and gaylussite. Greenish-black (5GY 2/1) to grayishblack (N 2) to dusky-yellow (5Y 6/4) to dusky yellow-green 

(5GY 5/2) faintly finely laminated clay with 30 percent 

disseminated euhedral gaylussite silt.

120.5 .1 Trona and clay. Well-consolidated grayish-black (N 2) 

dense aggregate of trona blades averaging 15 mm in length; 

25 percent interstitial black (AT 1) clay in upper 20 mm.

121. 0 . 5 Trona and clay. Vuggy aggregate of colorless to superficially 

stained grayish-yellow (5Y 8/4) trona blades up to 35 mm 

in length, averaging 20 mm, with 1 percent interstitial 

greenish-black (5GY 2/1) clay; intermixed pockets of 

medium-gray (N 5) massive trona in lower 0.1 ft.
268 GEOLOGIC INVESTIGATIONS IN MOJAVB DESERT REGION

Depth Unit thick-

(feet) ness (feet) Description

121.4 0. 4 Trona. Well-consolidated white (N 9) to dark greenishgray (5GY 4/1) to medium dark-gray (N 4) massive trona 

with pockets of colorless trona blades in upper 0.1 ft.

123. 4 2.0 Trona. Well-consolidated vuggy aggregate of colorless to 

superficially stained grayish-yellow (5F 8/4) to light olivebrown (5V 5/6) trona blades averaging 10 mm in length; 

numerous large pockets and irregular seams of white (N 9) 

to medium-gray (N 5) massive trona in upper 1.0 ft, gradually changing to pockets of bladed trona in massive trona 

in lower 1.0 ft; trace of greenish-black (5GY 2/1) clay 

locally present in some vugs with trona blades.

123.8 . 4 Clay and gaylussite. Moderate olive-brown (5Y 4/4) to 

pale-olive (10F 6/2) to grayish-black (N 2) clay with 40 

percent disseminated euhedral gaylussite crystals up to 

30 mm in length, averaging 10 mm.

124. 8 1. 0 No core.

127. 1 2. 3 Clay and gaylussite. Grayish-black (N 2) to grayish-green 

(WGY 5/2) to grayish-yellow (5Y 8/4) to dark yellowishorange (IOYR 6/6) to dusky yellowish-brown (WYR 2/2) 

clay, locally finely laminated, with 30 percent disseminated 

euhedral gaylussite crystals averaging 10 mm in length.

127. 3 .2 Clay. Olive-gray (57 3/2) to medium dark-gray (N 4) to 

grayish-yellow (5Y 8/4) to greenish-gray (5(? 6/1) faintly 

finely laminated clay.

127. 6 .3 Trona*, nahcolite*, and clay. Well-consolidated light bluishgray (5B 7/1) to bluish-white (5B 9/1) compact massive 

trona with intermixed nahcolite*, probably discolored by 

intermixed clay; 1 percent grayish olive-green (5GY 3/2) 

to light olive-brown (5F 5/6) intermixed clay in thin streaks 

and irregular Yz- to 1-in. pockets.

127.8 .2 Thenardite. Vuggy aggregate of euhedral to subhedral 

colorless thenardite crystals up to 95 mm in length, averaging 25 mm.

128.0 .2 Clay. Grayish-olive (10F 4/2) to grayish olive-green (5GY 

3/2) to dusky-yellow (5F 6/4) to moderate olive-brown 

(5Y 4/4) fainly finely laminated clay.

128. 2 .2 Clay and gaylussite. Greenish-black (5GY 2/1) to moderate 

olive-brown (5Y 4/4) to grayish-green (WGY 5/2) to 

grayish-black (N 2) to olive-gray (5F 3/2) clay with 40 

percent disseminated euhedral gaylussite crystals from 2 

to 10 mm in length, averaging 5 mm.

128. 3 . 1 Gaylussite*, nahcolite*, trona, and clay. Friable aggregate 

of gaylussite* crystals with 20 percent intermixed duskyyellow (5F 6/4) nahcolite* crystals averaging 10 mm in 

length; 1 percent disseminated colorless trona blades 

averaging 5 mm in length and 1 percent interstitial dusky 

yellow-green (5GF 5/2) to grayish-yellow (51 8/4) clay.

128.9 .6 Clay and gaylussite. Moderate olive-brown (5F 4/4) to 

olive-gray (5F 3/2) clay with 40 percent disseminated 

gaylussite crystals averaging 10 mm in length.

130. 0 1. 1 No core.
CORE LOGS FROM SEARLES LAKE, CALIFORNIA 269

Searles drill hole GS-21

LOCATION: Searles Lake, Calif., approx. % mile west of % sec., sees. 20 and 21, 

^*: in sec. 20, T. 25 S., R. 43 E., Mount Diablo base line and meridian. 

ELEVATION AT TOP OP HOLE: 1,618 ft. 

ELEVATION AT BOTTOM OP HOLE: 1, 538.5 ft. 

TOTAL DEPTH: 79.5 ft. 

DATES DRILLED: May 9-17, 1955.

CASING USED: 16.3 ft of 16-in. casing; 53.8 ft of 3-in. pipe. 

MINERAL DETERMINATIONS: Minerals identified microscopically are denoted by 

an asterisk (*).

Depth Unit thick-

(feet) ness (feet) Description

0. 7 0. 7 Trona, clay, sand, and silt. Well-consolidated vuggy white 

(N 9) massive trona discolored dusky-yellow (5Y 6/4) 

by 1 percent intermixed clay; 5 percent intermixed sand 

and silt.

1. 9 1. 2 Clay and thenardite*. Dark greenish-gray (5(? 4/1) to light 

olive-gray (5Y" 5/2) soft silty clay; a few disseminated 

colorless blades and cruciform twins of thenardite*..

2. 0 . 1 No core.

2. 2 .2 Clay. Dusky yellow-green (5(77 5/2) to black (N 1) dense

tenacious clay. 

2. 6 .4 Clay and trona. Black (N 1) tenacious clay with 50 percent

disseminated colorless trona blades averaging 15 mm in

length.

2. 8 .2 Clay. Black (N 1) very tenacious gumbo clay.

3. 2 .4 Trona and clay. Well-consolidated vuggy aggregate of colorless trona blades averaging 5 mm in length, up to 20 mm, 

with 35 percent black (N 1) tenacious clay in interstices 

and pockets.

3. 5 .3 Clay. Black (N 1) tenacious gumbo clay.

4. 0 .5 No core.

5. 4 1. 4 Clay. Black (N 1) tenacious gumbo clay.

5. 7 .3 Trona, clay, and hanksite. Well-consolidated aggregate of 

colorless trona blades averaging 10 mm in length, with disseminated subhedral to anhedral yellowish hanksite crystals 

averaging 10 mm in length; 30 percent black (N 1) tenacious 

clay in interstices and pockets throughout. Trona 60 

percent, clay 30 percent, hanksite 10 percent.

6. 1 . 4 No core.

6. 3 .2 Clay, trona, and hanksite. Black (N 1) tenacious clay with 

well-consolidated pockets of densely packed trona blades 

averaging 15 mm in length, locally in radiating clusters, 

containing 5 percent interstitial black (AT 1) clay and 10 

percent disseminated anhedral to subhedral hanksite crystals 

averaging 5 mm in length. Clay 50 percent, trona 40 percent, hanksite 10 percent.

8. 3 2.0 Trona and clay. Well-consolidated aggregate of colorless 

trona blades up to 15 mm in length, averaging 5 mm, with 

5 percent black (N 1) clay in irregular streaks and pockets.
270 GEOLOGIC INVESTIGATIONS IN MOJAVE DESERT REGION

Depth Unit thick-

(feet) ness (feet) . Description

10. 1 1. 8 Hanksite, trona, borax, and clay. Moderately friable aggregate of subhedral to euhedral yellowish hanksite crystals 

up to 15 mm in length, averaging 30 mm, with disseminated 

interstitial anhedral colorless borax crystals up to 50 mm in 

length, averaging 15 mm; interstitial colorless trona blades 

up to 20 mm in length, averaging 5 mm; 5 percent black 

. . (N 1) clay in irregular streaks chiefly confined to lower 

0.5 ft. Hanksite 65 percent, trona 20 percent, borax 10 

percent, clay 5 percent.

10. 9 .8 No core.

11.9 1.0 Hanksite, borax, trona, and .clay. Moderately friable aggregate of euhedral to subhedral hanksite crystals averaging 

20 mm in length, with 10 percent interstitial colorless trona 

blades averaging 5 mm in length; 30 percent disseminated 

interstitial euhedral to anhedral borax crystals averaging 

10 mm in length; 10 percent black (N 1) clay in irregular 

pockets and in interstices throughout.

12. 0 .1 Hanksite and clay. Friable aggregate of euhedral hanksite 

crystals averaging 40 mm in length, with 50 percent intermixed interstitial black (N 1) clay; a few hanksite crystals 

showing basal pinacoid.

12.1 .1 Clay. Well-consolidated black (ATI) clay.

12.4 .3 Trona and clay. Well-consolidated aggregate of colorless 

trona blades averaging 5 mm in length, with 50 percent black 

(N 1) clay in interstices and pockets.

12. 7 . .3 Clay and pirssonite. Well-consolidated black (N 1) clay 

with 10 percent disseminated pirssonite sand.

13. 1 .4 Clay, pirssonite*, and hanksite. Well-consolidated black 

(N 1) clay with 30 percent disseminated subhedral pirssonite* crystals averaging 1 mm in length; pockets of 

euhedral to subhedral hanksite crystals averaging 20 mm 

in length. Clay 55 percent, pirssonite 30 percent, hanksite 

15 percent.

13. 6 .5 Trona. Well-consolidated aggregate of colorless trona blades 

averaging 5 mm in length; trace of intermixed black (N 1) 

clay in scattered streaks and pockets.

13. 8 .2 Clay and hanksite. Poorly consolidated black (N 1) soft 

clay with 35 percent disseminated subhedral hanksite 

crystals averaging 30 mm in length.

14.2 .4 Trona and clay. Well-consolidated aggregate of colorless 

trona blades averaging 5 mm in length, discolored by 

1 percent interstitial black (N 1) clay; seam, 10 mm wide, 

of well-consolidated black (N 1) clay at top. Trona 91 

percent, clay 9 percent.

15. 2 1. 0 No core.

15. 4 .2 Clay and pirssonite.. Well-consolidated black (ATI) to grayishblack (N 2) with 30 percent disseminated medium to coarse 

subhedral pirssonite sand.
CORE LOGS FROM SEARLES LAKE, CALIFORNIA 271

Unit thick- 

(feet) ness (fed) Description

16. 2 0. 8 Hanksite, trona, and clay. Dense moderately vuggy granular 

massive aggregate of subhedral to anhedral hanksite crystals 

with pockets of subhedral hanksite crystals averaging 15 

mm in length; numerous pockets of colorless fine trona blades 

averaging 5 mm in length; a few irregular streaks of interstitial black (N 1) clay. Hanksite 79 percent, trona 20 

percent, clay 1 percent.

16.4 .2 Trona. Well-consolidated slightly vuggy yellowish-gray 

(5 Y 8/1) to medium-gray (N 5) massive trona with numerous 

1-in. pockets of colorless fine trona blades averaging 3 mm 

in length; trace of intermixed black (N 1) clay.

17. 4 1.0 Hanksite and trona. Well-consolidated vuggy aggregate of 

euhedral to subhedral hanksite crystals up to 20 mm in 

length, averaging 10 mm, with seams of 20 percent intermixed interstitial very pale orange (IQYR 8/2) massive 

trona from 16.5 to 16.7 ft; scattered small pockets of interstitial very pale orange (10YR 8/2) massive trona throughout. Hanksite 97 percent, trona 3 percent.

17. 7 .3 Halite, trona, and hanksite. Well-consolidated moderately 

vuggy aggregate of halite cubes averaging 3 mm in length, 

with 30 percent interstitial white (N 9) soft massive trona; 

numerous lenticular horizontal vuggy seams containing 

halite cubes with a few euhedral to subhedral hanksite 

crystals from 3 to 30 mm in length. Halite 60 percent, 

trona 30 percent, hanksite 10 percent.

20. 4 2,7 No core.

20. 7 .3 Halite. Friable aggregate of anhedral colorless halite crystals 

averaging 60 mm in length.

21.4 .7 Trona, hanksite, and halite. Fractured core. Fragments of 

white (AT-9) massive trona with 50 percent disseminated 

colorless halite cubes and subhedra, averaging 2 mm in 

length; fragments.of anhedral to subhedral granular massive 

smoky hanksite with seams of white (N 9) massive trona; 

fragments consisting of. aggregates of euhedral to subhedral 

hanksite crystals 20 mm in length. Trona 50 percent, 

hanksite 30 percent, halite 20 percent.

22. 3 .9 Hanksite. Well-consolidated granular aggregate of smoky 

hanksite with 1- to 2-in. pockets of euhedral hanksite 

crystals averaging 10 mm in length; core vuggy in lower 

0.4 ft with euhedral hanksite crystals up to 40 mm in length; 

vugs locally lined with colorless fibrous trona.

24. 0 1. 7 No core.

24. 9 .9 Hanksite, trona, and clay. Well-consolidated dense slightly 

vuggy granular aggregate of anhedral to subhedral smoky 

hanksite crystals averaging 4 mm in length, with scattered 

%- to 1-in. pockets of colorless fine fibrous trona, locally 

strained grayish-yellow (5Y 8/4), and #-in. pockets of white 

(N 9) massive trona; 1 percent interstitial greenish-black 

(5GY 2/1) clay. Hanksite 97 percent, trona 2 percent, 

clay 1 percent.
272 GEOLOGIC INVESTIGATIONS IN MOJAVE DESERT REGION

Depth Unit thick'

(feet) ness (feet) Description

27.0 2. 1 Trona and sulfohalite. Well-consolidated porous slightly 

vuggy aggregate of colorless fibrous trona, locally stained 

grayish-black (N 2) to dark greenish-gray (5GY 4/1) by 

trace of interstitial clay; wavy seams, averaging 5 mm'in 

width, of grayish olive-green (5(7 Y" 3/2) to grayish-black 

(N 2) massive trona discolored by trace of intermixed clay 

from 26.1 to 26.3 ft; euhedral to subhedral yellowish sulfohalite octahedra, averaging 2 mm in length, commonly 

diseminated throughout; core fractured in lower 0.7 ft.

28. 1 1.1 Trona. Well-consolidated slightly vuggy white (N 9) to 

greenish-gray (5GY 6/1) massive to very fine fibrous trona; 

horizontal lenticular vugs lined with colorless fibrous trona 

from 27.7 to 27.9 ft; seam, 2 mm wide, of olive-gray (5F 

3/2) clay at 27.5 ft; core fractured in lower 0.2 ft.

32. 0 3. 9 No core.

35. 5 3. 5 Trona. Well-consolidated white (N 9) massive trona with a 

few seams, from 2-to-10 mm wide, discolored light olive-gray 

(5Y 5/2) to olive-gray (5Y 3/2) by trace of intermixed clay; 

seam, 5 mm wide, of fine colorless fibrous trona, locally discolored grayish-yellow (5F 8/4) at 33.9 ft; seams are wavy 

in lower 0.2 ft and contain traces of grayish-black (N 2) clay 

seams.

35. 9 .4 Clay and pirssonite. Well-consolidated grayish-black (N 2) 

to grayish-green (5(7 5/2) to dusky-yellow (5F 6/4) finely 

laminated clay with 10 percent disseminated subhedral to 

anhedral pirssonite crystals averaging 3 mm in length, in 

lower 0.2 ft. Clay 95 percent, pirssonite 5 percent.

36. 1 .2 Clay and pirssonite. Black (N 1) to grayish-black (N 2) clay 

with 40 percent disseminated anhedral pirssonite crystals.

36. 6 .5 Clay and pirssonite*. Black (N 1) clay with 40 percent disseminated subhedral to anhedral pirssonite* crystals averaging 3 mm in length.

37. 3 .7 Clay, pirssonite, and borax. Well-consolidated grayish-black 

(N 2) to grayish-green (10(77 5/2) to grayish-yellow (5Y 

8/4) to dark-gray (N 3) finely laminated clay with 10 percent 

disseminated subhedral to anhedral pirssonite crystals averaging 5 mm in length; irregular seam, 5 mm wide, of anhedral 

borax at base. Clay 88 percent, pirssonite 10 percent, 

borax 2 percent.

37. 8 .5 Clay and pirssonite. Black (N 1) to olive-black (5Y 2/1) 

clay with 25 percent disseminated subhedral pirssonite 

crystals up to 35 mm in length, averaging 10 mm.

38. 5 .7 Clay. Well-consolidated black (N 1) to grayish-black (N 2) 

to greenish-black (5GY 2/1) clay with fine widely spaced 

grayish yellow-green (5GY 7/2; to pale greenish-yellow 

(10y 8/2) laminae.

40. 2 1. 7 Clay and gaylussite*. Well-consolidated grayish-black (AT 2) 

to grayish-yellow (57 8/4) to dusky-yellow (57 6/4) to 

greenish-gray (5G 6/1) to very light-gray (N 8) to white 

(N 9) finely laminated clay; a few 1-in. pockets of subhedral 

gaylussite* crystals averaging 10 mm in length; laminae 

slightly wavy in upper 0.1 ft.
CORE LOGS FROM SEARLES LAKE, CALIFORNIA 273

Depth Unit thick-

(feet) ness (feet) Description

42. 4 2. 2 No core.

44. 0 1. 6 Clay and gaylussite. Dark greenish-gray (5(7 4/1) to greenish-gray (5(77 6/1) to grayish-black (N 2) to grayish-yellow 

(57 8/4) to dark yellowish-orange (107/2 6/6) to very light 

gray (N 8) finely laminated clay with 15 percent subhedral 

gaylussite crystals up to 20 mm in length, averaging 5 mm, 

in pockets and disseminated throughout.

44. 3 .3 Clay. Greenish-black (5(3 Y 2/1) to grayish-black (AT 2) to 

grayish-yellow (57 8/4) to dusky yellow-green (5(77 5/2) to 

olive-gray (57 3/2) to very light gray (N 8) finely laminated 

clay.

46. 4 2. 1 Clay and gaylussite. Grayish-black (N 2) to grayish olivegreen (5(77 3/2) to light bluish-gray (5B 7/1) to medium 

bluish-gray (5B 5/1) to olive-gray (57 3/2) coarsely laminated clay revealed by color differences, with scattered 

irregular pockets of subhedral to anhedral gaylussite 

crystals averaging 5 mm in length; distinct laminae, 0.5 to 

1 mm wide, of moderate reddish-brown (10/2 4/6) »lgae(?) 

at 44.4, 44.5, 45.0, and 45.2 ft, with vague moderate reddishbrown (10/2 4/6) discolorations from 45.2 ft to base. Clay 

95 percent, gaylussite 5 percent.

48. 2 1. 8 No core.

49. 6 1. 4 Clay and gaylussite. Grayish-black (N 2) to dark greenishgray (5(7 6/1) to grayish blue-green (5BG 5/2) to dusky 

yellow-green (5(77 5/2) coarsely laminated clay revealed by 

color differences, with 15 percent disseminated subhedral 

to anhedral gaylussite crystals averaging 10 mm in length, 

locally in radiating clusters; vague local blackish-red 

(5R 2/2) algae (?) discolorations in clay.

50. 1 .5 Clay and gaylussite. Grayish-black (N 2) to dusky yellowgreen (5(77 5/2) to grayish blue-green (5BG 5/2) coarsely 

laminated clay revealed by color differences, with 30 percent 

disseminated euhedral to subhedral gaylussite crystals 

averaging 2 mm in length.

50. 8 .7 Clay and gaylussite. Grayish-black (N 2) to blackish-red 

(5/2 2/2) to dark greenish-gray (5(7 4/1) coarsely larrinated 

clay with seams of disseminated euhedral to subhedral 

gaylussite sand; vague moderate reddish-brown (10/2 4/6) 

algae(?) laminae at 50.3 to 50.5 ft. Clay 95 percent, 

gaylussite 5 percent.

61. 2 .4 Clay, gaylussite*, and trona. Grayish-black (N 2) to greenishgray (5(7 6/1) clay with 40 percent disseminated euhedral 

gaylussite* crystals averaging 1 mm in length; 25 percent 

disseminated colorless to white (Af 9) fine fibrous trona in 

pockets and streaks, averaging 5 mm in length, in lower 

10 mm.

62. 0 .8 Clay and gaylussite. Grayish-black (N 2) to dusky yellowgreen (5(77 5/2) to moderate olive-brown (57 4/4) coarsely 

laminated clay revealed by color differences, with 20 percent 

intermixed anhedral gaylussite.
274 GEOLOGIC INVESTIGATIONS IN MOJAVE DESERT REGION

Depth Unit thick-

(feet) ness (feet) Description

52. 3 0. 3 Clay and gaylussite. Grayish-black (N 2) to moderate olivebrown (5 Y 4/4) clay with 40 percent disseminated anhedral 

gaylussite crystals averaging 5 mm in length, with a few 

intermixed euhedral gaylussite crystals, averaging 2 mm 

in length, in upper 0.1 ft.

52. 8 .5 Clay and gaylussite. Grayish-black (N 2) to greenish-gray 

(5G 6/1) to moderate olive-brown (5Y 4/4) coarsely laminated clay revealed by color differences; 30 percent dis- 

: geminated anhedral gaylussite in upper 0.4 ft, with dissemi- 

; nated euhedral gaylussite crystals, averaging 5 mm in 

length, in lower 0.1 ft.

53. 0 .2 Clay and gaylussite. Black (N 1) clay with 10 percent 

disseminated euhedral gaylussite crystals from sand size 

to 2 mm in length; disseminated pinpoint discolorations in 

clay of moderate reddish-brown (10JB 4/6) algae (?).

53. 1 .1 Trona and clay. Well-consolidated dense aggregate of 

colorless trona blades averaging 10 mm in length, with 

5 percent interstitial black (N 1) clay chiefly confined to 

upper 10 mm.

53. 4 .3 Trona. Well-consolidated dense white (N 9) massive trona 

with scattered vuggy J4-in. pockets lined with colorless 

fibrous trona; local traces of interstitial black (N 1) clay.

53.5 .1 Trona. Well-consolidated vuggy aggregate of colorless fine 

! fibrous trona with intermixed pockets and streaks of 

medium-gray (N 5) massive trona.

55. 8 2. 3 Trona. Well-consolidated white (N 9) massive trona, locally 

discolored medium-gray (N 5) by trace of intermixed clay; 

scattered vugs, %- to 1-in. long, lined with colorless fine 

fibrous trona; distinct seams, 5 mm wide, discolored orange 

to dark yellowish-orange (WYR 6/6) by intermixed algae (?) 

at 54.7 and 55.4 ft.

56. 8 1. 0 No core.

57.6 .8 Trona. Well-consolidated white (N 9) to grayish yellow- 

. green (5GY 7/2) massive trona,-locally discolored darkgray (N 3) by intermixed clay; seam of colorless fine 

fibrous trona from 57.2 to 57.3 ft; a few #-to 1-iri. vugs

 ; lined with colorless fine fibrous trona; irregularly discolored

 moderate reddish-orange (10JR 6/6) seams in upper 0.3 ft 

1 due to intermixed algae (?).

57. 7 .1 Clay and gaylussite. Well-consolidated grayish-black (N 2) 

to greenish-black (5GF2/1) to grayish olive-green (5073/2) 

faintly finely laminated clay with 5 percent disseminated 

fine gaylussite silt.

58. 9 1. 2 Clay and gaylussite. Black (N 1) to grayish-black (N 2) to 

olive-gray (5Y 3/2) clay with 35 percent disseminated 

anhedral to euhedral gaylussite crystals averaging 4 mm 

in length; seams, averaging 0.5 mm wide, of anhedral 

massive gaylussite from 57.8 to 57.9 ft and from 58: 6 to 

58.9ft.
CORE .LOGS FROM SEARLES LAKE, CALIFORNIA 275

Depth Unit thick- 

(feet) ness (feet) Description

59. 4 0. 5 Clay, gaylussite* and northupite*. Black (N 1) to grayishblack (N 2) clay with 50 percent disseminated euhedral 

colorless gaylussite* crystals averaging 5 mm in length; 

scattered %-in. pockets of disseminated yellowish northupite* octahedra averaging 1 mm in length.

60. 1 .7 Clay and pirssonite*. Black (AT 1) to grayish-black (N 2) 

clay with 40 percent disseminated pirssonite* sand; irregular 

moderate reddish-brown (10/2 4/6) algae(?) streaks at 59.6 

to 59.7 ft.

60. 9 . . 8 Trona and clay. Well-consolidated white (N 9) massive to 

colorless fine fibrous trona, locally discolored grayish-black 

(N 2) by 2 percent intermixed clay.

61. 2 .3 No core.

61. 3 .1 Trona and clay. Well-consolidated colorless fibrous trona, 

locally stained yellowish-gray (5Y 8/1) to greenish-gray 

(5GY 6/1) to light-brown (5YR 6/4); irregular wavy seam, 

3 mm wide, containing 10 percent interstitial black (N 1) 

clay at base. Trona 99 percent, clay 1 percent.

61.6 .3 Trona.. Well-consolidated white (N 9) to greenish-gray 

(5GY 6/1) to light olive-gray (5Y 6/1) massive trona with 

trace of black (N 1) clay in local irregular pockets and 

streaks; .vuggy seam, 5 mm wide, lined with colorless 

fibrous trona at 61.4 ft.

61. 7 .1 Trona. Well-consolidated vuggy aggregate of colorless fine 

fibrous trona, locally superficially stained grayish-yellow 

(5Y 8/4) to dark-gray (N 3) with disseminated small 

pockets and irregular streaks of medium-gray (N 5) massive 

trona; disseminated irregular nodules, averaging 1 mm in 

length, of moderate reddish-brown (10JB 4/6) algae(?).

62. 1 .4 Trona. Well-consolidated slightly vuggy yellowish-gray 

(5 Y 8/1) massive trona with irregular wavy anastomosing 

seams discolored dark-gray (N 3) to greenish-gray (5GY 6/1) 

by trace of intermixed clay; vugs, % to 1 in. long, lined 

with colorless fine fibrous trona.

62.5 .4 Trona. Pulverulent vuggy porous aggregate of colorless: 

fibrous trona, locally stained grayish-yellow (5Y 8/4);: 

common disseminated nodules, up to 3 mm in length,, 

averaging 1 mm, of moderate reddish-brown (IQR 4/6) 

algae (?).

62. 6 .1 Clay. Core fractured. Black (N 1) to grayish-black (N 2) 

clay, locally discolored vague blackish-red (5R 2/2) by 

algae(?).

63.2 .6 Trona. Well-consolidated white (N 9) to yellowish-gray 

(5Y 8/1) massive trona, locally discolored greenish-gray 

(50 6/1) to dark greenish-gray (5(? 4/1) by trace of intermixed clay.

63. 9 .7 Trona and clay. Fractured core. Well-consolidated fragments of white (JV 9) to yellowish-gray (5Y 8/1) massive 

trona with irregular pockets of colorless fine fibrous trona, 

locally stained grayish-yellow (5F 8/4); 15 percent interstitial black (N 1) clay between fragments possibly representing clay seams or pockets.
276 GEOLOGIC INVESTIGATIONS IN MOJAVB DESERT REGION

Depth Unit thick-

(feet) ness (feet) Description

64. 2 0.3 Trona. Well-consolidated colorless to yellowish-gray (5Y 

8/1) compact fibrous trona.

65.3 1.1 Trona. Well-consolidated grayish-orange (10 YR 7/4) to 

very pale orange (10 YR 8/2) massive trona; a few pockets 

and streaks of colorless to very pale orange (10 YR 8/2) 

fine fibrous trona from 64.6 ft to base; thin streaks and 

spots of moderate reddish-orange (1QR 6/6) algae(?) in 

lower 0.4 ft.

65. 9 .6 No core.

66. 1 .2 Trona. Fractured core. Fragments of white (N 9) soft 

massive trona with fragments of well-consolidated white 

(N 9) hard massive trona containing vuggy pockets of 

colorless fine fibrous trona; moderate reddish-orange (10/J 

6/6) algae(?) stains locally present.

67. 5 1. 4 Trona. Well-consolidated slightly vuggy white (N 9) to 

yellowish-gray (5Y 8/1) to greenish-gray (5(7^6/1) massive 

trona with common irregular pockets and streaks of colorless 

fibrous trona, locally stained grayish-yellow (5Y 8/4) to 

greenish-black (bOY 2/1) by trace of intermixed clay; 

discolored seams, streaks, and spots of intermixed orange 

to moderate reddish-orange (10JB 6/6) algae (?) throughout; 

wavy seams of trona, averaging 5 mm in width, revealed 

by color differences, and thin seams of intermixed clay, 

averaging 2 mm in width, between 67.2 and 67.4 ft.

67.6 .1 Northupite and clay. Well-consolidated grayish-orange 

(lOFB 7/4) to dark greenish-gray (50Y 4/1) soft massive 

northupite with thin streaks of intermixed dark-gray (N 3) 

to grayish-black (N 2) clay throughout. Northupite 95 

percent, clay 5 percent.

67. 7 .1 Clay and trona. Grayish-black (N 2) clay with seams and 

streaks, averaging 2 mm in width, of white (N 9) soft 

massive trona. Clay 70 percent, trona 30 percent.

68.3 .6 Clay and northupite. Well-consolidated black (N 1) to 

grayish-black (N 2) clay with a few seams, 2-3 mm wide, 

of disseminated round to oval white (N 9) to light-gray 

(N 7) nodules, averaging 1 mm in diameter, of massive 

northupite; very faint fine closely spaced very light gray 

(W 8) to light greenish-gray .(5OY 8/1) laminae in lower 

0.3 ft. Northupite less than 1 percent.

68.5 .2 Clay and gaylussite. Well-consolidated black (N 1) to 

grayish-black (N 2) to olive-gray (5Y 3/2) to moderate 

olive-brown (5F 4/4) clay with 60 percent disseminated 

subhedral gaylussite crystals averaging 5 mm in length.

«68. 9 .4 Clay. Well-consolidated grayish-black (N 2) to greenishblack (5GY 2/1) clay with faint fine closely spaced very 

light gray (N 8) laminae; a few seams of disseminated 

gaylussite silt.
CORE LOGS FROM SEARLES LAKE, CALIFORNIA 277

Depth Unit thlck-

(feet) ness (feet) Description

69.5 0.6 Clay and northupite*. Well-consolidated grayish-black (AT 2) 

clay with seam, 5 mm wide, containing fine streaks of pale 

yellowish-brown (IQYR 6/2) massive northupite* in clay 

at 69.0 ft. Clay 99 percent, northupite 1 percent.

74, 4 .2 Clay. Well-consolidated grayish-black (N 2) to very light 

gray (N 8) faintly finely laminated clay; a few scarce 

nodules, averaging 1 mm in length, of massive northupite.

74. 7 .3 Clay and gaylussite. Friable black (N 1) to greenish-black 

(50 Y 2/1) to dusky-yellow (5(7 Y 6/4) clay with 50 percent 

disseminated euhedral colorless gaylussite crystals 0.5 to 1 

mm in length.

74.9 .2 Clay. Well-consolidated grayish-black (N 2) to dusky 

yellow-green (50 Y 5/2) to very light gray (N 8) faintly 

finely laminated clay.

75. 0 .1 Clay. Well-consolidated grayish-black (N 2) clay.

75. 5 .5 Trona and northupite. Well-consolidated slight vuggy aggregate of colorless trona blades averaging 5 mm in length, 

with pockets and streaks of interstitial yellowish-gray 

(5Y 8/1) soft massive northupite. Trona 95 percent, 

northupite 5 percent.

75.7 .2 Clay, trona, and borax. Black (N 1) to greenish-black 

(50 Y 2/1) clay with 15 percent disseminated colorless trona 

blades 5-25 mm in length, averaging 10 mm; 5 percent 

disseminated subhedral borax crystals averaging 25 mm 

in length.

76.2 .5 Clay. Well-consolidated grayish-black (N 2) to grayish 

olive-green (50 Y 3/2) to greenish-gray (5(7 Y 6/1) to grayishyellow (5F 8/4) finely laminated clay; trace of disseminated 

gaylussite silt.

76. 6 .4 Clay and gaylussite. Friable grayish-black (N 2) to olivegray (5F 3/2) clay with 50 percent disseminated euhedral 

gaylussite crystals up to 25 mm hi length, averaging 10 mm.

76. 9 .3 Clay and gaylussite. Well-consolidated grayish-black (N 2) 

clay with 50 percent disseminated colorless euhedral gaylussite sand.

77. 3 .4 Clay. Well-consolidated grayish-black (N 2) to dusky yellowgreen (50 Y 5/2) to grayish olive-green (50 Y 3/2) to very 

light gray (AT 8) finely laminated clay.

77. 4 .1 Clay and gaylussite. Well-consolidated grayish-black (N 2) 

to olive-gray (5F 3/2) clay with 30 percent disseminated 

gaylussite silt.

77.7 .3 Trona, borax, and clay. Fractured core. Fragments of 

well-consolidated slightly vuggy white (N 9) to mediumgray (N 5) massive trona with vuggy pockets of colorless 

fine fibrous trona; 5 percent disseminated anhedral borax 

crystals, averaging 15 mm in length; 5 percent intermixed 

black (N 1) clay in seams and pockets; scattered moderate 

reddish-brown (iOR 4/6) algae(?) discolorations.

77. 8 .1 No core.
278 GEOLOGIC INVESTIGATIONS IN MOJAVE DESERT REGION

Depth Unit thick-

(feet) ness (feet) Description

79. 5 1. 7 Clay and gaylussite. Friable olive-black (5Y 2/1) to grayishblack (N 2) to dusky yellowish-brown (10 YR 2/2) clay 

with 20 percent disseminated euhedral to subhedral gaylussite crystals up to 40 mm in length, averaging 15 mm; 

locally finely laminated greenish-gray (50Y 6/1) to medium 

bluish-gray (5(? 5/1) to dark-gray (N 3) to dark yellowishorange (10YR 6/6) to dusky-yellow (5Y 6/4) to moderate 

olive-brown (5 Y 4/4) clay.

Searles drill hole GS-22

LOCATION: Searles Lake, Calif., about 50 ft southwest of center sec. 31, T. 25 S.,

R. 44 E., Mount Diablo base line and meridian. 

ELEVATION AT TOP OF HOLE: 1,617 ft. 

ELEVATION AT BOTTOM OF HOLE: 1,511.6 ft. 

TOTAL DEPTH: 105.4 ft. 

DATES DRILLED: June 1-17, 1955.

CASING USED: 19.5 ft of 16-in. casing; 77.7 ft of 3-in. pipe. 

MINERAL DETERMINATIONS: Minerals identified microscopically are denoted by

an asterisk (*).

Depth Unit thick-

(feet) ness (feet) Description

0. 3 0. 3 Halite and clay. Friable vuggy aggregate of colorless halite 

cubes and cubes modified by octahedron, averaging 5 mm in 

length, with 5 percent interstitial dusky yellow-green 

(5GY 5/2) soft'moist clay; upper 10 mm stained pale-red 

(WR 6/2) by algae(?).

2. 1 1. 8 Halite and clay. Unconsolidated aggregate of colorless halite 

cubes modified by octahedron and subhedra, up to 35 mm 

in length, averaging 10 mm, with 5 percent interstitial 

dusky yellow-green (5GY 5/2) soft moist clay grading to 

grayish olive-green (5GY 3/2) clay in lower 0.6 ft.

2. 3 . 2 No core.

2. 8 .5 Halite and clay. Unconsolidated aggregate of colorless halite 

cubes modified by octahedron and subhedra, up to 35 mm 

in length, averaging 10 mm, with 2 percent interstitial 

greenish-black (5GY 2/1) soft moist clay.

3. 1 .3 Thenardite*, clay, and halite. Well-consolidated slightly 

vuggy aggregate of colorless tabular then'ardite* crystals 

averaging 20 mm in length; 5 percent interstitial greenishblack (5GY 2/1) clay with 2 percent disseminated colorless 

halite cubes modified by octahedron, averaging 2 mm in 

length, in lower 20 mm.

3. 6 .5 Hanksite, halite, and clay. Unconsolidated aggregate of 

euhedral to subhedral pale yellowish hanksite crystals up 

to 10 mm in length, averaging 2 mm, with 5 percent interstitial greenish-black (5GY 2/1) soft moist clay; 10 percent 

intermixed disseminated colorless halite cubes modified by 

octahedron and subhedra, up to 10 mm in length, averaging 

2 mm.
CORE LOGS FROM SEARLES LAKE, CALIFORNIA 279

Depth Unit thick- 

(feet) ness (feet) Description

4. 0 0. 4 Hanksite and trona. Well-consolidated slightly vuggy 

granular aggregate of yellowish euhedral hanksite crystals 

from 0.5 to 2 mm in length, with 25 percent interstitial white 

(N 9) massive to colorless fine fibrous trona.

4. 2 .2 Trona, hanksite, and clay. Vuggy aggregate of colorless fine 

fibrous trona with ^-in. pockets and streaks of white (N 9) 

massive trona; 20 percent disseminated yellowish euhedral 

hanksite crystals 3-10 mm in length; interstitial greenishblack (5(7 2/1) clay in lower 0.2 ft with irregular seam, 

10-30 mm wide, of 75 percent greenish-black (5GY 2/1) 

clay at base. Trona 47 percent, clay 33 percent, hanksite 

20 percent.

4. 4 . 2 No core.

4. 9 .5 Clay and halite. Grayish-black (N 2) to greenish-black 

(5G 2/1) soft moist clay with 50 percent disseminated 

colorless halite cubes modified by octahedron and subhedra, 

up to 15 mm in length, averaging 5 mm.

5. 7 .8 Clay. Well-consolidated dusky yellow-green (5(7 Y 5/2) clay 

with numerous irregular thin stringers of grayish-black 

(N 2) clay.

6. 3 . 6 No core.

6.6 .3 Clay and halite. Grayish-black (N 2) to greenish-black 

(5G 2/1) soft moist clay with 25 percent disseminated colorless halite cubes modified by octahedron, averaging 5*mm 

in length.

7. 2 .6 Clay. Well-consolidated dusky yellow-green (5GY 5/2) clay 

with scattered %-in. pockets and thin irregular stringers_of 

grayish-black (N 2) clay.

7. 4 . 2 No core.

7. 6 .2 Clay and halite. Well-consolidated dusky yellow-green 

(5GY 5/2) clay, locally grayish-black (N 2) clay; with 25 

percent disseminated colorless halite cubes modified by 

octahedron and subhedra, averaging 5 mm in length.

9. 1 1. 5 Clay. Well-consolidated dusky yellow-green (5GY 5/2) to 

grayish olive-green (5GY 3/2) clay with irregular wavy 

streaks of grayish-black (N 2) clay.

9. 3 . 2 No core.

10. 8 1. 5 Clay. Well-consolidated dusky yellow-green (5GY 5/2)Tto 

grayish-green (10(7 F 5/2) clay with numerous irregular 

wavy stringers and pockets of grayish-black (N 2) clay.

14. 7 3. 9 No core.

15. 8 1.1 Clay. Fractured core. Fragments of black (N 1) to greenishblack (5GY 2/1) silty clay.

16. 1 .3 Clay. Black (N 1) silty clay.

16.5 .4 Halite and clay. Well-consolidated aggregate of colorless 

halite cubes modified by octahedron and subhedra, up to 

10 mm in length, averaging 3 mm, with 10 percent interstitial black (N 1) soft clay.

16. 7 .2 Clay and halite. Black (N 1) soft silty clay with 35 percent 

disseminated colorless halite cubes modified by octahedron 

and subhedra, averaging 5 mm in length.

491349 59 10
280 GEOLOGIC INVESTIGATIONS IN MOJAVE DESERT REGION

Depth Unit thkk-

(feet) ness (feet) Description

17. 8 1.1 Halite and clay. Poorly consolidated aggregate of colorless 

halite cubes, cubes modified by octahedron, and subhedra, 

averaging 5 mm in length, with 10 percent interstitial 

black (N 1) soft clay.

18. 5 . 7 No core.

19. 1 .6 Halite and clay. Friable aggregate of colorless halite cubes 

modified by octahedron and subhedra, up to 20 mm in 

length, averaging 4 mm, with 5 percent interstitial black 

(N 1) soft moist clay mainly confined to irregular interstitial 

streaks.

19. 9 .8 No core.

20. 3 .4 Halite and clay. Moderately friable aggregate of colorless 

halite cubes modified by octahedron and subhedra, averaging 5 mm in length, with 1 percent interstitial dark greenishgray (50 4/1) clay.

20. 4 .1 Trona and clay. Fractured core. Fragments of white (N 9) 

to yellowish-gray (5Y 8/1) dense hard massive trona with 

10 percent interstitial black (N 1) clay.

21. 4 1.0 Halite, trona, and clay. Moderately friable vuggy aggregate 

of colorless halite cubes modified by octahedron and subhedra, up to 20 mm in length, averaging 5 mm, with 5 percent soft massive trona in irregular streaks discolored dark 

greenish-gray (50 4/1) to grayish-black (N 2) by intermixed clay; seam, 10 mm wide, of black (N 1) clay at 21.1 

ft. Halite 91 percent, trona 5 percent, clay 4 percent.

22. 4 1.0 Halite and trona. Well-consolidated dense granular moderately vuggy aggregate of colorless.halite crystals averaging 

5 mm in length, with 2 percent interstitial white (N 9) massive trona; a few pockets and streaks of halite cubes and 

cubes modified by octahedron, up to 15 mm in length; 

trace of local interstitial greenish-black (50 Y 2/1) clay.

22. 7 .3 Hanksite, halite, and clay. Unconsolidated mixture of yellowish euhedral to subhedral hanksite crystals from 5 to 

40 mm in length, averaging 35 mm, with 10 percent interstitial colorless halite cubes modified by octahedron and 

subhedra, averaging 4 mm in length, discolored dark 

greenish-gray (50 4/1) by 1 percent interstitial clay.

23. 4 . 7 Halite, trona, and hanksite. Well-consolidated slightly vuggy 

aggregate of colorless halite crystals with 25 percent interstitial white (Af9) to yellowish-gray (578/1) massive trona; 

lenticular horizontal vugs in upper 0.2 ft lined with colorless fibrous trona; a few streaks, averaging 5 mm in width, 

of yellowish anhedral hanksite; trace of local grayish-black 

(N 2) interstitial clay. Halite 70 percent, trona 25 percent, 

hanksite 5 percent.

25. 0 1. 6 No core.

25. 1 .1 Clay and pirssonite. Well-consolidated black (N 1) to grayish-black (N 2) clay with streaks of moderate-brown (5YR 

4/4) algae(?) discolored clay; 40 percent disseminated 

euhedral pirssonite crystals averaging 1 mm in length.
CORE LOGS FROM SEARLES LAKE, CALIFORNIA 281

Depth Unit thick- 

(feet) ness (feet) Description

25. 3 0. 2^ Hanksite and clay. Well-consolidated aggregate of euhedral 

yellowish hanksite crystals up to 70 mm in length, averaging 40 mm, with 20 percent interstitial black (N 1) clay.

"26. 5 1. 2 Halite, trona, and clay. Well-consolidated dense granular 

slightly vuggy aggregate of colorless halite crystals with 5 

percent interstitial white (N 9) massive trona; scattered 

vuggy pockets of colorless halite cubes modified by octahedron, averaging 2 mm in length; 0.1-ft seam containing 10 

percent interstitial grayish-black (N 2) clay at 26.0 ft.

26. 8 .3 Trona and clay. Well-consolidated massive to fine fibrous 

trona discolored dark greenish-gray (5(7 4/1) to grayishblack (N 2) by 5 percent intermixed clay.

28. 0 1. 2 Halite and trona. Well-consolidated moderately vuggy granular aggregate of colorless halite crystals with 2 percent 

interstitial white massive to fine fibrous trona; vuggy 

pockets of colorless halite cubes modified by octahedron, 

averaging 2 mm in length, with a few euhedral yellowishgray (5Y" 8/1) hanksite crystals; traces of grayish-black (N 

2) clay locally present.

28. 3 . S^fTrona and clay. Fractured core. Fragments of well-consolidated white (N 9) to yellowish-gray (5Y 8/1) massive 

trona; fragments of black (N 1) clay containing a few disseminated sulfohalite cctahedra from 3 to 12 mm in length. 

Trona 80 percent, clay 20 percent.

28. 5 ... 2^Halite. Fractured core. Fragments of well-consolidated aggregates of halite subhedra averaging 5 mm in length.

28. 8 . 3"Halite, hanksite, and clay. Well-consolidated slightly vuggy 

aggregate of colorless halite subhedra averaging 3 mm in 

length, with irregular horizontal streaks of yellowish 

anhedral hanksite and disseminated euhedral hanksite 

crystals up to 40 mm in length, in pockets in some places; 

10 percent interstitial black (N 1) clay throughout; single 

sulfohalite octahedron. Halite 60 percent, hanksite 30 

percent, clay 10 percent.

29.0 . 2~3Hanksite, clay, trona, and sulfohalite. Fractured core. Fragments consisting of euhedral colorless hanksite crystals, 

averaging 15 mm in length, containing apparent inclusions 

of white '('N 9) massive trona; 10 percent interstitial black 

(N 1) clay; a few sulfohalite octahedra averaging 4 mm in 

length.

29. 4 .4 No core.

29. 9 . 5 ^Halite, trona, hanksite, and clay. Well-consolidated slightly 

vuggy aggregate of colorless halite crystals with 10 percent 

interstitial white (N 9) massive trona; euhedral hanksite 

crystals, up to 40 mm in length, disseminated in upper 0.1 

ft and lower 0.1 ft; scattered streaks and pockets of interstitial black (N 1) clay. Halite 80 percent, trona 10 percent, hanksite 9 percent, clay 1 percent.
282 GEOLOGIC INVESTIGATIONS IN MOJAVE DESERT REGION

Depth Unitthick-

(feet) ness (feet) Description

30. 8 0. 9 Halite and trona. Well-consolidated slightly vuggy aggregate of colorless halite cubes modified by octahedron and 

subhedra, averaging 2 mm in length, with 10 percent interstitial yellowish-gray (5Y 8/1) massive to colorless fine 

fibrous trona, locally discolored dark-gray (N 3) by trace 

of intermixed clay.

31. 1 .3 Trona and halite. Well-consolidated seams of white (N 9) to 

yellowish-gray (5F 8/1) massive trona, locally discolored 

dark greenish-gray (5(7 Y 4/1) by trace of intermixed clay; 

a few seams, averaging 5 mm in width, of disseminated 

colorless halite cubes modified by octahedron and subhedra, 

averaging 2 mm in length; faint moderate reddish-orange 

(WR 6/6) algae(?) stains in upper 2 mm. Trona 90 percent, 

halite 10 percent.

31. 5 .4 Halite and trona. Friable fragments consisting of aggregates 

of colorless halite cubes modified by octahedron and subhedra, averaging 3 mm in length, with 5 percent interstitial 

white (AT 9) to greenish-gray (5 GY 6/1) massive trona.

31. 9 .4 Halite and trona; Well-consolidated slightly vuggy granular 

aggregate of colorless halite crystals with 35 percent interstitial white (N 9) massive trona, locally discolored darkgray (N 3) by intermixed clay; vugs in halite contain colorless halite cubes modified by octahedron, averaging 2 mm 

in length.

32. 6 .7 Halite and trona. Moderately friable aggregate of colorless 

halite cubes and subhedra, averaging 2 mm in length, with 

2 percent interstitial greenish-gray (5GY 6/1) massive to 

colorless fine fibrous trona.

33. 5 .9 Hanksite, halite and trona. Well-consolidated moderately 

vuggy aggregate of colorless to pale-smoky euhedral to 

subhedral hanksite crystals averaging 10 mm in length, with 

interstitial pockets, 2-5 in. long, of colorless halite crystals, 

averaging 3 mm in length, containing 30 percent interstitial 

white (N 9) massive to fine fibrous trona; trace of intermixed black (N 1) clay in upper 0.3 ft. Hanksite 60 percent, halite 30 percent, trona 10 percent.

34. 4 .9 No core.

34.7 .3 Hanksite. Well-consolidated colorless granular massive 

hanksite and densely packed subhedral hanksite crystal 

aggregates, crystals averaging 3 mm in length, discolored 

dark-gray (JV 3) by trace of interstititial clay.

35. 4 .7 Halite and trona. Moderately friable vuggy aggregate of 

flat distorted colorless halite crystals resembling cubes 

modified by octahedron, up to 20 mm in length, averaging 

5 mm, with apparent inclusions of white (N 9) massive 

trona; 10 percent interstitial white (N 9) to greenish-gray 

(5GY 6/1) massive to colorless fibrous trona; numerous 

lenticular horizontal vugs; core fractured in lower 0.4 ft.
CORE LOGS FROM SEARLES LAKE, CALIFORNIA 283

Depth Unit thick-

(feet) ness (feet) Description

35. 7 0. 3 Halite and trona. Well-consolidated aggregate of colorless 

halite cubes modified by octahedron and subhedra, averaging 2 mm in length, with 10 percent interstitial white (N 9) 

to greenish-gray (5GY 6/1) massive trona, in some places in 

seams and streaks up to 10 mm wide.

36. 3 .6 Halite and trona. Moderately friable slightly vuggy aggregate of colorless halite cubes modified by octahedron, averaging 5 mm in length, with 1 percent interstitial white (N 9) 

to yellowish-gray (5 Y 8/1) massive trona; trace of greenishblack (5GY 2/1) interstititial clay at 36.0 ft.

36.5 .2 Hanksite and halite. Well-consolidated granular massive 

light-smoky hanksite with irregular seams, averaging 15 

mm in width, of colorless halite cubes modified by octahedron, averaging 3 mm in length, at base and top. Hanksite 50 percent, halite 50 percent.

37. 0 .5 Trona and halite. White (N 9) to very pale orange (1QYR 

8/2) soft massive trona with 50 percent disseminated colorless halite cubes modified by octahedron and subhedra, 

averaging 3 mm in length.

37.2 .2 Hanksite, halite, and trona. Well-consolidated granular 

massive light-smoky hanksite with streaks, 1-3 mm wide, 

of interstitial white (N 9) to very pale orange (IQYR 8/2) 

soft massive trona; seam, averaging 15 mm in-width, of 

colorless halite cubes, cubes modified by octahedron, and 

subhedra, averaging 2 mm in length, containing interstitial 

white (N 9) soft massive trona at base. Hanksite 75 percent, halite 15 percent, trona 10 percent.

38.4 1.2 No core.

38. 8 .4 Halite and trona. Well-consolidated aggregate of colorless 

halite cubes modified by octahedron, from 2 to 10 mm in 

length, averaging 3 mm, with 10 percent interstitial white 

(N 9) to greenish-gray (5GY 6/1) massive trona.

39.1 .3 Trona and halite. Well-consolidated greenish-gray (5GY 6/1) 

massive trona with>streaks and pockets of colorless halite 

cubes modified by octahedron, averaging 3 mm in length. 

Trona 65 percent, halite 35 percent.

39. 8 .7 Halite and hanksite. Fractured core. Fragments of wellconsolidated aggregates of colorless halite cubes and cubes 

modified by octahedron, averaging 3 mm in length, with 

a few fragments containing irregular lenticular pockets of 

yellowish-gray (5Y 7/2) hard massive hanksite. Halite 70 

percent, hanksite 30 percent.

40. 4 .6 Halite and trona. Well-consolidated aggregate of colorless 

halite cubes and subhedra, averaging 3 mm in length, with 

streaks and pockets of white (N 9) to greenish-gray (50 Y 

6/1) massive trona mainly confined to upper 0.3 ft. Halite 

85 percent, trona 15 percent.

40. 5 . 1 No core.
284

Depth Unit thlck-

(feet) neas (feet) Description

41.0 0. 5 Trona, halite, and hanksite. Friable aggregate of white 

(N 9) to greenish-gray (5GY 6/1) massive trona with streaks, 

seams, and pockets of colorless halite cubes modified by 

octahedron and subhedra, averaging 2 mm in length; 

irregular lenticular seams, 0.1 ft wide, of smoky massive 

hanksite; locally subhedral hanksite crystals averaging 4 

mm in length at 40.7 to 40.8 ft; scattered streaks and pockets 

of colorless fine fibrous trona, locally stained grayish-yellow 

(5Y 8/4). Trona 60 percent, halite 20 percent, hanksite 

20 percent.

41.3 .3 Hanksite, halite, and trona. Well-consolidated aggregate 

of colorless to light-smoky subhedral hanksite crystals up 

to 20 mm in length, averaging 10 mm, with interstitial 

colorless halite cubes modified by octahedron and subhedra, 

averaging 3 mm in length, containing intermixed white 

(N 9) to greenish-gray (5GY 5/1) massive trona. Hanksite 

90 percent, halite 7 percent, trona 3 percent.

41.4 .1 Halite and trona. Unconsolidated aggregate of colorless 

halite cubes and subhedra, averaging 3 mm in length, 

with 10 percent interstitial white (N 9) massive trona.

41. 5 .1 Hanksite, halite, and trona. Well-consolidated moderately 

vuggy pockets of anhedral to subhedral smoky hanksite 

crystals averaging 3 mm in length, with 25 percent intermixed colorless halite cubes, cubes modified by octahedron 

and subhedra, averaging 3 mm in length; 10 percent 

interstitial white (N 9) massive trona.

41. 8 .3 Halite. Well-consolidated dense granular aggregate of colorless halite crystals; trace of white (N 9) massive trona in a 

few pockets 1-2 mm long.

42. 0 .2 Halite and trona. Friable aggregate of colorless halite cubes 

and subhedra, averaging 3 mm in length, with 1 percent 

interstitial colorless fibrous trona.

43. 8 1. 8 No core.

44. 4 .6 Halite and trona. Moderately friable aggregate of colorless 

halite cubes and subhedra, averaging 3 mm in length, with 

5 percent interstitial colorless fibrous trona.

44.7 .3 Halite, trona, and hanksite. Core fractured. Moderately 

friable aggregate of colorless halite cubes, cubes modified 

by octahedron, and subhedra, averaging 3 mm in length, 

with 5 percent disseminated euhedral colorless to light smoky 

hanksite crystals averaging 5 mm in length; 10 percent 

interstitial white (N 9) massive trona.

45. 0 .3 Halite and trona. Well-consolidated aggregate of colorless 

halite cubes and cubes modified by octahedron, averaging 

2 mm in length, with 20 percent interstitial colorless fine 

fibrous trona.

45. 3 .3 Trona, hanksite, and clay. Well-consolidated white (N 9) 

to yellowish-gray (5Y 8/1) massive trona with a few streaks, 

1-2 mm wide, of black (N 1) clay; vuggy seam, 15 mm wide, 

of smoky massive hanksite containing euhedral hanksite 

crystals in vugs in lower 0.1 ft. Trona 82 percent, hanksite 

17 percent, clay 1 percent.
CORE LOGS FROM SEARLES LAKE, CALIFORNIA 285

Depth Unit thick-

(feet) ness (feet) Description

45. 5 0. 2 Clay and pirssonite. Well-consolidated black (N 1) to grayish-black (N 2) clay with 35 percent disseminated euhedral 

pirssonite crystals averaging 1 mm in length.

45. 7 .2 Hanksite and trona. Well-consolidated aggregate of euhedral 

to subhedral smoky hanksite crystals up to 30 mm in length, 

averaging 10 mm, with 10 percent interstitial white (N 9) 

to greenish-gray (5GY 6/1) massive trona.

46. 2 .5 Halite and trona. Fractured and poorly consolidated core. 

Fragments consisting of aggregates of friable colorless halite 

cubes, cubes modified by octahedron and subhedra, averaging 3 mm in length, with 5 percent interstitial white (N 9) 

massive trona.

47. 5 1. 3 No core.

48. 0 .5 Halite, trona, and sulfohalite. Friable aggregate of colorless 

halite cubes, averaging 3 mm in length, with 20 percent 

interstitial colorless fibrous trona; a few disseminated yellowish sulfohalite octahedra averaging 5 mm in length.

48. 5 .5 Halite and trona. Well-consolidated moderately vuggy aggregate of colorless halite cubes and cubes modified by octahedron, averaging 3 mm in length, with 40 percent interstitial white (N 9) to yellowish-gray (5Y 8/1) massive trona; 

irregular pockets and streaks of interstitial colorless fine 

fibrous trona throughout.

48. 9 .4 Trona and sulfohalite. Well-consolidated colorless to white 

(N 9) fine fibrous trona with a few disseminated sulfohalite 

octahedra averaging 3 mm in length.

49. 0 .1 Halite and trona. Well-consolidated aggregate of colorless 

halite cubes and subhedra, averaging 3 mm in length, with 

30 percent interstitial white (N 9) massive to colorless fibrous 

trona.

49. 3 .3 No core.

49. 8 .5 Trona. Well-consolidated colorless to white (N 9) porous 

fine fibrous trona.

51. 1 1. 3 Trona, hanksite, and sulfohalite. Well-consolidated moderately vuggy fine colorless to white (N 9) fibrous trona with 

numerous pockets of euhedral to anhedral smoky hanksitecrystals averaging 10 mm in length; a few disseminated 

sulfohalite octahedra up to 10 mm in length, averaging 5 

mm. Trona 60 percent, hanksite 40 percent.

51.8 .7 Trona. Well-consolidated white (N 9) to light olive-gray 

(5Y 6/1) to medium-gray (N 5) seams of soft massive tofine fibrous trona.

52. 9 1. 1 No core.

53. 1 .2 Trona. Well-consolidated white (N 9) to colorless porousfine fibrous trona.

53. 4 . 3 Trona and hanksite. Well-consolidated yellowish-gray (5Y 

8/1) to light olive-gray (5Y 6/1) massive trona with streaks, 

averaging 3 mm in which, of anhedral to subhedral smoky 

hanksite. Trona 90 percent, hanksite 10 percent.

54. 6 1. 2 Trona. Well-consolidated white (N 9) to greenish-gray (50Y 

6/1) soft massive trona with a few seams of light olive-gray 

(5Y 6/1) trona.
286 GEOLOGIC INVESTIGATIONS IN MOJAVE DESERT REGION

Depth Unit thick-

(feet) ness (feet) Description

54. 8 0. 2 No core.

55. 4 .6 Trona. Well-consolidated white (N 9) to light greenish-gray 

(5GY 8/1) soft massive trona.

57. 3 1. 9 No core.

57. 6 .3 Trona, hanksite, borax, and clay. Well-consolidated moderately vuggy mixture of white (N 9) to dusky yellow-green 

(5(7 F 5/2) massive trona with disseminated colorless trona 

blades, euhedral smoky hanksite crystals, subhedral colorless borax crystals, averaging 10 mm in length, and local 

intermixed black (N 1) clay. Trona 60 percent, hanksite 

30 percent, borax 9 percent, clay 1 percent.

57.9 .3 Borax, clay, and trona. Moderately friable aggregate of 

colorless euhedral to subhedral borax crystals averaging 5 

mm in length; scattered pockets of light olive-gray (5Y 6/1) 

massive trona; local interstitial black (N 1) clay in pockets 

and irregular streaks. Borax 90 percent, clay 8 percent, 

trona 2 percent.

58. 1 . 2 Clay and pirssonite. Black (N 1) to dark greenish-gray (50 

4/1) to dusky-yellow (5F 6/4) to olive-gray (5Y 3/2) finely 

laminated clay; seam, 10 mm wide, of black (N 1) clay with 

30 percent disseminated euhedral pirssonite crystals, averaging 1 mm in length, at top. Clay 95 percent, pirssonite 

5 percent.

58. 6 .5 Clay and pirssonite. Black (N 1) to grayish-black (N 2) to 

olive-gray (5Y 3/2) clay with 40 percent disseminated subhedral to anhedral pirssonite crystals averaging 4 mm in 

length.

59. 5 .9 Clay and gaylussite*. Black (N 1) to grayish-black (N 2) 

to greenish-gray (5GY 6/1) to dark greenish-gray (5GY 4/1) 

to oh've-gray (5 Y 3/2) to very light gray (N 8) finely laminated clay with scattered pockets of subhedral to anhedral 

gaylussite* crystals averaging 5 mm in length. Clay 85 

percent, gaylussite 15 percent.

60. 9 1. 4 Clay. Black (N 1) to grayish-black (N 2) to greenish-black 

(5(?y 2/1) clay with fine widely spaced light greenish^gray 

(GY 8/1) to very light gray (N 8) laminae.

61. 5 .6 Clay and aragonite. Black (N 1) to greenish-black (5GY 

2/1) to very light gray (N 8) to greenish-gray (5GY 6/1) 

coarsely laminated clay with laminae averaging 1 mm wide 

of white (N 9) soft massive finely crystalline aragonite. 

Clay 95 percent, aragonite 5 percent.

61. 6 .1 Clay and gaylussite. Black (N 1) clay with 40 percent disseminated subhedral gaylussite* crystals averaging 2 mm 

in length.

61. 9 . 3 Clay. Black (AT 1) to greenish-black (5GY 2/1) to olive-gray 

(5F 3/2) to dark greenish-gray (5GY 4/1) to grayish-yellow 

(5F 8/4) to dusky-yellow (5F 6/4) finely laminated clay; 

laminae wavy and locally contorted.

62. 8 .9 Clay and gaylussite*. Black (N 1) to grayish-black (N 2) to 

greenish-gray (5(7 6/1) to olive-gray (5Y 3/2) to grayishyellow (5Y 8/4) to grayish-orange (IOYR 7/4) to very light
CORE LOGS FROM SEARLES LAKE, CALIFORNIA 287

/ Depth Unit thick-

(feef) ness (feet) Description

gray (N 8) finely laminated clay with scattered pockets of

j subhedral to anhedral gaylussite* crystals averaging 5 mm 

 in length. Clay 85 percent, gaylussite 15 percent, 

i 62.9 0.1 Clay and gaylussite. Grayish-black (AT 2) clay with 25 percent

disseminated anhedral gaylussite. 

64.0 1.1 Clay and gaylussite*. Grayish-black (N 2) clay with scattered

pockets of anhedral gaylussite*. Clay 95 percent, gaylussite

5 percent. 

}' 64.2 .2 No core.

64. 6 .4 Clay and gaylussite. Grayish-black (N 2) to dark greenishgray (5(r 4/1) to greenish-gray (5(7 6/1) to dusky-yellow 

(5Y 6/4) finely laminated clay with scattered pockets of

I subhedral gaylussite crystals averaging 5 mm in length.

Clay 85 percent, gaylussite 15 percent.

65. 1 .5 Clay and gaylussite. Grayish-black (N 2) to grayish-yellow 

' (5 Y 8/4) to very light gray (N 9) moderately coarsely laminated clay grading to finely laminated clay in lower 0.1 ft; 

a few pockets of anhedral gaylussite. Clay 95 percent, gaylussite 5 percent.

66. 0 .9 Clay, gaylussite*, and borax. Black (N 1) to grayish-black 

1 (N 2) clay with 40 percent disseminated anhedral gaylussite* 

5 crystals; numerous laminae, averaging 0.3 mm wide, of 

, white (N 9) to grayish-yellow (5Y 8/4) massive gaylussite;

irregular streaks and seams, averaging 3 mm in width, of 

colorless massive borax at 65.2 to 65.3 ft. Clay 55 percent, 

gaylussite 40 percent, borax 5 percent.

66. 6 .6 Clay and gaylussite. Grayish-black (N 2) to greenish-black 

(50Y 2/1) to grayish olive-green (56 Y 3/2) clay with 40 

percent disseminated subhedral gaylussite crystals averaging 

1 mm in length; distinct seams, 3 mm wide, of intermixed 

moderate reddish-brown (IQR 4/6) algae(?) at 66.3 ft and 

at base.

66. 7 .1 Clay. Grayish-black (N 2) clay with scattered vague discoloration of moderate reddish-brown (IQR 4/6) algae (?)

67. 6 .9 Clay and gaylussite. Grayish-black (N 2) to greenish-gray 

(5(7 6/1) to olive-gray (5Y 3/2) to grayish-yellow (5Y 8/4) 

clay with 40 percent disseminated euhedral gaylussite 

crystals averaging 1 mm in length; a few vague streaks of 

moderate reddish-brown (10R 4/6) algae (?).

68. 3 .7 Clay and gaylussite. Grayish-black (N 2) to greenish-gray 

(5(7 6/1) clay with 5 percent disseminated gaylussite silt; 

intermixed vague moderate reddish-brown (10/2 4/6) algae (?) 

discolorations.

68. 6 . 3 No core.

68. 9 .3 Clay and northupite*. Black (N 1) to grayish-black (N 2) 

clay with seams, averaging 2 mm in width, of 75 percent 

disseminated euhedral northupite octahedra, averaging 1 

mm in length, in upper 0.1 ft. Clay 97 percent, northupite 

3 percent.
288 GEOLOGIC INVESTIGATIONS IN MOJAVE DESERT REGION

Depth Unit thick-

(feet) ness (feet) Description

69. 3 0. 4 Clay and pirssonite. Black (N 1) to grayish-black (AT 2) to 

greenish-black (5(77 2/1) clay with 35 percent disseminated 

euhedral pirssonite crystals from sand size to 5 mm in 

length, averaging 2 mm; a few vague discolorations moderate 

reddish-brown (1072 4/6) algae(?).

69. 4 . 1 Clay. Black (N 1) clay with faint streaks of intermixed 

moderate reddish-brown (WR 4/6) algae(?).

70. 1 .7 Clay and pirssonite. Black (N 1) to grayish-black (AT 2) 

clay, locally greenish-gray (5(7 6/1) to dusky-yellow (57 

6/4) in upper 0.1 ft, with 35 percent disseminated euhedral 

pirssonite crystals 1 mm in length.

70. 5 . 4 Trona, clay, borax, and pirssonite. Fractured core. Fragments of well-consolidated moderately vuggy colorless 

fibrous trona, locally stained dusky yellow-green (50 Y 5/2), 

with streaks and pockets of medium-gray (N 5) massive 

trona; single fragments contain ing subhedral borax crystals 

20 mm in length; other fragments with seams of black (N 1) 

clay containing 30 percent disseminated euhedral pirssonite 

sand. Trona 95 percent, clay 3 percent, borax 1 percent, 

pirssonite 1 percent.

71. 1 . 6 Clay and pirssonite. Greenish-black (50 Y 2/1) clay with 40 

percent disseminated euhedral pirssonite crystals averaging 

5 mm in length.

71. 2 . 1 Clay. Black (N 1) clay with very faint very light gray (N 8) 

to moderate greenish-yellow (107 7/4) laminae.

72. 5 1. 3 Clay, gaylussite*, and borax. Black (N 1) to greenish-black 

(50 Y 2/1) to olive-gray (5Y 3/2) clay with 30 percent disseminated euhedral to subhedral gaylussite* crystals from 

1 to 10 mm in length, averaging 5 mm; a few disseminated 

anhedral borax crystals averaging 20 mm in length; seam, 

15 mm wide, of euhedral gaylussite sand between 72.2 and 

72.3 ft. Clay 69 percent, gaylussite 30 percent, borax 1 

percent.

'72. 7 . 2 Clay and pirssonite*. Black (N 1) to grayish-black (N 2) 

clay with 30 percent disseminated euhedral pirssonite* 

sand.

73. 0 . 3 No core.

73. 3 . 3 Trona, clay, and halite. Poorly consolidated colorless soft 

fine fibrous trona discolored dark greenish-gray (5(7 4/1) by 

3 percent intermixed clay; scattered clay fragments; 5 percent intermixed colorless halite sand. Probably cuttings, 

not core.

73. 8 . 5 Trona and clay. Well-consolidated aggregate of colorless to 

grayish-yellow (57 8/4) fine fibrous trona with irregular 

pockets and streaks of intermixed dark greenish-gray (5(7 

4/1) clay. Trona 98 percent, clay 2 percent.

74. 1 . 3 Trona and halite. Well-consolidated greenish-gray (5(77 6/1) 

to very pale orange (10 YR 8/2) massive trona with seams 

of grayish-orange (10772 7/4) massive trona; seam, 20 mm 

wide, of colorless halite cubes modified by octahedron,
\ CORE LOGS FROM SEARLES LAKE, CALIFORNIA 289

Depth UnitlhtckI (feet) ness_(feef) Description

averaging 3 mm in length, containing moderate reddish-

^. brown (10/2 4/6) algae(?) inclusions at 74.9 ft. Trona 78 

I percent, halite 22 percent.

* 75.0 0.9 Halite and trona. Moderately friable aggregate of colorless

halite cubes modified by octahedron, averaging 2 mm in 

length, with irregular pockets, streaks, and interstitial mas-, 

sive to colorless fibrous trona, locally discolored dark-gray 

(N 3) by intermixed clay; seam, 3 mm wide, of intermixed 

moderate reddish-brown (1072 4/6) algae(?) at base. Halite 

85 percent, trona 15 percent.

75.2 .2 Trona. Core fractured. Fragments of well-consolidated 

white (N 9) to greenish-gray (5GY 6/1) massive trona, 

locally discolored moderate reddish-brown (10R 4/6) by 

^ intermixed algae (?).

75. 7 .5 Clay and gaylussite*. Black (AT 1) to grayish-black (N 2) 

clay, locally moderate olive-brown (5V 4/4), with 50 percent

^ disseminated subhedral gaylussite* crystals averaging 3 mm

in length.

77. 6 1. 9 No core.

79. 0 1. 4 Clay, pirssonite, and borax. Black (N 1) to greenish-black 

(5GY 2/1) clay with 35 percent disseminated euhedral to 

Bubhedral pirssonite crystals averaging 3 mm in length; 

a few disseminated anhedral borax crystals averaging 20 mm 

in length.

79. 2 .2 Trona, clay, and pirssonite. Fragments of fine fibrous trona 

with 50 percent interstitial black (N 1) clay containing 

disseminated euhedral pirssonite crystals averaging 1 mm 

in length. Trona 50 percent, clay 35 percent, pirssonite 

15 percent.

79. 4 .2 Halite and trona. Well-consoldiated white (N 9) massive 

trona with pockets of intermixed colorless halite cubes 

modified by octahedron and subhedra, averaging 2 mm in

, length, with interstitial fine fibrous trona. Trona 90 percent, halite 10 percent.

79. 9 .5 Halite. Friable aggregate of colorless halite cubes modified 

by octahedron and subhedra, averaging 2 mm in length, with 

trace of interstitial colorless fibrous trona.

80. 4 .5 Halite and trona. Friable aggregate of colorless halite cubes 

modified by octahedron and subhedra averaging 2 mm in 

length, with 5 percent interstitial greenish-gray (5GY 6/1) 

' massive to colorless fibrous trona.

82. 2 1. 8 No core.

82.7 .5 Halite. Moderately friable aggregate of colorless halite 

cubes modified by octahedron and subhedra averaging 3 

mm in length.

83. 5 .8 Trona and halite. Well-consolidated aggregate of yellowishi gray (5Y 8/1) to light olive-gray (5Y 6/1) massive to fine

fibrous trona with irregular streaks, pockets, and disseminated crystals of colorless halite cubes modified by octahedron and subhedra, averaging 2 mm in length. Trona 

65 percent, halite 35 percent.
290

Depth Unit thick-

(feet) ness (feet) Description

83. 6 0. 1 Trona. Well-consolidated white (N 9) massive trona.

84. 2 .6 Halite. Friable aggregate of colorless halite cubes, cubes 

modified by octahedron, and subhedra, averaging 3 mm in 

length, up to 10 mm; trace of interstitial yellowish-gray 

(5Y 8/1) massive trona in lower 0.1 ft.

84.4 .2 Trona. Well-consolidated slightly vuggy white (N 9) to 

yellowish-gray (5Y 8/1) massive trona, with vugs lined 

with fine colorless fibrous trona.

84. 9 .5 Halite. Friable aggregate of colorless halite cubes modified 

by octahedron and subhedra, averaging 3 mm in length, 

with trace of interstitial white (N 9) massive and colorless 

fibrous trona.

85. 4 .5 Halite and trona. Well-consolidated aggregate of colorless 

halite cubes, cubes modified by octahedron, and subhedra, 

averaging 3 mm in length, with 40 percent white (N 9) 

to dusky yellow-green (5GY 5/2) massive trona in wavy 

seams, streaks, and interstices of halite; seam, 2 mm wide, 

of interstitial black (N 1) clay at 85.3 ft.

86. 2 .8 Halite, burkeite, and trona. Well-consolidated slightly vuggy 

aggregate of colorless halite cubes, cubes modified by octahedron, and subhedra, averaging 2 mm in length, with 15 

percent very pale orange (10Y.R 8/2) to light gray (N 7) 

massive to colorless fibrous trona in irregular pockets and 

streaks interstitial to halite; numerous irregular pockets, 

up to 2 inches wide by 6 inches long, of very pale orange 

(10 YR 8/2) to grayish-orange (10 YR 7/4) hard dense slightly 

vuggy massive burkeite. Halite 45 percent, burkeite 40 

percent, trona 15 percent.

86. 3 .1 No core.

86. 7 .4 Halite. Friable aggregate of colorless halite cubes and subhedra, averaging 3 mm in length, with trace of interstitial 

colorless fibrous trona.

87. 1 .4 Halite and trona. Well-consolidated aggregate of colorless 

halite cubes and subhedra, averaging 3 mm in length, with 

25 percent interstitial medium light-gray (N 6) massive 

trona; a few moderate reddish-brown (10R 4/6) algae(?) 

inclusions in halite crystals.

88. 7 1. 6 Halite, trona, and burkeite*. Friable aggregate of colorless 

halite cubes, cubes modified by octahedron, and subhedra, 

averaging 3 mm in length, with 10 percent greenish-gray 

(5GY 6/1) to white (AT 9) massive trona in interstices and 

irregular streaks throughout; seam, 10 mm wide, of slightly 

vuggy pockets of dense hard grayish-yellow (1QYR 7/4) 

massive burkeite* at 88.1 ft. Halite 88 percent, trona 10 

percent, burkeite 2 percent.

88. 8 .1 Clay and pirssonite. Black (AT 1) clay with 25 percent disseminated euhedral pirssonite crystals averaging 5 mm in 

length.

89. 0 .2 Trona and halite. White (N 9) to greenish-gray (50 Y 6/1) 

soft massive trona, locally discolored dark-gray (ATJJ)fcby
CORE LOGS FROM SEARLES LAKE, CALIFORNIA 291

Depth Unit thick-

(feet) nesa(feet) Description

trace of intermixed clay; 10 percent disseminated colorless 

halite cubes and subhedra, averaging 3 mm in length.

89.1 0.1 Halite and trona. Poorly consoldiated aggregate of colorless 

halite cubes modified by octahedron and subhedra, averaging 2 mm in length, with 5 percent interstitial greenish-gray 

(5GY 6/1) soft massive trona.

89. 4 .3 Halite and trona. Well-consolidated aggregate of colorless 

halite cubes modified by octahedron and subhedra, averaging 2 mm in length, with 40 percent white (N 9) massive 

trona in seams and streaks throughout.

89. 7 .3 Clay, borax> and pirssonite. Well-consolidated grayish-black 

(N 2) to greenish-black (5GY 2/1) clay with very faint fine 

very light gray (N 8) laminae; seam, 10 mm wide, of 75 

percent disseminated prismatic borax crystals, averaging 

10 mm in length at 89.6 ft, with a few disseminated borax 

crystals to base; 30 percent disseminated euhedral pirssonite 

sand in lower 15 mm; irregular moderate reddish-brown 

(10R 4/6) algae(?) stains in upper and lower 10 mm. Clay 

87 percent, borax 8 percent, pirssonite 3 percent.

90. 2 .5 Trona. Well-consolidated slightly vuggy white (N 9) massive 

trona with 0.1-ft seam of colorless fibrous trona 10 mm 

from top and scattered pockets of colorless fibrous trona 

throughout.

90. 4 . 2 Burkeite. Well-consolidated vuggy seam of irregular width 

consisting of yellowish-gray (5Y 8/1) to grayish-orange (IOYR 

7/4) dense hard massive burkeite; a few moderate reddishorange (1QR 6/6) algae(?) stains.

90. 7 . 3 Clay, borax, northupite, and gaylussite. Grayish-black (N 2) 

to greenish-black (5GY" 2/1) clay with very faint fine dusky 

yellow-green (5GY 5/2) to very light gray (N 8) laminae; 

seam, 10 mm wide, of 25 percent disseminated round to 

oval nodules of white massive northupite 10 mm from top; 

single large subhedral borax crystal, 65 mm in length, embedded in clay; a few seams, 1 mm wide, of disseminated 

gaylussite sand and pliable thin clay seams in lower 0.1 ft. 

Clay 91 percent, borax 5 percent, northupite 3 percent, 

gaylussite 1 percent.

90. 9 .2 Clay and gaylussite*. Grayish-black (N 2) to greenish-black 

(5GY 2/1) clay with 50 percent disseminated subhedral 

gaylussite crystals averaging 5 mm in length.

91. 1 .2 Clay, gaylussite, borax, and burkeite*. Grayish-black (N 2) 

clay with 40 percent disseminated clear colorless euhedral 

gaylussite crystals averaging 5 mm in length and grading 

to sand size in lower 0.1 ft; single large subhedral crystal, 

50 mm in length, embedded in clay with white (N 9) to 

very pale orange (WYR 8/2) massive burkeite* partially 

rimming borax crystal, rim up to 2 mm thick.

91. 5 .4 Clay. Grayish-black (N 2) clay with faint fine very light 

gray (N 8) laminae.
292 GEOLOGIC INVESTIGATIONS IN MOJAVE DESERT REGION

Depth Vnit thick-

(feet) nest (feet) Description

92.2 0. 7 Trona, clay, borax, northupite. Well-consolidated densely 

packed aggregate of trona blades 20 to 60 mm in length, 

averaging 50 mm, locally radiating, with 5 percent interstitial grayish-black (N 2) clay; irregular contorted seam, 

averaging 2 mm in width, of moderate orange-pink (5YR 

8/4) massive northupite at 91.8 ft with scattered pockets, 

averaging 1 in. in length, of very pale orange (5YR 8/4) 

dense hard massive northupite; a few disseminated anhedral 

to subhedral borax crystals averaging 20 mm in length. 

Trona 88 percent, clay 5 percent, borax 5 percent, northupite 2 percent.

92. 5 .3 Clay and trona. Fractured core. Fragments of black (N 1) 

to medium bluish-gray (5B 5/1) clay with 25 percent disseminated colorless trona blades averaging 10 mm in length; 

a few disseminated pinpoints of moderate reddish-brown 

(10R 4/6) algae(?).

93. 0 .5 Trona. Well-consolidated slightly vuggy aggregate of colorless fibrous trona with streaks and pockets of white (N 9) 

massive trona; trace of intermixed dark-gray (N 3) clay.

95. 1 2. 1 No core.

95. 3 .2 Clay, northupite, and trona. Black (N 1) to greenish-black 

(5GY 2/1) clay with a few lenticular pockets of colorless 

trona blades averaging 5 mm in length; seam, 10 mm wide, 

of grayish-orange (10F.R 7/4) soft massive northupite at 

top. Clay 73 percent, northupite 17 percent, trona 10 

percent.

95. 5 .2 Clay and northupite. Black (N I) clay with very faint fine 

very light gray (N 8) laminae; disseminated round to oval 

nodules, averaging 1 mm in length, of white (N 9) massive 

northupite in upper 10 mm. Clay 98 percent, northupite 

2 percent.

95.7 . 2 Clay and gaylussite. Black (N 1) clay with 35 percent disseminated euhedral clear colorless gaylussite crystals averaging 1 mm in length at top and grading to fine sand size 

at base.

96. 0 .3 Clay. Black (N 1) to grayish-black (N 2) clay with very 

faint fine very light gray (N 8) laminae.

98. 0 2. 0 Trona, northupite, and clay. Well-consolidated porous aggregate of colorless trona blades, averaging 5 mm in length, 

with pockets and irregular streaks of white (N 9) to very 

light gray (N 8) massive trona; seams, 5 mm wide, of 50 

percent interstitial yellowish-gray (5Y 8/1) to grayishorange (1QYR 7/4) soft massive northupite at 97.5 and 

97.6 ft; 5 percent interstitial grayish-black (N 2) clay in 

lower 0.3 ft. Trona 99 percent, northupite 1 percent.

98. 9 .9 Clay, gaylussite*, northupite. and schairerite*. Black (N 1) 

to grayish-black (N 2) clay with seams, 10 mm wide, of 

25 percent disseminated round to oval nodules, averaging 

0.3 mm in length, of white (N 9) massive northupite at 

98.2 and 98.5 ft; faint fine very light gray (N 8) laminae 

in lower 0.4 ft with scattered nodules, averaging 5 mm in
CORE LOGS FROM SEARLES LAKE, CALIFORNIA 293

Depth Unit thick-

(feet) new (feet) Description

length, of white (N 9) finely crystalline pulverulent schairerite*; 5 percent disseminated gaylussite* silt in lower 0.2 

ft, with seam, 15 mm wide, of 60 percent disseminated 

subhedral gaylussite crystals averaging 2 mm in length 

at base. Clay 93 percent, northupite 2 percent, gaylussite 

5 percent.

99. 0 0. 1 No core.

99. 5 .5 Clay and gaylussite. Black (N 1) to grayish-black (N 2) 

to grayish-green (10(7 F 5/2) clay with 40 percent disseminated subhedral gaylussite crystals averaging 5 mm in 

length.

99i 7 .2 Clay and gaylussite. Black (AT 1) to grayish-black (N 2) 

clay with 40 percent disseminated euhedral gaylussite sand. 

100. 3 . 6 Clay. Black (N 1) to grayish-black (N 2) to very light gray 

(N 8) finely laminated clay; traces of disseminated gaylussite silt throughout.

100. 4 . I Clay and gaylussite. Black (N 1) to grayish-black (N 2) 

clay with 30 percent disseminated gaylussite sand.

100. 6 . 2 Clay. Black (N 1) clay with scattered very faint blackish-fed 

(5R 2/2) algae (?) discolorations.

101. 1 . 5 Trona and clay. Well-consolidated densely packed aggregate 

of colorless trona blades, locally in radiating clusters averaging 25 mm in length, with horizontal lenticular pockets 

of greenish-gray (5GY 6/1) hard massive trona from 100.8 

to 100.9 ft; 10 percent interstitial black (N 1) clay 

throughout.

101. 4 . 3 No core.

101. 5 . 1 Clay. Black (N 1) clay with a few disseminated trona blades 

averaging 5 mm in length.

101. 8 . 3 Clay. Black (N 1) to grayish-black (N 2) to greenish-black 

(5GY 2/1) to very light gray (N 8) faintly finely laminated 

clay with traces of disseminated gaylussite silt.

103. 5 1. 7 Clay and gaylussite. Grayish-black (N 2) to dusky yellowish-brown (10YR 2/2) to moderate olive-brown (5Y 4/4) 

clay, locally finely laminated greenish-gray (5GY 6/1) to 

dusky-yellow (57 6/4) to dark-gray (N 3) clay, with 35 

percent disseminated euhedral to subhedral gaylussite crystals from 5 to 20 mm in length, averaging 10 mm.

104 3 .8 Clay and gaylussite. Olive-gray (5Y 3/2) to dark-gray (N 3) 

to greenish-gray (5GY 6/1) to dusky-yellow (57 6/4) to 

light bluish-gray (5J5 7/1) finely laminated clay with 

scattered pockets and disseminated crystals of anhedral 

gaylussite. Clay 90 percent, gaylussite 10 percent.

105. 4 1. 1 Clay and gaylussite. Olive-black (572/1) to dusky yellowishbrown (10 YR 2/2) to dark-gray (N 3) to greenish-gray 

(5G 6/1) to dark greenish-gray (5(774/1) to grayish-yellow 

(57 8/4) to dusky-yellow (57 6/4) finely laminated clay 

with 20 percent disseminated euhedral gaylussite crystals 

averaging 10 mm in length and a few pockets of anhedral 

gaylussite.
294 GEOLOGIC INVESTIGATIONS IN MOJAVE DESERT EEGION

Searles drill hole GS-28

LOCATION: Searles Lake, Calif., 20 ft northeast of common cor., sees. 10, 11, 14, 

and 15, in sec. 11, T. 26 S., R. 43 E., Mount Diablo base line and Meridian.

.ELEVATION AT TOP OF HOLE: 1,624 ft.

ELEVATION AT BOTTOM OF HOLE: 1,541.9. ft.

TOTAL DEPTH: 82.1 ft.

DATES DRILLED: June 17-30, 1955.

CASING USED: 31.4 ft of 16-in. casing; 58.2 ft of 3-in. pipe.

MINERAL DETERMINATIONS: Minerals identified microscopically are denoted by 

an asterisk (*).

Depth Unit thick-

(feet) ness (/erf) Description

12.0 12.0 Overburden mud, not cored. Moderate yellowish-brown 

(10 YR 5/4) tenacious slightly silty clay.

14. 6 2. 6 Overburden mud, not cored. Dusky yellow-green (5(?F 5/2) 

clay.

24. 0 9. 4 Overburden mud, not cored. Black (N 1) to grayish-black 

(N 2) tenacious clay with irregular streaks of dusky yellowgreen (5GY 5/2) to moderate yellowish-brown (WYR 5/4) 

clay.

30. 0 6. 0 Overburden mud, not cored. Black (N 1) clay.

31. 1 1. 1 Overburden mud, not cored. Black (N 1) clay with a few 

disseminated colorless halite subhedra averaging 2 mm in 

length.

32. 3 1. 2 Clay and gaylussite*. Black (N 1) clay with local irregular 

streaks of dusky yellow-green (5GY 5/2) clay; pockets of 

disseminated anhedral gaylussite* crystals averaging 1 mm 

in length. Clay 95 percent, gaylussite 5 percent.

32.4 .1 Trona. Fractured core. Fragments of well-consolidated 

dark-gray (N 3) fine fibrous to massive trona discolored by 

trace of intermixed clay, with fragments consisting of vuggy 

aggregate of colorless trona blades averaging 5 mm in length.

32. 7 .3 Thenardite, trona, and clay. Fractured core. Well-consolidated vuggy aggregate of colorless transparent blades of 

thenardite averaging 15 mm in length, with streaks and 

pockets of yellowish-gray (5Y 8/2) dense massive trona; 

local interstitial black (N 1) clay. Thenardite 78 percent, 

trona 20 percent, clay 2 percent.

33. 0 .3 Thenardite and trona. Well-consolidated seams of densely 

packed colorless thenardite blades, averaging 15 mm in 

length, intimately associated with lenticular pockets of 

massive yellowish-gray (5Y 8/1) trona; single 2-in. pocket 

of white (N 9) massive trona and local interstitial light-gray 

(N 7) massive trona. Thenardite 80 percent, trona 20 percent

33.8 .8 Trona. Well-consolidated white (N 9) to yellowish-gray 

(5 Y 8/1) massive trona with irregular slightly vuggy seams 

and pockets of colorless trona blades averaging 5 mm in 

length, locally stained grayish-yellow (5Y 8/4).

34 3 .5 Trona and clay. Well-consolidated slightly vuggy aggregate 

of white (N 9) massive trona, locally discolored dark-gray 

(N 3), in irregular streaks by intermixed clay; irregular
CORE LOGS FROM SEARLES LAKE, CALIFORNIA 295

Depth Unit thick-

(fset) ness ( jeet) Description

vuggy streaks and pockets of colorless fine fibrous to colorless bladed trona, locally stained grayish-yellow (5Y 8/4). 

Trona 99 percent, clay 1 percent.

36. 1 1. 8 Trona. Core fractured in upper 0.3 ft. Well-consolidated 

moderately vuggy aggregate of colorless fibrous trona, 

locally stained grayish-yellow (5 Y 8/4); numerous streaks 

and pockets of medium light-gray (N 6) to dark-gray (N 3) 

massive trona, discolored by trace of intermixed clay.

, 36. 3 .2 Trona, hanksite, and clay. Well-consolidated medium-gray 

(N 5) to grayish-black (N 2) massive trona, discolored by 

10 percent intermixed clay; irregular pockets and streaks 

of colorless fibrous to fine bladed trona, locally stained 

grayish-yellow (5 Y 8/4); disseminated anhedral yellowish 

hanksite crystals averaging 25 mm in length; a few disseminated smoky anhedral sulfohalite* crystals. Trona 70 percent, hanksite 20 percent, clay 10 percent.

36. 5 . 2 Trona. Fractured core. Fragments of colorless fibrous trona, 

superficially stained faint grayish-yellow (57 8/4).

37.0 . 5 No core. :

39. 1 2. 1 Trona. Well-consolidated aggregate of colorless fibrous trona, 

locally discolored medium-gray (N 4) by trace of interstitial 

clay; irregular streaks and pockets:of massive trona in 

lower 0.4 ft. . .

40.8 1.7 No core.

42.9 2.1 Trona. Well-consolidated white (N 9) to yellowish-gray 

(5Y 8/1) soft porous massive trona.

44.2 1.3 No core.

44.3 .1 Borax and clay. Poorly consolidated friable aggregate of 

colorless subhedral borax crystals averaging 1 mm in 

length; lower 10 mm consists of colorless subhedral borax 

crystals averaging 10 mm in length, with 30 percent interstitial black (N 1) clay. Borax 90 percent, clay 10 percent.

44.. 9 .6 Clay and gaylussite. Grayish-black (N- 2) to dark greenishgray (5G 4/1) to olive-gray -(5 Y 3/2) to dusky-yellow 

(57 6/4) finely laminated clay with 25 percent disseminated 

subhedral to anhedral gaylussite crystals, averaging 10 

mm in length.

45.1 .2 Clay and gaylussite*. Black (N 1) to olive-gray (57 3/2) 

clay with 50 percent disseminated subhedral gaylussite* 

crystals averaging 10 mm in length.

45.8 .7 Clay and gaylussite. Grayish-black (N 2) to olive-black 

(57 3/2) to grayish-yellow (57 3/4) to very light gray 

(N 8), locally finely laminated clay, with 30 percent disseminated subhedral gaylussite crystals averaging 10 mm 

in length.

46.8 1.0 Clay and gaylussite*. Grayish-black (N 2) to olive-gray 

(57 3/2) to greenish-gray (5(77 6/1) to dark greenish-gray 

(5(? 4/1) to yellowish-gray (57 8/1) finely laminated clay 

with a few 1- to 2-in. pockets and irregular streaks of subhedral gaylussite* crystals averaging 10 mm in length. 

Clay 99 percent, gaylussite, 1 percent.

491349 59 11
296 GEOLOGIC INVESTIGATIONS IN MOJAVE DESERT REGION

Depth Unit thick-

(feet) ness (feet) Description

48.0 1.2 Clay. Black (N 1) to grayish-black (N 2) clay with fine 

widely spaced very light gray (N 8) to grayish-yellow 

(578/4) laminae. .

48.3 .3 Clay and aragonite. Black (N 1) to greenish-black (5GY 2/1) 

clay with laminae, averaging 1 mm wide, of very light 

gray (N 8) to light gray (N 7) soft massive finely crystalline 

aragonite. Clay 95 percent, aragonite 5 percent.

50.4 2.1 Clay and gaylussite*. Black (N 1) to grayish-black (AT 2) 

to greenish-gray (5(? 6/1) to dark greenish-gray (5G 4/1) 

to dusky-yellow (5F 6/4) to grayish-yellow (5F 8/4) to 

very light gray (N 8) finely laminated clay with scattered 

pockets of disseminated subhedral gaylussite* crystals up 

to 20 mm in length, averaging 10 mm. Clay 99 percent, 

gaylussite 1 percent.

51.0 .6 No core.

52.6 1.6 Clay and gaylussite. Black (N 1) to grayish-black (N 2) 

to greenish-gray (5(7 6/1) to dark greenish-gray (5G 4/1) 

to dusky-yellow (5F 6/4) to grayish-yellow (5F 8/4) to 

very light gray (N 8) finely laminated clay with pockets 

of disseminated subhedral to anhedral gaylussite crystals 

averaging 10 mm in length. Clay 85 percent, gaylussite 

15 percent.

52.8 .2 Clay and aragonite. Grayish-black (N 2) clay with widely 

spaced laminae, averaging 1 mm in width, of yellowish-gray 

(5F 8/1) to very light gray (N 8) to white (N 9) soft finely 

crystalline massive aragonite. Clay 95 percent, aragonite 

5 percent.

55.3 2.5 Clay and gaylussite*. Black (N 1) to grayish-black (N 2) 

to greenish-gray (5G 6/1) to dark greenish-gray (5G 4/1) 

to grayish olive-green (5GY 3/2) to dusky yellow-green 

(5GY 5/2) to dusky-yellow (5F 6/4) to olive-gray (5Y 3/2) 

coarsely laminated clay revealed by color differences; 

seams and pockets of subhedral to anhedral gaylussite* 

crystals averaging 5 mm in length; a few faint moderate 

reddish-brown (10R 4/6) algae(?) discolorations in clay. 

Clay 90 percent, gaylussite 10 percent.

55.6 .3 No core.

56.3 .7 Clay and gaylussite. Greenish-gray (5G 6/1) to dark greenishgray (5G 4/1) to grayish-black (N 2) coarsely laminated 

clay revealed by color differences, with seams of disseminated subhedral to anhedral gaylussite crystals, averaging 

10 mm in length. Clay 90 percent, gaylussite 10 percent.

56.8 .5 Clay and gaylussite*. Grayish-black (N 2) to dark greenishgray (5G 4/1) to grayish olive-green (5GT 3/2) clay with 

30 percent disseminated subhedral gaylussite* crystals 

averaging 1 mm in length; local moderate reddish-brown 

(10.R 4/6) algae(?) inclusions in clay and gaylussite crystals.

57.0 .2 Clay. Black (N 1) to grayish-black (N 2) clay with faint 

local moderate reddish-brown (IQR 4/6) algae (?) inclusions.
CORE LOGS FROM SEARLES LAKE, CALIFORNIA 237

3 Depth Unit thick- 

) (feet) ness (feet) Description

57.2 0.2 Clay and gaylussite*. Dark greenish-gray (56? 4/1) to grayish

-, olive-green (5GY 3/2) to grayish-black (N 2) faintly coarsely

laminated clay revealed by color differences, with 20 percent disseminated euhedral to subhedral gaylussite* crystals 

averaging 1 mm in length.

» 57.4 .2 Clay and gaylussite. Black (N 1) to grayish-black (A'' 2)

clay with scattered pockets and streaks of disseminated 

euhedral gaylussite sand; irregular moderate reddishA brown (IOR 4/6) algae(?) streaks in lower 0.1 ft. Clay 98

percent, gaylussite 2 percent.

57.8 .4 Trona and clay. Well-consolidated white (N 9) to light 

gray (N 7) soft massive trona, locally discolored dark-gray

A . (N 3) in pockets and streaks by 1 percent intermixed clay.

 59.7 1.9 Clay and gaylussite*. Black (N 1) to grayish-black (N 2)

to moderate olive-brown (5Y 4/4) to greenish-gray (5GY

6/1) clay with 50 percent disseminated subhedral gaylus-

' site* crystals averaging 5 mm in length and anhedral

gaylussite.

60.0 .3 No core.

60.6 .6 Clay and gaylussite. Black (N 1) to greenish-black (5GY 2/1) 

clay with 45 percent disseminated euhedral to anhedral 

gaylussite crystals averaging 3 mm in length.

60.8 .2 Clay and gaylussite. Black (N 1) clay with 1 percent disseminated gaylussite silt; trace of intermixed moderate 

reddish-orange (IOR 6/6) algae(?).

63.2 2.4 Trona and clay. Well-consolidated moderately vuggy yellowish-gray (5Y 8/1) massive trona, locally discolored 

dark-gray (N 3) by intermixed clay in streaks and pockets; 

colorless fibrous trona in small pockets, irregular seams, 

and lining vugs; distinct orange algae (?) discolorations in 

seams, 5 mm wide, at 61.9 and 62.4 ft. Trona 99 percent, 

clay 1 percent.

63. 3 .1 Clay. Black (AT 1) clay with very faint fine dusky yellowgreen (50? F 5/2) laminae.

64. 1 -.8 Clay and gaylussite*. Black (AT 1) to greenish-black (5GY 

A 2/1) clay with 40 percent disseminated subhedral gaylussite* 

, jjjjt crystals averaging 2 mm in length. 

1'-'5 N 64.2 . 1 No core.

65. 8 1. 6 Clay and gaylussite. Black (AT 1) to greenish-black (5GY 2/1) 

clay with 40 percent disseminated subhedral to euhedral 

gaylussite crystals averaging 10 mm in length.

66. 0 .2 Clay. Dark greenish-gray (50? 4/1) to medium bluish-gray 

(5J5 5/1) to dusky yellow-green (50? F 5/2) to grayishyellow (57 8/4) to grayish-black (N 2) finely laminated clay.

66. 2 .2 Clay and gaylussite. Black (N 1) clay with irregular pockets 

and streaks of disseminated euhedral colorless gaylussite

, , crystals averaging 1 mm in length; trace of moderate

reddish-brown (10ft 4/6) algae(?) discolorations. Clay 90 

percent, gaylussite 10 percent.
298 GEOLOGIC INVESTIGATIONS IN MOJAVE DESERT REGION

Depth i Unit thick- 

(feet) ness (feet) Description

67. 9 1. 7 Trona, clay, and northupite*. Well-consolidated white (N 9) 

to grayish-yellow (5Y 8/4) massive trona with numerous 

pockets and streaks of colorless fine fibrous trona; local intermixed black (N 1) to grayish-black (N 2) clay with irregular 

seam of black (N 1) to grayish-black (N 2) clay at 66.4 to 

66.5 ft, varying from 15 mm to 30 mm in width, and containing irregular streaks of moderate reddish-brown (10jR 

4/6) algae(?); seam, 10 mm wide, of yellowish-gray (5Y 8/1) 

to grayish-orange (10 YR 7/4) soft massive northupite* at 

base, containing 10 percent intermixed fine fibrous trona 

and 5 percent black (N 1) clay. Trona 93 percent, clay 

5 percent, northupite 2 percent.

68. 3 .4 Clay and trona. Black (N 1) to grayish-black (N 2) clajwith irregular pockets of white (N 9) to colorless fine 

fibrous trona in lower 0.1 ft; distinct laminae, 0.3 mm 

wide, of moderate reddish-brown (10.R 4/6) algae(?) at 

68.0 and 68.1 ft. Clay 95 percent, trona 5 percent.

69. 1 .8 No core.

69. 7 .6 Clay, northupite, and trona. Black (N 1) to grayish-black 

(N2) clay with very fine faint very light gray (N 8) laminae; 

disseminated round to oval nodules of massive white (N 9) 

to yellowish-gray (5F 8/1) northupite up to 3 mm in 

length, averaging 1 mm, arranged in layers; seam, 5 mm 

wide, of 50 percent grayish-orange (1QYR 7/4) soft massive 

northupite, 30 percent colorless fibrous trona, and 20 percent 

intermixed clay at top, with a few radiating clusters of 

colorless trona blades averaging 20 mm in length in upper 

0.1 ft. Clay 94 percent, northupite 5 percent, trona 1 

percent.

69. 9 .2 Clay. Black (N 1) to grayish-black (N 2) clay with fine 

very light gray (N 8) laminae; a few laminae, averaging 1 

mm wide, of disseminated colorless gaylussite silt.

70. 0 .1 Clay and gaylussite. Greenish-black (5GY 2/1) clay with 50 

percent disseminated euhedral to subhedral gaylussite 

crystals averaging 5 mm in length.

70. 9 .9 Clay, northupite, and gaylussite. Black (N 1) to grayishblack (N 2) c'.ay with faint fine very light gray (N 8) laminae; 

irregular streaks and laminae of disseminated gaylussite silt in upper 0.4 ft; seam, 5 mm wide, of intermixed 

grayish-orange (IQYR 7/4) massive northupite and black 

clay at 70.7 ft, with seam, 2 mm wide, of yellowish-gray 

(5F 8/1) massive northupite at 70.8 ft. Clay 97 percent, 

northupite 2 percent, gaylussite 1 percent.

71.3 .4 Trona and clay. Well consolidated slightly vuggy aggregate 

of colorless trona blades averaging 20 mm in length, with 

pockets of white (N 9) to yellowish-gray (5V 8/1) massive 

trona; 10 percent interstitial black (N 1) to greenish-black 

(5GY 2/1) clay in upper 0.1 ft and locally present throughout. Trona 97 percent, clay 3 percent.
C.ORE LOGS FROM SEARLES LAKE, CALIFORNIA 299

Depth Unit thick-

(feet) ness (feet) Description

71. 6 0. 3 Clay and northupite. Black (N 1) to grayish-black (N 2) 

clay with faint fine very light gray .(N 8) laminae; disseminated massive northupite nodules, averaging 0.5 mm in 

length, chiefly confined to upper 0.1 ft. Clay 95 percent, 

northupite 5 percent.

71. 9 .3 Clay and gaylussite. Black (N 1) clay with 40 percent disseminated clear colorless euhedral gaylussite crystals 

averaging 1 mm in length.

72. 2 .3 Clay and trona. Grayish-black (N 2) clay with 50 percent 

disseminated colorless trona blades up to 30 mm in length, 

averaging 10 mm, in lower 0.1 ft. Clay 83 percent, trona 

17 percent.

73. 9 1. 7 No core.

74. 1 .2 Trona. Well-consolidated porous aggregate of colorless 

trona blades averaging 5 mm in length; scattered irregular 

pockets and streaks of white (N 9) massive trona; trace 

of interstitial dark gray (N 3) clay.

74. 8 .7 No core.

75.3 .5 Clay and northupite. Grayish-black (N 2) to olive-gray 

(5F 3/2) clay with faint fine very light gray (N 8) laminae; 

disseminated nodules, averaging 0.3 mm in length, of 

white (N 9) massive northupite in upper 0.1 ft. Clay 99 

percent, northupite 1 percent.

75. 6 .3 Gaylussite and clay. Friable aggregate of subhedral gaylussite crystals, averaging 15 mm in length, with 25 percent interstitial black (N 1) clay.

76. 4 .8 Clay and gaylussite. Black (N 1) to olive-gray (5Y 3/2) 

clay with 35 percent disseminated clear colorless euhedral 

gaylussite crystals averaging 1 mm in length.

.76. 6 . 2 Clay and gaylussite. Black (N 1) to grayish-black (N 2) to 

grayish-olive (10 Y 4/2) to greenish-gray (5(? 6/1) to duskyyellow (5Y 6/4) poorly laminated clay with irregular 

streaks of gaylussite sand and silt. Clay 95 percent, 

gaylussite 5 percent.

77. 0 .4 Clay and trona. Grayish-black (N 2) clay with irregular

pockets, streaks, and seams, averaging 3 mm in width, of

white (N 9) to medium light gray (N 6) massive trona,

. . locally intermixed with clay. Clay 60 percent, trona

40 percent.

77. 3 .3 Clay and gaylussite. Grayish-black (N 2) to greenish-gray 

(5GY 6/1) to dark greenish-gray (5GY 4/1) to dusky-yellow 

(5F 6/4) faint finely laminated clay with seam. 5 mm wide, 

of 40 percent disseminated euhedral gaylussite crystals, 

averaging 1 mm in length, at base. Clay 98 percent, 

gaylussite 2 percent.

77. 9 .6 Clay and gaylussite. Olive-gray (57 3/2) to moderate 

olive-brown (5Y 4/4) clay, locally greenish-gray (5(? 6/1) 

to dark greenish-gray (56 4/1) to dusky-yellow (5Y 6/4) 

finely laminated clay, with 45 percent disseminated euhedral 

to subhedral gaylussite crystals up to 30 mm in length, 

averaging 15 mm.
300' GEOLOGIC INVESTIGATIONS IN MOJAVE DESERT REGION

Depth Unit thick- . 

(feet) ness (feet) ; Description

78. 6 0. 7 No core.

79. 4 .8 Clay. Olive-gray (5F 3/2) to moderate olive-brown (5F 4/4) 

to greenish-gray (5G 6/1) to dark greenish-gray (5G 4/1) to 

dusky-yellow (576/4) finely laminated clay.

82. 0 2. 6 Clay and gayix ssite. Dark greenish-gray (5(? 4/1) to greenishgray (5G 6/1) to grayish-black (N 2) to dark-gray (N 3) 

to olive-gray (5Y 3/2) to moderate olive-brown (5Y 4/4) 

to dusky-yellow (5Y 6/4) to grayish-yellow (5Y 8/4) to 

very light gray (N 8) finely laminated clay with scattered 

pockets of subhedral to anhedral gaylussite crystals averaging 15 mm in length. Clay 95 percent, gaylussite 5 

percent.

82. 1 . 1 No core.

Searles drill hole GS-26

LOCATION: Searles Lake, Calif., about 800 ft S. 74° E. of center sec. 30, T. 25 S.,

R. 44 E., Mount Diablo base line and meridian. 

ELEVATION AT TOP OF.HOLE: 1,617 ft. 

ELEVATION AT BOTTOM OF HOLE: 1,532 ft. 

TOTAL DEPTH: 85.0 ft. 

DATES DRILLED: July 27 to Aug. 12, 1955. 

CASING USED: 20.0 ft of 16-in. casing; 58.8 ft of 3-in. pipe. 

MINERAL DETERMINATIONS: Minerals identified microscopically are denoted by

an asterisk (*)'.

Depth Unit thick-

(feet) ness (feet) Description

0. 2 0. 2 Overburden mud, not cored. Grayish-olive (10 Y 4/2) to 

dusky-yellow (5Y 6/4) soft tenacious clay.

I. 5 1. 3 Overburden mud, not cored. Poorly consolidated aggregate 

of colorless anhedral to subhedral halite crystals up to 

80 mm in length, averaging 50 mm, with 10 percent interstitial grayish-olive (10 V 4/2) clay.

9. 2 7. 7 Overburden mud, not cored. Dusky yellow-green (5GY 5/2) 

clay with irregular streaks of grayish-black (N 2) clay.

II. 0 1. 8 Overburden mud, not cored. Black (N 1) to grayish-black 

clay with irregular streaks of dusky yellow-green (5GY 5/2) 

clay.

15. 8 4. 8 Overburden mud, not cored. Black (N 1) dense tenacious 

clay.

17. 9 2. 1 Overburden mud, not cored. Black (N 1) clay with local 

dusky yellowish-green (IQGY 3/2) clay streaks; a few 

streaks and pockets of disseminated anhedral pirssonite* 

crystals averaging 1 mm in length; pocket. 10 mm wide, 

of 75 percent disseminated colorless trona blades averaging 

2 mm in length at 17.4 ft. Clay 95 percent, pirssonite 5 

percent.

18. 2 .3 Overburden mud, not cored. Fragments of well-consolidated 

densely packed very slightly vuggy colorless to yellowishgray (5Y 8/1) fibrous to fine-bladed trona, blades averaging 

2 mm in length, locally discolored dark-gray (N 3) by 

trace of interstitial clay.
CORE LOGS FROM SEARLES LAKE, CALIFORNIA 301

Depth Unit thtck-

(feef) ness (feet) Description

19.0 0.8 Trona, clay, and sulfohalite. Fractured core. Fragments 

of well-consolidated moderately vuggy white (A^ 9) massive 

to colorless trona blades averaging 3 mm in length, generally discolored dark-gray (N 3) to grayish-black (N 2) 

by 5 percent interstitial clay; numerous lenticular horizontal vugs lined with colorless trona blades; a few loose 

yellowish sulfohalite octahedra 4 mm in length.

19. 6 .6 Trona and clay. Well-consolidated slightly vuggy aggregate 

of colorless trona blades averaging 2 mm in length, generally 

discolored dark-gray (N 3) by 1 percent interstitial clay; 

seam, 5 mm wide, of black (N 1) clay with 10 percent disseminated colorless trona blades, averaging 2 mm in length, 

at base. Trona 96 percent, clay 4 percent.

19. 8 .2 Trona and clay. Well-consolidated very light gray (N 8) to 

light-gray (N 7) slightly vuggy massive trona, discolored 

dark gray (N 3) by 5 percent intermixed clay in upper 

10 mm; lenticular horizontal vugs and pockets lined with 

colorless fine trona blades averaging 2 mm in length.

21. 9 2. 1 Hanksite and halite. Well-consolidated vuggy aggregate of 

subhedral to euhedral yellowish to colorless hanksite 

crystals from 2 to 25 mm in length, averaging 15 mm; 

irregular 4-in. pocket, at 21.3 to 21.5 ft, of colorless halite 

cubes and cubes modified by octahedron, averaging 3 mm 

in length. Hanksite 98 percent, halite 2 percent.

24. 1 2. 2 No core.

24. 6 .5 Halite and hanksite. Well-consolidated moderately vuggy 

aggregate of colorless glassy halite subhedra from 5 to 

45 mm in length, averaging 25 mm, with seam, 20 mm wide, 

consisting of aggregates of anhedral to subhedral dense 

colorless to moderate-brown (5YR 4/4) hanksite crystals 

at top, with scattered irregular pockets of similar hanksite 

crystals throughout; vugs lined with colorless euhedral 

hanksite crystals, up to 12 mm in length, averaging 5 mm. 

Halite 80 percent, hanksite 20 percent.

25. 1 .5 Hanksite. Well-consolidated slightly vuggy dense aggregate 

of subhedral colorless to light-smoky hanksite crystals 

averaging 4 mm in length, with vuggy pockets lined with 

euhedral hanksite crystals up to 10 mm in length.

25.5 .4 Hanksite and halite. Well-consolidated moderately vuggy 

aggregate of dark-smoky anhedral to subhedral hanksite 

crystals, averaging 4 mm in length; irregular streaks and 

pockets of friable colorless halite cubes and subhedra, 

averaging 2 mm in length; vugs lined with colorless to 

light-smoky euhedral hanksite crystals up to 15 mm in 

length, averaging 5 mm; trace of interstitial black (N 1) 

clay. Hanksite 95 percent, halite 5 percent.

26. 3 .8 Halite and hanksite. Well-consolidated moderately vuggy 

dense aggregate of anhedral colorless halite crystals averaging 3 mm in length, with vuggy pockets of colorless 

faint-yellowish euhedral hanksite crystals averaging 10 mm 

in length; local traces of interstitial black (AT 1) 

Halite 90 percent, hanksite 10 percent.
302 GEOLOGIC INVESTIGATIONS IN MOJAVE DESERT REGION

Depth Unitthick- 

(feet) ness (feet) Description

27. 6 1.3 Hanksite and sulfohalite*. Well-consolidated moderately 

vuggy dense aggregate of anhedral to subhedral faintyellowish to dark-smoky hanksite approaching granular 

texture, with vuggy pockets lined with euhedral hanksite 

crystals averaging 10 mm in length; single subhedral 

transparent pale yellowish-orange (10 YR 8/6) sulfohalite* 

crystal 21 mm in length, at 2(5.7 ft.

28. 8 1. 2 No core.

31. 8 3. 0 Hanksite, halite, and trona. Well-consolidated vuggy dense 

granular aggregate of light- to dark-smoky anhedral to 

subhedral hanksite crystals, averaging 4 mm in length, 

with large vuggy pockets lined with euhedral light-smoky 

hanksite crystals up to 20 mm in length, averaging 10 mm; 

irregular 6-in. pockets of friable aggregate of colorless halite 

cubes averaging 2 mm in length, with 10 percent interstitial 

white trona in uppev 0.4 ft; fine colorless fibrous to white 

(N 9) massive trona locally present in vugs; large euhedral 

hanksite crystals up to 40 mm in length from 30.0 to 30.4 

ft. Hanksite 96 percent, halite 3 percent, trona 1 percent.

32. 5 .7 Hanksite, trona, and sulfohalite. Well-consolidated slightly 

vuggy aggregate of euhedral to subhedral to anhedral lightsmoky hanksite crystals averaging 5 mm in length, with 10 

percent interstitial fine colorless fibrous to yellowish-gray 

(5F 8/2) massive trona; a few scarce sulfohalite octahedra 

up to 7 mm in length.

32. 8 .3 Hanksite and trona. Fractured core. Fragments of slightly 

vuggy euhedral to anhedral light-smoky hanksite crystals 

averaging 5 mm in length, with 10 percent interstitial colorless fine fibrous to yellowish-gray (5Y 7/2) massive trona; 

fragments of white (N 9) soft massive trona containing 15 

percent disseminated anhedral colorless hanksite crystals 

averaging 1 mm in length. Hanksite 85 percent, trona 15 

percent.

37. 0 4. 2 No core.

37. 9 .9 Halite, trona, and hanksite. Unconsolidated aggregate of 

colorless halite sand with 10 percent interstitial white (N 9) 

to yellowish-gray (5Y 8/1) massive trona; scattered fragments of well-consolidated dense anhedral to subhedral 

light-smoky hanksite crystal aggregates. Probably cuttings, 

not core.

38. 1 .2 Trona. Well-consolidated white (N 9) porous massive trona.

38. 4 .3 Trona. Well-consolidated colorless to white (N 9) slightly 

vuggy porous fine fibrous trona.

39. 6 1. 2 Trona. Well-consolidated white (N 9) porous massive trona 

with a few seams from 2 to 20 mm wide discolored paleolive (10Y 6/2) to grayish-olive (WY 4/2) to light olivegray (57 5/2) by trace of intermixed clay.

41. 8 2. 2 No core.

41. 9 .1 Borax and clay. Friable aggregate of colorless euhedral to 

subhedral borax crystals from 1 to 5 mm in length, averaging 3 mm, with 10 percent interstitial black (N 1) clay 

chiefly confined to lower 10 mm. ... :...
CORE LOGS FROM SEARLES LAKE, CALIFORNIA 303

Depth Unit thick- 

(feet) ness (feet) Description

42. 1 0. 2 Clay and pirssonite. Black (N 1) clay with 20 percent disseminated euhedral pirssonite crystals averaging 1 mm in 

length.

42. 6 .6 Clay and pirssonite. Grayish-black (N 2) to grayish olivegreen (5GY 3/2) to grayish-green (5(7 5/2) to dusky-yellow 

(5Y 6/4) to moderate olive-brown (5F 4/4) to medium 

bluish-gray (5B 5/1) to finely laminated clay with irregular 

seams and pockets of anhedral to subhedral pirssonite 

crystals averaging 5 mm in length. Clay 90 percent, 

pirssonite 10 percent.

43. 4 .8 Clay and pirssonite. Black (N 1) to grayish-black (AT 2) clay, 

locally grayish-green (10GY 5/2) to dusky yellow-green 

(5GY 5/2) to olive-gray (5Y 3/2) finely laminated clay with 

35 percent disseminated subhedral pirssonite crystals 5 to 

20 mm in length, averaging 10 mm.

44. 2 .8 Clay and gaylussite*. Black (AT 1) to grayish-black (N 2) to 

grayish-yellow (5Y 8/4) to dusky-yellow (5F 6/4) to olivegray (573/2) to greenish-gray (5(? 6/1) to grayish yellowgreen (5GY 7/2) finely laminated clay with large pockets of 

disseminated subhedral gaylussite* crystals up to 30 mm in 

length, averaging 15 mm. Clay 80 percent, gaylussite 20 

percent.

45. 7 1. 5 Clay. Black (N 1) to grayish-black (N 2) to grayish olivegreen (5GY 3/2) clay with fine widely spaced dusky yellowgreen (5GY 5/2) to grayish-yellow (5Y 8/4) to very light 

gray (N 8) laminae. Core fractured in upper 0.4 ft.

46. 1 .4 Clay, gaylussite*, and aragonite. Black (N 1) to grayishblack (N 2) clay with laminae, .averaging 1 mm wide, of 

very light gray (N 8) soft massive finely crystalline aragonite; 40 percent disseminated subhedral gaylussite* crystals 

averaging 10 mm in length. Clay 55 percent, gaylussite 

40 percent, aragonite 5 percent.

4a 2 2. 1 Clay and gaylussite. Black (N 1) to grayish-black (AT 2) to 

dusky-yellow (5Y 6/4) to grayish-yellow (5Y 8/4) to olivegray (5Y 3/2) to greenish-gray (5GY 6/1) to very light gray 

(N 8) finely laminated clay with scattered 1-to 3-in. pockets 

of disseminated anhedral to subhedral gaylussite* crystals 

averaging 5 mm in length; seam, 20 mm wide, of disseminated gaylussite crystals at 47.8 ft; laminae wavy to 

contorted and faulted in lower 0.2 ft. Clay 95 percent, 

gaylussite 5 percent.

48. 8 . 6 No core.

50. 4 1. 6 Clay and gaylussite*. Greenish-gray (5G 6/1) to dark greenish-gray (5<? 4/1) to grayish-black (N 2) to grayish-olive 

(107 4/2) to dusky-yellow (5Y 6/4) to' grayish-yellow 

(5Y 8/4) to very pale gray (N 8) finely laminated clay with 

2- to 3-in. pockets of subhedral to anhedral gaylussite* 

crystals averaging 10 mm in length; seam, 3 mm wide, of 

75 percent disseminated euhderal gaylussite sand at 50.0 ft. 

Clay 95 percent, gaylussite 5 percent.

491349 69 12
304 GEOLOGIC INVESTIGATIONS IN MOJAVE DESERT REGION

Depth Unit thick- 

(fea,) ness (feet) Description

60. 8 0. 4 Clay, gaylussite, and aragonite. Black (N 1) to grayishblack (N 2) clay with laminae, averaging 1 mm wide, of 

dusky-yellow (5Y 6/4) to very light gray (N 8) soft finely 

crystalline massive aragonite; seams, avei aging 5 mm in 

width, of disseminated subhedral to anhedral gaylussite 

crystals averaging 10 mm in length. Clay 80 percent, 

gaylussite 15 percent, aragonite 5 percent.

51. 3 .5 Clay and gaylussite. Black (N 1) to grayish-black (N 2) 

to greenish-black (5GY 2/1) to greenish-gray (5(7 6/1) 

coarsely laminated clay revealed by color differences, with 

20 percent disseminated anhedral to subhedral gaylussite 

crystals averaging 10 mm in length; a few distinct laminae, 

averaging 0.3 mm in width, of moderate reddish-brown 

(WR 4/6) algae(?) discolored clay.

51. 7 .4 Clay, gaylussite, and borax. Black (N 1) to grayish-black 

(N 2) clay with 5 percent disseminated gaylussite silt; 

vague light-brown (5YR 5/6) algae(?) discolorations; 

irregular wavy streak, 5 mm wide, of massive anhedral 

borax in lower 0.1 ft. Clay 92 percent, gaylussite 5 percent, 

borax 3 percent.

53. 2 1. 5 No core.

54. 8 1. 6 . Clay and gaylussite. Black (N 1) to grayish-black (N 2) to 

greenish-black (5(7 Y 2/1) to greenish-gray (5(7 6/1) to dark 

greenish-gray (5(7 4/1) coarsely laminated clay revealed by 

color differences, with 30 percent disseminated euhedral 

clear colorless gaylussite crystals from medium-sand size to 

10 mm in length, averaging 5 mm; distinct laminae, 2 mm 

in width, of intermixed moderate reddish-brown (10R 4/6) 

algae(?) at top with faint laminae and streaks at 53.9 and 

54.5 ft.

56. 4 1. 6 Clay and gaylussite. Black (N 1) to grayish-black (N 2) to 

greenish-gray (5GY 6/1 and 5(7 6/1) coarsely laminated clay 

revealed by color differences, with 3 percent disseminated 

gaylussite silt chiefly confined to upper 0.2 ft; faint moderate 

reddish-brown (10JR 4/6) algae (?)-discolored laminae at 55.6 

to 55.7 ft.

57.0 .6 Clay, pirssonite, and trona. Black (N 1) to grayish-black 

(N 2) clay with 40 percent disseminated euhedral pirssonite 

crystals from fine sand size to 5 mm in length, averaging 3 

mm; embedded fractured fragments of white (N 9) soft 

massive trona to well-consolidated vuggy aggregates of 

trona blades, averaging 10 mm in length, in lower 0.1 ft. 

Clay 52 percent, pirssonite 40 percent, trona 8 percent.

57. 4 . 4 Trona and clay. Well-consolidated slightly vuggy aggregate 

of yellowish-gray (5F 8/1) massive trona, generally discolored medium light-gray (N 6) to dark-gray (N 3) by 

intermixed clay; vuggy pockets of trona blades, averaging 

5 mm in length, with trace of interstitial black (N 1) clay 

throughout. Trona 95 percent, clay 5 percent.

57. 5 .1 Borax. Vuggy aggregate of colorless euhedral to subhedral 

borax crystals from 20 to 80 mm in length.
CORE LOGS FROM SEARLES LAKE, CALIFORNIA 305

Depth Unit thick- 

(feet) ness (feet) Description

57. 8 0. 3 Trona and clay. Well-consolidated vuggy porous aggregate 

of colorless trona blades from 10 to 35 mm in length, 

averaging 15 mm, with irregular streaks of yellowish-gray 

(5Y 8/1) hard massive trona; 5 percent interstitial black 

(N 1) clay.

58. 4 .6 Clay and pirssonite. Black (N 1) to olive-gray (5 Y 3/2) clay 

with 35 percent disseminated euhedral pirssonite crystals 

averaging 4 mm in length.

58. 5 .1 Clay and pirssonite. Black (N 1) to grayish-black (N 2) clay 

with streaks of disseminated euhedral pirssonite sand. 

Clay 90 percent, pirssonite 10 percent.

60.2 1.7 Clay, pirssonite, and borax. Black (N 1) to greenish-black 

(5(7 y 2/1) moist poorly consolidated clay with a few 

greenish-gray (5(7 6/1) to dusky yellow-green (5GY 5/2) 

clay streaks; 35 percent disseminated euhedral pirssonite 

crystals from 1 to 15 mm in length, averaging 10 mm; a few 

disseminated subhedral borax crystals averaging 40 mm in 

length. Clay 62 percent, pirssonite 35 percent, borax 3 

percent.

60.8 .6 Trona. Well-consolidated white (N 9) to yellowish-gray 

(5Y 8/1) soft massive to colorless fine fibrous trona, locally 

discolored dark-gray (N 3) by trace of intermixed clay.

62. 2 1. 4 No core.

62.6 .4 Trona and clay. Poorly consolidated dark greenish-gray 

(5(7 F 4/1) to dark-gray (N 3) soft massive to colorless fine 

fibrous trona, discolored by 1 percent intermixed black 

(N 1) clay. May be cuttings, not core.

62. 8 .2 Trona. Well-consolidated white (N 9) massive trona, locally 

discolored dark-gray (N 3) in streaks by trace of intermixed 

clay; distinct moderate reddish-orange (10/2 6/6) algae(?)- 

discolored seams, 3 mm in width, at 62.7 ft.

63. 1 .3 Trona. Well-consolidated white (N 9) to dark greenish-gray 

(5(7 4/1) slightly vuggy massive trona, locally discolored 

dark-gray (N 3) by trace of intermixed clay; vugs lined with 

colorless fine fibrous trona.

64. 9 1. 8 Clay, gaylussite*, and borax. Black (N 1) to grayish-black 

(N 2) to greenish-black (5(7 Y 2/1) moist poorly consolidated 

clay with numerous seams, 0.5 to 1 mm thick, of pale 

greenish-yellow (10 Y 8/2) anhedral gaylussite*; 35 percent 

disseminated euhedral to subhedral gaylussite crystals 

averaging 5 mm; a few disseminated subhedral borax 

crystals averaging 40 mm throughout. Clay 59 percent, 

gaylussite 40 percent, borax 1 percent.

65. 2 .3 Clay and pirssonite*. Clay as in preceding unit with 40 percent disseminated subhedral pirssonite* crystals.

65. 3 . 1 Clay and pirssonite. Well-consolidated black (N 1) clay with 

20 percent disseminated euhedral pirssonite sand.

66.0 .7 Trona. Well-consolidated colorless fibrous trona with 

streaks and pockets of white (N 9) to dark greenish-gray 

(5GV 4/1) massive trona.

67. 7 1. 7 No core.
306 GEOLOGIC INVESTIGATIONS IN MOJAVE DESERT REGION

Depth Unit thick- 

(feet) nets (feet) Description

68. 1 . 0. 4 Halite and trona. Moderately friable aggregate of colorless 

halite cubes, cubes modified by octahedron, and subhedra, 

averaging 3 mm in length, with irregular lenticular streaks, 

up to 0.1 ft wide, of greenish-gray (50? F 6/1) massive trona 

in upper 0.1 ft. Halite 80 percent, trona 20 percent.

68. 3 .2 Halite and trona. Well-consolidated aggregate of colorless 

halite cubes, cubes modified by octahedron, and subhedra, 

up to 10 mm in length, averaging 3 mm, with 30 percent 

interstitial greenish-gray (5(7 Y 6/1) massive to fine colorless 

fibrous trona; a few moderate reddish-orange (10jR 6/6) 

algae (?) inclusions in halite crystals at base.

69. 2 .9 No core.

69. 5 .3 Halite and trona Moderately friable aggregate of colorless 

halite cubes modified by octahedron and subhedra, averaging 3 mm in length, with 20 percent yellowish-gray (5Y 8/1) 

to light-olive (5Y 6/1) massive trona to fine colorless 

fibrous trona in irregular streaks and interstices of halite; 

numerous moderate reddish-orange (10/2 6/6) pinpoint 

inclusions of algae(?) in halite; trace of interstitial black 

(N 1) clay locally.

69.8 .3 Trona, halite, and clay. Well-consolidated yellowish-gray 

(5Y 8/1) slightly vuggy soft massive trona to fine fibrous 

trona; seam, 15 mm wide, of trona discolored dark-gray 

(N 3) by 5 percent intermixed clay containing 20 percent 

disseminated colorless halite subhedra averaging 3 mm in 

length at 69.6 ft. Trona 96 percent, halite 3 percent, clay 

1 percent.

70. 6 .8 Halite and trona. Friable aggregate of colorless halite cubes 

modified by octahedron and subhedra, 2 to 10 mm in length, 

averaging 5 mm, with 5 percent interstitial fine fibrous 

trona; trace of black (N 1) clay in upper 0.1 ft.

70. 7 .1 Clay, halite, and trona. Black (N 1) to grayish-black (N 2) 

clay with faint traces of moderate reddish-brown (10R 4/6) 

algae (?) discolo rations; embedded colorless halite cubes 

modified by octahedron in upper 10 mm and fine colorless 

fibrous trona at base. Clay 75 percent, halite 20 percent, 

trona 5 percent.

71. 1 .4 Trona, clay, and halite. Well-consolidated slightly vuggy 

white (N 9) massive trona, locally discolored medium dark 

gray .(AT 4) by trace of intermixed clay, with irregular pockets 

and streaks of colorless fibrous trona; 20 percent black (N 1) 

to grayish-black (N 2) clay in streaks in upper 0.1 ft; seam, 

5 mm wide, of 90 percent disseminated colorless halite 

subhedra averaging 4 mm in length at 71.0 ft. Trona 91 

percent, clay 5 percent, halite 4 percent.

71. 5 .4 Halite and trona. Moderately friable aggregate of colorless 

halite cubes and subhedra, averaging 2 mm in length, with 

15 percent interstitial light-gray (N 7) massive trona and 

a few seams, 3-5 mm wide, of white (N 9) trona. Halite 

75 percent, trona 25 percent.
CORE LOGS FROM SEARLE8 LAKE, CALIFORNIA 307

Depth Unit thick- 

(feet) nest (feet) Description

72. 2 0. 7 Trona, halite, and burkeite. Well-consolidated slightly vuggy 

aggregate of yellowish-gray (57 8/1) to light-gray (N 8) 

massive trona in lenticular seams and pockets of colorless 

halite cubes modified by octahedron and subhedra, averaging 3 mm in length; a few vuggy pockets, % to 1 in. long, 

of colorless fibrous trona; irregular pockets, 1-4 in. long, of 

light grayish-yellow (5Y 8/4) hard massive dense burkeite 

in lower 0.3 ft; trace of interstitial grayish-black (N 2) 

clay locally. Trona 50 percent, halite 35 percent, burkeite 

15 percent.

72. 6 .4 Clay, sulfohalite*, northupite*, and tychite*. Well-consolidated black (N 1) to grayish-black (N 2) to dusky-yellow 

(5Y 6/4) to dusky yellow-green (50Y 5/2) finely laminated 

clay with a few fine laminae of moderate reddish-brown 

(lOfl 4/6) to moderate-red (5ft 4/6) algae(?) in upper 0.2 ft; 

seam, 5 mm wide, at base, con tain ing 75 percent clay, 20 

percent grayish-orange (WYR 7/4) soft massive northupite 

in thin streaks, 1-2 mm wide, and 5 percent crystals, averaging 7 mm in length, of sulfohalite* containing microscopic 

crystals of northupite* and tychite*.

72. 9 .3 Trona, borax, and clay. Complex core consisting of seams 

as follows from top to base: seam, 20 mm wide, of friable 

colorless euhedral prismatic borax crystals averaging 2 mm 

in length, with some intermixed fine borax sand; seam, 

10 mm wide, of grayish-black (N 2) to very light gray (N 8) 

finely faintly laminated clay; seam, 20 mm wide, of dusky 

yellow-green (50Y 5/2) hard massive dense trona with 

clay seam, 2 mm wide, containing 30 percent euhedral prismatic borax crystals, averaging 2 mm in length, at top, with 

distinct moderate reddish-brown (10/2 4/6) algae(?) discoloration in clay; seam, 20 mm wide, of black (N 1) clay 

with 50 percent intermixed fibrous trona and 25 percent 

disseminated euhedral borax crystals averaging 2 mm in 

length; seam, 20 mm wide, of compact colorless fine fibrous 

trona. Trona 55 percent, borax 28 percent, clay 17 percent.

74. 5 1. 6 No core.

75.2 .7 Trona. Poorly consolidated yellowish-gray (5Y 8/1) to 

greenish-gray (50Y 6/1) soft massive trona. May be 

cuttings, not core.

75.3 .1 Burkeite, trona, and northupite. Fractured core. Wellconsolidated intermixed irregular streaks of colorless to 

moderate orange-pink (5YR 8/4) dense hard transparant 

burkeite, white (N 9) massive trona, and thin seams, averaging 2 mm in width, of yellowish-gray (5Y 8/1) to lightbrown (5YR 6/4) massive northupite; a few disseminated 

colorless subhedral hanksite crystals averaging 4 mm in 

length. Burkeite 50 percent, trona 35 percent, northupite 

15 percent.
308 GEOLOGIC INVESTIGATIONS IN MOJAVE DESERT REGION

Depth Unit thick- 

(feet) ness (feet) Description

75. 7 0. 4 Trona and clay. Well-consolidated slightly vuggy aggregate of colorless fine fibrous trona with pockets of white 

(N 9) massive trona, locally discolored dark-gray (N 3) 

by trace of intermixed clay; irregular seam, 5 mm wide, 

containing faint light-brown (SYR 6/4) algae (?) discoloration at 75.5 ft; 10 percent black (N 1) soft moist clay in 

irregular streaks in lower 0.1 ft. Trona 97 percent, clay 

3 percent.

75. 8 .1 Northupite, clay, trona, and hanksite. Well-consolidated 

grayish-orange (10 YR 7/4) to yellowish-gray (5F 7/2) soft 

massive northupite in irregular seam locally mixed with 

streaks of grayish-black (N 2) clay, colorless fibrous trona, 

and white (N 9) massive trona; a few disseminated hanksite 

crystals with basal pinacoid, averaging 3 mm in length, at 

base. Northupite 70 percent, clay 15 percent, trona 10 

percent, hanksite 5 percent.

76. 1 .3 Clay, hanksite, northupite, and borax. Black (N 1) to 

grayish-black (N 2) clay with disseminated irregular masses, 

up to 35 mm in length, of granular massive hanksite; a few 

disseminated euhedral hanksite crystals with basal pinacoid 

averaging 3 mm in length, frequently intergrown in clusters; 

a few disseminated anhedral to subhedral' borax crystals 

averaging 10 mm in length; trace of seam, 10 mm wide, of 

grayish-orange (10YJ? 7/4) soft massive northupite at base. 

Clay 55 percent, hanksite 40 percent, northupite 4 percent, 

borax 1 percent.

76. 2 . 1 Clay and gaylussite. Black (N 1) to grayish-black (N 2) to 

light olive (10Y 5/4) to very light gray (N 8) faintly finely 

laminated clay; numerous laminae of gaylussite silt. Clay 

90 percent, gaylussite 10 percent.

76. 6 .4 Clay and gaylussite. Black (N 1) to greenish-black (50 Y 2/1) 

clay with 50 percent disseminated euhedral to subhedral 

gaylussite crystals averaging 7 mm in length; seam, 15 mm 

wide, of 50 percent disseminated euhedral gaylussite crystals 

averaging 1 mm in length at base.

77. 0 .4 Clay and gaylussite. Black (N 1) to grayish-black (N 2) to 

very light gray (N 8) faintly finely laminated clay with 

5 percent disseminated gaylussite silt.

77. 7 .7 Clay, trona, and northupite. Black (N 1) to grayish-black 

(N 2) clay with 49 percent disseminated colorless trona 

blades averaging 20 mm in length; irregular wavy streaks of 

grayish-orange (10F.R 7/4) massive northupite in seam, 3 

mm wide, at 77.3 ft; traces of moderate reddish-brown (IQR 

4/6) algae(?) in faint laminae in clay. Clay 50 percent, 

trona 49 percent, northupite 1 percent.

78. 1 .4 Trona. Well-consolidated dense aggregate of colorless trona 

blades averaging 20 mm in length, with interstitial white 

(N 9) to greenish-gray (5GY 6/1) massive trona.

78. 3 .2 Trona and northupite. Well-consolidated aggregate of colorless trona blades averaging 20 mm in length, locally in radiating clusters, with irregular wavy seams, from 5 to 20 mm 

in width, of yellowish-gray (5F8/1) to grayish-orange (IQYR
CORE LOGS FROM SEARLES LAKE, CALIFORNIA 309

Depth Unit thick- 

(feet) ness (feet) Description

7/4) massive northupite. Trona 50 percent, northupite 50 

percent. . -

78. 6 0. 3 Clay, trona, and northupite. Black (N 1) to grayish-black 

(N 2) clay with faint fine very light gray (N 8) laminae; 

disseminated round to oval nodules, averaging 0.3 mm in 

length, of white (N 9) massive northupite arranged in layers; 

disseminated colorless trona blades, averaging 5 mm in 

length, in upper 10 mm. Clay 93 percent, trona 5 percent, 

northupite 2 percent.

78. 8 .2 Clay and gaylussite. Black (N 1) clay with 50 percent disseminated euhedral gaylussite crystals averaging 1 mm in 

length, with predominantly fine gaylussite sand in lower 10 

mm; soft pliable greenish-black (5GY 2/1) clay seams, averaging 0.5 mm in thickness, in upper 0.1 ft.

78. 9 .1 Clay. Grayish-black (N 2) to very light gray (N 8) finely 

laminated clay; laminae wavy and locally contorted.

79. 1 .2 Trona and clay. Well-consolidated dense aggregate of colorless trona blades, averaging 25 mm in length, with 30 percent 

interstitial grayish-black (N 2) clay in upper 20 mm,

79. 3 .2 Trona and clay. Well-consolidated white (N 9) massive to 

colorless fine fibrous trona with irregular seam, 5 mm wide, 

of 25 percent grayish-black (N 2) clay at 79.2 ft. Trona 98 

percent, clay 2 percent.

79. 5 .2 No core.

79. 9 .4 Clay, trona, northupite*, and hanksite*. Black (N 1) to 

grayish-black (N 2) clay with seam, 5 mm wide> of very pale 

orange (10YR 8/2) soft massive northupite* at top and seam, 

- - 2 mm wide, of pale olive (10 Y 6/2) soft massive northupite 

at 79.6 ft; a few scattered Yz- to 1-in. pockets of colorless to 

grayish-yellow (5Y 8/4) fine fibrous trona associated with 

colorless to light-smoky subhedral to anhedral hanksite* 

crystals averaging 5 mm in length; irregular seam, 5-15 mm 

wide, of fine fibrous trona at base; core fractured in lower 

0.2 ft. Clay 83 percent, trona 10 percent, northupite 6 

percent, hanksite 1 percent.

80. 0 .1 Clay. Black (N 1) to grayish-black (N 2) clay.

80. 2 .2 Clay and northupite: Grayish-black (N 2) clay with faint fine 

.very.light gray (N 8) laminae;.numerous disseminated round 

to oval nodules, averaging 0.2 mm in length of white (N 9) 

massive northupite arranged in layers. Clay 90 percent, 

northupite 10 percent.

80. 5 .3 Clay. Grayish-black (N 2) to very light gray (N 8) finely 

laminated clay.

81. 1 .6 Clay and gaylussite. Olive-gray (5F 3/2) to moderate olive- 

. brown (5F 4/4) to grayish-black (N 2) clay with 50 percent 

disseminated euhedral to subhedral gaylussite crystals averaging 10 mm in length.

81. 8 .7 Clay. Grayish-black (N 2) to dark greenish-gray (5GY 4/1) 

to dusky yellow-green (5GY 5/2) to dusky-yellow (5Y 6/4) 

to very light gray '(N 8) finely laminated clay; laminae 

faulted with measured 10-mm displacement downdip; a few 

seams of disseminated gaylussite silt.
3lO GEOLOGIC INVESTIGATIONS IN MOJAVE DESERT REGION

Depth Unitthick-

(feet) ness (feet) . Description

82. 0 0. 2 Clay. Grayish-black (N 2) clay.

82. 2 .2 Clay and trona*. Grayish-black (N 2) clay with 50 percent 

disseminated white (N 9) to dusky yellow-green (5GY 5/2) 

sugary-textured massive trona*.in irregular streaks and Yv 

to %-in. pockets; traces of moderate reddish-brown (1012 

4/6} clay discolored by algae(?).

82. 6 .4 Clay and gaylussite. Black (N 1) to grayish-black (AT 2) to 

greenish-gray (5G 6/1) to very Jight gray (N 8) faintly finely 

laminated clay with 10 percent disseminated gaylussite silt 

in lower 0.1 ft.

. 84. 5 . 1. 9 Clay and gaylussite. Greenish-gray (5GY 6/1 and 5G 6/1) to 

dark greenish-gray (5GY 4/1 and 5G 4/1) to olive-gray (5F 

3/2) to moderate olive-brown (5Y 4/4) to dusky-yellow (5F 

6/4) to grayish-black (N 2) finely laminated clay with 35 

percent disseminated euhedral to subhedral gaylussite crystals from 0.5 to 30 mm in length, averaging 20 mm.

85. 0 .5 No core.

Searles drill hole GS-S9

LOCATION: Searles Lake, Calif., 20 ft southwest of % sec. marker for sees. 9 and 10, 

in sec. 9, T. 25 S., R. 43 E., Mount Diablo base line and meridian.

ELEVATION AT TOP OF HOLE: 1,621 ft.

ELEVATION AT BOTTOM OF HOLE: 1,538.2ft.

TOTAL DEPTH: 82.8 ft.

DATES DRILLED: Oct. 6-19, 1955.

CASINO TTSED: 24.0 ft of 16-in. casing; 54.7 ft of 3-in. pipe.

MINERAL DETERMINATIONS: Minerals identified microscopically are denoted by 

an asterisk (*).

Depth Unit thick-

(feet) nett(feet) Description

7.0 7.0 Overburden mud, not cored. Moderate yellowish-brown 

(10FB 5/4) sandy clay; clayey sand at 2.0 to 3.0 ft.

11. 6 4. 0 Overburden mud, not cored. Dark greenish-gray (6(? 4/1) 

clay.

23. 5 12. 5 Clay, and trona, not cored. Black (N 1) clay with hard 

seam of trona blades beginning at 22.5 ft.

24.1 . 6 No core.

. 25. 5 1. 4 Trona and clay. Well-consolidated slightly vuggy aggregate 

of colorless trona blades averaging 3 mm in length, locally 

discolored medium light-gray (N 6) to dark-gray (N 3) by 

1 percent interstitial black (N 1) clay; irregular seam, up 

to 0.1 ft wide, of black (N 1) clay at 24.5 to 24.6 ft. Trona 

95 percent, clay 5 percent.

. 27. 5 2. 0 Trona*, clay, sulfohalite*, and pirssonite*. Well-consolidated 

slightly vuggy aggregate of colorless fibrous trona, locally 

discolored medium-gray (N 5) by trace of interstitial clay; 

seam, 15 mm wide, of black (N 1) clay with streaks of 

yellowish-gray (5F 8/1) massive trona at 27.1 ft, with 10 

percent disseminated crystal silt consisting mainly of 

trona* with intermediate amounts of sulfohalite* and 

pirssonite*.
GORE LOGS FROM SEARLE8 LAKE, CALIFORNIA 311

Depth UnU thick-

(fat) ness (feet) Description

28.0 0.5 Trona and clay. Fractured core. Fragments of loosely 

consolidated porous colorless fibrous trona, discolored

: medium dark-gray (N 4) by 1 percent interstitial clay.

31. 7 3. 7 Trona. Well-consolidated white (N 9) soft massive trona 

with a few seams, 3-40 mm wide, discolored light olive-gray 

(5Y 6/1) by trace of intermixed clay; moderately vuggy in 

upper 0.4 ft, with lenticular horizontal vugs lined with 

colorless fine fibrous trona.

34. 0 2. 3 No core.

34. 4 .4 Trona and borax. Fractured core. Well-consolidated seams, 

2-10 mm wide, of white (AT 9) massive trona with seams, 

1-2 mm wide, of light olive-gray (5F 6/1) trona discolored 

by trace of intermixed clay; seams are wavy in lower 0.2 

ft; 10 percent disseminated anhedral colorless borax crystals, 

averaging 30 mm in length, in lower 0.1 ft. Trona 97 

percent, borax 3 percent.

35. 5 1.1 No core.

36. 8 1. 3 Clay, pirssonite*, and borax. Black (N 1) to grayish-black 

(N 2) clay with 35 percent disseminated anhedral pirssonite 

crystals averaging 5 mm in length; single subhedral borax 

crystal 60 mm in length at base.

37. 2 .4 Clay and borax. Grayish-black (AT 2) to dusky yellow-green 

(5GY 5/2) to grayish olive-green (5GY 3/1) to very light 

gray (N 8) finely laminated clay; single embedded euhedral 

borax crystal 60 mm in length, at 37.1 ft.

37. 6 .4 Clay and pirssonite. Black (AT 1) to olive-black (5Y 2/1), 

locally dusky yellow-green (5GY 5/2) to grayish olive-green 

(5GY 3/2) to very light gray (N 8), finely laminated clay 

with 40 percent disseminated subhedral pirssonite crystals 

up to 25 mm in length, averaging 5 mm.

37. 8 .2 Clay. Grayish-black (N 2) to olive-black (57 2/1) to dusky 

yellow-green (5GY 5/2) to very light gray (N 8) finely 

laminated clay.

39. 2 1. 4 Clay. Black (N 1) to grayish-black (N 2) clay with widely 

separated fine pale greenish-yellow (10 Y 8/2) laminae.

39. 9 .7 Clay and aragonite. Black (N 1) to grayish-black (N 2) clay 

coarsely laminated with very light gray (N 8) to pale 

greenish-yellow (10 Y) 8/2 to greenish-gray (5GY 6/1) 

laminae up to 1 mm wide, averaging 0.5 mm, of finely 

crystalline massive aragonite. Clay 95 percent, aragonite 

5 percent.

41.1 1.2 Clay and gaylussite*. Grayish-black (N 2) to olive-gray 

(5Y 3/2) to dusky-yellow (5Y 6/4) to grayish-yellow 

(5F 8/4) to very light gray (AT 8) finely laminated clay; 

laminae contorted in lower 0.4 ft; 40 percent disseminated 

subhedral gaylussite* crystals 10-30 mm in length, averaging 

10 mm, in irregular pockets in lower 0.2 ft. Clay 93 percent, 

gaylussite 7 percent. 

: 41. 5 :. 4 No core.
312 GEOLOGIC INVESTIGATIONS IN MQJAVE DESERT REGION

Depth Unit thick- . . - 

(feet) ness (feet) . _ Description

42. 9 1. 4 Clay and borax. Grayish-black (N 2) to dark greenish-gray- 

(5GY 4/1) to greenish-gray (5GY 6/1) to dusky-yellow 

(5Y 6/4) to grayish-orange (IOYR 7/4) to very light gray 

(N 8) finely laminated clay; 10 percent disseminated' 

subhedral borax crystals, averaging 15 mm in length, in 

irregular pockets from 41.8 to 41.9 ft.

43.4 .5 Clay and aragonite. Grayish-black .(N 2) to olive-black 

(5Y 2/1) to yellowish-gray (5Y8/1) clay, moderately coarsely 

laminated, with laminae up to 1 mm wide, of very light-gray 

(AT' 8) soft massive finely crystalline aragonite.

44. 3 .9 No core.

44. 5 .2 Pirssonite and clay. Black (N 1) clay with 60 percent 

anhedral to subhedral pirssonite seams averaging 1 mm in-, 

width.

44. 8 .3 Clay and aragonite. Grayish-black (A7" 2) to dark greenishgray (5GY 4/1) moderately coarsely laminated clay with, 

seams of very light gray (N 8) soft massive finely crystalline 

aragonite:

45.0 .2 Clay. Black (N 1) to grayish-black (N 2) to dusky yellowgreen (5GT 5/2) to dark greenish-gray (5(? 4/1) to duskyyellow (5Y 6/4) finely laminated clay.

45.2 .2 Clay and aragonite. Grayish-black (N 2) to. dark greenishgray (5GY 4/1) moderately coarsely laminated clay with 

laminae of very light gray (N 8) soft massive finely crystalline aragonite.

45.5 .3 Clay. Black (N 1) to grayish-black (N 2) to dusky yellowgreen (5GY 5/2) to dark greenish-gray (50? 4/1) to duskyyellow (5F 6/4) finely laminated clay.

47.0 1.5 Clay. Grayish-black (N 2) to dark greenish-gray (5GY 4/1) 

to grayish olive-green (5GY 3/2) to dusky-yellow (5Y 6/4) 

to moderate olive-brown (5Y 4/4) coarsely laminated clay 

revealed by color differences.

47.6 ".6 No core.

51.1 3.5 Clay, gaylussite*, and borax*. Grayish-black (N 2) to dark 

greenish-gray (5GY 4/1 and 5G 4/1) faintly laminated clay 

with scattered 2- to 3-in. pockets and disseminated crystals 

of anhedral gaylussite*; disseminated pockets of colorless 

 subhedral borax* crystals up to 35 mm in length; a few 

faint moderate reddish-brown (1QR 4/6) algae(?)-discolored laminae averaging 0.3 mm wide. Clay 90 percent, 

gaylussite percent, borax 5 percent.

52.4 1.3 Clay and gaylussite. Grayish-black (N 2) to dark greenishgray (5GY 4/1 and 5G 4/1) clay with seams, up to 0.2 ft 

wide, of disseminated euhedral gaylussite crystals from 1 

to 15 mm in length, averaging 10 mm; a few faint moderate 

reddish-brown (10.R 4/6) algae (?)-discolored laminae. 

Clay 75 percent, gaylussite 25 percent.

53.2 .8 No core.

53.4 .2 Clay and gaylussite. Black (N 1) to grayish-black (N 2) 

clay with 25 percent disseminated euhedral to subhedral 

gaylussite crystals from 1 to 10 mm long.
CORE LOGS FROM SEARLES LAKE, CALIFORNIA 313

Depth Unit thick-

(feet) ness (feet) Description

53.5 0.1 Trona and clay. Well-consolidated porous aggregate of 

colorless fibrous trona with 20 percent black (N 1) clay in 

irregular streaks and pockets.

53.7 .2 Clay and gaylussite. Black (N 1) clay with 10 percent disseminated gaylussite silt.

54.4 .7 Clay and gaylussite. Black (N 1) to olive-gray (5Y 3/2) to 

dusky-yellow (5F 6/4) to dusky yellow-green (5GY 5/2) 

clay with 50 percent disseminated subhedral gaylussite 

crystals averaging 5 mm in length.

54.9 .5 Clay and gaylussite. Dusky yellow-green (5GY 5/2) to 

grayish-black (N 2) to greenish-gray (5(? 6/1) faintly laminated clay with 20 percent disseminated subhedral gaylussite crystals 1-10 mm in length, averaging 5 mm.

56.4 1.5 Clay and gaylussite. Black (N 1) to olive-gray (57 3/2) to 

dark greenish gray (5GY 4/1) clay with 50 percent disseminated euhedral to subhedral gaylussite crystals 1-15 

mm in length, averaging 10 mm; faint moderate reddishbrown (10jR 4/6) algae(?)-discolored laminae and irregular 

discolorations from 56.1 to 56.2 ft.

56.9 .5 Clay and gaylussite. Grayish-black (AT 2) clay with 20 

percent disseminated gaylussite silt in fine streaks and 

seams throughout; faint moderate reddish-brown (10.R 4/6) 

algae(?)-discolored seams and irregular discolorations 

throughout.

57.2 .3 Trona and clay. Well-consolidated aggregate of colorless to 

white (N 9) fine fibrous to massive trona with 5 percent 

black (A7" 1) clay in irregular thin interstitial streaks.

58.2 1.0 Trona. Well-consolidated white (N 9) to light olive-gray 

(5F 6/1) to greenish-gray (5GY 6/1) massive trona with 

irregular vuggy pockets and streaks of colorless fibrous 

trona, fibers up to 20 mm in length, averaging 5 mm; traces 

of interstitial black (N 1) clay locally present in vugs with 

fibrous trona.

58.7 .5 No core.

59.7 1.0 Trona and clay. Well-consolidated slightly vuggy aggregate 

of white (N 9) to yellowish-gray (5F 8/1) massive trona, 

locally discolored medium light gray (N 6) by trace of 

intermixed clay; pockets and irregular streaks and thin 

seams, 2-3 mm wide, of colorless fibrous trona with local 

interstitial black (N 1) clay; faint to distinct moderate 

reddish-brown (10 R 4/6) to orange algae(?)-discolored 

seams from 59.0 to 59.4 ft. Trona 99 percent, clay 1 

percent.

60.5 .8 Clay, gaylussite and northupite. Black (N 1) soft friable 

clay with 40 percent disseminated fine to coarse euhedral 

gaylussite sand; irregular seam, up to 15 mm wide, of 

yellowish-gray (5F 8/1) to very pale orange (1QYR 8/2) 

soft massive northupite at top. Clay 56 percent, gaylussite 

40 percent, northupite 4 percent.
314

Dtpth Unit thick-

(feet) ness(fta) Description

63. 7 3. 2 Clay, gaylussite, and borax. Friable black (N 1) to greenishblack (5GY 2/1) clay, locally dusky yellow-green (5GY 5/2) 

to dusky-yellow (5Y 6/4) to dark greenish-gray (5(7 4/1) to 

grayish-black (N 2) finely laminated clay in upper 0.4 ft, 

with 50 percent disseminated euhedral to subhedral gaylussite crystals 2-10 mm in length, averaging 5 mm; a few 

seams, 1-2 mm wide, of anhedral pale greenish-yellow 

(10F 8/2) gaylussite; scattered 2- to 3-in. pockets of disseminated colorless anhedral borax. Clay 49 percent, 

gaylussite 49 percent, borax 2 percent.

64. 0 . 3 No core.

64. 2 .2 Clay and gaylussite. Black (AT 1) to greenish-gray (5(? 6/1)

coarsely laminated clay revealed by color differences, with

5 percent disseminated gaylussite silt.

64. 3 .1 Clay and gaylussite. Dark greenish-gray (5G 4/1) to black 

(N 1) clay with 50 percent disseminated euhedral gaylussite 

crystals averaging 1 mm in length.

 4. 7 .4 Clay and gaylussite. Black (N 1) to greenish-black (5GY 2/1) 

clay with 20 percent disseminated gaylussite silt; faint 

blackish-red (5/2 2/2) algae(?) discolorations throughout.

65. 1 .4 Trona and clay. Well-consolidated locally densely packed 

slightly vuggy aggregate of colorless trona blades averaging 

10 mm in length, with 50 percent interstitial black (N 1) 

clay in upper 20 mm and traces of black (N 1) clay throughout.

65.3 .2 Trona. Well-consolidated yellowish-gray (5Y 8/1) densely 

packed fibrous trona with irregular vuggy streaks and 

pockets of colorless fibrous trona.

65. 4 .1 Clay and trona. Black (AT 1) to grayish-black (N 2) clay 

with irregular streaks of colorless fine fibrous trona; faint to 

distinct moderate reddish-brown (10/2 4/6) algae(?) discolorations. Clay 75 percent, trona 25 percent.

65.8 .4 Trona and clay. Fractured core. Well-consolidated white 

(N 9) massive trona, locally discolored medium light gray 

(N 6) to intermixed clay; scattered pockets of colorless fine 

fibrous trona. Trona 99 percent, clay 1 percent.

66.7 .9 Trona and clay. Well-consolidated porous aggregate of 

colorless fibrous trona, locally discolored medium gray 

(N 5) to dark gray (N 4) by intermixed clay; seam, 20 mm 

wide, of yellowish-gray (5F8/1) massive trona at base. 

Trona 99 percent, clay 1 percent.

67. 2 .5 Clay, trona, and gaylussite. Black (N 1) to grayish-black 

(N 2) to very light gray (N 8) faintly finely laminated clay 

with numerous moderate reddish-brown (10/2 4/6) algae(?)- 

discolored laminae; lenticular horizontal pocket of colorless 

fine fibrous trona in lower 0.1 ft; 50 percent disseminated 

euhedral gaylussite crystals in upper 10 mm. Clay 84 

percent, trona 13 percent, gaylussite 3 percent.

67. 4 . 2 Trona and clay. Well-consolidated colorless fibrous trona 

with seams and irregular streaks of interstitial black (N 1) 

clay. Trona 97 percent, clay 3 percent.
CORE LOGS FROM SEARLES LAKE, CALIFORNIA 315

Depth Unit thick-

(feet) neat (feet) Description

67. 6 0. 2 Trona and clay. Well-consolidated white (N 9) massive to 

fine fibrous trona, locally discolored orange by intermixed 

algae(?); thin seams of intermixed black (ATI) clay in 

lower 0.1 ft with trace of anhedral borax. Trona 98 percent, 

clay 2 percent.

68.0 .4 Trona and clay. Fractured core. Fragments of white 

(N 9) massive to colorless fine fibrous trona, locally discolored orange by algae (?); with 35 percent interstitial 

black (N 1) soft clay.

68.2 .2 Trona, northupite, and clay. Colorless to white (N 9) 

fine fibrous trona with irregular streaks of interstitial yellowish-gray (5F8/1) to grayish-orange (IQYR 7/4) soft 

massive northupite chiefly confined to lower 20 mm, 

associated with 10 percent intermixed streaks of black 

(N 1) clay. Trona 81 percent, northupite 17 percent, clay 

2 percent.

68. 9 .7 Clay and northupite. Black (AT 1) to grayish-black (N 2) to 

very light gray (N 8) finely laminated clay with 10 percent 

disseminated round to oval nodules, from 0.2 to 3 mm in 

length, averaging 1 mm, of white (N 9) massive northupite.

69. 1 .2 Clay and gaylussite. Black (N 1) to grayish-black (N 2) to 

very light gray (N 8) finely laminated clay with 20 percent 

disseminated euhedral gaylussite silt.

70. 3 1. 2 No core.

70.7 .4 Clay, gaylussite, trona, and northupite. Black (AT 1) to 

grayish-black (AT 2) to very light gray (N 8) faintly finely 

laminated clay with 5 percent disseminated gaylussite silt in 

small %-in. pockets and seams; 5 percent disseminated 

colorless trona blades up to 80 mm in length; irregular 

seam, 1-2 mm wide, of grayish-orange (IQYR 7/4) massive 

northupite at 70.6 ft. Clay 89 percent, gaylussite 5 percent, trona 5 percent, northupite 1 percent.

71. 2 .5 Trona, clay, and gaylussite. Well-consolidated slightly yuggy 

aggregate of colorless trona blades averaging 30 mm in 

length, locally in radiating clusters, with 20 percent interstitial grayish-black (N 2) clay containing 10 percent 

disseminated gaylussite silt; seam, 10 mm wide, of yellowishgray (5 Y 8/1) to medium gray (N 5) hard massive trona at 

base. . .

71.6 .4 Trona, northupite, and clay. Well-consolidated slightly 

vuggy porous aggregate of colorless trona blades up to 20 

mm in length, averaging 8 mm, with 2- to 3-in. pockets of 

white (N 9) sugary-textured massive trona; 2 percent .interstitial black (N 1) to grayish-black (N 2) clay; lower 20 

mm consists of seams of yellowish-gray (5 Y 8/1) to grayishorange (IQYR 7/4) soft massive northupite with intermixed 

very thin steaks :and seams of black (N 1) clay. Trona 81 

percent, northupite 16 percent, clay 3 percent.
316 GEOLOGIC INVESTIGATIONS IN MOJAVE DESERT REGION

Depth Unit thick- 

(feet) ness (feet) Description

72. 1 0. 5 Clay, gaylussite, and northupite. Black (N 1) to grayishblack (N 2) to dusky yellow-green (5GY 5/2) to very light 

gray (N 8) finely laminated clay with 10 percent disseminated gaylussite silt; disseminated round to oval nodules, 

averaging 0.5 mm in length, of white (N 9) to grayishorange (WYR 7/4) massive northupite chiefly confined to 

interval 71.8 to 71.9 ft. Clay 87 percent, gaylussite 10 

percent, northupite 3 percent.

72. 3 .2 Gaylussite and clay. Consolidated aggregate of colorless clear 

euhedral gaylussite crystals, grading from 1 mm in length 

at top to fine-sand size at base, with 40 percent interstitial 

black (N 1) clay.

72. 6 .3 Clay, trona, and gaylussite. Black (N 1) to grayish-black 

(AT 2) to very light gray (N 8) very finely laminated clay 

with 1 percent disseminated gaylussite silt in small streaks; 

10 percent colorless trona blades averaging, 20 mm in 

length, disseminated in lower 0.1 ft. Clay 96 percent, 

trona 3 percent, gaylussite 1 percent.

72.9 .3 Trona and clay. Fractured core. Rounded fragments of 

well-consolidated slightly vuggy white (N 9) to yellowishgray (5Y 8/1) massive trona with pockets of colorless 

fibrous trona containing interstitial black (N 1) clay. 

Trona 99 percent, clay 1 percent.

73. 1 .2 Clay, trona, and northupite. Black (N 1) to grayish-black 

(N 2) clay; seam, 3 mm wide, at top of fibrous to bladed 

trona associated with yellowish-gray (5Y 8/1) massive 

northupite. Clay 96 percent, trona 4 percent, northupite 

1 percent.

73. 4 .3 Clay and northupite. Black (N 1) to greenish-black (5GY 

2/1) clay with 10 percent disseminated round to oval 

nodules, averaging 0.5 mm in length, of white (N 9) massive 

northupite.

73. 7 .3 Clay and gaylussite. Black (N 1) to grayish--black (N 2) to 

olive-gray (5 Y 3/2) to very light gray (N 8) faintly finely 

laminated clay with 10 percent disseminated gaylussite silt.

73.8 .1 Clay. Poorly consolidated greenish-black (5GY 2/1) soft 

moist clay, locally finely laminated dark greenish-gray 

(5G 4/1) to dusky-yellow (57 6/4) clay.

73. 9 .1 Clay and gaylussite. Black (N 1) clay with 50 percent disseminated euhedral gaylussite sand.

74.1 .2 Clay. Black (N 1) to grayish-black (N 2) to very light gray 

(N 8) finely laminated clay.

74. 4 .3 Clay and gaylussite. Black (N 1) to grayish-black (AT 2) 

clay with irregular pockets of fine euhedral gaylussite sand. 

Clay 95 percent, gaylussite 5 percent.

74. 6 .2 Clay and gaylussite. Grayish-black (N 2) to greenish-gray 

(5G 6/1) to dusky-yellow (5Y 6/4) to olive-gray (5Y 3/2) 

faintly finely laminated clay; 10 percent disseminated 

gaylussite silt.
CORE LOGS FROM SEARLES LAKE, CALIFORNIA 317

Depth Unit thick- 

(feet) ness (feet) Description

75. 0 0. 4 Clay and gaylussite. Olive-gray (5F 3/2) to moderate olivebrown (5 Y 4/4) clay with 50 percent disseminated euhedral 

to subhedral gaylussite crystals up to 50 mm in length, 

averaging 20 mm.

77. 5 2. 5 No core.

78.9 1.4 Clay and gaylussite. Grayish-black (N 2) to olive-gray 

(5F 3/2) to dusky yellowish-brown (10YR 2/2) clay with 

35 percent disseminated euhedral to subhedral gaylussite 

crystals 5 to 50 mm in length, averaging 25 mm; locally 

finely laminated greenish-gray (5G 6/1) to dark greenishgray (5G 4/1) to grayish-black (N 2) to dusky-yellow 

(5Y 6/4) to dark yellowish-orange (10F.K 6/6) clay without 

gaylussite crystals.

' SI. 9 3. 0 Clay, gaylussite, and calcite*. Grayish-black (N 2) to olivegray (5F 3/2) to greenish-gray (5GY 6/1) to dark greenishgray (5GY 4/1) to dusky yellowish-brown (IOYR 2/2) to 

dusky-yellow (5Y 6/4) to dark yellowish-orange (IOYR 

6/6) to grayish-yellow (5F 8/4) to very light gray (N 8) 

finely laminated clay; 5 percent disseminated euhedral 

gaylussite crystals from sand size to 20 : mm in length, 

averaging 0.5 mm, in thin seams, 3 mm wide, locally crosscutting laminae; 5 percent disseminated finely crystalline 

white (N 9) massive calcite* in lenticular pockets 0.5 to 

2 mm long, at 81.1 to 81.2 ft.

-82. 8 .9 No core.

o