Hualapai Limestone Member of the 

Muddy Creek Formation: The Youngest 

Deposit Predating the Grand Canyon, 

Southeastern Nevada and Northwestern Arizona
HUALAPAI LIMESTONE MEMBER OF THE

MUDDY CREEK FORMATION: THE YOUNGEST

DEPOSIT PREDATING THE GRAND CANYON,

SOUTHEASTERN NEVADA AND NORTHWESTERN ARIZONA
. - . *'.2"V« ^^*- -i**** «S^VA,>:-;^5Ss

Hualapai Wash—Type locality for the Hualapai Limestone Member of the Muddy Creek Formation.
Hualapai Limestone Member of the 

Muddy Creek Formation: The Youngest 

Deposit Predating the Grand Canyon, 

Southeastern Nevada and Northwestern Arizona

By WILL N. BLAIR and AUGUSTUS K. ARMSTRONG

GEOLOGICAL SURVEY PROFESSIONAL PAPER 1111

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1979
UNITED STATES DEPARTMENT OF THE INTERIOR 

CECIL D. ANDRUS, Secretary

GEOLOGICAL SURVEY 

H. William Menard, Director

Library of Congress Catalog-card No. 79-600142

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

Washington, D.C. 20402

Stock Number 024-001-03222-8
CONTENTS

Abstract ——————————————-

Introduction ————————————-

Muddy Creek Formation —-——-

Hualapai Limestone Member

Page

-- 1

- 1

- 1

-- 1

Distribution ——-———————-—————-—————-—— 2

Rock types -——————-———-———-——-—————-——- 4

Minerals —————-——-—-————-——-———....... 4

Chert ——————————————————————— 4

Fossils ———————-—-—-—-———-———-————. 5

Algal stromatolites -—-—-——————-————-— 5

Diatoms ———————————————————— 7

Plant fossils —————————————--———— 7

Gastropods ———-—-—————————.——.—— 8

Page

Muddy Creek Formation—Continued

Hualapai Limestone Member—Continued 

Fossils—Continued

Ostracodes ————————————————------ 8

Trace fossils ———-—————-————————-———— 8

Carbonate rocks —————————————————————— 8

Diagenesis -————-—-—————-————-———— 9

Matrix ———————————————————— 9

Sparry calcite ———-———————-———-————— 9

Radiaxial fibrous calcite —-——-————-———— 10

Age ————————————————————————10

Discussion and conclusions —————————————————————— 10 

References cited ——————...—.———.......———.————— 12

ILLUSTRATIONS

	[Plates follow references]

FRONTISPIECE. Hualapai Wash—Type locality for the Hualapai Limestone Member of the Muddy Creek Formation.

PLATE 1. Diatoms.

2. Conversion of biogenic silica to cristobalite-rich chert.

3. Lepispheres of bladed cristobalite.

4. Opaline and chert samples.

5. Opaline material.

6. Ostracode valves etched from siliceous matrix.

7. Fossil plants.

8. Algal limestone.

9. Pisolites and microstructures.

10. Fenestrate peloid packstone.

11. Algal oncolites, Grapevine Canyon.

12. Opalized plant stems, Juncus?sp. indet.

13. Peloid packstones.

14—19. Specimens from north of Grapevine Canyon.

FIGURE 1. Index map of southeastern Nevada and northwestern Arizona ——————————————————————————-

2. Photograph showing bedded oncolitic limestone of the Hualapai Limestone Member near Grapevine Wash

3. Photograph showing westernmost exposure of Hualapai Limestone Member ——————————————————-

4. Graph of X-ray diffraction patterns of marine rocks ————————————————————————————————-

5. Photograph showing bedding surface covered with transverse section of algal oncolites ———-—-————-

6. Diagram and photographs of nest of a large, solitary, ground-nesting bee ———-———-—-——————-——-

7. Drawing of radiaxial fibrous calcite cement and inclusion patterns in the Hualapai Limestone Member —-

8. Map showing Miocene and Pliocene embayment of the Gulf of California —--————-—-——————-—

Page

-- 2

- 3

- 3

- 5

-- 6

- 9

--10

--11

TABLE

TABLE 1. K-Ar analytical data and ages

Page

--10

HUALAPAI LIMESTONE MEMBER OF THE

MUDDY CREEK FORMATION:

THE YOUNGEST DEPOSIT PREDATING THE GRAND CANYON, 

SOUTHEASTERN NEVADA AND NORTHWESTERN ARIZONA

By WILL N. BLAIR and AUGUSTUS K. ARMSTRONG

ABSTRACT

The Hualapai Limestone Member of the Tertiary Muddy Creek 

Formation is exposed as erosional remnants in the Lake Mead area 

of southeastern Nevada and northwestern Arizona and at the base of 

the Grand Wash Cliffs in northwestern Arizona. Earlier investigators 

have considered that this limestone was originally deposited along with 

mudstone, claystone, and siltstone from interior drainage in a lacustrine environment. On the basis of an analysis of chert and of the 

observed occurrence of diatoms typical of estuarine conditions, we interpret the limestone as having been formed in marine or brackish 

waters. The presence of radiaxial fibrous calcite cementing algal oncolites in the Hualapai Limestone Member also indicates early marine 

sedimentation.

Siliceous rocks within the Hualapai Limestone Member exhibit the 

diagenetic sequence of biogenic opal to cristobalite to chert, which is 

characteristic of rocks deposited in a marine environment.

The Hualapai Limestone Member was most likely deposited in an 

estuary at the end of an embayment of the Gulf of California, which 

extended northward to the edge of the Colorado Plateau in the vicinity 

of Lake Mead.

INTRODUCTION

This paper presents information on the rock types 

and environment of the Hualapai Limestone Member 

of the Muddy Creek Formation. The Muddy Creek Formation has been considered to be an interior basin deposit by most workers (Longwell, 1928; Hunt, 1956; 

Lucchitta, 1967). We believe that there is good evidence for a marine or brackish-water origin for the 

Hualapai Limestone Member. The site for this kind of 

deposition would have been at the north end of an embayment of the ancestral Gulf of California or in an 

estuary at the north end of the ancestral gulf.

MUDDY CREEK FORMATION

The Muddy Creek Formation was named the Muddy 

Creek Beds by Stock (1921, p. 146-147) for exposures 

between Overton and Logan (now Logandale), Nevada. 

Longwell (1928, p. 90-96) renamed it the Muddy Creek 

Formation and (1936, p. 1423) lowered its base to include strata previously assigned to the underlying 

Horse Spring Formation. The formation is a complex 

deposit, largely basin and trough type, composed of 

conglomerate, sandstone, siltstone, mudstone, and 

crystalline precipitates. It interfingers and is overlain 

by volcanic flows at several localities. Its uppermost 

part is distinguished by the Hualapai Limestone Member, a widespread flat-lying unit. The Muddy Creek includes abundant salt and gypsum lenses and other indicators of aridity (Longwell, 1954). North of the 

Colorado River, near the head of Boulder Canyon (now 

under Lake Mead), the Muddy Creek Formation is 

largely gypsum, which in places is at least 90 m thick. 

Before the creation of Lake Mead, large beds and plugs 

of rock salt of Miocene and Pliocene(?) age were exposed in part of the Virgin Valley (Longwell and others, 1965). Moreover, the paleobasin of Red Lake, 

about 32 km south of Hualapai Wash, contains a minimum of 1,200 m of evaporites, mainly halite (Peirce, 

1976, p. 328). This lake basin appears to have been 

largely filled by 10 m.y. ago, before the establishment 

of the Grand Canyon. Peirce (1976) believes that the 

halite of Red Lake is the same age as the Muddy Creek 

Formation.

HUALAPAI LIMESTONE MEMBER

C. R. Longwell (1936), in his study of the Boulder 

Reservoir floor of Arizona and Nevada, named the Hualapai Limestone for the excellent limestone exposures 

along Hualapai Wash, its type locality.

Lucchitta (1972, p. 1939) considered the Hualapai to 

be the highest and youngest member of the Muddy 

Creek Formation. This usage was adopted by Blair 

(1978).

The Hualapai Limestone Member crops out in the 

northwestern part of Arizona, south of Lake Mead in 

Mojave County and in southeastern Nevada, north of 

Lake Mead in Clark County (fig. 1). It is exposed as
HUALAPAI LIMESTONE MEMBER OF THE MUDDY CREEK FORMATION

MESQUITE72 KM

I ——— ^~)

-———- ——— - -- ———

Hualapai Limestone Member of 

Muddy Geek Formation

©

Sample 

locality

Boundary of Lake Mead 

National Recreation Area

FIGURE 1.—Southeastern Nevada and northwestern Arizona showing distribution of Hualapai Limestone Member.

erosional remnants astride the present course of the 

Colorado River at the base of the Grand Wash Cliffs 

in northwestern Arizona.

Ancestral Colorado River gravel is found in siltstone 

conformably overlying the Hualapai (Blacet, 1975}; 

however, nowhere in the Hualapai is there evidence 

of a vigorous through-flowing stream such as the present Colorado River. Therefore, the Hualapai Limestone Member probably is one of the youngest deposits 

formed before the establishment of the Colorado River 

in its present course from the mouth of the Grand Canyon.

DISTRIBUTION

Outcrops of the Hualapai Limestone Member occupy 

topographic lows that are generally bounded on the 

west by the Black Mountains and on the north by the 

Virgin Mountains (fig. 1). The White Hills form an approximate boundary to the south. To the east the Hualapai is bounded by the Grand Wash Cliffs, which 

form a steeply eroded fault scarp across the present

course of the Colorado River where it emerges from the 

Grand Canyon.

The best exposure and the type locality of the Hualapai Limestone Member is along Hualapai Wash, 

beginning from the point where the wash joins Lake 

Mead and extending south for about 9 km (fig. 1). Here 

the Hualapai is over 240 m thick. A thick section of 

the Hualapai is also well exposed for about 2 km in 

steep cliffs along Grapevine Wash, about 8 km south 

of Pierce Ferry.

A third remnant, smaller than the first two, lies exposed near Detrital Wash, 8 km southwest of the Lake 

Mead marina at Temple Bar. Across the lake, smaller 

and thinner limestone beds cap Delmar Butte, The 

Temple, and an area just north of Iceberg Canyon.

Large exposures of the Hualapai to the south of Lake 

Mead can easily be reached by a paved road to Temple 

Bar from Highway 93, and by another paved road 

through Dolan Springs to Pierce Ferry. This road also 

departs from Highway 93 but further to the south.

Exposures of the Hualapai Limestone Member on 

the north shore of Lake Mead can be reached by a jeep
DISTRIBUTION

road from Mesquite, Nev., through the Virgin Mountains, a distance of some 72 km. However, a short boat 

ride across the lake from the Temple Bar marina will 

bring one to within easy walking distance of the Hualapai on the north shore.

The easternmost exposures of the Hualapai Limestone Member are those south of Pierce Ferry. They 

extend northward up Gravevine Wash for 12 km, 

roughly paralleling the Grand Wash Cliffs (fig. 2). 

Here the Hualapai rests conformably on and interfingers with conglomerate of the Muddy Creek Formation. The thickest unit is in Grapevine Wash where it 

forms rugged and steeply dissected cliffs, in contrast 

to the softer clayey limestone near the Pierce Ferry 

airport where the beds thin to about 60 m. The Hualapai and the conglomerate cover the Grand Wash fault, 

the exact location of which is unknown. There has 

been no movement on this fault during the last several 

hundred meters of deposition of the Muddy Creek.

The westernmost exposure of the Hualapai Limestone Member is 8 km south of Bonelli Bay (fig. 1) at 

a point on the east edge of Detrital Wash; it extends 

eastward from there for about 5 km. The Hualapai at 

this locality measures over 120 m and dips 5° to the 

east (fig. 3). The Hualapai overlies 6 m of massive gypFIGURE 3.—Westernmost exposure of the Hualapai Limestone Member from locality 1 (fig. 1): (1) marl bed with fossil plants, (2) 8.66- 

m.y.-old tuff, (3) bed with radioactive material, (4) gypsum bed at 

the base of the Hualapai Limestone Member. View west.

FIGURE 2.—Bedded oncolitic limestone of Hualapai Limestone Member in tributary on west side of Grapevine Canyon near locality 7 

(fig. 1). Lake Mead and Grand Wash Cliffs can be seen in distance. View east.
HUALAPAI LIMESTONE MEMBER OF THE MUDDY CREEK FORMATION

sum of the Muddy Creek Formation. Above the gypsum is a 75-m sequence of well-bedded marl, limy claystone, and limy mudstone which is well exposed in 

steep ravines. Interfingering with this sequence are 

several layers of water-laid volcanic cinders and basalt 

cobbles. At about 36 m above the base of this sequence, 

a 150-mm bed of air-fall tuff (fig. 3) can be traced for 

more than 30 m. The volcanic glass shards in this bed 

have a K-Ar date of 8.66 ±2.2 m.y. (Blair and others, 

1977). Gypsum lenses up to 50 mm thick and 6 m long 

occur intermittently near the volcanic debris near the 

base of the Hualapai. Plant fossils are abundant (fig. 

3). At places clumps and bundles of stems can be observed in positions of growth, and horizontal root 

structures weather out of the steep banks. The marl, 

claystone, and mudstone is overlain by 45 m of dense 

hard limestone which forms steep cliffs and resistant 

caps.

ROCK TYPES

The Hualapai Limestone Member consists of limestone interbedded with thin beds of limy claystone, 

mudstone, and siltstone. The weathered limestone 

beds of the Hualapai have a predominantly reddish 

color and form steep cliffs where they are dissected by 

Hualapai Wash. These cliffs are undercut in many 

places by erosion of the thin (5-15 cm) softer limy argillaceous interbeds. These argillaceous interbeds 

thicken and thin laterally over short distances.

Scattered chert nodules occur near the top of the 

Hualapai in a few places. Plant stems replaced by calcite and plant leaf impressions in the limestone are 

common locally. A few casts of small gastropods can be 

found in the dense limestone layers. Algal structures 

are abundant in some places. Thin lenses of impure 

gypsum beds as much as 50 mm thick are sparsely 

scattered throughout.

MINERALS

Chert nodules in some beds in the Hualapai Limestone Member in the western part of the study area 

(fig. 1, Iocs. 2 and 3) are weakly radioactive. The radioactive material consists of thin coatings of carnotite 

and autunite along bedding planes in the mudstone 

and claystone. These beds were staked as mineral 

claims in 1956. Preliminary reconnaissance reports 

from the Atomic Energy Commission (unpub. data) 

were submitted in 1955 and 1956 on these claims. The 

radioactive material ranged from 0.05 to 10.0 mR/hr 

on the Geiger counter. At the time of these reports, 

pockets of ore were considered too small and too widely 

scattered to be of commercial value. Some chert lenses 

were found to be radioactive. In several places bright

yellow secondary uranium minerals can be seen sur- /' 

rounding the stems of opalized reed fossils. A few small 

chert lenses near a prospect pit in the top of the Hualapai in the vicinity of the type locality at Hualapai 

Wash are also weakly radioactive (fig. 1, loc. 6).

Chert nodules and thin beds of opal are much more 

common in the westernmost outcrop than at other exposures. Volcanic vents and flows that are associated 

with these outcrops probably supplied some silica to 

the waters in which the deposits were formed (Taliaferro, 1933), but no volcanic particulate material was 

seen in the siliceous rocks, so this source of silica is 

thought to be minor.

CHERT

The diagenetic sequences of siliceous rocks in the 

Hualapai Limestone Member are similar to opaline 

chert recovered from a wide variety of recent and ancient marine sedimentary deposits. We have examined 

samples of biogenic opal and cristobalite-rich rocks 

(called chert in this report) of the Hualapai Limestone 

Member under the scanning electron microscope 

(SEM) (pi. 5, figs. 2, 4, 6). This study reveals numerous 

free-growth forms of disordered cristobalite called lepispheres (Wise and Kelts, 1972, p. 188). These are microscopic spheres and hemispheres consisting of aggregates of cristobalite blades, usually 12-21 (Jim in 

diameter (pi. 4, figs. 1, 2; pi. 5, figs. 5, 6). The characteristic appearance of these minute lepispheres permits their identification by the SEM even when only 

one crystal cluster with a diameter of 2 (Jim is present 

(pi. 4, fig. 2).

X-ray diffraction patterns for siliceous material in 

the Hualapai Limestone Member (fig. 4A) are similar 

to those of marine rocks from opaline claystone of 

South Carolina (Wise and Weaver, 1973) (fig. 4B) and 

those from cores taken in the Antarctic Ocean (Wise 

and others, 1972) (fig. 4O. The X-ray patterns for siliceous material from the Hualapai are also similar to 

those produced by Calvert (1971) from deep-sea chert 

in the North Atlantic, those labeled "common opals" 

from Australia (Jones and others, 1964), and those 

from chert of the Monterey Shale of Miocene and Pliocene age (Ernst and Calvert, 1969).

The sedimentary rocks of the Muddy Creek Formation have been presumed to be derived from fresh to 

brackish waters (Longwell, 1928; Hunt, 1956; Lucchitta, 1972). However, the cristobalite-rich rocks of 

the Hualapai Limestone Member cannot be distinguished from marine rocks on the basis of SEM studies 

and X-ray analysis. Examples of marine siliceous 

rocks that resemble siliceous rocks of the Hualapai 

Limestone Member are: (1) opaline claystone of Eocene 

marine shallow shelf strata from Alabama to South
FOSSILS

I I

I__I

B

aCristobalite

I I I I I I I I I I I I I

aCristobalite

36

DEGREES 26

FIGURE 4.—X-ray diffraction patterns of marine rocks. A, Siliceous 

material from the Hualapai Limestone Member. B, Opaline claystone of South Carolina (Wise and Weaver, 1973). C, Core taken in 

the Antarctic Ocean (Wise and others, 1972).

Carolina (Wise and Weaver, 1973), (2) siliceous rocks 

of the Monterey Shale deposited in marginal Tertiary 

basins (Bramlette, 1946; Ingle, 1973; Murata and Larson, 1975; Murata and Nakata, 1974), and (3) deep-sea 

chert from the Antarctic, Pacific, and Atlantic Oceans 

(Berger and von Rad, 1972; Calvert, 1971; Heath and 

Moverly, 1971; Weaver and Wise, 1972a, b; Wise and 

Weaver, 1974).

Lepispheres in the opaline part of the Hualapai 

Limestone Member appear to be larger on the average

but not as well formed as those seen in some marine 

chert (pi. 6, figs. 5, 6). At least one exception can be 

noted, however, in the micrographs of plate 3, figure 

1. The larger lepisphere pictured here is very well 

rounded and symmetrical. A stereoscopic view shows 

that it is probably attached to the cavity walls by the 

small quartz crystals near its surface.

The scanning electron micrograph of plate 5, figure 

4, shows clean cristobalite crystal blades with scalloped and serrated edges. Wise and Weaver (1973) 

noted cristobalite blades with similar serrated-edge 

patterns from marine opaline claystone of Alabama 

and from deep-sea chert.

Diatomaceous biogenic opal (opal-A of Jones and 

Segnit, 1971) is one of the most important sources of 

silica in pelagic sediment of recent oceans (Riedel, 

1959). In fact, biogenic opal is the silica source for most 

deep-sea chert (Wise and others, 1972; Davies and 

Supko, 1973; Wise and Weaver, 1974). The evidence 

from the siliceous rocks in the Hualapai Limestone 

Member indicates that diatom frustules were the initial most important contributor to its nodular chert. 

This evidence reinforces the concept of the diagenetic 

sequence of biogenic opal (opal-A) to cristobalite (opalCT) to chert. The authors subscribe to this kind of maturation sequence as advocated by Heath and Moberly

(1971), Weaver and Wise (1972b), Berger and von Rad

(1972), and Wise and Weaver (1974).

FOSSILS 

ALGAL STROMATOLITES

The Hualapai Limestone Member contains circular 

to irregular oval objects from less than a millimeter to 

10 cm in diameter (fig. 5). In thin section these show 

irregular banding (pi. 9, figs. 2, 4, 6; pi. 10, figs. 1-6, 

pi. 11, figs. 1-6, pi. 13, figs. 2-6; pi. 17, fig. 1; pi. 18, 

figs. 1-6). These we consider to be algal oncolites. Oncolites are unattached stromatolites with encapsulating laminae (Walter, 1976, p. 691). The specimens 

from the Hualapai Limestone Member (pi. 9, figs. 2, 4, 

6; pi. 10, figs. 1-6) are similar in shape and size to 

Bradley's (1929, pis. 35, 42) digitated algae from the 

Green River Formation of Utah. Johnson (1961, pis. 

132-133) shows similar specimens from the Green 

River Formation of Wyoming and Colorado.

Specimen 892D (pi. 9, figs. 2, 4, 6) of a digitate oncolite, is composed of irregular dark-brown and light 

bands of calcite which form botryoidal intergrowths. 

The narrower dark bands are composed of 3—5 jxm calcite rhombs, whereas the lighter bands are formed by 

long slender calcite rhombs 50-100 jxm long (pi. 9, fig.
HUALAPAI LIMESTONE MEMBER OF THE MUDDY CREEK FORMATION

FIGURE 5.—Outcrop of bedding surface covered with transverse section of algal oncolites, typical of much of the thick Hualapai Limestone 

Member. Photograph taken in first canyon north of Grapevine Canyon. Coin is 21 mm across.

6). Algal oncolites contain detrital quartz grains and 

fragments of volcanic rocks. The matrix that surrounds the algal oncolites is composed of detrital 

grains of quartz and volcanic rock in peloid-lime mudstone. These oncolites commonly have as their center 

or at their bases grains or pebbles of volcanic rocks or 

micritic mudlumps. Gebelein (1976) states:

The environment of formation of oncolites at Joulters Cays, Bahamas, is similar to that for attached stromatolites, except that periodic turbulence, causing initial detachment of the forms, is higher. 

In the Joulters, this increase in turbulence corresponds to a decrease 

in depth. Maximum formation occurs in depths less than 1 m. Concentrations of 10-100 oncolites per m2 are common in the shoal 

areas. Lags of oncolites carpet the floor of some tidal channels which 

cut through the shoals.

Algal oncolite specimen 846A (pi. 8, figs. 1-7) is a 

digitated form, with individual branches up to 1 mm 

in diameter. In transverse section the dark and light 

banding is somewhat circular, and in longitudinal section, the banding shows a distinct arched growth pattern. The long axes of the calcite crystals are tangential to the circular bands of the algae. Algal oncolites 

in transverse section, with crossed nicols, show a 

pseudo-uniaxial cross.

The algal oncolites from Grapevine Canyon (pi. 11, 

figs. 1—6) are up to 3 cm in diameter, are spherical in

shape, and retain void spaces between oncolites. Voids 

within the oncolite and between growth bands are 

lined with cryptocrystalline quartz (opal) (pi. 11, 

figs. 5, 6).

Some algal oncolites (pi. 13, figs. 2, 4, 6) contain 

within their bands appreciable amounts of detrital 

quartz grains. Algal oncolites commonly are crusts on 

compound micrite mudlumps, formed of detrital quartz 

and micritic peloids (pi. 17, fig. 1). These algal crusts 

show a tendency for laminations developed on one side 

of the mudlump, suggesting growth upward (pi. 18, 

fig. 2).

Colloform algal stromatolites formed by digitate fabric occur in the Hualapai Limestone Member at 

Grapevine Canyon. Individual algal branches are 1-3 

mm in diameter and may be up to 20-30 cm tall (pi. 

8, figs. 1-6). Hoffman (1976) and Playford and Cockbain (1976) report colloform mat structures from the 

sublittoral shelf of Hamelin Pool, Shark Bay, Australia. These recent stromatolites have shapes similar 

to colloform stromatolites from the Hualapai Limestone Member. Hoffman's (1976, p. 269, figs. 6d, 6e) 

photographs of recent colloform tilted stromatolites 

are morphologically similar to the colloform stromatolites in the Hualapai. The Hamelin Pool colloform 

stromatolites live in a semiarid climate and subtidal
FOSSILS

environment with salinity nearly twice that of normal 

seawater. Hoffman states that on the sublittoral floor, 

stromatolites with digitate columnar internal structure occur beneath ovoid patches of colloform mats. 

These colloform stromatolites are buried in pelleted 

lime mud. The Hamelin Pool fauna has low species 

diversity because of the hypersaline condition, and algae-consuming organisms are largely absent (Playford 

and Cockbain, 1976). As a result algal stromatolites 

flourish on the sublittoral and intertidal platforms. In 

Hamelin Pool lithification of stromatolites has taken 

place in both the intertidal and subtidal environments. 

Laminations are only crudely developed or absent in 

many Hamelin Pool stromatolites, and fenestrate 

(birdseye) fabrics are characteristic.

Shinn (1968) recognized two kinds of birdseye structures in recent and ancient carbonate rocks: (1) planar 

isolated vugs 1-3 mm high by several millimeters wide 

and (2) isolated bubblelike vugs 1-3 mm in diameter. 

Both types are generally filled with calcite or anhydrite.

Shinn's study of more than 100 cores and samples of 

recent carbonate sediments showed that birdseye voids 

are preserved in supratidal sediments (sediments deposited above normal high-tide level), sometimes in 

intertidal sediments (sediments deposited between 

normal and high-tide level), sometimes in intertidal 

sediments (sediments deposited between normal high 

and normal low tide), and never in subtidal sediments 

(sediments permanently below water). Both kinds of 

birdseyes are particularly abundant in supratidal dolomitic sediments.

Playford and Cockbain's (1976, p. 410, fig. 11 A) example of a well-lithified intertidal stromatolite from 

Hamelin Pool, showing the characteristic fenestral 

fabric in weakly laminated pellet wackestone, is similar to fenestrate pellet packstone of the Hualapai 

Limestone Member (pi. 10, figs. 1-6; pi. 13, figs. 1, 3, 

5; pi. 15, figs. 1, 6).

DIATOMS

Diatoms were recovered by J. Platt Bradbury, of the 

U.S. Geological Survey, from opalized rock samples we 

collected near the top of the Hualapai Limestone Member at localities 1 and 4 (fig. 1). He identified the specimens from locality 1 as Scoliopleura sp., Nitzchia sp., 

Mastogloia cf. M. aquilegiae, Rhopalodia gibberula, 

Navicula cf. N. radiosa tenella, Amphora or Cymbella 

sp., and Denticula sp.

White opal from an outcrop of the Hualapai Limestone Member 6 km southeast of Temple Bar (fig. 1, 

loc. 4) was studied by the authors under the scanning 

electron microscope. This study revealed the existence

of exceptionally well preserved diatoms imbedded in 

the opal. Scanning electron micrographs of these diatoms are presented on plate 1. Bradbury has identified 

these species (written commun., 1976) as Navicula cf. 

N. cuspidata (pi. 1, fig. 1) which is widespread in alkaline freshwater habitats. Navicula halophila (pi. 1, 

fig. 2) is a true brackish-water diatom that can tolerate 

considerable variations in salinity. This diatom is 

characteristic of inland lakes and marshes of moderate 

salinity but it is also found in coastal (marine) environments.

Melosira moniliformis? (pi. 1. figs. 5, 6), Amphora 

hyalina (pi. 1, fig. 4), and Amphora arcus var. sulcata 

(pi. 1, fig. 3) are marine or brackish-water diatoms that 

are common in coastal littoral habitats. Frequently 

Amphora species occur in estuarine environments.

According to Bradbury, Melosira moniliformis?, Amphora arcus var. sulcata, and Amphora hyalina seldom 

characterize inland saline aquatic environments. 

Their presence suggests that a coastal, perhaps estuarine, environment existed when the diatomaceous 

sediments were deposited.

The diatoms suggest that the Hualapai Limestone 

Member is not older than Neogene. The diatom family 

Epithemiaceae which includes the genera Denticula 

and Rhopalodia is thought not to be older than Pliocene.

PLANT FOSSILS

The remains of grasses, reeds, and rushes are the 

most abundant macrofossils found in the Hualapai 

Limestone Member. These can be observed as layered 

horizontal mats entirely replaced by limestone. Others 

form vertical hollow calcite tubes, having inner surfaces lined with drusy quartz and exteriors encrusted 

with travertine. In at least one locality (fig. 1, loc. 1) 

the reed stem structures have been perfectly replaced 

by opal, preserving the cell walls (pi. 12, figs. 1-6). 

Molds and casts of the plants resemble Juncus (Juncaceae, the rush family), but they have not been identified with certainty.

Some of the plant fossils with hollow stem structures 

look like scouring rushes (Equisetacae): these rushes 

are now represented only by a single genus, Equisetum 

(Robinson and Fernald, 1908, p. 51; Scott, 1962, p. 13). 

The stems usually have hollow internodes with a coating of silex, which is the zone that is normally preserved. Equisetum is a silica accumulator plant that 

takes silica into its system from the soil. This silica is 

precipitated around the cell walls in the form of plant 

opal (Lovering and Engel, 1967, p. B15). When the 

plant dies, the silica then is either dispersed in the 

form of phytoliths, or, if the plant is buried before this 

dispersal, its opalized structure can be preserved in the
8 HUALAPAI LIMESTONE MEMBER OF THE MUDDY CREEK FORMATION

rock record. The amount of silica contributed to the 

Hualapai Limestone Member in this manner, however, 

was probably minor.

GASTROPODS

Gastropod molds and steinkerns were collected at 

several localities in the Hualapai Limestone Member 

and were studied by J. H. Hanley (unpub. data). One 

poorly preserved complete steinkern of a sinistral gastropod may represent the Physidae. This specimen was 

one of several collected by the authors from Hualapai 

Wash (fig. 1, loc. 5). Twenty incomplete external molds 

and four incomplete steinkerns collected from locality 

4 (fig. 1) may represent a single species of Flumnicola 

Stimpson. Flumnicola is known from two other localities in the Muddy Creek Formation in Clark County, 

Nev.: (1) USGS Cenozoic locality 22250, Dry Lake 

quadrangle. EVfe sec. 35, and WVfe sec. 36, T. 19 S., R. 

63 E., carbonate facies. Collected by C. R. Longwell, 

1960, and (2) USGS Cenozoic locality 22252 (L10-58). 

SWVfe sec. 26, T. 19 S., R. 63 E., calcareous facies. Collected by W. H. Hays, 1958.

The Hydrobiidae, which includes Flumnicola, are 

herbivorous, ingesting algae and algal detritus, but 

diatoms constitute the principal food source for some 

species. Hydrobiids occur in aquatic habitats of many 

sizes, from creeks and springs to the Great Lakes. 

Some species occur in brackish and marine habitats. 

These gastropods live on a variety of substrates including mud, sand, gravel, and aquatic plants.

The wide-ranging habitats of the fossil gastropods of 

the Hualapai Limestone Member preclude their use as 

indicators of the paleoenvironment.

OSTRACODES

Ostracodes are locally abundant in the Hualapai 

Limestone Member. Several ostracodes were observed 

in thin section. None could be definitely classified, but 

at least one individual resembles a species of Candona 

(J. P. Bradbury, written commun., 1976). Candona is 

typical of the freshwater forms, which are characterized by smooth and monotonous surface features (Benson, 1961). Species of Candona are found in all types 

of freshwater environments, ranging from deep water 

to marshes. They are nonswimmers, usually burrowing in the mud. Over 100 species of Candona have been 

described (Van Morkhoven, 1963). Its eggs not only 

require no care but can stand desiccation for long periods of time. On the other hand, the eggs of marine 

ostracodes cannot survive any drying out whatsoever 

(Kesling, 1961).

Ostracode remains from limestone near Grapevine 

Canyon appear relatively abundant under the scanning electron microscope (pi. 6, figs. 1, 3), and in thin 

section (pi. 17, fig. 4). These were too poorly preserved 

to be classified, but they also resemble Candona.

Opaline rocks containing reed fossils from an area 

12 km southwest of Temple Bar (fig. 1, loc. 1) were 

etched for 24 hours in a solution of one part hydrofluoric acid to nine parts of water. Many silicified ostracode valves were freed from the matrix, but these were 

also poorly preserved (pi. 6, figs. 1, 3).

TRACE FOSSILS

Distinctive flask-shaped casts about 2 cm in diameter 

occur in the Hualapai Limestone Member 12 km 

southwest of Temple Bar marina. These distinctive fossils weather out from clayey limestone beds in the side 

of a road cut.

These casts invariably have much the same shape 

and dimensions. They are alined perpendicular to the 

bedding planes of the sediments within a few centimeters of each other, probably much in the same position as they were formed in life. They are calcareous 

thin-walled tubular structures, broken at the upper 

end and closed in a bulbous form at the lower end. The 

open end tapers inward slightly to form a neck, which 

then enlarges downward to produce the ovoid base.

Jerome G. Rozen, Jr., of the American Museum of 

Natural History, has suggested (written commun., 

1976) that these fossils are cells of aculeate Hymenoptera (bees and wasps). Probably these casts are remains of nests of a large, solitary, ground-nesting bee. 

That is, they are chambers into which the female bee 

carried pollen and nectar and in which she laid her 

eggs. The narrow rounded ends of the cell in these 

chambers seem to be unusual and remind Rozen of a 

bee of the southwest, Ptiloglossa, which he has studied. This genus belongs to a primitive family of bees 

which could easily have been here 8.5 m.y. ago.

Nest patterns of solitary bees vary from species to 

species and genus to genus. They usually consist of a 

burrow descending into the ground with branching 

passages and with cells at the ends of the branches 

(fig. 6).

CARBONATE ROCKS

Dunham's (1962) carbonate rock classification is 

used in this report. The Hualapai Limestone Member, 

as studied in the stratigraphic section near Grapevine 

Canyon (fig. 2), is composed predominantly of micritic 

limestone. The only significant fossil bioclasts here are 

algal oncolites, rare fragments of ostracodes, and mollusks. The limestone is porous, owing to incomplete 

sparry calcite cementation between micrite mudlumps, algal oncolites, and pellets.
CARBONATE ROCKS

Surface

.

Large - 

feeding 

larva

5 cm

FIGURE 6.—Nest of a large, solitary, ground-nesting bee with photographs of fossil casts for comparison. Modified from Rozen (1974).

Terrigenous admixtures are abundant in the micritic carbonate rocks of the Hualapai Limestone Member. They are silt- and sand-size quartz grains and 

fragments of volcanic rocks (pi. 9, fig. 2; pi. 10, fig. 1; 

pi. 12, figs. 4-6; pi. 13, figs. 2, 4, 5; pi. 16, figs. 2-6; pi. 

18, figs. 1, 2; pi. 19, figs. 1, 2, 4).

DIAGENESIS

For the purpose of this paper, diagenesis will include 

all changes that sediments undergo from the time of 

deposition until the present (Wood and Armstrong, 

1975, p. 15). One of these changes is lithification, the 

change from unconsolidated sediment to consolidated

sediment by compaction, cementation, and pressure 

solution.

MATRIX

Matrix is usually composed of carbonate mud (micrite) and is dominantly of biologic origin. The separation of grains and matrix is to some extent a function 

of the scale of observation, but in practice a tendency 

toward a bimodal size distribution in micritic limestone makes the distinction easy. Individual crystals 

of micrite have an upper size limit of 3-4 fxm (Bathurst, 1959). Choquette and Pray (1970, p. 247) define 

interparticulate porosity for between-particle porosity 

in sedimentary carbonates. It can be used for lime mud 

and micrites as well as for coarser clastic carbonate.

Recent carbonate mud is largely bioclastic in origin, 

whether originally aragonite (described by Cloud, 

1962) or calcitic in composition (Davies, 1970). The 

only known examples of inorganic precipitation of calcium carbonate are in the lagoon of Abu Dhabi (Kinsman and Holland, 1969) and Trucial Cast, Persian 

Gulf (Evamy, 1973), and the lower to middle intertidal 

zone of Shark Bay, Australia (Logan, 1974). Stockman, 

Ginsburg, and Shinn (1967) have shown that great 

quantities of aragonite mud can be produced by codiacean algae in Florida Bay and can more than account 

for the aragonite mud present.

The abundant micrite (pis. 14-18) in the Hualapai 

Limestone Member is probably the result of organic 

activity by codiacean and other algae. The absence of 

fossil bioclasts, other than algal oncolites and a rare 

ostracode, precludes significant formation of micrite 

derived from larger shelled invertebrates.

SPARRY CALCIl E

Primary pore space and interparticle space are still 

present within the Hualapai Limestone Member. Two 

distinct phases of sparry calcite cement are found 

within the interparticle space. The first-phase cement 

forms a thin fringe of relatively constant thickness of 

40 fxm around the algal oncolites and peloids (Shinn, 

1969) (pi. 10, figs. 2, 3, 5; pi. 13, figs. 1, 5, 6; pi. 18, fig. 

6). These are stubby calcite crystals with pyramidal 

terminations growing at right angles to the grain margins. Bathurst (1971, p. 432) shows that the first generation of cement crystals, besides being smaller, are 

commonly scalenohedral in habit (dogtooth spar) and 

are preserved under the later overgrowth of secondgeneration rhombohedra. The sharp distinction in size 

and habit between the earlier and later crystals may 

indicate a time interval between formation of the two 

sizes.
10 HUALAPAI LIMESTONE MEMBER OF THE MUDDY CREEK FORMATION

The source of the calcium carbonate necessary for 

the complete cementation implies that the secondphase cement is from another source. Bathurst (1971, 

p. 457) suggested that neither solution of local aragonite nor pressure solution will provide sufficient volume 

to nearly obliterate the intergranular space. Within 

the Hualapai Limestone Member a very large proportion of the originally aragonitic micrite and bioclasts 

has gone into solution by vadose waters and has been 

redeposited as void-filling sparry calcite. This process 

could provide the large amount of sparry calcite cement seen in the Hualapai (pi. 10, figs. 1-6; pi. 13, figs. 

1-6; pi. 15, figs. 1-6; pi. 16, figs. 1-4; pi. 17, fig. 4; pi. 

18, figs 1-6).

RADIAXIAL FIBROUS CALCITE

Limestone specimens from the section south of 

Grapevine Canyon have numerous cavities filled with 

fibrous radiaxial calcite (pi. 15, figs. 4, 5; pi. 16, figs. 

4, 5; pi. 19, figs. 1-6). The radiaxial cement occurs as 

void-filling material between algal oncolites, in lime 

mudlumps, and in fenestrate voids in the lime mudstone. The radiaxial fibrous calcite typically contains 

numerous zones of inclusions (fig. 7) The inclusion

Impurity zones

Inclusion zone par- 

^ allel to substrate

^& VMicrite substrate .•••••'•J - J

0.5 mm

FIGURE 7.—Radiaxial fibrous calcite cement and inclusion patterns in 

the Hualapai Limestone Member. Greater part of mosaic is composed of fibrous crystals, long axes oriented normal to substrate. 

Marginal zones exhibit decrease in crystal size toward substrate.

zones may be parallel to the substrate. The most common type of inclusion is scalenohedral forms that may 

reveal the positions of former calcite crystal faces (pi. 

18, fig. 1).

Kendall and Tucker (1973) in the detailed discussion 

of the origin and environmental significance of radiaxial fibrous calcite indicate that it is a replacement after 

acicular cement. They state, "* * *acicular cement appears to be largely restricted to marine, early diagenetic environments. Consequently, formation of radiaxial fibrous mosaics also occurs during early 

diagenesis."

AGE

An air-fall tuff 15 cm thick, that is completely 

within the lower part of the Hualapai Limestone Member, crops out at locality 1 (fig. 1) 12 km southwest of 

Temple Bar. The glass shards of this tuff have yielded 

a K-Ar date of about 8.7 ±2.2 m.y. (Blair and others, 

1977; see table 1), considered to be late Miocene.

The maximum and minimum age limits of the Hualapai Limestone Member are not known. However, a 

basalt in the lower part of the exposed section of the 

Muddy Creek Formation 6 km southeast of Temple 

Bar (fig. 1, loc. 4) underlies the Hualapai. This basalt 

has been dated using the K-Ar method by McKee (unpub. data; see table 1) at about 10.9 m.y. 

A basalt flow at Sandy Point (fig. 1) separated from the 

underlying Muddy Creek Formation by fluvial gravel 

has been dated at 3.79 ±0.46 m.y. by Damon (Damon 

and others, 1978, p. 102).

DISCUSSION AND CONCLUSIONS

The Hualapai Limestone Member, considered by 

most workers to be freshwater in origin, has many similarities to marine deposits (Blair, 1978). The water 

which deposited the Hualapai was most likely conTABLE 1.—K-Ar analytical data and ages of samples

[Analysis by E. H. McKee, U.S. Geological Survey]

Locality Sample

K2O 

(percent) (mole/g) (percent)

Agei 

(m.y.) (m.y.) Source

(fig. 1, loc. 1) Basaltic shards in air-fall

tuff, lower part of

Hualapai Limestone

Member ———————— 2.462

(fig. 1, loc. 4) Basalt below Hualapai Lime- J 1.045

stone Member ........... LI.C.067

Blair and others, 

3.07633xlOii 7.1 8.44 + 2.23 8.66 ±2.2 (1977).

E. H. McKee (unpub. 

1.66192x10-" 17.1 10.62 ±1.10 10.90 ±1.1 data).

'Ages based on old constants for comparison with published ages. 

Ae = 0.58 x 10-10yi-l 

xp = 4.72 x 10-iOyr-i

C|>4 ft-Illy, I

'"K/K^^ 1.22 xl(Hg/g

2Ages based on new constants. 

\€ = 0.581 x 10-lOyr-i 

\P = 5.96 x 10-iOyr 1 

40K/Ktotal = 1.17xlO-"g/g
DISCUSSION AND CONCLUSIONS 11

nected with the upper reaches of the Gulf of California 

in late Miocene time and was hence the upper estuarine part of the ancestral gulf. Marine beds of the Pliocene Bouse Formation (Metzger, 1968), which were 

deposited in the ancestral Gulf of California, have been 

mapped as far north as the Parker area, about 180 km 

south of the southernmost exposures of the Hualapai 

Limestone Member (fig. 8). This embayment no doubt

reached further north. This arm of the ancestral Gulf 

of California (Karig and Jensky, 1972) probably extended to the foot of the Grand Wash Cliffs as a shallow estuary.

Marine, brackish, and freshwater fossil assemblages 

occur together in the Bouse Formation, a phenomenon 

that puzzled Smith (1970) when she studied the fossils 

of that formation. She speculated, however, that such

WYOMING

NEVADA

^

%

CALIFORNIA

36°

COLORADO

: vjgl ^-/-"^ X __ i Hualapai pSf- —————— ~FT/ ~~ ——"————^C——— '

her of ^ . Ou/^ I ^--^ i.

Hualapai Limestone Member of 

Muddy Creek Formation

EW MEXICO

Bouse Formation and ancestra! 

Gulf of California

Boundary of Colorado Plateau

200 KILOMETERS

114°

FIGURE 8.—Miocene and Pliocene embayment of Gulf of California. Modified from Schuchert, (1955); Metzger, (1968); and Smith, (1970).
12 HUALAPAI LIMESTONE MEMBER OF THE MUDDY CREEK FORMATION

an assemblage might be due to mixing of fossils by sedimentary processes. The restricted number of species 

of foraminifers found in the northern areas of the 

Bouse is typical of modern bays and estuaries. Freshwater mollusks and ostracodes are found with the foraminifers, but the presence of marine clams and snails 

classifies the Bouse Formation as marine.

Several lines of evidence indicate that as the Hualapai Limestone Member was being deposited, seawater 

was mixing with fresh water in an estuary:

(1) Marine coastal and estuarine diatoms occur 

together with freshwater forms in the upper 

part of the Hualapai Limestone Member (pi. 

1, figs. 1-6).

(2) Freshwater and marine fossil assemblages 

are mixed in the Hualapai, as in the Bouse 

Formation to the south. A logical source for 

the freshwater types would be from a river 

(the ancestral Colorado River) entering 

from the north.

(3) Existing data suggest that the diagenesis of 

biogenic opal conversion to chert occurs predominantly in marine environments. However, Oehler (1973) experimentally produced lepispheres in water with only about 

700 ppm of Na + ; this concentration approaches fresh water. This study may show 

that lepispheres can also form an estuarine 

environment.

(4) The mass of limestone (over 100 km3 ) indicates a large volume of water containing 

calcium, probably seawater.

(5) Radiaxial fibrous calcite cement fills voids between algal oncolites and micritic lithoclasts in the Hualapai Limestone Member. 

Radiaxial fibrous calcite cement is considered to be largely restricted to marine environments.

(6) Stromatolites from the Hualapai Limestone 

Member are typical of forms found in shallow marine environments (fig. 6).

(7) An air-fall tuff in the lower part of the Hualapai was dated at about 8.7 m.y. (table 1). 

The hypothesis that would account for all this data 

is that a shallow, marshy, marine estuary existed in 

late Miocene time, extending up the area of the lower 

Colorado River to the base of the Colorado Plateau 

where the river now emerges from the Grand Canyon. 

The elevation at this point was then at sea level, some 

420 m lower than it is now. A large slow-moving river 

(the ancestral Colorado River?) entered the estuary 

from some unknown direction.

REFERENCES CITED

Bathurst, R. G. C., 1959, Diagenesis in Mississippian calcilutites and 

pseudobreccias: Jour. Sed. Petrology, v. 29, p. 365-376.

———1971, Carbonate sediments and their diagenesis: Amsterdam, 

Elsevier, 620 p.

Benson, R. H., 1961, Ecology of ostracode assemblages, in Moore, R. 

C., ed., Treatise on invertebrate paleontology, Pt. Q, Arthropoda 

3: Lawrence, Kans., Geol. Soc. American and Kansas Univ. 

Press, p. Q56-Q63.

Berger, W. H., and Rad, Ulrich von, 1972, Cretaceous and Cenozoic 

sediments from the Atlantic Ocean, in Hayes, D. E., and others, 

eds., Initial reports of the Deep Sea Drilling Project; Lisbon, 

Portugal to San Juan, Puerto Rico: Deep Sea Drilling Proj. Initial Rept. v. 14, p. 788-954.

Blacet, P. M., 1975, Preliminary geologic map of the Garnet Mountain quadrangle, Mojave County, Arizona: U.S. Geol. Survey 

Open-File Rept. 75-93, scale 1:48,000.

Blair, W. N., 1978, Gulf of California in Lake Mead area of Arizona 

and Nevada during Late Miocene time: Am. Assoc. Petroleum 

Geologists Bull., v. 62, no. 7, p. 1159-1170.

Blair, W. N., McKee, E. H., and Armstrong, A. K., 1977, Age and 

environment of deposition of the Hualapai Limestone member 

of the Muddy Creek Formation [abs.]: Geol. Soc. America Abs. 

with Programs, v. 9, no. 4, p. 390-391.

Bradley, W. H., 1929, Algae reefs and oolites of the Green River 

Formation: U.S. Geol. Survey Prof. Paper 154-G, p. G203-G223.

Bramlette, M. N., 1946, The Monterey Formation of California and 

the origin of its siliceous rocks: U.S. Geol. Survey Prof. Paper 

212, 57 p.

Calvert, S. E., 1971, Nature of silica phases in deep sea cherts of the 

North Atlantic: Nature, v. 234, no. 50, p. 133-134.

Choquette, P. W., and Pray, L. C., 1970, Geologic nomenclature and 

classification of porosity in sedimentary carbonates: Am. Assoc. 

Petroleum Geologists Bull., v. 54, no. 4, p. 207-250.

Cloud, P. E., Jr., 1962, Environment of calcium carbonate deposition 

west of Andros Island, Bahamas: U.S. Geol. Survey Prof. Paper 

350, p. 1-138.

Damon, P. E., Shafiqullah, M., and Scarborough, R. B., 1978, Revised 

chronology for critical stages in the evolution of the lower Colorado River: Geol. Soc. America Cordilleran Sec., Abs. with Programs, v. 10, no. 3, p. 101-102.

Davies, G. R., 1970, Carbonate bank sedimentation, Eastern Shark 

Bay, Western Australia, in Carbonate sedimentation and environment, Shark Bay, Western Australia: Am. Assoc. Petroleum Geologists Mem. 13, p. 85-168.

Davies, T. A., and Supko, P. R., 1973, Oceanic sediments and their 

diagenesis; Some examples from deep drilling: Jour. Sed. Petrology, v. 43, p. 381-390.

Dunham, R. J., 1962, Classification of carbonate rocks according to 

depositional textures, in Hams, W. E., ed., Classification of carbonate rocks: Am. Assoc. Petroleum Geologists Mem. 7, p. 108- 

121.

Ernst, W. G., and Calvert, S. E., 1969, An experimental study of the 

recrystallization of porcelanite and its bearing on the origin of 

some bedded cherts: Am. Jour. Sci, v. 267-A, p. 114-133.

Evamy, B. D., 1973, The precipitation of aragonite and its alteration 

to calcite on the Trucial Coast of the Persian Gulf, in Purser, B. 

H., ed., The Persian Gulf: New York, Springer-Verlag, p. 329- 

431.

Gebelein, C. D., 1976, Open marine subtidal and intertidal stromatolites, in Walters, M. R., ed. Developments in sedimentology 

20, Stromatolites: Amsterdam, Elsevier, p. 261-271.
REFERENCES CITED 13

Heath, G. R., and Moberly, R., 1971, Cherts from the western Pacific, 

Leg 7, in Winterer, E. L., and others, eds., Initial reports of the 

Deep Sea Drilling Project: Deep Sea Drilling Proj. Initial Rept., 

v. 7, p. 991-1007.

Hoffman, P., 1976, Stromatolite morphogenesis in Shark Bay, Western Australia, in Walter, M. R., ed., Developments in sedimentology 20, Stromatolites: Amsterdam, Elsevier, p. 261-271.

Hunt, C. B., 1956, Cenzoic geology of the Colorado plateau: U.S. 

Geol. Survey Prof. Paper 279, 99 p.

Ingle, J. C., 1973, Pliocene-Miocene sedimentary environments and 

biofacies, southeastern Los Angeles Basin-San Joaquin Hills 

area, Orange County, California, in Miocene sedimentary environment and biofacies, southeastern Los Angeles Bay: Am. 

Assoc. Petroleum Geologists, Soc. Econ. Paleontologists and 

Mineralogists, and Soc. Econ. Geologists Ann. Mtg., 1973, SEPM 

Trip 1 Guidebook, pi. 1-6.

Johnson, J. H., 1961, Limestone building algae and algal limestones: 

Golden, Colo., Colorado School Mines, 297 p.

Jones, J. B., Sanders, J. V., and Segnit, E. R., 1964, Structure of opal: 

Nature, v. 204, p. 990-991.

Jones, J. B., and Segnit, E. R., 1971, The nature of opal. I. Nomenclature and constituent phases: Geol. Soc. Australia Jour., v. 18, 

p. 56-68.

Karig, D. E., and Jensky, W., 1972, The proto-Gulf of California: 

Earth and Planetary Sci. Letters 17, p. 169-174.

Kendall, A. C., and Tucker, M. E., 1973, Radiaxial fibrous calcite— 

A replacement after acicular carbonate: Sedimentology, v. 20, 

p. 365-389.

Kesling, R. V., 1961, Reproduction of ostracoda, in Moore, R. C., ed., 

Treatise on invertebrate paleontology, pt. Q, Arthropoda 3: Lawrence, Kans., Geol. Soc. America and Kansas Univ. Press, P. 

A17-A19.

Kinsman, D. J. J., and Holland, H. D., 1969, The co-precipitation of 

cations with CaCO3 . The co-precipitation of Sr2+ with aragonite 

between 16° and 96°C: Geochim. et Cosmochim. Acta, v. 33, p. 

1-17.

Logan, B. W., 1974, Inventory of diagenesis in Holocene—Recent 

carbonate sediments, Shark Bay, Western Australia, in Evolution and diagenesis of Quaternary carbonate sequences, Shark 

Bay, Western Australia: Am. Assoc. Petroleum Geologists Mem. 

22, p. 195-247.

Longwell, C. R., 1928, Geology of the Muddy Mountains, Nevada: 

U.S. Geol. Survey Bull. 798, 152 p.

———1936, Geology of the Boulder Reservoir floor, Arizona: Geol. 

Soc. America Bull., v. 47, p. 1393-1476. 

-1954, Geologic setting of Lake Mead, in Smith, W. O., and

others, Lake Mead comprehensive survey of 1948—49, Volume

I: U.S. Dept. Interior and U.S. Dept. Navy coop, project, p. 1116-

1128. 

Longwell, C. R., Pampeyan, E. H., Bowyer, Ben, and Roberts, R. J.,

1965, Geology and mineral deposits of Clark County, Nevada:

Nevada Bur. Mines Bull. 62, 218 p. 

Lovering, T. S., and Engel, Celest, 1967, Translocation of silica and

other elements from rock into Equisetum and three grasses: U.S.

Geol. Survey Prof. Paper 594-B, 16 p. 

Lucchitta, Ivo, 1967, Cenozoic geology of the upper Lake Mead area

adjacent to the Grand Wash Cliffs, Arizona: University Park,

Penn., Pennsylvania State Univ., Ph.D. thesis, 218 p. 

———1972, Early history of the Colorado River in the Basin and

Range province: Geol. Soc. America Bull., v. 83, no. 7, p. 1933-

1947. 

Metzger, D. G., 1968, The Bouse Formation (Pliocene) of the ParkerBlythe-Cibola area, Arizona and California, in Geological Survey research 1968: U.S. Geol. Survey Prof. Paper 600-D, p. 

D126-D136.

Murata, K. J., and Larson, R. R., 1975, Diagenesis of Miocene siliceous shales, Temblor Range, California: U.S. Geol. Survey 

Jour. Research, v. 3, no. 5, p. 553-566.

Murata, K. J., and Nakata, J. K., 1974, Cristobalitic stage in the 

diagenesis of diatomaceous shale: Science, v. 184, p. 567-568.

Oehler, J. H., 1973, Tridymite-like crystals in cristobalitic "cherts": 

Nature, Phys. Sci., v. 241, no. 107, p. 64-65.

Playford, P. E., and Cockbain, A. E., 1976, Modern algal stromatolites at Hamelin Pool, a hypersaline barred basin in Shark Bay, 

Western Australia, in Walters, M. R., ed., Developments in 

sedimentology 20, Stromatolites: Amsterdam, Elsevier, p. 389- 

411.

Peirce, H. W., 1976, Tectonic significance of Basin and Range thick 

evaporite deposits: Arizona Geol. Soc. Digest, v. 10, p. 325-339.

Riedel, W. R., 1959, Siliceous organic remains in the pelagic sediments: Soc. Econ. Paleontologists and Mineralogists Spec. Pub. 

7, p. 80-91.

Robinson, B. L., and Fernald, M. L., 1908, Grey's new manual of 

botany, a handbook of the flowering plants and ferns of the central and northeastern United States and Canada: New York, 

America Book Co., 926 p.

Rozen, J. G., Jr., 1974, Nest biology of the Eucerine bee Thygater 

analis (Hymenoptera, Anthoporidae): Jour. New York Entomol. 

Soc., v. 82, no. 4, p. 230-234.

Schuchert, Charles, 1955, Atlas of paleogeographic maps of North 

America: New York, John Wiley & Sons, 177 p.

Scott, D. H., 1962, Studies in fossil botany (3d ed.): New York, Hafner, v. 1, 434 p.

Shinn, E. A., 1968, Practical significance of birdseye structures in 

carbonate rocks: Jour. Sed. Petrology, v. 38, no. 1, p. 221-224. 

1969, Submarine lithification of Holocene carbonate sediments in the Persian Gulf: Sedimentology, v. 12, p. 109-144.

Smith, P. B., 1970, New evidence for Pliocene marine embayment 

along the lower Colorado River area, California and Arizona: 

Geol. Soc. America Bull., v. 81, p. 1411-1420.

Stock, Chester, 1921, Late Cenozoic mammalian remains from the 

Meadow Valley region, southeastern Nevada [abs.]: Geol. Soc. 

America Bull., v. 32, p. 146-147.

Stockman, K. W., Ginsburg, R. N., and Shinn, E. A., 1967, The production of lime mud by algae in south Florida: Jour. Sed. Petrology, v. 37, p. 633-648.

Taliaferro, N. L., 1933, The relation of volcanism to diatomaceous 

and associated siliceous sediments: California Univ. Pubs. Geol. 

Sci., v. 23, no. 1, 56 p.

Van Morkhoven, F. P. C. M., 1963, Post-Paleozoic ostracoda: Amsterdam, Elsevier, v. 2, 478 p.

Walter, M. R., 1976, Glossary of selected terms, Appendix I of Walter, M. R., ed., Developments in sedimentology 20, Stromatolites: Amsterdam, Elsevier, p. 687-692.

Weaver, F. M., and Wise, S. W., 1972a, Chertification phenomena 

in Antarctic and Pacific deep sea sediments—A scanning electron microscope and X-ray diffraction study: Am. Assoc. Petroleum Geologists Bull. 56, p. 1905. 

1972b, Ultramorphology of deep sea cristobalitic chert: Nature Phys. Sci., v. 237, p. 56-57.

Wise, S. W., Buie, B. F., and Weaver, F. M., 1972, Chemically precipitated sedimentary cristobalite and the origin of chert: Eclogae Geol. Helvetiae, v. 65/1, p. 157-163.

Wise, S. W., and Kelts, K. M., 1972, Inferred diagenetic history of 

a weakly silicified deep sea chalk: Gulf Coast Assoc. Geol. Soc. 

Trans., v. 22, p. 177-203.
14 HUALAPAI LIMESTONE MEMBER OF THE MUDDY CREEK FORMATION

Wise, S. W., and Weaver, F. M., 1973, Origin of cristobalite-rich Tertiary sediments in the Atlantic and Gulf Coastal Plain: Gulf 

Coast Assoc. Geol. Soc. Trans., v. 23, p. 305-323.

——1974, Chertification of oceanic sediments: Internat. Assoc. Sedimentology Spec. Pub. 1, p. 301-326.

Wood, G. V., and Armstrong, A. K., 1975, Diagenesis and stratigraphy of the Lisburne Group limestones of the Sadlerochit 

Mountains and adjacent areas, northeastern Alaska: U.S. Geol. 

Survey Prof. Paper 857, 47 p.
PLATES 1-19

Contact photographs of the plates in this report are available, at

cost, from U.S. Geological Survey Library, Federal Center,

Denver, Colorado 80225
PLATE 1

FIGURES 1-6. Scanning electron micrographs of diatoms found together in opaline rock in the 

Hualapai Limestone Member. The diatoms range in habitat from freshwater to marine. All are 

from locality 4 (text fig. 1).

1. Navicula cf. N. cuspidata.

Diatom widespread in freshwater habitats.

2. Navicula halophila.

This is a true brackish-water diatom.

3. Amphora arcus v. sulcata.

Marine or brackish-water diatom.

4. Amphora hyalina.

Marine or brackish-water diatom.

5. Melosira moniliformis?

Interior view. Marine or brackish-water diatom.

6. Melosira moniliformis?
GEOLOGICAL SURVEY PROFESSIONAL PAPER 1111 PLATE 1

A*tf r s*>^<*^ ••*=>'«*:

10jum

0 10jum

30jum

DIATOMS
PLATE 2

FIGURES 1-6. Scanning electron micrographs showing*progressive conversion of biogenic silica to 

cristobalite-rich chert.

1. Slightly altered diatom frustules.

2. Diatom frustules filled with bladed cristobalite.

3. Diatom frustule partly filled with bladed cristobalite. 

Remainder is filled with chert.

4. Altered diatoms which are gradually losing their identities.

5. Vestiges of diatom frustules merging in chert.

6. Cristobalite chert with textures and fossil evidence obliterated.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 1111 PLATE 2

;*

60^171

5r«

10MIT1

0__________30M m 0 _____ 20jum

CONVERSION OF BIOGENIC SILICA TO CRISTOBALITE-RICH CHERT
PLATE 3

FIGURES 1, 2. Scanning electron micrographs showing lepispheres of bladed cristobalite in chert 

sample from locality 4 (text fig. 1).

1. Stereopair set at 65 mm interocular distance. Well-formed lepisphere was growing in 

cavity in chert. Small embryonic lepispheres are scattered about cavity. Note small 

quartz crystal penetrating sphere at its upper right quadrant.

2. Enlargement of embryonic lepispheres indicated by arrow in figure 1.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 1111 PLATES

TB^

Gym

1/j.m

LEPISPHERES OF BLADED CRISTOBALITE
PLATE 4

FIGURES 1-6. Scanning electron micrographs and elemental distribution maps of opaline and chert 

samples from locality 2 (text fig. 1).

1. Slightly altered diatom frustules.

2. Silicon distribution map of figure 1.

3. Feathery cristobalite crystals lining vug in plant fossil (pi. 7, fig. 1).

4. Silicon distribution map of figure 3.

5. Diatom mold filled with cristobalite crystal blades.

6. Silicon distribution map of figure 5.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 1111 PLATE 4

»

OPALINE AND CHERT SAMPLES
PLATE 5

FIGURES 1-6. Scanning electron micrographs of opaline material. Figures 1—4 from locality 4 (text 

fig. 1). Figures 5, 6 from locality 2 (text fig. 1).

1. Altered diatom frustule embedded in chert.

2. Diatom frustule similar to that shown in figure 1 but with part of its outer shell gone. 

Well-developed cristobalite crystals line interior of mold.

3. Diatom frustule exposed after grinding surface of opaline sample.

4. Enlargement of cristobalite crystals in figure 2. Note scalloped and serrated edges of 

crystal blades.

5. Irregular-shaped lepispheres growing in vug in chert.

6. Symmetrical lepispheres in opaline cavity.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 1111 PLATE 5

0 10/um

0 10/um 3/um

10/um 6

OPALINE MATERIAL
PLATE 6

FIGURES 1—6. Scanning electron micrographs of ostracode valves and seed etched from siliceous 

matrix using 10 percent hydrofluoric acid. Samples from locality 2 (text fig. 1).

1. Single ostracode valve replaced by silica.

2. Enlargement of figure 1 showing surface features. /

3. Two ostracode valves replaced by silica. '*.

4. Enlargement of figure 3 showing surface features.

5. Unidentified fossil seed replaced by calcite.

6. Enlargement of figure 5 showing surface composed of calcite crystals.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 1111 PLATE 6

100/um 6/um

0 100/Lim 6/um

100/um 6/um

OSTRACODE VALVES ETCHED FROM SILICEOUS MATRIX
PLATE 7

FIGURES 1-6. Scanning electron micrographs of fossil plants in the Hualapai Limestone Member. 

Samples from locality 1 (text fig. 1).

1. Transverse section of fossil reed showing interior filling of chalcedony.

2. Enlargement of reed filling in figure 1.

3. Fossil plant molds in limestone.

4. Enlargement of surface of fossil shown in left side of figure 3.

5. Chalcedony filling of cavity between reed fossils in limestone.

6. Chalcedony filling cavity between fossil plants in limestone.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 1111 PLATE 7

FOSSIL PLANTS
PLATE 8

FIGURES 1-7. Algal limestone; Hualapai Limestone Member, Grapevine Canyon. Specimen 846A. 

1, 2. Longitudinal and transverse view of nearly parallel branches of calcareous algae. 

3, 4. Transverse view of calcareous algae branch showing radial banding. 3, White areas

shown by arrow are detrital quartz fragments. Circular bands are composed of radiaxial calcite. Light bands are composed of fibrous calcite up to 0.2-0.3 mm long.

Narrower dark bands are formed by subhedral calcite crystals 20 to 50 mm in size

and possibly iron-rich inclusions. 

5, 6. Longitudinal view, showing arched dark and light banding of algal branches. Figure

6 shows in detail fibrous calcite that forms bands. 

7. Scanning electron micrograph of calcareous algae. Calcite rhombs range in size from

3 to 15 m. Siliceous, microcrystalline silica (S) and clay (cy) minerals stand in relief.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 1111 PLATE 8

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0.2mm 10jum

ALCyAL LIMESTONE
PLATE 9

FIGURES 1-6. Pisolites and microstructures, Hualapai Limestone Member.

1. 3, 5. Pisolite structures formed by radiaxial fibrous calcite (cr); dark bands formed by iron 

oxide-rich zones. 3, Pisolitic structures formed by radiaxial fibrous calcite (cr); dark 

area in upper half of view formed of microcrystalline chalcedony (ch). 5, Details of 

light bands of radiaxial calcite (cr) and dark narrow bands of iron oxide-rich calcite 

(D). Specimen 876B.

2. 4, 6. 2, Rock is formed of volcanic fragments (vf), dark areas, silt- and sand-size grains of 

angular quartz, and algal nodules and branches (A). 4, 6, Enlarged view of structure 

illustrating wide light bands and narrow dark bands. Specimen 892D.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 1111 PLATE 9

0.5mm 10mm

0.5mm 1mm

PISOLITES AND MICROSTRUCTURES
PLATE 10

FIGURES 1-6. Fenestrate peloid packstone, Hualapai Limestone Member.

1. Pellets are from 50 to 100 jxm in size, have poorly denned outlines, and are composed 

of calcite crystals 2^4 jxm in size. Subrounded quartz grains are up to 0.3 mm in size.

2. Details of peloids, showing surface of peloids covered by early-stage, first-phase calcite 

cement that is stubby calcite crystals with pyramidal terminations growing at right 

angles to grain margins (cp); voids between peloids were then filled by sparry calcite 

(cs). Specimen 800A.

3, 4. Peloid packstone; rock is free of quartz sand grains. 3, Outlines of peloids are poorly 

defined; peloids are typically 50—100 jxm in diameter. 4, Peloids are composed of calcite crystals 3-6 jxm in size. Areas between peloids are filled by sparry calcite cement 

(cs). Specimen 800B.

5, 6. Peloid packstone. Peloids are formed by 4-8-jxm calcite crystals. Outlines of individual 

peloids are poorly defined. Area between peloids is filled by sparry calcite (cs). Specimen 800C.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 1111 PLATE 10

0.5mm 0.2mm

FENESTRATE PELOID PACKSTONE
PLATE 11

FIGURES 1-6. Algal oncolites; Hualapai Limestone Member, Grapevine Canyon.

1. Cut and polished surface of algal oncolites.

2, 3. 2, Transverse thin section of oncolites showing concentric banding. 3, Enlarged view 

of banding composed of fibrous, calcite, wide light bands, and narrow dark concentric 

bands.

4. Scanning electron micrograph of algal oncolites, cavity lined with crystals of calcite. 

5, 6. Cavity within oncolite lined with microcrystalline chert. 5, Polished and etched surface 

of algal oncolite illustrating small (5-10 p,m) calcite rhombs and silica-lined cavity 

within banding. 6, Scanning electron micrograph of silica-lined cavity shown in 

figure 5.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 1111 PLATE 11

3cm

. ALGAL ONCOLITES, GRAPEVINE CANYON
PLATE 12

FIGURES 1-6. Juncus?sp. indet. Specimen 876.

1, 2. Transverse section of stems of Juncus? sp. Dark areas are calcite preservation, light

areas are opal. 

3-6. Enlarged views of stems, showing plant wall and cell structure; fine details of plant

structure are preserved by opal and jasper.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 1111 PLATE 12

OPALIZED PLANT STEMS, JUNCUS1 SP. INDET.
PLATE 13

FIGURES 1-6. Peloid packstones; Hualapai Limestone Member, Grapevine Canyon.

1. Peloid packstone; outlines of peloids are blurred. Peloids are 75-125 (Jim in size and

composed of calcite crystals 5-10 (am in size. Specimen 800C.

2, 4, 6. Arenaceous peloid-pisoid-oncolitic packstone. Specimen 809. 2, Typical concentricbanded arenaceous pisoid. Quartz sand is subrounded, spaces between pisoids are 

composed of recrystallized micrite and contain quartz sand. 4, Enlarged view of 

pisoids, showing centers to be formed by peloids, and exterior by crudely banded 

concentric rings of micrite. Space in upper right of view is a void (V). 6, Enlarged 

view of area between peloids, showing space filled by sparry calcite (cs). 

3. Peloid packstone, illustrating fuzzy outlines of peloids and sparry calcite (cs) filling

of void between peloids. Specimen 800B.

5. Arenaceous peloid packstone. Photomicrograph shows sequence of diagenetic events. 

Formation of micritic peloids: deposition on peloids of first-phase calcite cement as 

stubby calcite crystals with pyramidal terminations growing at right angles to 

grain margins (cp); and final void filling by sparry calcite (cs). Specimen 800A.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 1111 PLATE 13

0.5mm

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^-•vS

0.2mm 0.5mm

0.2mm 0.2mm

PELOID PACKSTONES
PLATE 14

FIGURES 1—6. Hualapai Limestone Member. First canyon north of Grapevine Canyon.

1. Dolomitic peloid packstone. Calcite crystal averages 100—125 jxm in size, dark relict 

peloids are now inclusions within larger calcite crystals. Rock is porous. Dolomite 

rhombs are in cavity walls. Specimen 902.

2. Scanning electron micrograph of etched calcite surface. Calcite rhombs are 5-10 jxm in 

size. Specimen 903.

3. Peloid packstone. Crossed nicols. Black areas are pores. Elongate gray peloids are composed of 4 jxm-size calcite crystals. White areas are sparry calcite fillings. Specimen 

904.

4, 5. 4, Arenaceous peloid-mudlump packstone. Crossed nicols. Mudlump and peloids show 

evidence of two periods of cementation; band of gray radiaxial cement lines each particle (cr), followed by sparry calcite (cs) void-filling cement. 5, Scanning electron micrograph of mudlump. Gray areas are 1—4 jxm calcite rhombs; linear white material 

is clay. Specimen 908.

6. Arenaceous peloid-mudlump packstone. Crossed nicols. Cemented by sparry calcite (cs) 

and radiaxial calcite.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 1111 PLATE 14

0.2mm

0 3/um 0.5mm

SPECIMENS FROM NORTH OF GRAPEVINE CANYON
PLATE 15

FIGURES 1-6. Hualapai Limestone Member. First canyon north of Grapevine Canyon.

1. Arenaceous peloid-mudlump packstone. Voids are filled by sparry calcite (cs). Specimen 

910.

2, 3. 2, Fenestrate arenaceous peloid-mudlump packstone. Quartz sand grains (Q) are subangular to subrounded. Void between micritic particles is now filled by two generations of calcite; vadose silt composed of fine crystalline calcite (vs) and later sparry 

(cs) void filling. 3, Micrite envelope? (me) filled by sparry calcite (cs) in microspar 

matrix. Micrite envelope may represent former aragonite mudlump. Specimen 911.

4, 5. 4, Vuggy arenaceous peloid-mudlump packstone to lime mudstone. Sequence of vug 

filling is two distinct bands of radiaxial fibrous calcite (crp cr2 ) and void filling by 

sparry calcite (cs). 5, Enlarged view of small vug, showing micrite matrix (cm), two 

bands of light and dark radiaxial fibrous cement (crp cr2 ), and final sparry calcite (cs) 

void filling.

6. Vuggy arenaceous peloid-mudlump-lime mudstone. Microfabric is dark micrite matrix 

(cm), quartz sand (Q), and sparry calcite (cs) vuggy filling. Specimen 912.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 1111 PLATE 15

0.2mm 0.2mm

0.2mm

0.5mm

SPECIMENS FROM NORTH OF GRAPEVINE CANYON
PLATE 16

FIGURES 1—6. Hualapai Limestone Member. First canyon north of Grapevine Canyon.

1—3. Peloid-mudlump packstone. Photomicrograph shows particle size, peloid to pisolitic configuration of micritic particles, and possible vadose silt (vs); area between particles 

is filled by sparry calcite (cs). Specimen may represent ancient caliche. 2, Enlarged 

view between micritic particles shows long slender calcite (cr) crystals and final 

sparry calcite (cs) void filling. 3, Scanning electron micrograph of etched micritic surface. Quartz sand (Q) grain in center of view is surrounded by calcite crystals. Specimen 913.

4—6. Fenestrate arenaceous peloid-mudlump packstone to lime mudstone with sparry calcite 

void filling. 4, Abundant subrounded quartz sand grains (Q), sparry calcite (cs), and 

irregular voids (V). 5, Details of void fillings, showing early stage radiaxial fibrous 

(cr) cement followed by sparry calcite (cs) void filling. 6, Scanning electron micrograph showing quartz grain (Q) within micrite. Calcite crystals within micrite are 

only 2^4 |o.m in size. Specimen 914.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 1111 PLATE 16

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0.2mm

0.5mm

0.5m m SOjum

SPECIMENS FROM NORTH OF GRAPEVINE CANYON
PLATE 17

FIGURES 1—6. Hualapai Limestone Member. First cannon north of Grapevine Canyon.

1—3. Arenaceous peloid-lime mudlump oncolitic packstone. 1, Left half of view shows irregular banded or circular objects, which are believed to be of algal origin; but interior 

of circular objects is made of arenaceous compound mudlumps and peloids. Right half 

of view shows poorly denned peloids, quartz grains (Q), and micritic matrix. 2, Enlarged view of small cavity filled by sparry calcite (cs). Micritic matrix contains quartz 

grains (Q). 3, Scanning electron micrograph of etched surface of micrite. Linear white 

bands in center of view are concentrations of clay minerals. Clays are relatively 

abundant between calcite rhombs.

4—6. Arenaceous lime mudstone. 4, Cross section of ostracode filled by sparry calcite and 

surrounded by micrite. 5, 6, Scanning electron micrographs. 5, Linear fractures or 

stylolites filled by clay minerals. 6, Detailed view of micrite calcite crystals in 

l-4-|xm size range, white objects between calcite crystals are clay (cy) minerals. Specimen 916.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 1111 PLATE 17

0.5mm 0.2mm

10jum 0.2mm

10jum 3jum

SPECIMENS FROM NORTH OF GRAPEVINE CANYON
PLATE 18

FIGURES 1-6. Hualapai Limestone Member. First canyon north of Grapevine Canyon.

1-3. Fenestrate arenaceous peloid-mudlump-oncolitic packstone. 1, Quartz grains (Q) are 

subrounded and in micritic matrix. Straight object (Is) in center of mudlump may be 

molluscan fragment, on which algal lamination grew. 2, Details of irregular-shaped 

oncolite, which has center formed by peloids and quartz sand. Algal laminations are 

seen on outer parts. Two stages of void filling can be seen. Radiaxial cement (cr), 100- 

300 (xm wide and a final void-filling sparry calcite (cs). 3, Details of void filling, dark 

micritic matrix (cm), radiaxial calcite (cr), and final void-filling sparry calcite cement 

(cs). Long-axial fibrous cement is well displayed under polarizing microscope. Specimen 918.

4—6. Specimen 892C. 4, Algal oncoids and platy laths of calcite set in sparry calcite cement. 

5, Algal oncoids in lower left side (ao) and platy laths in upper part of view. Sparry 

calcite cement (cs) and void space (V). 6, Algal oncolites (ao); note large platy lath 

(pi) at extreme left of view and dark central band in lath; voids are filled by sparry 

calcite (cs).
GEOLOGICAL SURVEY PROFESSIONAL PAPER 1111 PLATE 18

CS

0.5m m 0.5mm

0.2mm 10mm

V

SPECIMENS FROM NORTH OF GRAPEVINE CANYON
PLATE 19

FIGURES 1-6. Hualapai Limestone Member. First canyon north of Grapevine Canyon.

1. Radiaxial fibrous calcite, filling void in arenaceous pellet-mudlump-lime mudstone. 

Marginal portion of radiaxial fibrous mosaic exhibits preferred elongation and crystallographic orientation of crystals normal to micritic substrate. Numerous inclusion 

zones can be observed in fibrous crystals. Text figure 7 illustrates crystal sizes and 

inclusion patterns found in this specimen. Specimen 908.

2—4. Arenaceous peloid-algal-oncolitic packstone to grainstone. Crossed nicols. 2, Right half 

of view shows dark and light laminations of large algal oncolite with quartz sand 

inclusions (Q). 4, Arenaceous mudlump and algal oncolites. Light and dark bands of 

algal oncolites are seen in right third of view. Radiaxial fibrous calcite filling can be 

observed (cr) between mudlumps and algal oncolites. Specimen 918.

3. Radiaxial fibrous calcite (crossed nicols) that appears to have developed on a micritic 

envelope. Interiors of micritic envelope filled with sparry calcite (cs). Inclusion zone 

(iz) is more or less parallel with micrite substrate. Specimen 911.

5-6. Arenaceous pellet-mudlump packstone to grainstone. 5, Radiaxial fibrous calcite void 

filling. Plane light. 6, Specimen shows marginal portions of radiaxial fibrous mosaic 

with preferred elongation and crystallographic orientation normal to substrate. 

Crossed nicols. Specimen 914.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 1111 PLATE 19

i»M,^i^*# «>*W-^:^^^^l

0.5mm

SPECIMENS FROM NORTH OF GRAPEVINE CANYON