. 

~ 

( 

' 

./\ 

U.S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 1409-C 
AVAILABILITY OF BOOKS AND MAPS OF THE U.S. GEOLOGICAL SURVEY 

In truction on ordering publication of the U .. Geological urvey, along with prices of the Ia t offering , are given in the currentyear i ues of the monthly catalog " ew Publication of the .. Geological Surve ." Pri es of available U .. Geological Survey publi ations released prior to the current year are listed in the mo t recent annual ''Price and Availability List." Publicati ns that may be li . ted in 

variou U.S. Geological urvey catalog ( ee back inside cover) but not li ted in the mo t recem annual ''Pri e and Availability Li t" may 

be no longer available. 

Order .S. Geological Survey publications by mail or over the counter from the office given below. 

BY MAIL 

Books 

Profe sional Paper , Bulletins, Water-Suppl y Papers. Technique of Water-Re ource Inve tigation , Circular . publications 

of general intere t ( uch a leaflet , pamphlet . booklet ). single 

copie of Preliminary Determination of Epicenter , and s me miscellaneous report , incl uding some of the foregoing eries that have 

gone ou t of print at the Superintendent of Documem , are obtainable by mail from 

U.S. Geological Survey, Information Services 

Box 25286, Federal Center, Denver, CO 80225 

Sub cription to Preliminary Determination of Epicenter can 

be obtained ONLY from the 

Superintendent of Documents 

Government Printing Office 

Washington, DC 20402 

(Check or money" order mu t be payable to Superintendent of 

Document .) 

Maps 

For map , addres mail orders to 

U.S. Geological Survey, Information ervices 

Box 25286, Federal Center, Denver, CO 80225 

OVER THE COUNTER 

Books and Map 

B oks and maps of the . Ge logica l Survey are avai lable 

o er the counter at the following . . Geological Survey Earth Science lnfom1ation enter (E I 's), all of which are au thorized 

agents of the uperi ntendent of D uments: 

• A C HORAGE Alask Rm. I 0 I, 4230 ni ersiry Dr. 

• LAKEWOOD, olorad Federal enter. Bldg. 10 

• ME LO P RK, alifornil Bldg. , Rm. 3 128, 345 

Middlefield Rd . 

• RE TO , Virgini ati nal enter, Rm. I 402. 

1220 I unri e Valley Dr. 

• SALT LAKE CITY, Federal Bldg .. Rm. 105. 125 

outh tate St. 

POKANE, Wa hingto U .. Po. t Office Bldg .. Rm. 135, 

We t 904 Ri ver ide Ave. 

• WASHINGTON, D.C.- Main Interior Bldg .. Rm. 2650, 18th 

and C t .. 

Maps Only 

Map may be purchased over the counter at the following 

. Geological Survey ffice: 

• ROLLA Missour· 1400 Independence Rd . 
Geochemistry and Isotope Hydrology of 

Representative Aquifers in the Great Basin Region of 

Nevada, Utah, and Adjacent States 

By JAMES M. THOMAS, ALAN H. WELCH, and MICHAEL D. DETTINGER 

REGIONAL AQUIFER-SYSTEM ANALYSIS-GREAT BASIN, NEVADA-UTAH 

U.S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 1409 - C 
U.S. DEPARTMENT OF THE INTERIOR 

BRUCE BABBITT, Secretary 

U.S. GEOLOGICAL SURVEY 

Gordon P. Eaton, Director 

Any use of trade, product, or firm names in this publication 

is for descriptive purposes only and does not imply 

endorsement by the U.S. Government. 

Library of Congress Cataloging in Publication Data 

Thomas, James M. 

Geochemistry and isotope hydrology of representative aquifers in the Great Basin region of evada , 

Utah , and adjacent states I by James M. Thomas, Alan H. Welch , and Michael D. Dettinger. 

p. em. - (Regional aquifer-system analysis- Great Basin, evada- Utah) (United States 

Geological Survey professional paper : 1409-C) 

Includes bibliographic references. 

Supt. of Docs. no. I 19.16:1409-C 

1. Aquifers- Great Basin. 2. Water chemistry. 3. Ra dioisotopes in hydrology - Great Basi n. I. Welch, 

Alan H. II. Dettinger, M.D. III. Title. IV. Series: U.S. Geological Survey professional pape r : 1409- C. 

GB1199.3.G73T48 1996 

551.49"0979-dc20 96- 38746 

lP 

ISBN 0-607-86369- 2 

For sale by the U.S. Geological Survey, Branch of Information Services, Box 25286, 

Federal Center, Denver, CO 80225. 
FOREWORD 

THE REGIONAL AQUIFER-SYSTEM ANALYSIS PROGRAM 

The Regional Aquifer-System Analysis (RASA) Program was started 

in 1978 following a congressional mandate to develop quantitative appraisals of the major ground-water systems of the United States. The RASA 

Program represents a systematic effort to study a number of the Nation's 

most important aquifer systems, which in aggregate underlie much of the 

country and which represent an important component of the Nation's total 

water supply. In general, the boundaries of these studies are identified by 

the hydrologic extent of each system and accordingly transcend the political 

subdivisions to which investigations have often arbitrarily been limited in 

the past. The broad objective for each study is to assemble geologic hydrologic, and geochemical information, to analyze and develop an understanding of the system, and to develop predictive capabilities that will contribute 

to the effective management of the system. The use of computer simulation 

is an important element of the RASA studies, both to develop an understanding of the natural, undisturbed hydrologic system and the changes brought 

about in it by human activities, and to provide a means of predicting the 

regional effects of future pumping or other stresses. 

The final interpretive results of the RASA Program are presented in 

a series of U.S. Geological Survey Professional Papers that describe the 

geology, hydrology, and geochemistry of each regional aquifer system. Each 

study within the RASA Program is assigned a single Professional Paper 

number, and where the volume of interpretive material warrants, separate 

topical chapters that consider the principal element of the investigation 

may be published. The serie of RASA interpretive reports begins with 

Professional Paper 1400 and thereafter will continue in numerical sequence 

as the interpretive product of sub equent studies become available. 

Gordon P . Eaton 

Director 

CONTENTS 

Page Page 

Abstract............. ..... .. .... ..... ... ............ ..... ..... ..... ... ................ ......... Cl Geochemical and Isotopic Characterization of Representative 

Great Basin Flow Systems-Continued Introduction............... ..... ...... ...... ..................... .. ............... ...... ..... C2 

Purpose and Scope.. .... ......... ................................................ .. C3 Geochemical and Isotopic Delineation of Ground-Water 

Flow in a Typica l Ca rbonate-Rock Aquifer-Continued 

Stable Isotopes of the Ground Water.............................. C31 

Isotopic Composition ofGt·ound Water in Source 

Sampling Methods and Geochemical Data .. ................... ..... C3 

Acknowledgments. .................... .. ........ .......... .. ..... ... ............... C4 

General Chemical Character of Great Basin Ground Water.... C4 

Areas and Flow Systems................... .. ............. C32 Geochemical and Isotopic Cha racteri zation of Paleoclimatic Effects on Isotopic Composition .......... 33 Representative Great Basin Flow System ....... ...... ....... C5 

Geochemica l Evolution of Ground Wa ter in a Typical Flow-System Delineation on the 

Basis of Deuterium .... ................................. .. .... C34 Basin-Fill Aquifer........... ....... ...... ..... ...... .................... C6 

Geologic Framework . . .. .. . ..... ... ...... ....... ... ... ... ... ... ... .. . ..... .. C6 

Hydrologic Framework .................................................... ClO 

Water Chemistry ....... .. .... ..... ... ... ...... ........... ..................... Cll 

Evolution of Precipitation to Recharge Water. ...... ... Cll 

Evolution of Rechar ge to Sodium Calcium 

Bicarbonate Water........... .. ...................... ... ..... Cl6 

Evolution of Sodium Calcium Bicarbonate to 

Sodium Bicarbonate Water............................. Cl7 

Evolution of Sodium Bicarbonate to the Most 

Dilute Sodium Chloride Water .. .... .. ....... ..... ... CI S 

Evolution of Dilute to Concentrated Sod.ium 

Chloride Water................................................. C21 

Water Chemistry..... ......................................................... 39 

White River Flow System.. ... ...................................... 45 

Ash Meadows Flow System............... ........ ... .............. C47 

Las Vegas Valley.... ........... ... .... ... ........ ........... .... ..... .... 49 

Pahrump Valley..... ..... .... .... ................ .................. .. .... C50 

Summa1-y of Mass-Balan ce Reaction Models............. 50 

Ground-Water Age.................................. ................. .... ..... C50 

White River Flow System ........................................... C55 

Ash Meadows Flow System ... . .. . ..... ....... ... ... .... .... ... .... C57 

Las Vegas Valley....... ................................ .... .............. C57 

Pahrump Valley...... .............. ................ .... ..... ............. 59 

Summary of Ground-Water Ages ......................... ..... C59 

Ground-Water Flow Velocities............................................... C59 

Geochemica l and Isotopic Delineation of Ground-Water Implications of Chemical and Isotopic Composition of 

Flow in a Typical Carbonate-Rock Aquifer ............... . C22 Ground Water in Aquifer of t he Great Ba in ................ C63 

Geologic Framework ....................................................... . C24 Summ ary. ...... ................ ... ... ....... .... ............ .......... ..... ........ ... ..... ... C64 

Hydrologic Framework ...................... ...... ...... ... ... ... ... .......... . . C28 References Cited ...... ................ ................... ....... .................. ........ 66 

PLATE 

FIG RE 

ILLUSTRATIONS 

Page 

1-2. Maps showing, in southern evada and southeastern California: 

1-3. 

4. 

5. 

6. 

7. 

1. Geology and potentiometric surface in carbonate-rock aquifers and rock-sample sites 

2. Average deuterium composition for wells a nd springs 

in 

pocket 

Maps howing: 

1. The 39 major flow sy tern of the Great Basin ..... .............. .. ...... ... ... ......... ............... .. ................ .... ...... ...... ... ....... . 

2. Location a nd general features of Smith Creek Valley .......... ........ .... ............... ......... ............... .. ..... ... ............. ..... . . 

3. Water-table configw·ation in central Smith Creek Valley, Jw1e 1982 ............. ...... .. .. ... ... ................ ......... .......... .. 

Hydr ogeologic sections across central Smith Creek Valley .... ........ .. ......... ..... ..... .. ... .... ..... ... ... .... ..... ....... ....................... . 

Map howing upwa rd hydraulic gradient in the di charge ar ea of central Smith Creek Valley ................. ............... .. 

Graph showing chemical evolution of ground water in the ba in-fill aquifer of Smith Creek Valley ......... ... .... .... ... ... . 

Map showi ng water type in shallow basin-fill aquifer of central Smith Creek VaHey, based on dominant ions ....... . 

C2 

C7 

CB 

C9 

Cl2 

Cl4 

Cl 5 

v 
vi CONTE TS 

FIGURES 8-15. Graphs showing (for Smith Creek Valley): 

8. Aqueous activities for the system CaO-C02-Na20 -Si02-AI20 3-H20 ·· ······ ·········· ········ ·· ···················· ············· 

TABLE 1. 

2. 

3. 

4. 

5. 

6. 

7. 

8. 

9. 

10. 

11. 

12. 

13. 

14. 

15. 

16. 

17. 

18. 

19. 

16. 

17. 

18. 

19- 20. 

21- 23. 

24-26. 

9. Sodium and chloride concentrations ................................... ........... ..... .. ..... ... ........... .... ....... ............ ............ ... . . 

10. Sulfate and chloride concentrations .. .......... .. ..................... ... .......................... .. ..................... .. ....................... . 

11. Calcium and chloride concentrations ............... ...... .. .......... ...... ............. ......... .... ............... ............ ...... ...... .. .. .. . 

12. Magnesium and chloride concentrations .............. ............ ........ .............. ...... .......... ......... ....... .... ..................... . 

13. Potassium and chloride concentrations .. .. .................... ........ .......... ..... ..... .. ... ..... .. ..................... ...................... . 

14. Deuterium and oxygen-18 ...... ............................. ............................... ............... ..... ..... ...... .... .... .. .. ... ......... ..... .. . 

15. Deuterium and chloride concentrations ........ ........... .... ...... ....... ............ ...... .................. .............. ....... ... ..... ..... . 

Map showing ground-water flow systems in southern Nevada, as delineated in this study .. ...... .... ........ ............. .. 

Map showing ground-water flow directions and hydrogeologic features associated with 

carbonate-rock aquifers in southern Nevada .................. ..... ...... ...... ....... .................... ........................ .............. . .. 

Geologic section across southern Sheep Range north of Las Vegas, Nev .... .............. ...... ....................................... .. . 

Graphs showing relation between mean deuterium and mean oxygen-18 for ground-water samples 

sites in outhern Nevada and southeastern California: 

19. All sites ........... .... ..... ...... ............. .................................... .................... ...... ...... ...... .......... ...... .... ........ ................ . 

20. Samples that have not undergone significant evaporation ....... ...... .... ........... .. ................ ...... ........ .... ..... ... .... . 

Graphs showing relation for southern Nevada, between: 

21. Mean deuterium composition and altitude for springs and well samples that contain tritium in the 

Spring Mountain ... ..... ................ ............... ........ ...... ...... ... ........ ..... : ........................... ........................... ... .. . 

22. Mean deuterium and carbon-14 for water recharged in the Spring Mountains ..... ..................................... .. 

23. Mean deuterium and carbon-14 for water recharged in the Sheep Range .......... .. ......... .. .. .. ..... .... ..... ... ....... . 

Ma ps of t he carbonate-rock aquifers of southern Nevada showin g: 

24. Deuterium-derived delineation of ground-water flow ......... .......... ..... ... ......... ......... .. ..... ... .. ........................... . 

25. Average carbon-13 and carbon-14 compositions of ground water ...... ........................................... ................. . 

26. Traveltimes and ages of ground water, based on adj usted carbon-14 ages ..... ...... .............................. ..... ..... . 

TABLES 

Modal mineralogy a nd whole-rock ch emistry of crystal-poor and crystal-rich ash-flow tuffs in the Desatoya 

Mountains and whole-rock chemistry of the Fish Creek Mountains Tuff, Nev ........ ........................................ ...... ... .... . 

X-ray diffraction analyses of playa-area sediments, Smith Creek Valley, ev ... .... .......... ........... ....... .......... ............ ........ .. . 

Chemical an~;~lyses of water from Smith Creek Valley, Nev ........................ ........ .. ............................................................... .. 

Average constituent concentrations of water types used in mass-balance calculations, Smith Creek Valley, Nev .. ........ .. 

Saturation indices for selected minerals in water of Smith Creek Valley, Nev ................................................................... . 

Mass transfer of constituents in Smith Creek Valley, ev ........ .... .. .... .... ................... ....... ............ ............... ....................... .. 

Hydrostratigra phy in southern Nevada and southeastern California ... .. .... .... .. .. ........... ....... .............................. ..... .... ....... . 

X-ray diffraction analyses of rock samples from southern Nevada .... ........ ...... ...................... .......... .. .... .............................. . 

Whole-rock chemical analyses of rock samples from southern Nevada .............................................................. ............... .. . 

Sulfur content of rock samples from southern Nevada ......... ........ ....................... .......... ........... ................ ....... .................... . . 

X-ray diffraction an alyses of insoluble residues from whole-rock chemical analysis of rock samples 

from southern evada .. ... ...................................................... ............ ............................ .. .... ...... ........................... ............. . 

X-ray diffraction analyses of Miocene volcanic rocks from southern Nevada ... ..... .... ..... ...... ................................. ........ ..... . 

Deutel'ium composition of ground water in source areas of southern Nevada ................................ ...... .. ............................ . 

Mass transfer of constituents and mixing of waters along flow paths in carbonate-rock aquifers of southern Nevada ... . 

aturation indices for selected minerals in water from carbonate-rock aquifers of southern Nevada .............. ............ .... . 

Carbon-13, carbon-14, and tritium compositions of ground water in carbonate-rock aquifers of southern Nevada ...... .. .. 

Carbon-13 composition of calcite and dolomite in southern Nevada .................. ..... .......... ........................... ....................... . 

Ground-water ages in carbonate-rock aquifers of southern Nevada ............... .................................. ... ............... ................. . 

Flow velocities in t he carbonate-rock aquifers of southern Nevada, calculated from adjusted carbon-14 ages 

and hydrol ogic da ta ............. .... .... .. ...... .. .. ............ .. .. ... ...... ... ... .... ...... ... ... .. ............. ..... .................... ................ ...... ............. . 

APPE DIX A. Deuterium and oxygen-18 compositions of water from wells and springs in southern Nevada and southeastern 

Page 

18 

19 

19 

C20 

C20 

C21 

C21 

22 

C23 

C25 

C28 

C32 

C32 

33 

C35 

C35 

C40 

C53 

C58 

Page 

10 

C11 

C13 

C16 

C16 

C17 

C26 

C29 

C30 

C30 

C31 

C31 

C34 

C42 

C44 

C52 

C55 

C56 

C61 

Californ ia between latitudes 35 and 38 degrees north, and longitudes 114 and 117 degrees east...... .. ................ C74 

B. Aver age chemical and isotopic compositions of water from wells and spring in southern Nevada and southeastern California, between latitudes 35 and 38 degrees north and longitudes 114 and 117 degrees east....... .... C85 
CO TE TS 

CONVERSION FACTORS AND VERTICAL DATUM 

Inch-pound units of measure used in this report may be converted to International System of 

units (SI) by using the following factors 

Multiply By To obtain 

acre-foot per year (acre-ft/yr) 1,233 cubic meter per year 

foot (ft) 0.3048 meter 

foot per day (ftJd) 0.3048 meter per day 

foot per mile (ftJmi) 0.1894 meter per kilometer 

foot per year (ftJyr) 0.3048 meter per year 

gallon (gal) 3.785 liter 

inch (in.) 25.40 millimeter 

square mile (mi2) 2.590 square kilometer 

Temperature: Degrees Celsius (°C) can be converted to degrees Fahrenheit (°F) by using the 

formula °F = [1.8(°C)]+32. 

Sea level: In this report, "sea level" refers to the National Geodetic Vertical Datum of 1929 (NGVD 

of 1929)-a geodetic datum derived from a general adjustment of the first-order level nets of both the 

United States and Canada, formerly called Sea Level Datum of 1929. 

II 

REGIONAL AQUIFER- SYSTEM ANALYSIS-GREAT BASIN, NEVADA-UTAH 

GEOCHEMISTRY AND ISOTOPE HYDROLOGY OF REPRESENTATIVE 

AQUIFERS IN THE GREAT BASIN REGION OF NEVADA, 

UTAH, AND ADJACENT STATES 

By JAMEs M. THoMAs, A LAN H. W ELCH, and MICHAEL D. D EITINGER 

ABSTRACT 

The Great Basin region of evada, Utah, and adjacent States, 

conta ins approximately 260 ba!<i n , which form 39 ground-water flow 

systems. The e flow systems are primarily in uncon olidated basinfill deposits and in carbonate rock that surround the basin-fill deposits in the eastern Great Basin. This report briefly describes the 

general quality and chemical character of the ground water, di -

cu ses in detail the geochemical and hydrologic processe that produce the chemical and isotopic compositions of water in the two 

principal flow sy terns (basin fill and carbonate rock), deli neates flow 

ystems in carbonate-rock aquifers of southern evada, and discusses ground-water· ages and resulting flow velocitie within those 

carbonate-rock aquifer . 

Wa ter in aquifers of the Great Basin generally contains les 

than 1,000 milligrams per liter of di olved solids, except in naturaldischarge a nd geothermal areas. Aquifers in industrial, mining, 

urban, a nd agricultw·al a rea and aquifer contain.ing highly soluble 

eva porative salts and mineral may conta.in water having either d.i -

solved-solids concentrations greater than 1,000 milligram per liter 

or elevated concentrations of con tituents that are considered undesirable for certa in uses of the water or both. Genera lly, the chemical 

character of ground water in the Great Basin i dominated by 

odium, calcium, and bicarbonate in basin-fill aqu ifer in the predominantly volcan.ic terrain of the we tem part of the ba in; calcium, 

odium, magnesium, and bicarbonate in ba in-fill aquifers in the 

ea tern pa rt of the ba in; and calcium, magne ium, and bicarbonate 

in carbonate-rock aquifers in the eastern part of the basin. The chemical charact r of ground water concentrated by vapotran pi ration in 

discharge area is generally dominated by sodium, chloride, a nd sulfate. 

In Smith reek Valley in we t-central evada, the chemical and 

i otopic compo ition of ground water in a hyd rologica lly closed basinfill aquifer evolve as the water moves from recha rge areas to the di -

charge ar a. Evapotran piration concentrate the di solved olids of 

precipitation in the recharge areas. This concentrated precipitation 

di solves carbon dioxide gas a nd volcanic groundma s and phenocry. Ls (dominantly albite a nd anorthite), chalcedony precipitate 

from the water, a nd kaolinite form by incongruent di solution, produci ng a sodium calcium bicaJ"bonate water. In addition, small 

amounts of gypsum, potas ium feld paT, and biotite dissolve. In the 

termina l playa a r·ea, where the basin-fill depo its grade into finer 

grained sediments, the exchange of calcium and magnesium in the 

water· for od.ium on clay mineral cau es the sodium calcium bicarbonate water to evolve into a sodium bicarbonate water. Calcium al o 

may be removed from the water by the weathering of plagiocla e to 

calcium odium montmorillonite a nd the preci pitation of a zeolite 

minera l. In this part of the aquifer, the dissolution of carbon dioxide 

gas, a lbite, anort hite, and pota sium feld pa r, the precipitation of 

chalcedony, and the formation of kaolin.ite contin ue. In addition, sulfate is reduced to hydrogen sulfide gas. Where ground water discharges by transpiration and evaporation, chloride-containing 

evaporative salts dissolve and calcite and zeolite mineral precipitate, cau ing the sodium bicarbonate water to evolve into a sodium 

chloride water. Evapotran pi ration of the ground water also re ults 

in heavier deuterium and oxygen-18 compo itions. 

In the carbonate-rock aquifers of southern evada, water in 

recharge areas dissolves calcite, dolomite, and carbon dioxide gas 

and rapidly reaches saturation with respect to calcite and dolomite. 

This water contains predominantly calcium, magnesium, and 

bica rbonate. Heating of this calcite-saturated waLer during deep circulation result in the precipitation of calcite. In mo t of the ca r·bonate-rock aquifers, the following reactions take place: Gypsum (or 

anhydrite) dis olves, causing dolomite to d.i solve, which in turn 

cause calcite to precipitate (dedolomitization); chalcedony precipitates; calcium and magnesium in the water exchange for sodium 

in clay ; kaolinite forms; and, in some spring area , cru·bon dioxide 

ga e.xsolve . In parts of the aquifers, water with high concentrations 

of ulfate a nd sodium leak into the aquifer from an overlying low-permeability unit. In addition, halite dis olve , sodium and potassium 

probably are added to the water by the dis olution of volcanic glass, 

volcanic-rock minerals (dominantly a.lbite and potassium feld spaT), 

and zeolite minerals (proba bly clinoptilolite); all of which are present 

in parts of the tudy area. Thus, outside the recharge areas of the carbonate-rock aquifers in southern Nevada, sod.ium, sulfate, and chloride can be major constituents di solved in the water. Waters within 

the carbonate-rock aquifers that originate in different areas and contain d.ifferent chemical and isotopic compo ition can mix, producing 

a water that is chemically and isotopica lly d.ifferent from the ource 

water . 

Regional ground-water flow systems in the cru·bonate-rock aquifers of southern Nevada were delineated using deuterium, water 

chemistry, and adjusted carbon-14 ages. The results ar e as follows: 

(1) Ground water dischaTging at the terminus of the White River flow 

Cl 
C2 REGIONAL AQUIFER-SYSTEM ANALYSIS-GREAT BASIN, NEVADA-UTAH 

system (Muddy River springs) is a mixture of 40 percent Pahranagat 

Valley water, 38 percent Sheep Range water, and 22 percent southern Meadow Valley Wash water. (2) Ground water discharging at the 

terminus of the Ash Meadows flow system (Ash Meadows springs) is 

a mixture of60 percent Spring Mountains water a nd 40 percent Pahranagat Valley water. (3) Las Vegas Valley receives all, or almost all, 

its ground water from the Spring Mountains (the Sheep R.ange may 

supply a small amount to northern Las Vegas Valley). (4) Pahrump 

Valley receives all its ground water from the Spring Mountains. 

Ground-water flow velocities in the carbonate-rock aquifers calculated from adjusted carbon-14 ages are slower than those calculated from hydrologic data. Velocities calculated from adjusted ages 

range from 9.6 to 144 feet per year, whereas velocities calculated 

from hydrologic data range from 50 to 740 feet per year. The discrepancy in velocities indicates that ages and average hydraulic conductivities used for the calculations may be overestimated, and effective 

porosity and flow path length may be underestimated. 

INTRODUCTION 

The Great Basin, as delineated in this study, 

includes approximately 260 individual hydrographic 

areas. These areas can be grouped into 39 flow systems 

(Harrill and others, 1988), in which ground water flows 

toward a common hydrographically low discharge area 

(fig. 1). Some of the larger systems contain subsystems 

that discharge water at intermediate (higher) positions. The principal aquifers within these flow systems 

are basin-fill deposits and carbonate rock (Harrill and 

others, 1988). Volcanic rock form aquifers of local 

importance, but in Nevada less than 1 percent of total 

ground-water withdrawal is from volcanic rock (Frick 

and Carman, 1990, p. 354-356). Highly permeable 

basin-fill aquifers can be surrounded by generally lowpermeability volcanic rock, or by high-permeability 

carbonate rock. Where basin-fill aquifers are surrounded by low-permeability rock, ground-water flow 

is mostly contained within the basin-fill sediments. 

Basin-fill aquifers are present primarily in the western 

Great Basin, where volcanic rock predominate, and 

they consist of single-valley, or multivalley, flow systems. In multi valley systems, the basin-fill aquifers are 

linked by ground-water flow through basin-fill deposits. Basin-fill aquifers also may be hydrologically 

linked by rivers because of the interaction of surface 

water and ground water near the rivers. The basin-fill 

aquifers surrounded by high-permeability rock (mostly 

carbonate rock) are generally in good hydrologic connection with the underlying and adjacent rock, resulting in deep (several thousand feet) and extensive 

(hundreds of square miles) ground-water flow within 

the basin-fill deposits and the surrounding rock. 

Highly permeable carbonate-rock aquifers form 

regional systems in which ground water flows in basinfill deposits and in carbonate rock that transmit the 

flow beneath topographic boundaries. These flow 

0 

0 50 100 150 KILOMETERS 

1 Continental Lake 

2 Virgin Valley 

3 Swan Lake Valley 

4 Long Valley 

5 Duck Lake Valley 

6 Black Rock Desert 

7 Humboldt 

8 Buffalo Valley 

9 Buena Vista Valley 

10 Granite Springs 

11 Winnemucca Lake 

12 Truckee 

13 Lemmon Valley' 

14 Cold Spring Valley 

15 Fernley Sink 

16 Carson 

17 Walker 

18 Dixie Valley 

19 Edwards Creek 

20 Smith Creek Valley 

EXPLANATION 

Study-area boundary 

Flow-system boundaryDashed where uncertain 

Flow systems 

21 Rawhide Flats 

22 Gabbs Valley 

23 Monte Cristo Valley 

24 South Central Marshes 

25 Grass Valley 

26 Northern Big Srnoky Valley 

27 Diamond Valley 

28 Death Valley 

29 Newark Valley 

30 Railroad Valley 

31 Penoyer Valley 

32 Independence Valley 

33 Ruby Valley 

34 Colorado 

35 Goshute Valley 

36 Mesquite Valley 

37 Great Salt Lake Desert 

38 Great Salt Lake 

39 Sevier Lake 

• Part of multibasin system. Not known whether subsurface drainage is to 

the northwest (out of study area) or to the Truckee system. 

FIGURE I.-The 39 major flow ystems of the Great Basin , 

as delineated by Harrill and others (J 983, fig. 3). 
GEOCHEMISTRY AND ISOTOPE HYDROLOGY, GREAT BASI C3 

systems are in the eastern part of the study area 

(fig. 1), where sequences of carbonate rock generally 

are more than 20,000 ft thick (Plume and Carlton, 

1988). 

In 1978, the U.S. Geological Survey began a series 

of Regional Aquifer-System Analysis (RASA) studies to 

aid effective management ofthe Nation's ground-water 

resources by providing information on the hydrology 

and geochemistry of the Nation's major aquifers (Bennett, 1979). The Great Basin RASA study is the lOth in 

this series. The objectives of the geochemistry part of 

the RASA studies are to describe the quality of water in 

aquifers on a regional scale and to determine the 

geochemical processes that produce the observed water 

chemistry. As work on the Great Basin RASA study 

was nearing completion, the State of Nevada began a 

study of the carbonate-rock aquifers of eastern and 

southern Nevada involving the U.S. Geological Survey, 

Bureau of Reclamation, and the Desert Research Institute. The overall objective of this study was to explore 

the potential for developing the carbonate-rock aquifers as water supplies (U.S. Department of the Interior, 

1985). In the carbonate-rock aquifers study, geochemical information was used extensively to delineate 

ground-water flow systems of sou.thern Nevada. This 

report incorporates the geochemical findings of both 

studies. 

PURPOSE AND SCOPE 

The purposes of the study upon which this report is 

based were to (1) briefly describe the general chemical 

character of ground water in the Great Basin; (2) identify and illustrate by examples the processes that produce the chemical and isotopic compositions of water in 

representative aquifers of the Great Basin; (3) delineate ground-water flow paths and mixing of water in 

the carbonate-rock aquifers of southern Nevada using 

chemical and isotopic data ; and (4) determine groundwater age and use these ages to calculate flow velocities of ground water in the carbonate-rock aquifers in 

southern Nevada, and compare the e velocities with 

velocities calculated using hydrologic data. 

The Great Basin RASA study encompassed most of 

Nevada, the west half of Utah, and small part of Arizona, California, Idaho, and Oregon. This 140,000-mi2 

area contains 39 gro und-water flow ystems (fig. 1; 

Harrill and others 1988, table 1). In this report general ground-water quality is briefly described for the 

entire area and geochemical processes affecting chemical and isotopic compositions of ground water are 

desctibed in detail for two principal types of flow systems: a hydrologically closed basin-fill aquifer (Smith 

Creek Valley) and a regional system in which ground 

water flows through several valleys in basin-fill and 

carbonate-rock aquifers (southern Nevada). 

SAMPLING METHODS AND 

GEOCHEMICAL DATA 

Alkalinity, pH, temperature, specific conductance, 

and dissolved oxygen were measured at each sampling 

site. Water samples for major-ion analyses were filtered through a 0.45-~.J.m membrane filter and stored in 

polyethylene bottles. Samples for cation analysis were 

acidified to a pH of about 1.5 with nitric acid (Wood, 

1976). Samples for nutrient analyses were stored in 

opaque bottles, preserved with mercuric chloride, and 

kept at 4°C until analyzed. Dissolved organic carbon 

samples were filter ed in a stainless steel assembly 

using a 0.45-~.J.ID silver membrane filter, stored in glass 

bottles, and kept at 4°C until analyzed. Samples for 

deuterium, oxygen-18, and tritium analy es were collected in glass bottles. Samples for carbon-14 analysis 

were collected in a 2-L linear polyethylene bottle that 

was attached to th e bottom of a 50-gal precipitation 

tank. The tank wa flushed with nitrogen gas prior to 

being filled with water. The pH of the water was raised 

to above 10 by adding a C02-free sodium hydroxide 

solution to convert all dissolved carbon to carbonate, 

and then a C02-free strontium chloride solution was 

added to the water to precipitate strontium carbonate. 

Samples for carbon-13 analysis were collected in a 1-L 

glass bottle by flushing the bottle with several volumes 

of sample water, filling th e bottle with sample water, 

and then precipitating strontium carbonate with a 

C02-free ammoniacal strontium chloride solution. For 

both carbon isotope sampl es, suspended particles were 

filtered out of the water with an in-line filter closed to 

the atmosphere. 

Major-ion and nutrient concentrations were determined by the National Water-Quality Laboratory of the 

U.S. Geological Survey, in Arvada, Colo., and the 

Desert Research Institute Laboratory in Reno, Nev. 

Dissolved organic carbon was analyzed at the U.S. Geological Survey National Water-Qual!ty Laboratory. 

Deuterium and oxygen-18 were analyzed by the U.S. 

Geological Survey Research Laboratory in Reston , Va., 

and the Desert Research Institute Isotope Laboratory 

in Las Vegas, Nev. Carbon isotopes were analyzed by 

the U.S. Geological Survey National Water-Quality 

Laboratory, the Desert Research Institute Isotope Laboratory in Las Vegas, Nev., and the Teledyne Isotope 

Laboratory in Westwood, N.J. Tritium was analyzed at 

the U.S. Geological Survey National Water-Quality 

Laboratory and the Desert Research Institute Isotope 

Laboratory in Reno, Nev. 
C4 REGIO AL AQUIFER-SYSTEM ANALYSIS-GREAT BASIN, EVADA-UTAH 

ACKNOWLEDGMENTS 

The authors thank the numerous people who contributed to this report by helping collect, compile, and 

manipulate data and by providing pertinent discussions of ideas and concepts. In particular, we thank 

Brad F. Lyles, John W. Hess, Roger L. Jacobson, and 

Michael E. Campana of the Desert Research In titute. 

We also thank Bruce Zeller and Floyd Oliver of the U.S. 

Fish and Wildlife Service for access and support of 

activities in the Desert National Wildlife Refuge. 

The authors also thank the many individuals who 

allowed us to sample their springs and wells. 

GENERAL CHEMICAL CHARACTER OF 

GREAT BASIN GROUND WATER 

Most water in the principal aquifers of the Great 

Basin, except in natural discharge and geothermal 

areas, contains less than 1,000 milligrams per liter 

(mg!L) of dissolved solids. Ground water in industrial, 

mining, urban, or agricultural areas, as well as in 

areas affected by dissolution of readily soluble minerals, can contain dissolved-solids concentrations in 

excess of 1,000 mg/L or constituent concentrations 

above National and State drinking water standards, or 

both (Lamb and Woodward, 1988; Parliman, 1988; Thomas and Hoffman, 1988; Waddell and Maxell, 1988). 

Water containing natural (in contrast to humanaffected) concentrations of dissolved solids exceeding 

1,000 mg/1 generally is in areas of evapotranspiration, 

evaporite deposits, or geothermal activity. Evapotranspiration in areas of shallow ground water (generally 

less than 20 ft below land surface) increases the dissolved-solids concentration of the residual water. 

Evapotranspirative concentration is most prevalent in 

ground-water discharge areas such as playa , at the 

distal end of flow systems. 

Evaporite salts and minerals, such as gypsum and 

halite, are highly soluble, and their dissolution results 

in a marked increase in dissolved solids. Evaporite 

salts and minerals are generally present in playa areas 

and in carbonate rock of Permian and younger age in 

the Great Basin (Hintze, 1980; Stewart, 1980). 

Geothermal heating of water in aquifers generally 

produces higher concentrations of dissolved solids 

because the solubility of most minerals increases with 

temperature. Geothermal waters also can contain high 

concentrations of undesirable constituents, such as 

arsenic, boron, fluoride, and lithium. Geothermal activity occurs in localized areas throughout the Great 

Basin because of the extensional tectonic processes 

that have formed the characteristic basin-and-range 

tructure (Fiero, 1986). 

Human-induced degradation of water quality in 

industrial, mining, urban, and agricultural areas of the 

Great Basin is covered in several articles of the 1986 

National Water Summary (Lamb and Woodward, 1988; 

Parliman, 1988; Thomas and Hoffman, 1988; Waddell 

and Maxell, 1988). 

The chemical composition of water in basin-fill 

aquifers of the Great Basin containing less than 1,000 

mg/1 dissolved solids generally is dominated by calcium, sodium, magnesium, and bicarbonate. The chemical composition of water in basin-fill aquifers 

containing more than 1,000 mg/1 dissolved solid generally is dominated by sodium, chloride, and sulfate. 

The chemical composition of water in carbonate-rock 

aquifers of the Great Basin generally is dominated by 

calcium, magnesium, and bicarbonate. Sodium also can 

be a dominant ion in these waters if volcanic rock or 

clay minerals are present before the ground water 

enters the carbonate-rock aquifers, or are found within 

the aquifers. 

The chemical composition of water recharging 

aquifers in the Great Basin is derived from dissolution 

of soil-zone minerals and C02 gas. Chemical composition can change along flow paths as different processes 

take effect or as ground water comes in contact with 

different minerals. The chemical types of ground water 

in the principal aquifers of the Great Basin, ba ed on 

the dominant ions dissolved in the water, are shown on 

four State maps at a scale of 1:500,000 (Thompson and 

Chappell, 1984a, b; Thompson and Nutter, 1984; 

Thompson and others, 1984) and in detail on 14 maps 

showing most of the Great Basin at a scale of 1:250,000 

(Welch and Williams, 1986a-d, 1987a-j). 

Basin-fill aquifers in the western Great Basin are 

derived by erosion of the predominantly volcanic rock 

in mountains that surround the basins (Plume and 

Carlton, 1988). Thus, these aquifers contain sediments 

that consist of volcanic glass and minerals primarily 

composed of sodium, potassium, calcium, silica, aluminum, and oxygen. Water chemistry in recharge areas 

and the upgradient part of the aquifers is dominated by 

sodium, calcium, and bicarbonate ions (Thompson and 

Chappell, 1984a, b; Thompson and Nutter, 1984; 

Thompson and others, 1984; Welch and Williams, 

1986a-d, 1987a-j) because of the dissolution of volcanic 

glass and minerals by C02-rich water. Most of the e 

basins and flow systems contain a discharging playa 

area. Near, or within, these playa areas, the chemical 

composition of ground water may evolve into a sodium 

dominated water, and with increasing dissolved-solids 

concentration, chloride and sulfate become dominant 

over bicarbonate. The water type changes because of 

(1) exchange of calcium and magnesium dissolved in 

the water for sodium on clay minerals; (2) dissolution of 
GEOCHEMISTRY AND ISOTOPE HYDROLOGY, GREAT BASIN C5 

evaporative salts and minerals in sediments in the discharge area; (3) precipitation of minerals that removes 

select ions from the water; or (4) any combination of 

these processes. 

Basin-fill aquifers in the eastern Great Basin are 

derived by erosion of the predominantly carbonate- and 

volcanic-rock mountains (Plume and Carlton, 1988). 

Thus, these aquifers contain sediments that consist of 

carbonate and volcanic minerals primarily composed of 

calcium, magnesium, and carbonate, in addition to 

sodium, potassium, silica, aluminum, and oxygen. 

Water chemistry in recharge areas and the upgradient 

part of aquifers, consisting mainly of carbonate rock, is 

dominated by calcium, magnesium, and bicarbonate 

ions, whereas aquifers consisting mainly of volcanic 

rock are dominated by sodium, calcium, and bicarbonate ions. Most basins in this part of the Great Basin do 

not have discharging playas, instead the basin-fill 

aquifers drain through carbonate rock to large springs. 

Thus, water chemistry along a flow path generally 

changes little in composition. 

Carbonate-rock aquifers in the eastern Great Basin 

are composed primarily of calcite and dolomite. Water 

chemistry in recharge areas and the upgradient part of 

these aquifers is dominated by calcium, magnesium, 

and bicarbonate ions. AJ3 water flows through the carbonate-rock aquifers and comes in contact with volcanic rock and clay minerals, sodium ion concentration 

increases. Some carbonate-rock aquifers in the southeastern Great Basin contain interbedded evaporite 

deposits; as a result, sulfate, chloride, and sodium ions 

may predominate in ground water in these areas. 

GEOCHEMICAL AND ISOTOPIC 

CHARACTERIZATION OF 

REPRESENTATIVE 

GREAT BASIN FLOW SYSTEMS 

The Great Basin does not contain a single aquifer 

(as is common in other regional ground-water flow systems, such as, the Floridan, Madison, and Ogallala 

aquifers) but in tead contains numerou aquifers. The 

two principal types of flow sy terns in the Great Basin 

are basin-fill and carbonate-rock aquifers. This report 

discusses geoch emical processes that produce the 

major-ion chemistry and isotopic compo ition of ground 

water in aquifers representative of these two types. 

These proce es are (1) evapotran piration, (2) dissolution of minerals and C02 gas, (3) precipitation of mineral or formation by incongruent dissolution, (4) ion 

exchange, (5) mixing of chemically or isotopically different waters, and (6) geothermal heating. 

Ground water is concentrated by evapotran piration in areas of shallow water (less than about 20 ft 

below land surface) generally in the di charge area of 

flow systems. This process is important in large areas 

of shallow ground water, such as playas. 

Dissolution of soil-zone mineral and C02 gas in 

recharge areas of aquifers produces the chemical composition of water in the upper parts of aquifers. As residence time of water in an aquifer increase , 

constituent concentrations may increase until the 

water reaches saturation with respect to the dis olving 

mineral or gas. Water chemistry also changes as different minerals along the flow path di solve. 

Precipitation or formation of minerals can change 

the chemical composition of water because select ions 

are removed from the water. Mineral precipitation, in 

the principal aquifers of the Great Basin, is generally 

the result of evapotranspirative concentration of the 

water, temperature changes, or dedolomitization. 

Evapotranspirative concentration of ground water 

causes the water to become supersaturated with 

respect to some mineral , resulting in precipitation of 

those minerals. An increase in water temperature, generally caused by water circulating to depths of everal 

thousand feet, causes some mineral to precipitate. For 

example, an increase in temperature from 10°C to 25°C 

of a water that is saturated with respect to calcite 

results in an approximately 25 percent decrease in 

total carbonate content because of calcite precipitation 

(Palmer and Cherry, 1984). Dedolomitization is the dissolution of dolomite and precipitation of calcite from a 

water saturated with respect to calcite and dolomite 

and undersaturated with respect to gyp urn. Thi reaction is driven by the dissolution of gypsum (or anhydrite). Dedolomitization al o increases sulfate and 

magnesium concentrations in the water. 

Ion exchange removes one or more ions from the 

water while simultaneously adding one or more ions to 

the water. For example, calcium and magnesium ions 

may be removed from the water by exchanging with 

sodium and potassium ions on clay minerals. 

Mixing waters of different chemical or isotopic compositions produces a water that is chemically or isotopically different from the original waters. For example, 

a mixture of 50 percent water with a chloride composition of 10 mg/L and 50 percent water with a chloride 

composition of 30 mg/L would result in a water containing 20 mg/L chloride. 

Increased temperature due to deep circulation of 

ground water can increase or decrease the solubility of 

minerals (Palmer and Cherry, 1984) and cause a shift 

in the oxygen-18 composition of the water. For example, chalcedony becomes more soluble with increasing 

temperature, resulting in an increase in silica concen-
C6 REGIO AL AQIDFER- YSTEM ANALYSIS - GREAT BASIN, NEVADA- UTAH 

tration with increased water temperature. Conversely, 

calcite solubility decreases with increasing temperature and calcite precipitates, so increased temperature 

removes calcium and carbon from the water. Higher 

water temperature also can result in a shift in oxygen18 composition of the water because the exchange rate 

of oxygen in water for oxygen in minerals increases 

with increasing temperature (Gat and Gonfiantini, 

1981). 

GEOCHEMICAL EVOLUTION OF GROUND 

WATER IN A TYPICAL BASIN-FILL AQUIFER 

Typical basin-fill aquifers consist of unconsolidated 

sedimentary deposits ranging from high-permeability 

sand and gravel to low-permeability clay and silt. 

These generally mixed deposits grade inward from 

poorly sorted alluvial-fan deposits, consisting of boulders to clay-size particles, around the margin of the 

basin to well-sorted sand and gravel deposits and ultimately into fine-grained playa deposits near the center 

of the basin. In some valleys the basin-fill deposits are 

surrounded and underlain by relatively low-permeability rock, such as volcanic rock, and in other valleys the 

basin-fill deposits are surrounded and underlain by 

rock that includes relatively high-permeability carbonate rock. Basin-fill aquifers surrounded by low-permeability rock are found throughout the Great Basin but 

are more common in the western part where low-permeability volcanic rock predominates. Smith Creek 

Valley in west-central Nevada is a typical basin-fill 

aquifer surrounded and underlain by low-permeability 

rock. 

In most basin-fill aquifers surrounded by low-permeability rock, ground water flows within the basin-fill 

deposits and is discharged in an extensive area (tens to 

hundreds of square miles), commonly a centrally 

located playa surrounded by phreatophytic vegetation. 

Smith Creek Valley is hydrologically closed. Precipitation that falls within the topographic basin is discharged within the basin, except in the extreme 

southern part of the valley. Ground water flows southward from this part, because in this area the aquifer is 

hydrologically separated from the main basin-fill aquifer by igneous intrusions that form a banier to northward ground-water flow (figs. 2, 3). 

Smith Creek Valley encompasses 583 mi2 and 

ranges in altitude from about 6,000 ft above sea level at 

the playa surface to more than 10,000 ft in the surrounding mountains. Climate differs from arid (about 

6 in. of precipitation a year on the valley floor) to semiarid (up to about 20 in. of precipitation) in the mountains (Thomas, Carlton, and Hines, 1989, p. 5-8). 

The principal source of ground-water recharge probably is precipitation in the mountains above an altitude 

of 7 000 ft (Everett and Rush, 1964). ' The hydrology of Smith Creek Valley has been 

studied by Everett and Rush (1964) and Thomas, Carlton and Hines (1989). These studies describe the 

hyd,rology of the shallow part of the basin-fill aquifer 

and include a water budget for the basin. The groundwater chemistry of Smith Creek has been described by 

Thomas, Welch, and Preissler (1989). 

GEOLOGIC FRAMEWORK 

Consolidated rock and unconsolidated deposits in 

Smith Creek Valley can be divided into three hydrogeologic units: (1) low-permeability consolidated rock, (2) 

high-permeability basin-fill deposits, and (3) low-permeability playa deposits (fig. 2). Consolidated rock surrounds and underlies the unconsolidated basin-fill 

deposits. Basin-fill deposits consist of poorly sorted heterogeneous sediments at the basin margin that grade 

sequentially inward to well-sorted coarse-grained sediments, to mixed coarse-, medium-, and fine-grained 

sediments ·(heterogeneous sediments), to fine-grained 

playa sediments near the center of the basin (fig. 4). 

The mineralogy of the basin-fill sediments and the 

water chemistry reflect to differing degrees the mineral 

composition of the rock composing the surrounding 

mountains. About 95 percent of the exposed consolidated rock are volcanic rock of Tertiary to Quaternary 

age (Stewart and McKee, 1977; Kleinhampl and Ziony, 

1985). Rock composing the Desatoya Mountains on the 

west side of the basin and the southern Shoshone 

Mountains on the east side of the basin is almost 

entirely rhyolitic tuff. These mountain ranges are the 

principal source area for the basin-fill depo its and 

al o the source areas for approximately 95 percent of 

the recharge to the basin (Thomas, Carlton, and Hines 

1989, p. 16). 

The Desatoya Mountains are composed primarily 

of an unnamed densely welded cry tal-poor rhyolite 

ash-flow tuff containing less than 10 percent phenocrysts (Stewart and McKee, 1977, p. 42). Modal (mineralogic) analyses of this tuff (Barrows, 1972, p. 41 and 

67) show that the phenocrysts consist mainly of plagioclase feldspar with lesser amounts of alkali feldspar 

and quartz (table 1). Four plagioclase samples range in 

calcium content from 17 to 45 percent (Banows, 1972). 

A crystal-rich biotite-bearing ash-flow tuff composes 15 

percent of the rock exposed in the Desatoya Mountains 

(Stewart and McKee, 1977); this tuff occupies the highest altitude zone of the range, the source area for about 

35 percent of the recharge to the basin-fill aquifer 

(Thomas, Carlton, and Hines, 1989). This tuff contain 
NEVADA 

~ 

STUDY 

AREA 

R 37 E 

GEOCHEMISTRY AND ISOTOPE HYDROLOGY, GREAT BASIN 

R 39 E 

0 

0 

, 5, AND 7 

14 

N 

5 MILES 

5 KILOMETERS 

15 

N 

T 

20 

N 

T 

16 

N 

R 41 E 

I I 

1·: ... ·.:·_.·.· .. ··. 1 

1 

• 

3 

EXPLA ATION 

Basin-fill deposits 

Consolidated rock 

Playa deposits 

Phreatophytic vegetation 

Hydrographic area boundary 

Ground-water divid 

Approximately located 

Precipitation sample localityumber indicates analysi , table 3 

.a. Stream sample locality- umber 

indicates analy i , table 3 

FrcunE 2.-Location a nd gener·al featw·es of Smith Creek Va Uey, Nev., showing precipitation and stream sample localities. 

C7 
C8 REGIONAL AQUIFER-SYSTEM ANALYSIS- GREAT BASIN, NEVADA-UTAH 

( A' 

) 

\ 

A I 

0 4 MILES ~ 

~~ _,~,__,LI -.,~--~~ \ I 

c=J 

c::::J 

j·: . .-·.::··.·:":1 

4 KILOMETERS 

R 39 E 

Basin-fill deposits 

Consolida ted rock 

Playa deposits 

Phreatophytic vegetation 

( 

R 40 E R 41 E 

EXPLANATIO 

A ----A' 

-6035-

• 

Line of hydrogeologic section 

Hydrographic area boundary 

Water-level contour- Shows altitude 

of water table. Contour interval 5 feet. 

Datum is sea level 

Well- Water-level measurements used 

in contouring 

FrGUHE 3.-Water-table configurati?n in centra l Smith Creek Valley, Nev. , June 1982. 

SecttonsA-A and B-B ' shown in figure 4. 

T 

18 

N 

T 

17 

N 

T 

16 

N 
GEOCHEMISTRY AND ISOTOPE HYDROLOGY, GREAT BASIN 

_J 

UJ 

> 

UJ 

_J 

A 

6,100 

6,000 

5,900 

5 ,800 

5,700 

5,600 

0 

I 

0 

I 

2 

I 

2 

I 

Fine-grained 

sediments 

3 MILES 

I 

3 KILOMETERS 

VERTICAL SCALE GREATLY EXAGGERATED 

z 

0 

i= 

() 

w 

(f) 

€oarse-grained 

sediments 

A' 

<( 

UJ 5,500 -'--------- ------------ (/) 

UJ 

> B 0 

~ 6,400 

fUJ 

UJ 

lL 6 ,300 

z 

UJ 

0 6,200 

:::> 

ff= 

_J 

<( 6 ,100 

6,000 

5,900 

5,800 

5,700 

5,600 

5,500 

FIGU RE 4. - Hydrogeologic sections across central mith 

Creek Valley, ev. Heterogeneou sediments consist of 

poorly sorted ediments at the margin of the ba in and 

mixed coarse-, medium-, and fine-grained sediments near 

the center of the basin; coarse-grained sediments are 

coa rse- to medium-grained well-sorted sand and gravel : 

0 

0 

Fine-grained 

sediments 

2 MILES 

2 KILOMETERS 

VERTICAL SCALE GREATLY EXAGGERATED 

B' 

and fine-grained sediments are primarily silts and clays. 

Hydrogeologic section locations are shown in figure 3. Wells 

(vertical lines) used to construct the sections, in addition to 

wells shown in figure 3, include geothermal temperatw·e-gradient holes and observation well that were destroyed prior to 

this tudy. 

C9 
C10 REGIO AL AQUIFER-SYSTEM ANALYSIS- GREAT BASIN, NEVADA- UTAH 

11 to 36 percent phenocrysts of predominantly plagioclase and alkali feldspar (table 1; Barrows, 1972, p. 87-

88). 

TABLE !.-Modal mineralogy and whole-rock chemistry of crystal-poor and 

crystal-rich ash-flow tuffs i" the Desatoya Mountains and whole-rock 

chemistry of the Fish Creek Mountains Thff(Smith Creek Valley), Neu. 

Mineralogic analyses (volume percent) 

Crystal-poor Crystal-rich 

ash-flow tu£1'1 ash-flow tu ~ 

Mean Ra nge Mean Range 

Ground mass 93.0 90.2-96.0 74.2 64.2-89.2 

Phenocrysts: 

Quartz .7 0.0- 1.4 1.9 7 

Alkali feldspar 1.1 0.5-1.9 8.2 0.4-13.2 

Plagioclase 4.9 0.9- 9.0 13.2 8.7- 18.9 

Biotite .1 0.0-0.2 1.5 0.0-3.6 

Pyroxene .0 0.0 .2 0.0-1.1 

Chemical analyses3 (weight percent) 

Crystal- poor Crystal-rich Fish Creek 

ash-flow tul'f' ash-flow tuff6 Mountains TurF 

SiOz 69.0 68.9 74.6 

Alz03 15.1 13.9 12.9 

CaO 1.0 1.6 .7 

MgO .2 .3 .1 

a20 3.9 3.6 3.8 

K20 5.1 4.4 5.2 

1 Based on analyses by Barrows (1972, p. 41 and 67, samples 12-9-3, 13-10-1, 

13-11 -1, and 14-9-1). Modal (mineralogical) analyses are based on a n average of 1,021 

point counts per ~am le. 

2 Based on analyses by Barrows (1972, p. 87-88, samples 11-11-01, 0 2, 03, 04, 

06, 07, 08, 09; ll-10-010, 011, 013, 015; 12-10-4 ; 13-11-3, and 13-11-12). Modal 

(mineralogical) analyses are based on an average of 1,003 point counts per sample. 

3 By long-standing convention, whole-rock chemical analyses are expressed in 

weight percent of constituent oxides. Oxides listed are of silicon, aluminum, calcium, 

magnesium, sodium, and potassium. 

4 Analysis by Barrows (1972, p. 337, sample 13-10-1). 

6 Based on analyses by Barrows (1972, p. 338, samples ll-10-09, 11-11-04, and 

11-ll-05). 

6 Based on two analyses by McKee (1970, p. 11 ). 

The southern part of the Shoshone Mountains is 

capped almost entirely by the Toiyabe Quartz Latitea crystal-rich ash-flow tuff containing 35 to 50 percent 

phenocrysts of smoky quartz and sanidine, with minor 

amounts of plagioclase and trace amounts of biotite. 

This so-called latite is mineralogically similar to the 

rhyolitic Fish Creek Mountains 'lUff, hence the term 

"quartz latite" is misleading (Stewart and McKee , 

1977, p. 43). Although modal and chemical analyses 

are not available for the Toiyabe Quartz Latite, its mineralogic similarity to the Fish Creek Mountains 'lUff 

implies that the whole-rock chemistry also may be similar (table 1). 

Playa sediments are composed of 77 to 93 percent 

silt and clay- on the basis of six soil-core samples CF.E. Rush and J.R. Harrill, U.S. Geological Survey, written 

commun. , 1965). Clay-mineral analyses indicate the 

playa-area sediments consist primarily of illite and 

mixed-layer montmorillonite and illite, with lesser 

amounts of montmorillonite and kaolinite (table 2). 

Quartz, plagioclase, potassium feldspar, and calcite 

a lso are present in the playa-area deposits (Keith 

Papke, Nevada Bureau of Mines and Geology, written 

commun., 1983). X-ray diffraction analysis of bulk sediment samples from sites B, C, and D (see fig. 7) indicate that the zeolite minerals natrolite, thomsonite (or 

a zeolite intermediate between the two), and clinoptilolite are present also. In addition, the nonclay minerals 

quartz , feldspar, chlorite, gypsum, and calcite were 

identified in the bulk samples (Nelson Shaffer, Indiana 

State Geological Survey, written commun., 1987) 

HYDROLOGIC FRAMEWORK 

Basin-fill aquifers in Smith Creek Valley are 

recharged by subsurface inflow from the surrounding 

mountains and infiltration of surface water into alluvial-fan deposits at the margin of the basin. Streams 

are perennial along some stretches in the mountains 

but generally are ephemeral less than 1 mi from the 

mountain-front basin-fill contact as they traverse the 

permeable alluvial-fan deposits. Surface flow caused by 

severe storms, rapid snowmelt, or both can reach the 

playa in the central part of the basin, but most of this 

water is lost by evaporation prior to recharging the 

aquifer. If water flows onto a dry playa surface, an initial pulse of water may recharge the water-table aquifer by flowing through cracks in the dry playa 

sediments. However, after initial wetting, the finegrained sediments swell quickly, restricting the downward flux of water (J.R. Harrill, written commun., 

1967). The remaining water stands on the playa surface until it evaporates. Recharge to the aquifer is estimated to be approximately 8,000 acre-ftJyr (Thomas, 

Carlton, and Hines, 1989, p. 15-16). 

Ground water generally flows toward the centrally 

located playa, which is the topographically lowest point 

in the valley. Shallow ground water is consumed by 

evapotranspiration in an area of phreatophytic vegetation surrounding the playa, where depth to water 

ranges from about 8 to 30 ft below land surface, or by 

direct evaporation from the bare soil of the playa, 

where depth to water is about 6 to 10 ft below land surface . Ground water moves upward in the discharging 

playa area, as indicated by the upward gradient measured in pairs of shallow wells (fig. 5). The vertical gradient remains relatively constant over time. Even 

when water is standing on the playa surface , the 
GEOCHEMISTRY AND ISOTOPE HYDROLOGY, GREAT BASIN Cll 

TABLE 2.- X-ray diffraction analyses of playa-area sediments, Smith Creek Valley, Neu. 

[Analyses by Keith Papke, Nevada Bureau of Mines and Geology, Reno, ev.; .. , not identified in sample) 

Relative abundance2 

Sample Clay Site 1 depth content Clay minerals onclay minerals (feet) 

lllite Montmorillonite Mixed layer3 Kaolinite Quartz Plagioclase K-feldspar Calcite 

A 2.0 moderate 3 2 1 2 3 

21.5 minor 2 1 2 

B 5.5 abunda nt 3 1 2 1 3 2 

23.0 minor 1 2 1 2 

34.0 moderate 1 2 3 1 3 2 

c 7.5 moderate 2 3 1 4 1 2 3 4 

22.5 minor 1 2 1 2 

34.0 abundant 2 1 3 2 3 l 

D 5.5 moderate 1 2 1 2 3 

22.5 abundant 2 1 3 1 2 3 

27.0 abundant 2 1 3 1 2 3 

E 16.5 moderate 2 1 3 1 2 3 

1 Site designation from figure 7. 

2 Mineral abundance is arbitrary ranking of relative amounts of mineral in sample, with 1 representing most abundant mineral and 4 least abundant mineral. 

3 Jnterlayered montmorillonite-illite. 

upward gradient remains virtually unchanged and 

depths to water in wells remain at 6 to 10 ft beneath 

the playa surface. Ground water in the valley is mostly 

undeveloped; less than 1,000 acre-ftJyr is pumped for 

irrigation and livestock use. 

WATER CHEMISTRY 

Water in the basin-fill aquifer evolves from a dilute 

sodium calcium bicarbonate (Na-Ca-HC03) type to a 

more concentrated sodium bicarbonate (Na-HC03) type 

to a briny sodium chloride (Na-Cl) type as it flows from 

recharge to discharge areas (table 3; figs. 6, 7). Measured dissolved-solids concentration increases from 90 

mg/L in the recha rge area to 51,000 mg/L in the discharge area 

Chemical evolution of ground water and surface 

water in hydrologically closed basins of the Western 

United States has been studied by Jones (1965), Hardie 

(1968), Phillips and Van Denburgh (1971), Van Denburgh (1975), and Smith and Drever (1976), and outside the Western United States by Lerman (1967), 

Eugster (1970), Jones and others (1977), Rettig and 

others (1980), Yuretich and Cerling (1983), Green and 

Canfield (1984), and Macumber (1984). Jones (1966), 

Hardie and Eugster (1970), and Eugster and Jones 

(1979) summarized the geochemical processes that 

affect the chemical evolution of water from dilute 

waters to brines in hydrologically closed basins. 

Deuterium, oxygen-18, geochemical data, and interpretive methods described in previous studies were used to 

determine the processes that affect the chemical evolution of ground water in Smith Creek Valley (Thoma , 

Welch, and Preissler, 1989). 

Mass-balance descriptions of the evolution of one 

water chemistry to another along a flow path generally 

are not unique. However, a mass-balance solution that 

includes phases which are mineralogically possible and 

thermodynamically feasible can be used to determine 

the processes that control th e evolution of observed 

water chemistry. Stoichiometry of reactions associated 

with the chemical evolution were identified using 

mass-balance calculations by the computer program 

BALANCE (Parkhurst and others, 1982). Plausible 

phases used in the calculations were based on the mineralogy and whole-rock chemistry of the rocks and sediments in the study area (tables 1, 2) and the water 

chemistry (tables 3 , 4). The computer program 

WATEQ4F (Ball and others, 1987) was used to calculate saturation indices for phases used in the mass-balance calculations (table 5). Phases that are below 

saturation in the water (negative value) can dissolve, if 

present in the aquifer, whereas phases above saturation (positive value) generally can precipitate. 

EV L T l N F PRE lPlTATlON T RECHARGE \VATER 

Water recharging the basin-fill aquifer is a sodium 

calcium bicarbonate type (samples from sites 2 and 3; 

table 3, fig. 6). Dissolved constituents in the recharge 

water are primarily from evapotranspirative concentration of dissolved constituents before the water 
Cl2 

0 

I 

0 

REGIO AL AQUIFER-SYSTEM ANALYSIS- GREAT BASIN, NEVADA-UTAH 

c=J 

, ...... ·.:~··<: ! 

I 

4 MILES 

I 

4 KILOMETERS 

R 39 E 

Basin-fill deposits 

Consolidated rock 

Playa deposits 

Phreatophytic vegetation 

""I .. . (; : 

~\ 

R 40 E R 41 E 

EXPLA ATIO 

-0.15-

0.003 

• 

Hydrographic area boundary 

Line of equal vertical hydraulic gradientInterval, in feel per foot, i variable 

Vertical hydraulic gradient at well, 

in feet per foot 

• Well pair- Used in determining hydraulic 

gradient 

FtGURE 5.-Upward hydraulic gradient in the discharge area of central Smith Creek Valley, Nev. 

T 

18 

N 

T 

17 

N 

T 

16 

N 
TABLE 3. -Chemical analyses of water from Smith Creek Valley, Neu. 

[Milligrams per liter, unless noted otherwise. Symbol:--, not determined) 

Water pH 

Dis- Delta Delta 

Well temper- (stan- Mag- Potas- Bicar- Car- solved deute- Site1 Site name depth ature Calcium Sodium Sulfate Chloride Silica solids2 oxygendard nesium sium bonate bonate rium 18 (feet) (degrees units) (calcu- (permil) (permil) Celsius) Ia ted) 

Precipitation 

1 Carroll Summit3 -- -- 1.1 0.2 0.7 0.3 -- -- 1.5 2.2 -- -- -- -- Q 

tz:l 

Recharge water 0 

(") 

2 Peterson Creek 15.3 7.6 6.6 1.0 13 1.5 41 0 10 3.8 34 90 - 123 - 16.2 g) 

~ 3 Campbell Creek 12.9 8.0 13 2.1 19 2.6 76 0 12 7.3 38 130 - 118 - 15.2 rn 

>-3 

Sodium calcium bicarbonate water ~ 

4 

5 USGS 

S. Brown 

well35 

well 282 

66 

10.6 

9.8 6

6.8 

.5 

20 

29 

3.8 

4.2 33 

24 3.8 

7.9 100 

94 0 

0 43 

13 

28 

8.2 

56 

56 

250 

180 -

-

123 

118 

-

-

15

14.7 

.7 ~ 6 N. Brown well 200 14.7 7.5 35 5.5 48 6.8 150 0 52 25 62 310 - 130 - 16.2 rn 

0 

>-3 

Sodium bicarbonate water 0 

'1:! 

tz:l 

7 USGS well 67 22 9.0 6.7 12 1.9 56 6.7 160 0 21 11 34 220 - 124 - 15.6 

8 USGS well 50 22 10.0 7.2 10 1.1 110 6.0 300 0 11 20 19 320 - 122 - 15.9 ~ 9 USGS well27 22 8.1 6.9 21 3.1 170 8.4 400 0 12 85 12 510 - 117 - 14.8 ::0 

0 

r-< Sodium chloride water 0 

Q 

>< 

10 USGS well23 66 10.4 8.4 110 13 710 17 32 0 180 1,200 11 2,300 - 132 - 16.4 -

Q 

11 USGS well 55 66 9.8 8.1 76 14 2,200 27 170 0 380 3,600 5.2 6,400 - 124 - 15.2 

12 USGS well70 22 9.2 7.4 73 41 6,400 75 1,300 0 2,700 8,900 24 19,000 - 122 - 14.2 ~ > 13 USGS well 56 22 10.8 9.2 10 1.2 11,000 81 3,500 280 3,500 12,000 5.0 29,000 - 98 - 9.7 >-3 

tp 

14 USGS well68 22 9.1 6.6 150 10 13,000 86 480 0 4,300 20,000 3.8 38,000 - 101 - 10.0 ~ 15 USGS well32 (4) 6,000 21,000 42,000 - 110 - 12.0 ...... 10.9 7.5 490 100 14,000 140 140 0 2.5 z 

16 USGS well24 22 9.0 6.8 850 340 16,000 290 200 0 8,700 25,000 20 51,000 - 118 -13.8 

1 Number corresponds to site shown in figures 2 or 7. 

2 Summation includes bicarbonate multiplied by 0.4916 to make result comparable t.o a "residue-on-evaporation" value. 

3 Analysis is average for 11 samples. 

4 Sample probably represents shallow water at depth of about 15 feet, rather than at 66-foot total depth. 

(") 

,_, 

c.> 
Cl4 REGIONAL AQUIFER-SYSTEM ANALYSIS-GREAT BASIN, NEVADA-UTAH 

<:> 100 

~ $' 

ct> ~ 

80 ~ -<> 

,j ('<(p 

$' -<> (;j a ... #i 60 

0 -y<Jl 

$" ~ 

c3' ~ 40 

.?1t, 

c§' 

20 

0 

% "b "b 11 ,12 

CALCIUM 

~ 

~ 

~ $' 

# 

~ '& «" 

~ 

?" 

~ "b 

<1.' 

v" 

<:> ct> 

EXPLANATION 

0 

100 

'b 

$' 

CHLORIDE 

Chemical evolution pathFrom recharge areas to 

discharge area 

Sample-Number refers to 

table 3 

80 

~ 60 ('-<' 

-y~ 

40 

16 

PERCENTAGES OF MILLIEOUIVALENTS PER LITER 

FIGURE 6.-Chemical evolution of ground water in the bastn-fill aquifer of Smith Creek Valley, Nev. 

percolates below the root zone and dissolution of soilzone carbon dioxide gas and the volcanic groundmass and phenocrysts. These dissolution processes 

are similar to dissolution processes in the Absaroka 

Mountains in Wyoming (Miller and Drever, 1977) 

and in the Oasis Valley in Nevada (White , 1979). 

Constituents dissolved in precipitation are concentrated by evapotranspiration in the recharge areas. 

This evapoconcentration is accounted for by assuming the increase in chloride in the recharge water 

(table 4) is due only to evapotranspiration before the 

water percolates below the root zone. 

Windblown gypsum is commonly deposited in 

uplands of desert environments (Pewe, 1981) and 

is the main component of dust in southern Nevada 

(Ronald Amundson, University of California, Berkeley, oral commun., 1987; Marith Reheis, U.S. Geological Survey, oral commun., 1987). Thus, gypsum is 

the most likely source of sulfate dissolved in 

recharge waters in Smith Creek Valley. Pyrite, if 

present in the volcanic rock, also may supply sulfate 

to the ground water in the upland areas. The 

increase in chloride concentration was assumed to 

result from evapotranspiration; however, part of the 

increase could be from dissolution of salts containing chloride that have blown into the recharge area. 

The small increase in magnesium concentration 

[0.04 millimoles per liter (mmol!L; table 4)] is most 

likely the result of magnesium biotite dissolution, 

because biotite is in volcanic rock in the recharge 

areas (table 1). Dissolution of illite, chlorite, or both, 

which are in the basin-fill sediments, also may be a 

source of magnesium. Aluminum and silica released 

by the weathering of volcanic groundmass and phenocrysts probably are removed from the water by 

formation of kaolinite, or some other clay mineral, 

and chalcedony (table 5). A mass-balance solution 

for the evolution of precipitation, concentrated by 

evapotranspiration, to recharge water is given by 

mass-balance solution 1 in table 6. 
0 

I 

0 

GEOCHEMISTRY AND ISOTOPE HYDROLOGY, GREAT BASIN 

11 ?035' 

I 

4 MILES 

I 

4 KILOMETERS 

R 39 E 

Basin fill with wa ter types 

Sodium alcium bicarbonate water 

Sodium bicarbonate water 

Sodium chloride water 

Consolidated rock 

4 

• 

.,I "' . 

\\ 

(Y. 

'}.-

EXPLANATIO 

R 40 E 

9,8 

• 

11?025' 

\ 

( 

R 41 E 

Playa deposits 

Pbreatophytlc vegetation 

Hydrographic area boundary 

Sediment and (or) water-quality sample 

sit Letter indicates sediment analy is, 

table 2. Number indicates water-quality 

analysis, table 3 

F IGURE 7 .-Water types in shallow basin-fill aquifer of central Smith Creek Valley, Nev., based on dominant ions. 

Sites having two wells Ust the deeper well (66 feet) first and the hallower well (22 feet) second. 

Cl5 

T 

18 

N 

T 

17 

N 

T 

16 

N 
C16 REGIONAL AQUIFER-SYSTEM ANALYSIS- GREAT BASIN, NEVADA- UTAH 

TABLE 4.-Auerage constituent concentrations of water types used in. mass-balance calculations, Smith Creek Valley, Neu. 

[Millimoles per Hter) 

Thta l 

Water type Calcium Mag- Sodium Potassium inorganic Sulfate hloride Silica nesium carbon 

Precipitation 0.03 0.01 0.03 0.01 20.03 0.02 0.06 3o.oo 

Precipitation, concentrated by evapotraospiration1 .07 .02 .08 .02 .12 .04 .16 8 00 

Recha rge water (samples 2 and 3) .24 .06 .70 .05 .99 .11 .16 .60 

Sodium calcium bicarbonate water (samples 4-6) .70 .19 1.52 .16 2.50 .37 .58 .97 

Sodium bicarbonate water (samples 7- 9) .36 .08 4.87 .18 6.21 .15 1.09 .36 

Sodium chloride water (sample 10) 2.75 .54 30.95 .44 .51 1.88 33.93 .18 

1 oncentration of precipitation before percolation below root zone was assumed to be proportional io the increase in chloride from precipitation to recharge water. 

2 Tht.a l inorganic ca rbon calculated using the computer program PHREEQE (Parkhurst and others, 19 0), assuming precipitation was in equilibri um with the atmosphere; that is, 

Lhe loganthm of the partial pressure of carbon dioxide gas is -3.6 (Sundquist and others, 1979). 

3 Si0 2 was assumed to be zero in precipitation. 

EVOL TIO OF RE HARGE TO 

0 01 M C LCI I BICARBO ATE WATER 

As water recharging the basin-fill aquifer flows 

toward the playa from around the margin of the basin, 

constituent concentrations increase because of the dissolution of tuff-derived deposits and chloride and sulfate evaporative salts (samples from sites 4-6; tables 3, 

4). Dissolution of albite, anorthite, and K-feldspar 

results in increased sodium, calcium, and potassium 

concentrations. Dissolution of salts formed by evapotranspiration in the unsaturated zone or in ephemeral 

stream channels are probable sources of chloride, 

sodium, and sulfate. During extremely wet periods, 

some water probably flushes through the unsaturated 

zone, dissolving the salts and carrying them to the 

water table. Chloride, sodium, and sulfa te form the 

most soluble salts in desert soils and are r eadily dissolved by water flushing through the unsaturated zone 

(Drever and Smith, 1978). In addition, evaporative 

salts buried by sedimentation also may dissolve as 

ground water flows through the basin-fill sediments. In 

the mass-balance calculations, halite dissolution is 

used for the input of chloride and sodium, and gypsum 

dissolution is used for the input of sulfate. Bicarbonate 

TABLE 5. - Saturation indices for selected minerals in water of Smith Creek Valley, Neu. 1 

[Calcula ted using computer program WATEQ4F (Ball and others, 1987).] 

Site2 Al bite Anorthite Ca-montmorillonjte Calcite Chalcedony Gypsum Halite Kaolinjte K-feldspa r Mg-biotite 

Recharge water 

2 - 2.2 -6.1 0.3 - 1.4 0.4 - 3.3 -8.8 0.7 - 0.7 - 34.0 

3 - 1.5 - 5.1 .8 -.6 .5 -3.0 -8.4 .8 .1 - 30.5 

Sodium calcium bicarbonate water 

4 - 2.1 - 7.2 1.1 - 1.5 .7 - 2.8 -8.2 1.2 -.4 -37.9 

5 - 2.2 - 7.7 1.0 - 1.7 .7 - 2.2 - 7.6 1.2 -.3 - 39.8 

6 - 1.0 - 5.2 1.4 - .4 .7 - 2.1 - 7.5 1.2 .6 -31.6 

Sodium bicarbonate water 

7 - 2.4 -8.2 .2 - 1.7 .5 -2.8 - 7.7 .8 - .8 - 40.2 

8 - 2.4 - 7.7 - .6 - 1.0 .2 - 3.2 - 7.2 .3 - 1.2 - 38.1 

9 - 3.1 - 8.6 - 1.3 - .9 .0 -3.0 - 6.4 -.1 -1.9 - 39.8 

Sodium chloride water 

10 - 1.2 - 4.9 - .9 .0 .0 - 1.4 -4.7 - .2 - .3 27.3 

I Saturation index = lo [i on · activit y produ ct] - . . . g Kr ' where KT - eqmh bnum constant at temperature T. By convention, positi ve value indicates mineral can precipitate from 

sol ution, whereas negative value indicates mine ral can dissolve if present in the aquifer Aluminum concentrafo . · a nd others, 1980), assuming each water was saturated wich respect to gibbsite and usin.g thermod . d t.a 'r ns ~bbre calfrculatRed usmg computer program PHREEQE (Pa rkhurst 

2 . . . ynam1 c a oor g. s1te om ob1e a nd others (1978, p. 140). 

Number corresponds to s1te hst.ed m table 3 and shown in fi gures 2 or 7. 
GEOCHEMISTRY AND ISOTOPE HYDROLOGY, GREAT BASI C17 

TABLE 6. - Mass transfer of con.stituents in Smith Creek Valley, Neu. 1 

[Symbol: --, ph a e not included in mas -balance calculation] 

Albite [NaAISi30sJ 

Anorthite [CaAI2Si20 sl 

K-feldspar [KA1Si30 sl 

Gypsum [CaS04• 2H20l 

H2S (gas) 

C0 2 (gas) 

Calcite [CaC03l 

Hali te [NaCI) 

Phase 

Mg-biotite [KMg3Si3Al0w(0H)2J 

Chlorite rMg5 Al2 Si3 Ow(OH)a] 

Chalcedony [Si02l 

Kaolinite lAl2Si20 s(OH)4] 

Ca,Mg-Na exchange3 

CaiN a-montmorillonite [Cao.o83 ao 167Al2.33Si3.670 10(0H)2) 

Clinoptil olite [(Na0_3Ko.4Cao.3)(AlSis 0 d·4H20 ) 

0.62 

.10 

.02 

.08 

.87 

.01 

- .71 

- .43 

Mas -balance solutions2 (mill imoles per liter) 

2 

0.41 

.19 

.06 

.26 

1.51 

.42 

.04 

- .66 

- .45 

3 

1.79 

.08 

.02 

- .22 

3.71 

.52 

-4.23 

-.99 

1.04 

4 5 

1.94 2.26 

.17 .57 

.02 .67 

-.22 -.22 

3.71 3.71 

.52 .52 

-3.22 

- 1.23 

1.06 1.06 

-.99 

- 1.62 

6 

1.72 

6.36 

.26 

1.73 

- 5.70 

32.8 

.09 

-3.21 

Natrolite [Na2(Al2Si30 10)·2H20 ] - 4.24 

l Mass-transfer value is change in mass of indicated phase, calcul ated from change in wat.er chemistry between different water types. egalive value indicates transfer out of 

solution, and positive va lue indicates tran fe r into solution. 

2 Mass-balance olutions 1-6 correspond to mass baJances between the following water types given in table 4: 

1. From preci pitation concentrated by evapotranspiration to recharge water; 

2. From recharge water to sodium calcium bicarbonate water; 

3-5. Three examples of mass·balance solut.ions for sod ium calcium bicarbonate water to sodium bicarbonate water; 

6. F-rom sodium bica rbonate water to the most dilute sodium chloride water. 

3 Positive vaJue indicates calcium and magnesium in water are being exchanged for sodium on c.lay minerals. Values are millimolcs of sodium per liter. 

concentration increases from the reaction of carbonic 

acid, which is derived from soil-zone carbon dioxide, 

with the volcanic groundmass and phenocrysts in the 

tuff-de rived deposits. Magnesium concentration 

increase is probably from biotite dissolution. Feldspar 

hydrolysis releases cations and results in the formation 

of kaolinite, or some other clay mineral, and chalcedony. A mass-bala nce solution for the evolution of 

recharge water to sodium calcium bicarbonate water is 

given by solution 2 in table 6. 

EVOL T lO 1 OF ODI l\1 'ALCl l\1 lllCARBO ATE 

TO .'ODl il l 13 1 .ARBO ATE \\'ATER 

Ground water in the aquifer evolve from a sodium 

calcium bicarbona te to a sodium bicarbonate type in 

the vicinity of the fine-grained playa area (tables 3, 4; 

figs. 6, 7). Average calcium and magnesium concentrations decrease from 28 to 14 and from 4.5 to 2.0 mg/L, 

respectively; average sodium and bicarbonate concentr a tions incre ase from 35 to 112 and from 115 to 

287 mg/L, respectively (samples from sites 4-6 and 7-

9; table 3). The r emoval of calcium and magnesium 

from the water may be the result of several processes, 

but the presence of montmorillonite in the discharge 

area (table 2, fig _ 7) indicates that cation exchange of 

calcium and magnesium in t h e wat er for odium 

adsorbed on clays is the most probable process (table 6, 

solution 3). The decrease in calcium concentra tion cannot result from calcite precipitation because samples 

from sites 4-9 are undersaturated with respect to calcite (table 5). The ratio of ca lcium t o magne ium 

exchanged for sodium is based on the average ratio of 

calcium to magnesium (4:1 ) in t h e sodium calcium 

bicarbonate and sodium bicarbonate waters (table 4). 

Calcium also may be removed by the weathering of 

plagioclase to Ca!Na-montmorillonite [Ca o.o 3Nao.l6? 

Al2.33Si3_670 10(0Hh ] (table 6, solution 4) or by the precipitation of a zeolite mineral, such as clinoptilolite 

[(Nao.3KoACa0.

3)(AlSi50 12}4H20] (table 6, solution 5). 

All three solutions would increase sodium and 

bicarbonate concentrations in the water by cation 

exchange and dissolution of plagioclase and evaporative salts, along with the addition of carbon dioxide gas. 

Any mix of these processes is possible given the 

observed chemistries. 

An activity diagram for the system Ca0-C02-

Na20-Si02-Al203-H20 (fig. 8) shows that the different 

water types plot a long a 2:1 slope, and in particular, 

sodium bicarbonate waters plot close to the phase 
Cl8 REGIO AL AQUIFER-SYSTEM ANALYSIS- GREAT BASIN, NEVADA- UTAH 

13.0 

"' + 

~ 12 0 . 

+ "' 

S2. "' 

g 11 .0 _J 

Ca-Montmorillonite 

• 

• • 

• Na-Montmorillonite 

• 

• 

• 0 

9.0 l___L___lj_,L__L____!_...L___L.~~__L_---:'-::--L.._-::9 0 

3.0 4.0 5.0 6.0 7.0 . 

LOG [Na+]/ [W] 

FIGURE 8.- Aqueou activities for the system Ca0-C0 2-Na20-Si02-

AJ20 3-H20 in Smith Creek Valley, ev. The phase boundary is 

ba ed on the thermodynami c data of Arnorsso n a nd others 

(1982). Chemical symbols: Ca2+, ca lcium; H+, hydrogen; a+, 

sodium. Bracketed items are ion activities. 

boundary between Ca-montmorillonite and Na-montmorillonite as would be expected for either cation 

exchange or formation of CaiN a-montmorillonite. 

Precipitation of zeolite minerals in the Smith 

Creek Valley basin-fill aquifer is evidenced by the presence of zeolite minerals in the basin-fill deposits. Furthermore, rhyolitic tuff and basin-fill aquifers derived 

from rhyolitic tuff in southern Nevada, similar to those 

in Smith Creek Valley, contain ground water in which 

calcium is removed by weathering of tuff or tuffderived deposits to montmorillonite and by precipitation of zeolite minerals, predominantly clinoptilolite 

with a composition of (Nao.3Ko.4Cao.3)(AlSis012).4HzO 

(Hoover, 1968; White, 1979; White and others, 1980; 

Claassen, 1985). 

Chloride and potassium concentrations increase 

and sulfate concentration decreases as the water 

evolves from a sodium calcium bicarbonate to a sodium 

bicarbonate type. Chloride concentration increases 

along the flow path by evapotranspiration of the water 

and dissolution of chloride salts. Potassium concentration increa es, probably because of K-feldspar dissolution. Sulfate concentration decreases along the flow 

path probably because of the reduction of sulfate to 

hydrogen sulfide gas and precipitation of FeS (Jones, 

1966; Phillips and VanDenburgh, 1971; Eugster and 

Jones, 1979) or possibly because of surface sorption 

(Wood, 1978; Eugster and Jones, 1979), because more 

fine-grained sediments with larger surface areas are 

present in the playa area. The sodium bicarbonate 

waters are undersaturated with respect to gypsum 

(table 5), so gypsum precipitation cannot be the cause 

of the decrease in sulfate . 

E OL TIO ' OF ODI M BI ARB 1 ATE TO TH E l\!0 T 

OIL TE SOD! M CHLORI DE \ 1\TER 

In the playa area, ground water evolves from a 

sodium bicarbonate to a sodium chloride water 

(tables 3, 4; figs. 6, 7). Constituent concentration 

increase because of the dissolution of evaporative salts, 

evapotranspiration, and mixing. 

Dissolution of evaporative salts probably is the 

major source of increasing chloride and sodium concentrations as the water evolves from sodium bicarbonat~ 

to sodium chloride type because ( 1) chloride and 

sodium concentrations increa e in about equal 

amounts, (2) other constituents increase less than ch\o. 

ride , and (3) the isotopic composition of the dilute 

odium chloride water is similar to that of the sodium 

bicarbonate water. Evaporative salt dissolution is the 

simplest explanation consistent with all three observations. 

Di~solution of evaporative salts containing chloride 

and sodium should add these constituents to the water 

in about equal amount (Drever and Smith, 1978). The 

approximately 30 mmol/L increase of chloride and 

sodium observed as the water evolves from sodium 

bicarbonate (samples from sites 7- 9; fig. 7) to the most 

dilute sodium chloride (sample from site 10; fig. 7) 

water (table 4) supports this dis olution process. The 

increase in sulfate, calcium, magnesium, and pota · 

sium also may be from the dissolution of salts or min· 

erals (table 6, solution 6) that are below saturation in 

the water [table 5; also the saturation index of chlorite 

(not shown) for the sample from site 10 is - 1.4]. 

Sodium, sulfate, calcium, magne ium, and pota · 

sium increase in concentration as the water evolve 

from a sodium bicarbonate to sodium chloride water, 

but they do not increase in proportion to chloride a 

would be expected if evapotranspiration were occurring 

(table 4, figs. 9-13). This is a second indication that di · 

solution of evaporative salts and minerals is a major 

source of constituents. Constituent concentrations 

resulting from salt or mineral dissolution would not 

increase in proportion to chloride but, rather, would 

increase in proportions determined by the chemical 

composition of the soluble salt or minerals. If chloride 

concentration were the result of only evapotranspira· 

tion, then 60 to 80 percent of sodium, sulfate, calcium, 

and magnesium ions and 92 percent of potassium ions 

would have to be removed from the water to obtain the 

chemistry observed in the most dilute sodium chloride 
GEOCHEMISTRY AND ISOTOPE HYDROLOGY, GREAT BASIN Cl9 

water (sample from site 10, fig. 7). The sample, however, is below saturation with respect to most minerals 

that could precipitate, thereby removing constituents 

from the water, with the exception of calcite, which will 

be discussed later. Thus, precipitation of most minerals 

is unlikely. 

The third indication that dissolution is the major 

process producing a sodium chloride water is the isotopic composition of the sample from site 10. Dissolution 

of evaporative salts would not alter the isotopic composition of the water, whereas evaporation would shift the 

isotopic composition of the water to a heavier (more 

negative) value. The sample from site 10 has an isotopic composition similar to the sodium bicarbonate 

waters (samples from sites 7-9), indicating that the 

sample has not been significantly evaporated (fig. 14). 

In addition, the sample from site 10 was obtained from 

66 ft below land surface, where evaporation would be 

improbable. The sample from site 10 is below saturation with respect to albite, so although another source 

of sodium is not needed to obtain the sodium concentration in the sample, a small amount of sodium is probably added to the water by albite dissolution. 

Transpiration also may be an important process for 

increasing chloride and sodium concentrations as the 

water evolves from a sodium bicarbonate to a sodium 

chloride type. Transpiration can concentrate dissolved 

solids in water to depths greatly exceeding evaporation 

depths and, thus, could have increased constituent concentrations in water sampled from site 10. Phreatoz· 

Qa: 

1-w 

~t: 1-...J 

za: 

ww 

oo... 

Zcn 

0 w 1.0 O...J 

~0 

::::>~ - _J O...J 

g~ 

(9~ 

0 

_J 

0 

-1.0 

• 

0 

0 

0 • 

• I 

0 

• Na-Ca-HC03 water 

0 Na-HC03 water 

• Na-CI water 

o Precipitation 

-1.0 0 1.0 2.0 3.0 

LOG CHLORIDE CONCENTRATION, 

IN MILLIMOLES PER LITER 

4.0 

FIG RE 9. - Relation between odium and chloride concentrations in Smith Creek Va lley, Nev. 

z0 

-a: 1-w 

a:_ .:x: ..... f-...J 

Za: 

ww 

Oo... 

Zcn 

Ow O...J 

wO 

~--~ 

<x:- u_...J 

...J=:! 

::::>~ 

cnz 

(9-

0 

_J 

4.0 

3.0 

2.0 

1.0 

0 

-1.0 

• Na-Ca-HC03 water 

0 Na-HC03 water 

• Na-CI water 

0 Precipitation 

.. 

0 -2.0 .___.__.___.__.____.__.____.__.____.__.____.____, 

-2.0 -1 .0 0 1.0 2.0 3.0 

LOG CHLORIDE CONCENTRATION, 

IN MILLIMOLES PER LITER 

4.0 

FIGURE 10.- Re lation be tween ulfate and chloride concentJ·ations in Smith Creek Va lley, ev. 

phyte roots will follow fresh water to depths exceeding 

60 ft (P.A. Glancy, U.S. Geological Survey, oral commun. 1989) and, unlike evaporation, transpiration has 

been shown to concentrate dissolved solids in residual 

water with little or no effect on isotopic composition 

(Wershaw and others, 1966; Zimmerman and others, 

1967, p. 576; Ziegler and others, 1976; Gat and Gonfiantini, 1981 p. 223-238; Szecsody and others 1983 · 

Koltermann, 1984; White and others, 1985; Turner and 

others, 1987). Thus, the observed higher constituent 

concentration and unchanged i otopic composition are 

consistent with transpiration r emoving water and 

thereby increasing constituent concentrations in the 

residual water. However, tran piration could account 

for only a 20 to 40 percent increase in constituent concentrations (or 8 percent for potassium), unless constituent are being removed from the water as they become 

more concentrated. 

Mixing deeper water that contains lower dissolved 

solids with shallower water that contains higher dissolved olids (whether by molecular diffusion, dispersion, or density-drive n flow ) is probably no t an 

important process for increasing constituent concentrations as the water evolves from sodium bicarbonate 

to sodium chloride. The Peclet number calculated for 

the fine-grained Smith Creek playa sediments is considerably les than one, indicating that molecular diffusion predominates over mechanical dispersion (Bear, 

1972). This indicates that molecular diffusion of chloride and sodium ions from shallow briny water to 
C20 REGIO AL AQUIFER-SYSTEM ANALYSIS-GREAT BASIN, NEVADA-UTAH 

greater depths is a possibility, whereas mechanical dispersion is less likely. Calculation of a Rayleigh number 

relating diffusive flow to density-driven flow (Combarnos and Bories, 1975; Clifford Voss, U.S. Geological 

Survey, oral commun., 1987) indicates that densitydriven flow does not occur in the Smith Creek playa 

sediments. 

A convincing argument against mixing deep and 

shallow waters also comes from the stable isotope composition of the deeper sodium chloride water (samples 

from sites 10 and 11; fig. 7). The molecular diffusion 

rate of deuterium and oxygen-18 is greater than that of 

chloride and sodium (Wang and others, 1953, p. 468; 

Sherwood and others, 1975, p. 37), and mechanical 

mixing mechanisms do not differentiate between ions 

and isotopes. Therefore, if mixing is important, the 

deuterium and oxygen-18 isotopes would mix as fast, or 

faster, than the chloride and sodium ions. A mixture of 

water containing low dissolved solids with water containing high dissolved solids that was concentrated by 

evaporation would have a mixed isotopic composition, 

as well as intermediate ionic concentrations. However, 

the deep sodium chloride water has a deuterium and 

oxygen-18 composition similar to sodium bicarbonate 

water unaffected by evaporation (fig. 14) and is different from that of the shallow sodium chloride water, 

which has been affected by evaporation. Therefore, 

mixing (by whatever mechanism) of isotopically heavy 

(less negative) water containing high chloride and 

sodium concentrations is not indicated at depth (66ft). 

z 

0 

-a: 1--w 

<(1--

CI:- f-_l 

Za: Ww 

Oa.. z(J) 

Ow 

o_J 

~0 

::J~ 

-:J 

()_J 

_J-

<(~ 

Oz 

0-

0 

_J 

• Na-Ca-HC03 water 

0 Na-HC03 water 

• Na-CI water 

o Precipitation 

0 

• 

0 

• 

• • 

• 

-1.0 0 1.0 2.0 3.0 

LOG CHLORIDE CONCENTRATION, 

IN MILLIMOLES PER LITER 

4.0 

FIG RE 11 .- Relation between calcium a nd chloride concentration s in Smith Creek Valley, Nev. 

z 2.0 

0 

~a: a:w !z ~ 1.0 

Wa: Ow 

Za.. o(J) 

() w 0 

~6 (j)~ 

w_J 

z_l 

0 ~-1.0 

~~ 

0 

g -2.0 

• Na-Ca-HC03 water 

o Na·HC03 water 

• Na-CI water 

o Precipitation 

0 

0 

• • 

• 

-1.0 0 1.0 2.0 3.0 

LOG CHLORIDE CONCENTRATION, 

IN MILLIMOLES PER LITER 

4.0 

FIGURE 12.-Relation between magnesium a nd chloride concen· 

trations in Smith Creek Valley, Nev. 

Ground water may mix in the shallower part of the 

aquifer beneath the playa or phreatophytic area surrounding the playa, but not within the approximately 

44-ft vertical interval between the shallow and deep 

wells. In the deep wells, the isotopic composition of the 

water shows little effect of evaporation. 

Evaporation is not an important process for 

increasing chloride and sodium concentrations as the 

water evolves from a sodium bicarbonate to sodium 

chloride type. This is shown by samples from sites 10 

and 11, which were collected from 66ft below land surface in an area of upward flow. This water already has 

evolved from sodium bicarbonate to sodium chloride 

type in a zone well below that where evaporation 

occurs. Also, as noted, significant evaporation would 

produce an isotopic shift to heavier values, and this 

was not observed in samples from sites 10 and 11. 

Bicarbonate concentration decreases as the water 

evolves from a sodium bicarbonate to a sodium chloride 

water (table 4) because of calcite precipitation (table 6). 

A sample from site 10 is saturated with respect to calcite (table 5). Calcium concentration is approximately 

5 percent of the bicarbonate concentration in the 

sodium bicarbonate water, but precipitation of calcite 

does not totally deplete calcium. Calcite precipitation 

reduces bicarbonate concentration because calcium 

ions are added to the water by the dissolution of gypsum: 
GEOCHEMISTRY AND ISOTOPE HYDROLOGY, GREAT BASIN C21 

z 2.0 

0 

~a: a:UJ 

1- t:: 1.0 z_J 

UJa: 

ow zo_ 

0(/) 

u UJ 0 ::;i;_J 

::::>0 

Ui~ (/)_J 

<t:_J 

1- 0 

Oz ()__ 

C!J 

g -2.0 

• Na-Ca-HC03 water 

0 Na-HC03 water 

• Na-CI water 

o Precipitation 

• 

0 

0~ 

• • 

0 

-3.0 L___L_L___L_L___L_J.___,_ _ _.____,_ _ _.____,_____J 

-2.0 -1.0 0 1.0 2.0 3.0 4.0 

LOG CHLORIDE CONCENTRATION, 

IN MILLIMOLES PER LITER 

FIGURE 13.- Relation between potassium and chloride concentrations in Smith Creek Valley, Nev. 

E O L T ION OF OIL TE TO CO! CE RATED 

S 0 M H LO RJDE WAT ER 

Ground water in the playa area evolves from a 

slightly saline (measured dissolved-solids concentration, 2,300 mg!L) to a briny (measured dissolved solids, 

51,000 mg/L) sodium chloride water (samples from 

sites 10- 16; table 3, fig. 7). The increase in sodium concentration is proportional to the increase in chloride 

concentration (fig. 9) as the water evolves from the 

most dilute to most concentrated sodium chloride 

water. This 1:1 increase can result from evaporation, 

dissolution of evaporative salts, or transpiration. 

A plot of deuterium in relation to oxygen-18 (fig. 14) 

indicate that ground water is being removed in some 

parts of the playa area by evaporation. A plot of deuterium in relation to chloride (fig. 15) shows that chloride 

concentration increases in areas in which isotopic compositions of ground water are largely unaffected by 

evaporation. The overall contribution of evaporation to 

the chemical evolution of the water was estimated from 

the stable isotope composition and chloride concentration by using the Rayleigh distillation equation (Dansgaard , 1964), assuming that chloride remains 

conservative during evaporation. The Rayleigh distillation curve for evaporative concentration was calculated 

u ing initial deuterium and chloride compositions of 

the average sodium bicarbonate water (samples from 

ites 7- 9, table 3) and a fractionation factor (1.0079) 

calculated for a basin-fill aquifer in northwestern 

Nevada (Welch and Preissler, 1990 p. 32- 41). The 

increase in chloride concentration in ample from 

sites 13, 14, and 15 is accompanied by a moderate shift 

in deuterium to heavier (less negative) values, indicating that some of the increase in chloride is cau ed by 

evaporation. In contrast, the increase in chloride concentration in samples from sites 10, 11, 12, and 16 is 

not accompanied by a deuterium shift characteristic of 

evaporation and, thus, must be there ult of other processes. 

Dissolution of evaporative salt could increase chloride and sodium concentrations more than evaporation. Salt dissolution induces no isotope shift . 

Dissolution of evaporative salts could greatly increase 

chloride and sodium concentrations and would account 

for the evolution of other constituents. For example, 

sulfate concentration in the sodium chloride water generally increases at a rate greater than 1:1 with respect 

to chloride (fig. 10). This increase requires addition of 

sulfate, most likely from dissolution of gypsum, in 

addition to concentration of sulfate by evapotranspiration. If gypsum is dissolving, other salts probably also 

are dissolving. 

Transpiration is an important hydrologic process in 

Smith Creek Valley that also may explain the increased 

constituent concentrations. Approximately 70 percent 

of ground water discharged from Smith Creek Valley is 

transpired from the phreatophytic area surrounding 

the playa (Thomas Carlton, and Hines, 1989). 

-90 

13 

_J • ~ -100 

a: 14 

UJ 

0... 

~ -110 ':t 

::J 

a: 

UJ 

1-

::J -120 UJ 

0 

<! 

1-

_J 

UJ -130 0 

-140 

-17 -16 -15 -14 -13 -12 -11 -10 -9 

DELTA OXYGEN-18, IN PERMIL 

FIG RE 14.-Relation between deute rium and oxygen -18 in 

Smith Creek Vall ey, Nev. The global me teoric wate r line 

LllD=8(8 180 )+10] is based on worldwide preci~itation da~a 

(Cra ig, 1961). The local water !me [llD=6.82(8 80 )-16.8] IS 

based on a linear regression of samples from sites 2 to 11 

(see figs. 2, 7; table 3). 
C22 REGIO AL AQUIFER-SYSTEM ANALYSIS- GREAT BASIN, NEVADA-UTAH 

-70 

_J -80 

~ a: 

w -90 Q_ 

~ 

-100 :::> 

cr 

w 

f- -110 :::> 

w 

0 

<( -120 f-

_J 

w 

0 -130 

-140 

0 

• 10 

13 

• 

TRANSPIRATION OR 

EVAPORATIVE SALT DISSOLUTION 

16 

• 

5,000 10,000 15,000 20,000 25,000 30,000 

CHLORIDE CONCENTRATION, 

IN MILLIGRAMS PER LITER 

FIGURE 15.- Relation between deuterium and chloride concentrations in samples from wells in Smith Creek Valley, Nev. 

Numbered circles corre pond to sites in figures 2 and 7 and 

table 3. 

Transpiration results in concentration of ions but 

induces no isotopic shift, so it is also a simple and reasonable explanation for concentration of constituents 

in the sodium chloride water. Sodium chloride water 

from shallow wells (22ft deep) in or along the phreatophytic area that surrounds the playa (samples from 

sites 12, 15, and 16) show the least effect of evaporation, whereas samples from shallow wells (samples 

from sites 13 and 14) directly beneath the playa surface 

show the greatest evaporative concentration, as indicated by the stable-isotope and chloride concentrations 

(figs. 7, 14, 15). A limit to transpirative concentration of 

dissolved solids in ground water is the unknown maximum salt tolerance of the phreatophytic plants in 

Smith Creek Valley. 

Other reactions also probably modify the chemistry 

of the ground water as it evolves into a more concentrated sodium chloride water. For example, evapotranspirative concentration would result in an increase 

of calcium, magnesium, and potassium concentrations 

in proportion to chloride. However, the observed 

increase in the concentrations of these three constituent generally is less than 1:1 with respect to chloride 

(figs. 11-13). Thus, other processes also are affecting 

calcium, magnesium, and potassium concentrations. 

These constituents could be removed from the water by 

precipitation of calcite and zeolite minerals, exchange 

on clay minerals, and the formation of clay minerals. In 

addition, dissolution of minerals and evaporative salts 

is probably adding calcium, magnesium, and potassium to the water, as well as sodium, chloride, and sulfate. 

GEOCHEMICAL AND ISOTOPIC DEUNEATION 

OF GROUND-WATER FLOW IN A TYPICAL 

CARBONATE-ROCK AQUIFER 

In carbonate-rock aquifers in the east half of the 

Great Basin, ground water generally flows in the basinfill deposits and the underlying and adjacent carbonate 

rock, thus resulting in large regional flow systems that 

encompass numerous topographic basins and have circulation depths of several thousand feet. The dominant 

geochemical processes in these flow systems generally 

are (1) dissolution of minerals and soil zone C02 gas, 

(2) precipitation or formation of minerals, (3) mixing of 

chemically or isotopically different waters, or both, (4) 

ion exchange, and (5) geothermal heating due to deep 

circulation. 

The carbonate-rock aquifers in southern Nevada 

are an example of these carbonate-rock flow system 

(fig. 16). The aquifers include two regional flow system 

that discharge in southern Nevada: the White River 

flow system, which discharges at Muddy River springs 

(fig. 16) and is a subsystem of the Colorado flow system 

(fig. 1), and the Ash Meadows flow system, which discharges at Ash Meadows springs (fig. 16) and is a subsystem of the Death Valley flow system (fig. 1; Eakin, 

1966; Mifflin, 1968; Winograd and Friedman, 1972; 

Winograd and Thordarson, 1975; Hess and Mifflin, 

1978; Thomas and others, 1986; Harrill and others, 

1988; Dettinger, 1989; Kirk and Campana, 1990). In 

the north-central part of the study area, ground water 

also flows from the White River system to the Ash 

Meadows system (figs. 16, 17). The e flow systems 

encompass thousands of square miles and include several valleys. Recharge to these regional systems is from 

several sources, and most of the flow discharges from a 

common area that contains numerous springs. Smaller 

carbonate-rock flow systems, such as the Las Vegas 

Valley flow system, also are present in the study area. 

In these smaller systems, recharge is primarily from 

one source and water may discharge from the aquifer 

in several places. 

Geochemical processes that produce the chemical 

and isotopic compositions of the water in carbonaterock aquifers were identified using stable and radioactive isotopes, major-ion chemistry, mass-balance calculations, thermodynamic calculations, and mineral 

identification. The isotopic and chemical compositions 

of water from different areas were u sed further to 

delineate regional flow systems. The primary processes 

that produce the isotopic and chemical content of the 
GEOCHEMISTRY AND ISOTOPE HYDROLOGY, GREAT BA IN 

EXPLA ATIO 

c=J Basin-fill deposits 

C=:=J arbonatc rock 

- onca rbonatc rock 

Flow system boundury 

Spring- Discharging from 

carbonate-rock aquifer 

0 

0 

25 

FIGURE 16. - Ma p showing groun d-water flow systems in southern evada, as delineated in this study. 

C23 
C24 REGJO AL AQUIFER-SYSTEM ANALYSIS- GREAT ~ASIN , EVADA- UTAH 

ground water in these regional systems of southern 

Nevada are (1) dissolution of C02 gas in the soil zone, 

(2) dissolution of carbonate sediments and rock (calcite 

and dolomite) in the recharge areas (most spring and 

well waters in recharge areas are at or near saturation 

with respect to calcite and dolomite), (3) precipitation 

of calcite, (4) leakage of water with high sulfate and 

sodium concentrations from the Tertiary confining 

unit, or dissolution of gypsum and halite, (5) mixing of 

different waters, (6) dissolution of volcanic rock, (7) 

exchange of calcium and magnesium in the water for 

sodium in clay minerals, (8) precipitation of chalcedony, and (9) formation of kaolinite 

GEOLOGIC FRAMEWORK 

Southern Nevada has had a complex geologic history of sedimentation, volcanic activity, and faulting. 

Miogeosynclinal se dimentation from Cambrian 

through Permian time produced thick sequences of carbonate and clastic sedimentary rock in southeastern 

Nevada and the Death Valley area of California. Widespread volcanism from Tertiary through present time 

produced extensive volumes of volcanic rock now 

exposed over much of the area. Major thrust faulting 

associated with the Sevier orogeny (late Mesozoic) and 

Cenozoic low-angle, near-surface thrust faulting and 

right-lateral strike-slip faulting have produced shear 

zones and high-angle basin-and-range faulting, resulting in the topography observed today (Stewart and 

Carlson, 1978). A detailed description of the hydrogeology of the entire Great Basin, as delineated by this 

RASA study, is given by Plume (1996). 

Stratigraphic units in the study area were grouped 

into six hydrogeologic units to correspond to Winograd 

and Thordarson's (1975) hydrogeologic units in the 

Nevada Test Site area of southern Nevada (table 7). 

The hydrogeologic units are (1 ) Cambrian and older 

noncarbonate rock, (2) Cambrian to Devonian carbonate rock, (3) Devonian and Mississippian noncarbonate 

rock, (4) Mississippian to Permian carbonate rock, (5) 

Triassic to Quaternary noncarbonate rock, and (6) Tertia ry and Quaternary basin-fill deposits (pl. 1). The 

hydrogeologic map is modified from that of Plume and 

Carlton (1988), which is based on geologic maps of 

Nevada and California compiled by Stewart and Carlson (1978) and Jennings (1977). Winograd and Thordarson's (1975) lower clastic confining unit was used in 

the Amargosa-Death Valley area of California to delineate the boundary between the Cambrian and older 

noncarbonate rock and the Cambrian to Devonian carbonate rock. 

The Cambrian and old er noncarbonate rock 

includes primarily siltstone, quartzite, shale, and 

sand tone in the northern and western parts of the 

study area and metamorphic and granitic rocks in the 

southern and eastern part of the study area (Longwell 

and others, 1965; Tschanz and Pampeyan, 1970; Cornwall, 1972; Winograd and Thordarson, 1975; Jennings, 

1977; Stewart and CaTlson, 1978). These rocks probably underlie most of the study aTea at differing depths. 

Hydraulic conductivity of this unit is low, less than 

0.1 ft/d, compared with the overlying carbonate-rock 

unit (median value of 2.0 ftJd: Dettinger and others 

1995). Thus, this unit retards ground-water flow and 

forms the base, or an adjacent boundary, to the carbonate-rock aquifers. 

Cambrian to Devonian carbonate rock include 

mostly limestone and dolomite. The limestone and 

dolomite formations contain numerous, generally 

basal, silty limestone and dolomite units. This hydrogeologic unit a lso contains numerous interbedded 

quartzites, sandstones, and shales, and many of the 

limestone and dolomite beds contain chert nodule 

(Langenheim and others, 1962; Longwell and others, 

1965; Tschanz and Pampeyan, 1970; Cornwall, 1972· 

Winograd and Thordarson, 1975; Jennings, 1977; 

Stewart and Carlson, 1978). In some places the 

hydraulic conductivity of this unit is high, as much a 

940 ftld (Dettinger and others, 1995), because of secEXPLANATIO 

Basin-fill deposits- In area underl ain by thick, laterall y 

continuous carbonate rock 

[ / / /J Basin-fill deposits- In areas out ide thick, laterall y 

continuous carbonate rock 

Carbonate rock- In areas of thick, laterally conti nuou. 

carbonate rock 

[///J Carbona te rock- In areas outside thick, latera ll y 

continuous carbonate rock 

- oncarbonate rock- In area of thick , laterall y continuou 

carbonate rock 

- oncarbonate rock- In areas out ide thick, latcrall 

continuous carbonate rock 

+ + + Gass Peak thrust fault awteeth on upper plate 

- - - - Boundary of laterally continuous carbonate rock 

A 

___ A' Line of geologic section (fig. IS) 

... Generalized direction of ground-water movement in 

carbonate-rock aquifers 

Spring-Emanates from carbonate-rock aquifer 

• Well ource of water is carbonate-rock aquifer 
GEOCHEMISTRY AND ISOTOPE HYDROLOGY, GREAT BASI 

0 25 50 MILES 

0 25 50 KILOMETERS 

FIGURE 17.-Ground-water flow diTections and hydrogeologic features a sociated with carbonate-rock aquifers 

in southern Nevada. Modified from Dettinger (1989, figs. 3, 4). 

C25 
C26 REGIO AL AQUIFER-SYSTEM ANALYSIS- GREAT BASIN, NEVADA- UTAH 

TABLE ?.-Hydrostratigraphy in southem Neuada and southeastern California 

Hydrogeologic unit 

and geologic age 

(see plate 1) 

Hydrogeologic unit names 

used by Winograd and 

Thordarson (1975) 

Calculated hydraulic conductivity (feet per day) 

Basin-fiLl deposits, 

Quaterna ry and Tert iary 

Valley-flU aquifer Ranges from 0.6 to 17 (Winograd and Thordarson , 1975; Ha r-rill, 1986; 

Morgan and Dettinger, 1996). 

oncarbonate rock, 

Quaternary to Triassic 

Tu.fT aquitards and aquifers Ran ges from 0.1 to 92, but most aquifers a re generally less than 1.0, 

except for highly permeable Pia pi Canyon Group (Winogr ad and 

Thorda rson, 1975). 

Carbonate rock, 

Permia n to Mississippian 

Upper carbonate aquifer Ranges from 0.1 to 900, with mean value of 102 and media n value of 5.2 

(Dettinger and others, 1995). 

Noncarbonate rock, 

Mississippian and Devonian 

Carbonate rock, 

Devonian to Cambrian 

Noncarbonate rock, 

Cambrian and older 

Upper clastic aquita rd 

Lower ca rbonate aquifer 

Lower clastic aquitard 

ondary permeability produced by fracturing (Winograd 

and Thordarson, 1975). Consequently, this unit can 

transmit vast quantities of water. 

Devonian to Mississippian noncarbonate rock 

includes mostly shale, argillite, siliceous siltstone, 

quartzite, and conglomerate (Cornwall, 1972; Winograd and Thordarson, 1975). Because the hydraulic 

conductivity of this unit is extremely low, 0.01 ft/d (Dettinger and others, 1995) this unit restricts groundwater flow (Winograd and Thordarson, 1975). However, 

this low-permeability unit is greater than 200 ft thick 

only in the north-central part of the study area. Elsewhere, the carbonate-rock units form one continuous 

aquifer. 

Mi sis ippian to Permian carbonate rock is mainly 

limestone. The limestone consists ofnumerous argillaceous, cherty, and fetid limestone beds and interbedded 

shale, siltstone, and sandstone, along with gypsum in 

the upper part of the unit (Langenheim and others, 

1962; Longwell and others, 1965; Tschanz and Pampeyan, 1970; Cornwall, 1972; Winograd and Thordarson , 1975 ; Stewart and Carlson, 1978). Hydraulic 

conductivity of this unit is as high as 900 ft/d (Dettinger and others, 1995) because of secondary permeability produced by fracturing (Winograd and 

Thordarson, 1975). Thus, this unit is capable of transmitting large quantities of water. 

Triassic to Quaternary noncarbonate rock is mostly 

volcanic rock consisting of welded to nonwelded ashflow and ash-fall tuffs, and basalt and rhyolite flows 

(Longwell and others, 1965; Tschanz and Pampeyan, 

1970; Cornwall, 1972; Winograd and Thordarson, 1975; 

J ennings, 1977; Stewart and Carlson, 1978). Although 

the hydraulic conductivity of this unit generally ranges 

0.01 for two wells (Dettinger and others, 1995). 

Ran ges from 0.01 to 940, with mean value of96 and media n value of2.0 

(Dettinger and others, 1995). 

Le s than 0.1 for two wells (Dettinger and others, 1995). 

from 0.1 to 2.0 ft/d, in places it is as high as 92ft/d. In 

areas of high hydraulic conductivity, the unit can form 

transmissive aquifers. The older and more pervasive 

volcanic rock generally form low-permeability aquifers, 

with an average hydraulic conductivity of about 0.2 ft/d 

(Winograd and Thordarson, 1975; Dettinger and others, 1995). This unit also includes sandstone, siltstone, 

and conglomerate, which generally have low hydraulic 

conductivity and commonly form a low-permeability 

layer on top of more permeable carbonate-rock units. 

This unit also includes small areas of low transmissivity, Triassic to Quaternary intrusive rock that have 

invaded the carbonate rock, primarily along the south 

edge of the study area. 

Tertiary and Quaternary basin-fill deposits are 

composed of alluvial-fan, fluvial, fanglomerate, lakebed, and mudfiow deposits (Winograd and Thordarson, 

1975; Jennings 1977 ; Stewart and Carlson, 1978). 

Basin-fill deposits are fairly conductive (0.6 to 17 ftJd) 

and can transmit large quantities of water (Winograd 

and Thordarson, 1975; Harrill, 1986; Morgan and Dettinger, 1996). Basin-fill deposits in southern Nevada 

commonly are underlain by or are adjacent to carbonate rock. Together the basin-fill deposits and carbonate 

rock may form a single, highly transmissive aquifer. 

Southern Nevada has undergone episodes of 

regional compression, extension, and volcanism, which 

have resulted in the disruption of the originally thick 

and continuous carbonate-rock strata deposited during 

the Paleozoic. Primarily because of extension over the 

last 25 million years, only a central corridor of thick, 

laterally continuous Paleozoic carbonate rock remains 

in southern Nevada (fig. 17; Dettinger, 1989). This central corridor contains most of the regional ground-
GEOCHEMISTRY AND ISOTOPE HYDROLOGY, GREAT BASIN C27 

water flow in southern Nevada, including both the 

White River and Ash Meadows flow systems (fig. 16). 

The corridor of thick, continuous carbonate rock is 

bounded in places on the east and west by thin or isolated carbonate rock, or noncarbonate rock. Groundwater flow in the carbonate rock outside this corridor is 

not significant in volume (Dettinger, 1989). 

Geologic constraints on flow within the central corridor of carbonate rock are caused primarily by noncarbonate rock that has been rotated or emplaced close to 

the land surface. One postulated geologic constraint 

(Dettinger, 1989) that could significantly impede westward ground-water flow from the Sheep Range to Ash 

Meadows (fig. 17) is a low permeability wedge of noncarbonate clastic rock several thousand feet thick 

(Guth, 1980) extending a minimum of 1,000 ft above 

the water table along the west side of the Sheep Range 

(fig. 18). Another postulated geologic constraint to 

ground-water flow to the west from the Sheep Range is 

the absence of carbonate rock between Three Lakes 

Valley and the northern Sheep Range (fig. 17; Guth, 

1989). 

A probable geologic constraint on southward and 

southeastward ground-water flow from the Sheep 

Range was recognized by Winograd and Thordarson 

(1975). Cambrian noncarbonate rock along the Gass 

Peak Thrust Fault (fig. 17, pl. 1; Longwell and others, 

1965) in the Las Vegas Range greatly reduces groundwater flow from the Sheep Range. Thus, mo t of the 

recharge to the southern part of the Sheep Range may 

flow north and then east toward Muddy River springs 

because of noncarbonate-rock barriers to westward, 

southward, and southeastward flow. Also, eastward 

flow is enhanced by the 5 to 50 degree eastward dip of 

the strata in the Sheep Range (Longwell and others, 

1965; Tschanz and Pampeyan, 1970). 

Major structural zone that intersect the central 

carbonate-rock corridor also may alter ground-water 

flow by impeding or enhancing flow in some areas and 

directions. The Las Vegas Valley shear zone and Pahranagat Valley shear zone are two major structural 

zones in the central corridor that may influence 

ground-water flow by reducing flow across the zones 

and enhancing (or allowing) flow along the strike ofthe 

zones (fig. 17; Winograd and Thordarson, 1968; Winograd and Friedman, 1972· Winograd and Pearson, 

1976; Kirk, 1987; Lyles and Hes , 1988; Thomas, Carlton, and Hines, 1989; Thomas, Welch, and Preissler, 

1989; Kirk and Campana, 1990). 

Aquifers in the study area from which regional 

springs emanate are primarily Cambrian to Devonian 

dolomite and limestone and Devonian through Permian limestone. X-ray diffraction analyses of rocks of 

Precambrian to Permian age show that the mineralogy 

of the upper and lower carbonate-rock aquifers i predominantly dolomite and calcite (table 8). Whole-rock 

major-element analyses indicate that the dolomite 

and limestones generally are composed of extremely 

pure carbonates containing less than 1.5 weight percent of major element oxides other than calcium carbonate and magnesium carbonate (ta ble 9). ulfur 

analyses (table 10) also show the limestone and dolomites are extremely pure. Samples used for whole-rock 

major-element analyses were limestones and dolomites 

with few fracture fillings or notable impurities· the 

chemistry of more veined or shaley limestones and 

dolomites may differ. X-ray diffraction analyses 

(table 8) and analyses of the insoluble re idue from the 

whole-rock chemical analyses (table 11) indicate that 

minerals other than calcite and dolomite in the carbonate rock are mostly quartz with lesser amounts of illite, 

smectite, feldspar, alunogen, chlorite, kaolinite palygorskite, clinoptilolite, and unidentified zeolite (table 

11). Fracture-filling vein minerals are primarily calcite 

and dolomite but also include quartz aragonite, iron 

and manganese oxides, and clays (table 8; Winograd 

and Thordarson, 1975). These vein minerals are primarily precipitated from the ground water, except for 

clays which are weathering products. Although the carbonate rock may contain inclusions of connate seawater, the low sodium and sulfur concentrations (tables 9, 

10) indicate they are not common. Because surface 

samples may have undergone leaching, sub urface 

rocks are more likely to contain inclusions. 

Interbedded quartzite, sand tone , iltstone, and 

shale, and silty limestone and dolomite in the lower 

and upper carbonate-rock aquifers contain major 

amounts of quartz and a lumino-silicate minerals in 

addition to the carbonate minerals (tables 8, 9, 11). 

X-ray diffraction analyses of Miocene volcanic rock 

from the Kane Springs Wash and Meadow Valley Wash 

areas (pl. 1) show the dominant minerals in these rocks 

are primarily plagioclase feldspar, K-feldspar, quartz, 

biotite, and clinoptilolite (table 12). Hornblende, halite, 

clinopyroxene, olivine, and mica also are present in the 

rock. Calcite, mordenite, and cristobalite also may be 

present. The volcanic rock also contain large amounts 

of volcanic glass. The e results are in good agreement 

with previous work on rock from this area by Ekren 

and other (1977). Tertiary volcanic rock in the Nevada 

Test Site area have similar mineralogies (Byers and 

others, 1976) and have undergone zeolitization, resulting in a downward zonation of clinoptilolite to mordenite to analcime, that cuts across volcanic-rock units 

(Hoover, 1968). 
C28 REGIONAL AQUIFER-SYSTEM ANALYSIS- GREAT BASIN, NEVADA- UTAH 

West 

A 

FEET 

12,000 

8,000 

4,000 

SEA LEVEL 

4,000 

8,000 

C/) 

....J 

....J 

I 

~ 

() 

:5 

(I) 

0 

0 

w 

(.!) East z 

<( 

a: A' Cl. 

w 

w 

I 

C/) 

5 MILES 

5 KILOMETERS 

EXPLANATION 

Basin-fill deposits- Quaternary and 

Terti ary interbedded and interfi ngered 

gravel, and, silt, and clay 

Carbonate rock- Predominantly 

Paleozoic marine lim tone and 

dolomite, with subordinate 

interbedded cia tic rock 

- lastic rock- Lower ambrian and 

Upper Precambrian, predominantl y 

marine quart zite and shale 

Ground-water level 

Fault 

FIGURE 18.-Geologic section across southern Sheep Range north of Las Vegas, Nev. Line of section hown in figu re 17. 

Modified from Guth (1980, pl. 2) and Dwight Schmidt (U.S. Geological Survey, Wl; tten commun., 1986). 

Evaporite minerals, primarily gypsum, are present 

in Permian and younger rock throughout the study 

area. Other minerals associated with these evaporite 

deposits are halite, magnesite, and glauberite (Longwell and others, 1965). 

HYDROLO GIC FRAMEWORK 

Water in carbonate-rock aquifers of southern 

Nevada primarily originates from high-altitude winter 

precipitation (Winograd and Riggs, 1984), mainly in 

the Spring Mountains and Sheep Range (fig. 17), and 

from ground water flowing into southern Nevada by 

way of the White River flow system to the north 

(fig. 16). Water recharged at high altitudes generally 

infiltrates carbonate rock and flows through carbonaterock aquifers to a sink, such as the springs at Ash 

Meadows, where the water is discharged. Water flowing through the aquifers often mixes with water from 

different source areas before reaching the common discharge area of the flow system. Ground water flowing 

into southern Nevada from other flow systems, such as 

the White River flow system to the north, mixes with 

water that has been recharged in southern Nevada and 

is part of the water discharging at regional springs. 

Water levels of springs emanating from the carbonate-rock aquifers in wells completed in carbonate rock 

and in wells completed in basin-fill deposits (where 

springs emanating from, or wells completed in, carbonate rock are absent) have been used to help delineate 

flow systems in the carbonate rock of southern Nevada 

(pl. 1; Eakin, 1966; Winograd and Thordarson 1975; 

Thomas and others, 1986). Water levels indicate that 

Muddy River springs at the terminus of the White 

River flow system receives water from the Pahranagat 

Valley area to the northwest as originally delineated by 

Eakin (1966). In addition, Muddy River springs also 
Site 1 Geologic unit, vein, or 

rock type sampled 

1 Eureka Quartzite 

2 Bonanza King Formation 

3 Nopah Formation 

4 Undifferentiated 

5 Toroweap Formation 

6 Gneiss 

Schist 

7 Tapeats Sandstone 

8 Pioche Formation 

9 Lyndon Limestone 

10 Limestone and dolomite 

11 Muddy Peak Formation 

12 Callville Limestone 

13 Undifferentiated vein 

14 Pogonip Group 

15 Lone Mountain Dolomite 

16 Pogonip Group (lower part) 

Vein in Pogonip Group 

17 Upper unnamed unit 

Vein in upper, unnamed unit 

18 Sevy Dolomite 

19 Bird Spring Formation 

20 Pogonip Group (Antelope 

Valley Formation) 

21 Undifferentiated Dolomite 

22 Monte Cristo Formation 

Vein in Dawn Limestone 

1 See plate 1. 

2 Listed in order of approximate abundance. 

TABLE 8. - X-ray diffraction analyses of rock samples from southern Nevada 

[Analysis by Robert Mariner, U.S. Geological Survey, Menlo Park, Calif. Symbol: --, no mineral identified] 

Minerals identified 

Geologic age 

Majo~ Minor Trace2 

Ordovkian quartz -- -- Cambrian dolomite -- quartz, aragonite 

Cambrian dolomite -- ca.Jcite 

Silurian dolomite -- calcite 

Permian calcite, quartz -- feldspar 

Precambrian quartz, plagioclase, biotite, chlorite, dolomite -- -- biotite, plagioclase, quartz -- amphibole 

Cambrian quartz -- calcite 

Cambrian quartz K-feldspar -- Cambrian calcite -- -- Cambrian dolomite calcite quartz 

Devonian dolomite quartz calcite 

Mississippian-Permian calcite quartz -- Devonian dolomite -- calcite 

Ordovician dolomite -- -- Silurian dolomite, quartz -- calcite, feldspar (microcline) 

Ordovician calcite -- quartz 

calcite, quartz, dolomite, aragonite -- -- Cambrian dolomite -- calcite 

calcite quartz 

Devonian dolomite -- -- Mississippian-Permian dolomite, quartz, calcite -- -- Ordovician -- -- dolomite 

Cambrian dolomite -- --

Mississippian calcite, dolomite - quartz 

calcite -- quartz 

Possible 

--

--

--

--

--

--

--

--

--

--

--

--

--

-- calcite 

sphene 

--

--

--

--

--

--

Q 

t?=:l 

0 

(') 

~ 

~ en 

;d 

...: 

~ en 

0 

>-3 

0 

'"0 

t?=:l 

~ :>:l 

0 

t"' 

0 

Q 

_...: 

Q 

~ > >-3 

tt! 

?;; 

z 

(') 

t-.:l 

<D 
C30 REGIONAL AQUIFER-SYSTEM ANALYSIS- GREAT BASIN, NEVADA- UTAH 

T ABI.E 9. - Whole-rock chemical analyses of rock samples from solithern Nevada 

[Analyses by ei on Shaffer, Indiana Geological Survey, Bloomington, Ind., except as noted. An ~se are recalculated to totailOO.O percent. Rock analyses are expressed in weight percent of constituent ox.ides or, for calcium and magne tum, carbonates. Symbol: --, not determmed.l 

E-1 

E-2 

E-3 

E-5 

E-6 

E-7 

E-8 

E-9 

Geologic unit or rock type sampled 

opab Dolomite 

Ely Springs Dolomite 

Yellowpine Limestone 

Monte Cz-isto Limestone, Dawn Member2 

Sultan Limestone

2 

Ca rrara Formation Shale 

Bright Angel Shale 

Indian Springs Shale 

Si02 A1203 

1.05 0.12 

.25 .070 

1.21 .12 

.30 .20 

.60 .40 

70.3 13.5 

57.4 22.1 

70.1 18.8 

Fe203 Ti02 MnO CaC0 3 

0.061 0.009 0.010 53.9 

.057 .008 .010 54.8 

.057 .006 .008 97.7 

.10 56.4 

.05 98.1 

5.30 .82 .10 2.07 

7.97 .92 .039 .87 

2.94 1.25 .092 3.10 

Geologic unit or rock type sampled MgC03 Na20 K20 P205 SrO Thtal 

E-6 

E-7 

E-8 

E-9 

opah Dolomite 

Ely Springs Dolomite 

Yellowpine Limestone 

Monte Cristo Limestone, Dawn Member

2 

ultan Limestone2 

Carra ra Forma tion Shale 

Bt·ight Angel Shale 

lndian Springs hale 

1 See plate 1. 

2 Analysis from Longwell and othera (1965, p. 157). 

44.8 

44.7 

.79 

43.0 

.90 

2.99 

4.17 

1.46 

receives water from the southern part of the Meadow 

Valley Wash flow system and, due to structural controls 

(see previous section titled "Geologic Framework"), 

receives most of the recharge to the Sheep Range 

(figs. 16, 17, pl. 1). 

The Ash Meadows flow system drains the Frenchman Flat-Yucca Flat area to the northeast of the Ash 

Meadows springs, and on the basis of water-level, isotopic, and geochemical data the Pahranagat Valley 

area also supplies water to Ash Meadows springs 

(Winograd and Friedman, 1972; Winograd and Thordarson, 1975; Winograd and Pearson, 1976). The carcity of wells between Frenchman Flat and Pahranagat 

Valley and Frenchman Flat and Sheep Range limits 

interpretation of ground-water flow in this area. However, geologic information (see section titled "Geologic 

Framework") indicates that the Pahranagat Valley 

area is connected to Ash Meadows by a thick and continuous carbonate-rock section, whereas the Sheep 

Range probably does not supply much water to the Ash 

Meadows flow system (figs. 16, 17, 18). 

Water levels in Las Vegas Valley indicate that the 

valley receives water from the Spring Mountains and 

Sheep Range (pl. 1). However, structural controls probably prevent significant amounts of recharge to the 

Sheep Range from flowing into Las Vegas Valley 

(figs. 17, 18). This conclusion is supported by groundwater flow models of the basin-fill aquifers in Las 

Vegas Valley by Harrill (1976) and by Morgan and 

0.011 0.050 0.016 0.006 100.0 

.018 .067 .011 .017 100.0 

.007 .036 .032 .019 100.0 

100.0 

100.0 

1.64 3.17 .13 .005 100.0 

.59 5.75 .24 .012 100.0 

.47 1.48 .18 .12 100.0 

Dettinger (1996). Water levels also indicate that 

ground water flows into southwest Las Vegas Valley 

from Ivanpah Valley (pl. 1). 

Water levels in Pahrump Valley indicate that 

recharge from the Spring Mountains is the source of all 

the water in Pahrump Valley (pl. 1). Water levels for 

areas outside the thick carbonate-rock aquifers in 

southern Nevada and southeastern California also are 

shown on plate L 

T ABLE 10.-Sulflir content of rock samples from Olilhern Neuacla 

[Analyses by eison hatTer, lndjana Geological urvey, 

Bloomi ngton, Ind.] 

Sulfur, asS 

Site 1 Geologic unit sampled 

(parts per million) (percent) 

E-1 opah Dolomite 22 0.0022 

E-2 Ely Springs Dolomite 82 .0082 

E-3 Yellowpine Limestone 72 .0072 

E-4 Dawn Limestone 100 .0100 

E-7 Carrara Formation Shale 29 .0029 

E-8 Bright Angel Shale 94 .0094 

E-9 Indian Springs Shale 130 .0130 

1 See plate 1. 

Hydrologic data for southern Nevada indicate that 

on a regional scale the White River flow system, which 

discharges at Muddy River springs, and the Ash Mead-
GEOCHEMISTRY AND ISOTOPE HYDROLOGY, GREAT BASIN 31 

TABLE 11.- X-ray diffraction analyses of insoluble residues from whole-rock chemical analyses of rock samples from southern Nevada 

[Analy es by elson hatTer, Indjana Geological Su.rvey, Bloomington, Ind.] 

Geologic unit sampled 

Insolubl e 

residue 

(percent) 

Minerais identified2 

E-1 

E-2 

E-3 

E-4 

Nopah Dolomite 1.33 

. 33 

1.34 

.28 

Quartz, illite, smectite, feldspar, and alunogen. 

Ely Springs Dolomite 

Yellowpine Limestone 

D avm Limestone 

Quartz, illite, chlorite, kaolinite, palygorskite, and po ibly K-feldspar . 

Quru--tz. 

Quartz, clinoptilolite, illite, and an unidentified zeolite. 

E-7 Carrara Formation Shale 

E-8 Bright Angel Shale 

E-9 Indian Springs Shale 

93.12 

91.08 

94.28 

Quartz, illite, feld par, smectite, kaolinite, and po sibly zeolites. 

Quartz, palygorskite, smectite, and chlorite. 

Quartz, kaolinite, mectite, and illite. 

1 See plate L 

2 Listed in order of approximate abundance. 

ows flow system, which discharges at Ash Meadows 

springs, encompass large areas that contain several 

topographic basins which drain to a common discharge 

area (figs. 16, 17). In addition, both Muddy River 

springs and Ash Meadows springs receive water from 

the Pahranagat Valley area. Las Vegas and Pahrump 

Valleys receive water primarily from recharge to the 

Spring Mountains. 

STABLE ISOTOPES OF THE GROUND WATER 

Deuterium and oxygen-18 data can be used to help 

delineate ground-water flow systems by identifying 

water from different source areas. Most water in carbonate-rock aquifers of southern Nevada is chemically 

similar because mineralogy of the carbonate rock is relatively homogeneous, so the stable isotopes deuterium 

and oxygen-18 become an important tool for delineating source areas and flow paths in this area. 

Deuterium rather than oxygen-18 is used to delineate 

flow systems in southern Nevada because it has been 

used in previous studies (Winograd and Friedman, 

1972; Claassen, 1985, 1986; Lyles and Hess, 1988; 

Noack, 1988; Kirk and Campana, 1990) and generally 

is not affected by water-rock interactions that can 

change oxygen-18 compositions. 

Deuterium data used for flow-system delineation 

are primarily from samples analyzed by the U.S. Geological Survey research laboratory in Reston, Va. Additional deuterium data are included for sample 

analyzed prior to 1973 by the U.S. Geological Survey 

research laboratory in Denver, Colo. [after correcting 

for interlaboratory differences, the deuterium values 

analyzed before 1973 were divided by 1.03 (LJ. Winograd, U.S. Geological Survey, written comrnun., 1985)] 

and by the Desert Research Institute Isotope Laboratory in Las Vegas, Nev. An interlaboratory comparison 

between the Desert Research Institute Laboratory and 

U.S. Geological Survey Reston laboratory analyse 

showed that the average difference between deuterium 

values for 9 duplicate samples analyzed at the two laboratories was less than 1.0 part per thousand (permil), 

with only 1 sample difference greater than 2 permil; 

the average difference for 18 samples (9 duplicate samples plus 9 amples from springs that have a constant 

TABLE 12.-X-ray diffraction analy es of Miocene volcanic rocks from southern Nevada 

(Analysi by Robert Ma rin r, .S. Geological Survey, Menlo Park, Calif. ymbol: --, no mineral identified] 

ite 1 Geologic unit or rock Lyp am pled 

V-1 

V-2 

V-3 

V-4 

V-5 

V-6 

V-7 

V-8 

A h-flow tuff 

Basalt 

Ash-flow a nd ash-fall tuffs 

Ba alt 

Kane Wash Tuff 

Rhyolite lava 

Hiko '!\tiT 

Bedded tuff 

1 See pl ate J. 

2 Listed in order of approximate abundance. 

Minerals identified 

ajo~ 

Plagiocla e, quartz, biotite, hornblende, halite 

Plagiocla e 

Quartz, plagioclase, K-feldspar 

Plagiocla e, cljnopyroxene, olivine 

linoptilolite 

Quartz, K-feldspar, plagioclase 

Biotite, plagiocl ase, K-feldspar, quat·tz 

Quartz, plagiocla e, K-feldspar, clinoptilolite Mica 

Po ible 

Calcite 

Mordenite 

Cristobalite 
C32 REGIONAL AQUIFER-SYSTEM ANALYSIS- GREAT BASIN, NEVADA- UTAH 

deuterium concentration over time) was less than -70 .----------.----,----r-----r---.------::r---., 

0.3 permil, with only 3 sample differences greater than 

2 permil (data are in appendix A). For consistency, if a 

sample site had data from the Reston laboratory and 

either of the other laboratories, only the Reston laboratory data were used to determine the average deuterium composition for that site. 

ISOTOPIC 01\ IPO IT ION 0 · GRO ND WATER ll 

0 R E AREA A D FLO\ Y TEM 

The average deuterium composition of ground 

water in recharge areas and in flow systems contributing to the carbonate-rock aquifers of southern Nevada 

(pl. 2) was determined from a data base compiled for 

this study (appendix A). All the data were plotted to 

eliminate samples significantly affected by evaporation 

(fig. 19). All samples that plot to the right of the line 

[8D=8(8 180 )+0] are assumed to have undergone significant evaporation and were not used in calculating the 

average deuterium composition of water from a sample 

site (fig. 20, pl. 2). Most samples plot to the right of the 

meteoric water line, indicating that water in southern 

Nevada has undergone a small amount of evaporation 

prior to infiltrating into aquifers. 

-60 

• 

• • 

-70 

__J • • ~ 

a: -80 w 

a.. • ~ 

-90 

::J 

a: 

w 

1-

::J -100 

w 

0 

<( 

1- -110 --80 = 8(8180 ) + 0 __J 

w 

0 

-120 

-130 -16 -14 -12 -10 -8 -6 -4 -2 0 

DELTA OXYGEN-18, IN PERMIL 

FJGURE 19. - Re lation betwee n mea n de u terium and mean 

oxygen-18 for gro und-water sampl es from sites in southern 

Nevada a nd southeast ern Ca lifornia. MWL is the meteoric 

water line (80 =8(81 0 )+10; Craig, 1961). 

- 80 __J 

~ a: 

w 

a.. 

~ - 90 

-:t 

::J 

a: 

w 

1-

::J 

w -100 

0 

<( 

1-

__J 

w 

0 - 110 • 

120 L--~~-~--L--~---L--L--~ 

- 16 - 15 - 14 - 13 - 12 - 11 - 10 -9 

DELTA OXYGEN-18, IN PERMIL 

FIGU RE 20.-Rel a tion between mean d e ute rium a nd mean 

oxygen-18 for ground-water samples that have not undergone 

significant eva poration, southe rn evada an d so utheastern 

Ca lifornia . MWL is the meteori c water line (80 =8(8 180 )+10; 

Craig, 1961). 

PRL'IG 1\IOUNTAIN 

Recharge from the Spring Mountains can be 

divided on the ba sis of isotopic composition into 

recharge from the central part of the mountains north 

of the Sandstone Bluffs area and from the Sandstone 

Bluffs area and everything south of that area (fig. 17; 

pl. 2). The central part ofthe Spring Mountains reaches 

an altitude of almost 12,000 ft, whereas the southern 

part of the Spring Mountains (Sandstone Bluffs and 

south of Sandstone Bluffs) reaches an altitude of only 

about 8,500 ft. The difference in a ltitude results in 

water in the higher central part having an average deuterium composition that is 9 permil lighter (more negative) than water in the lower southern part (table 13). 

The average deuterium composition of Spring 

Mountains recharge for the central part of the Spring 

Mountains is - 99 permil (table 13). This deuterium 

value is based on the average deuterium composition of 

the two largest discharging springs, Trout Spring and 

Cold Creek Spring (fig. 17), which also have the longest 

sampling r ecord (1968-89). Water from Trout Spring 

has a mean deuterium composition of - 97 .7 permil, 

standard deviation 1.3, for 19 samples, and water from 

Cold Creek Spring has a mean deuterium composition 

of - 100.1 permil, standard deviation 1.2, for 16 samples 

(Winograd and Riggs, 1984; I.J. Winograd, U.S. Geolog-
GEOCHEMISTRY AND ISOTOPE HYDROLOGY, GREAT BASIN C33 

ical Survey, written commun. , 1989; Thomas and others, 1991). The average value of - 99 permil for the 

central part of the Spring Mountains is the same as 

that presented by Winograd and Riggs (1984) for 

springs and wells in the Spring Mountains. Their data 

included 9 samples in addition to their combined 

28 samples at Trout Spring and Cold Creek Spring. 

The average deuterium value agrees with other isotope 

data collected during a shorter period from smaller 

springs in the Spring Mountains (appendix A; pl. 2). 

The average deuterium composition of recharge to 

the southern part of the Spring Mountains is -90 permil (table 13). 

Deuterium values are different for the two parts of 

the Spring Mountains, but within each part, deuterium 

composition does not discernibly change with altitude 

(fig. 21). Thus, deuterium composition of winter precipitation that recharges the Spring Mountains (Winograd 

and Riggs, 1984) is not affected by altitude (deuterium 

composition does not become lighter with increasing 

altitude). Consequently, recharge from each part of the 

Spring Mountains should have similar deuterium composition regardless of altitude. 

HEEP R AN E 

The average deuterium composition of recharge to 

the Sheep Range is -93 permil based on the average 

deuterium value of 17 samples at six springs (table 13, 

appendix A). This average deuterium composition is 

10,500 

• 10,000 

...J 

w 9,500 

> 

w 9,000 ...J • <( 

w 8,500 • (f) 

w 

> 8,000 • • 

0 

CD 7,500 <( 

t- • w 7,000 w I • lL 6,500 ~ • 

w 6,000 • • 0 

:::> 5,500 t- • i= 

...J 5,000 <( 

4,500 • 

4,000 

-102 -101 -100 -99 -98 -97 -96 -95 -94 -93 -92 

DELTA DEUTERIUM, IN PERMIL 

FIGURE 21. - Relation between mean deuterium compo ition and 

altitude for spring a nd well samples that contain tt·itium in the 

Spring Mountains, so uth ern Nevada. Tritium indicates the 

water was less than about 50 y ars old at the time of am piing. 

the same as that of water discharging from Corn Creek 

Springs (-93 permil; appendix A, fig. 17, pl. 2). Corn 

Creek Springs is on a fan on the south we t flank of the 

Sheep Range and, therefore, should be representative 

of water that flows either south to Las Vega Valley or 

west to Ash Meadows from the Sheep Range. 

Six springs in the Sheep Range are at altitudes 

from about 5,600 to ,400ft. Their average deuterium 

composition changes by only 4 permil, o on the ba i of 

limited data , altitude probably does not affect the deuterium composition of water in the Sheep Range. Thus, 

-93 permil represents the deuterium compo ition of 

recharge to the Sheep Range, as is observed at Corn 

Creek Springs, which is probably well-mixed wat r 

from the Sheep Range. 

So r HERi\" M EAD0\1" V AI.I.J:Y \\'A II FI.OII ."YS'l E~l 

The average deuterium compo ition of gTound 

water in the southern Meadow Valley Wash flow system (fig. 16) is -87 permil (table 13). Thi value is an 

average for springs and wells in the Meadow Valley 

Wash drainage south of Caliente, the Delamar Mountains, the Meadow Valley Mountains, and th southwest Clover Mountains (pl. 2). 

\VII i i"E RI \'ER FLOW SYSTE~I 

The average deuterium composition of springs 

emanating from carbonate-rock aquifer in Pahranagat Valley is -109 permil (fig. 17, pl. 2). This average 

value is for samples from Ash and Crystal Spring that 

were analyzed by the Reston laboratory (table 13). This 

value agrees with data for previous samples from Ash, 

Crystal, and Hiko Springs in Pahranagat Valley, which 

were analyzed at the Denver and Las¥ gas laboratories (appendix A). These samples were chosen as representative of water in the carbonate-rock aquifers of the 

White River flow ystem that flows into southern 

Nevada because t hey are large springs discharging 

from the carbonate-rock aquifers upgradient from 

Muddy River and Ash Meadows springs. 

PALEOCUl\IATI EFFE :r 0 I OTOPI Ol\lPO ITION 

Ground water discharging from the carbonate-rock 

aquifers in southern Nevada is a mixture of waters that 

were recharged primarily during the last 10,000 years 

(see table 18; Winograd and Pearson, 1976; Benson and 

others 1983 · Waddell and others, 1984; Claassen, 

1985, 1986; Kirk, 1987; Benson and Klieforth, 1989; 

Kirk and Campana, 1990). The average deuterium 

composition of waters recharging the carbonate-rock 

aquifers of southern Nevada would have had to remain 

relatively constant during this time for deuterium to be 
C34 REGIO AL AQUIFER-SYSTEM ANALYSIS - GREAT BASIN, NEVADA- UTAH 

TABLE 13.-Deuterium composition of ground water in source areas of 

southern Nevada 

[Analyses from U.S. Geological Survey research laboratory, Reston, Va., 

unless otherwise noted] 

Site 

Delta 

deuterium 

(permil) 

Central part of Spring Mountains 

Trout Springl! 

old Creek Sprin!(! 

Sites averaged 

19 

16 

2 

- 97.7 

- 100.1 

- 98.9 

Southern part of Spring Mountains 

Bird Sprinr(l 1 - 88.0 

Sandstone Spring 1 - 89.0 

BLM Visitors Center well 1 - 9.0 

Red Spring 1 - 9.0 

Willow Spl"ing 1 - 90.5 

White Rock Spring 1 - 91.0 

Castilio well3 1 - 94.0 

Site averaged 7 - 90.1 

Sheep Range 

Wiregrass Spring 9 -94.3 

Mormon Well Spri ng 3 -91.8 

Cow Camp Spring 2 -92.0 

Lamb Spring 1 -92.5 

Sawmill Spl"i ng 1 - 92.0 

Sheep Spr·i ng 1 - 96.0 

Sites averaged 6 - 93. 1 

Southern Meadow Valley Wash flow system 

Upper Riggs Spring . 1 - 88.0 

Boulder Spring 1 -87.0 

Kane Spring 1 - 86.5 

Grapevine Spring 1 -87.5 

Willow Spring 1 - 88.0 

Cali ente City well 1 -89.0 

Bishop Spring 1 - 5.5 

Bradshaw well 1 -88.5 

Rai lroad Elgin we ll 1 - 86.0 

Ra ndono well 1 - 87.5 

J ensen well 1 - 88.5 

orth Ella Spring 1 - 86.5 

Grassy Spring4 1 -85 

Stock well 5 1 - 88.0 

Sites ave raged 14 - 87.3 

White River flow system 

Ash Spring 1 - 108.0 

Crystal Spring 1 - 109.0 

Sites ave raged 2 - 108.5 

1 umber of samples per site, and number of sites averaged. 

Standard 

deviation 

1.3 

1.2 

1.7 

2.0 

1.8 

.8 

1.8 

1.7 

1.2 

0.7 

2 Dat.a from I.J. Winograd fU.S. Geological Survey, writt.en commun., 1989). 

3 Data from Desert Research Institute laboratory, Las Vegas, Nev. (Thomas and 

others, !991 ). 

1 Unpublished da ta from Desert Resea rch Institute laboratory, Las Vegas, Nev. 

5 Da t.a from Desert Research Institute laboratory, Las Vegas, ev. (Kirk , 1987, p. 8[). 

used to calculate mixing of water from different 

sources. This seems unlikely because of climatic 

changes during this period (Mifflin and Wheat, 1979; 

Winograd and Doty, 1980; Spaulding and others, 1984; 

Spaulding, 1985; Quade, 1986; Benson and Thomp on, 

1987; Quade and Pratt, 1989). However, a plot of 

deuterium and carbon-14 (fig. 22) for water that was 

recharged in the Spring Mountains shows that deuterium has remained relatively constant for a carbon-14 

range of 1.9 to 100 percent modern carbon (pmc). Deuterium composition varies by only a total of 6 penni!, 

with an average concentration of - 99 permil. A similar 

plot for water recharged in the Sheep Range contains 

fewer data points; it shows that deuterium composition varies by less than 2 permil for a carbon-14 range 

of 13.7 to 96.8 pmc (fig. 23). 

In summary, the deuterium composition of water in 

the Spring Mountains, Sheep Range, and surrounding 

areas has remained constant with time for a carbon-14 

range of 1.9 to 100 pmc. Thus, deuterium can be used 

to determine source areas, flow paths, and mixing of 

ground water in the carbonate-rock aquifers of southern Nevada. 

FLOW- Y TEM DELI NEATl N ON T HE BA. l 

F DE TERl M 

Deuterium composition of water discharging from 

large springs in southern Nevada can be used to determine the sources of water that supply the springs and, 

thus, help delineate flow paths. Mixing of isotopically 

different waters from different source areas can be 

determined from observed differences in the deuterium 

composition of the ground water upgradient from the 

springs. The two largest spring areas in southern 

Nevada are Muddy River springs (36,000 acre-ftlyT) in 

Moapa Valley, at the terminus of the White River flow 

system, and Ash Meadows springs (17 ,000 acre-ftlyr) in 

the Amargosa Desert, at the terminus of the Ash Meadows flow system (figs. 16, 17). These spring flow rates 

represent minimum ground-water flow, because additional water may be flowing past the springs in the carbonate-rock aquifers and because evapotranspiration 

in the spring areas may include ground water that is 

not discharged at the springs. However, the proportion 

of water from different sources determined on the basis 

of deuterium composition would be the same; only the 

absolute amount from the different areas would 

increase ifthe spring flow does not include all the water 

in the carbonate-rock aquifers in the spring area. In 

addition, the isotopic composition of water from wells, 

or discharging from springs, in Las Vegas and 

Pahrump Valleys can be used to determine sources of 

water in the carbonate and basin-fill aquifers in these 

areas. 
GEOCHEMISTRY AND I OTOPE HYDROLOGY, GREAT BASIN C35 

If deuterium is used as a tracer, the deuterium 

composition of the different source areas has to be different. Although waters from the two major recharge 

areas in southern Nevada, the Spring Mountains and 

Sheep Range, are only 6 permil different in mean deuterium composition (table 13), a Mann-Whitney test 

shows that the medians of the two populations are 

detectably different at the 0.001 significance level. 

Additional, and perhaps even more compelling, evidence that deuterium values from the two areas are different is that deuterium composition of water along 

flow paths from each area is the same as the deuterium 

composition in the recharge area (pls. 1, 2). The mean 

deuterium composition of 22 samples along flow paths 

from the central part of the Spring Mountains is -98.4 

permil (standard deviation 1.6) and ranges from -102.0 

to -95.0 permil; the mean composition of 4 samples 

along flow paths from the Sheep Range is -93.6 permil 

(standard deviation 0.5) and ranges from -94.0 to -93.0 

permil. Consequently, although waters from these 

recharge areas are only 6 permil different, they are statistically different populations, and ground water flowing from each recharge area maintains the same 

average deuterium value as the recharge-area water. 

Thus, the mean values of - 99 and -93 permil can be 

used as the isotopic inputs for the two recharge areas. 

Other significant sources of ground water in carbonaterock aquifers of southern Nevada are the southern part 

of the Spring Mountains (deuterium composition is -90 

permil), the White River flow system (deuterium com-

-95 

-96 • • • 

• _J 

~ -97 • •• a: 

w 

Cl. 

?; -98 • • • • • • 

::J 

([ -99 • • • w 

1- • ::J 

w -100 0 • • • <t 

1- • _J 

w -101 

0 

-102 • 

-103 ~----'-----'------'----'------' 

1 00 80 60 40 20 0 

CARBON-14, IN PERCENT MODERN CARBON 

FIGURE 22.-Relation between mean deuterium and carbon-14 for 

water recharged in the Spring Mountain , southern Nevada. 

_J 

~ a: 

UJ 

Cl. 

z 

~ 

::J 

a: 

UJ 

1-

::J 

UJ 

0 

<( 

~ UJ 

0 

-92 ,------.---,------,-----.------, 

-93 • • 

• 

-94 • 

• 

-95 L-----'-----'------'----'------l 

100 80 60 40 20 0 

CARBON-14, IN PERCENT MODERN CARBON 

FIGURE 23.-Relation between mean deuterium and carbon-14 for 

water recharged in the Sheep Ra nge, southern N vada. 

position is -109 permil), and the outhern Meadow Valley Wash flow system (deutetium composition is -87 

permil; table 13). 

\VI-liTE Rl\'ER Ft.0\1' SY 'TE~ I 

Muddy River springs discharge 36,000 acre-ftJyr of 

water at the distal end of the White River flow system 

(Eakin and Moore, 1964). The average deuterium composition of water from five springs in the Muddy River 

springs area, including Big Muddy Spring, which i the 

largest discharging spring, is - 98 permil (i otope analyses from the Reston laboratory; appendix A ). The 

sources of water discharging from the spring wer 

determined from hydraulic gradients in the carbonaterock aquifers in this area (s ee section "Hydrologic 

Framework" and pl. 1), the geologic and structural 

ground-water flow constraints (see section "Geologic 

Framework" and figs. 17, 18), and the average deuterium composition of possible source waters. 

Water emanating from Muddy River springs can be 

from three sources: (1) the Sheep Range, (2) the White 

River flow system, and (3) the southern Meadow Valley 

Wash flow system (including Kane Springs and 

Delamar Valleys). Directly upgradient from Muddy 

River springs is Coyote Spring Valley. In this valley, the 

average isotopic composition of water from three wells 

completed in carbonate rock is -101 permil, whereas 

water from a well completed in basin-fill deposits is -94 

permil. The basin-fill well is adjacent to one of the wells 

completed in carbonate rock. A downward head gradi-
C36 REGlO AL AQUIFER-SYSTEM ANALYSIS- GREAT BASIN, NEVADA- UTAH 

ent of 0.12 ft/ft over about a 500-ft vertical interval 

exists between the basin-fill and carbonate-rock wells 

(Berger and others, 1988). This downward head gradient and the isotope value similar to that of average 

Sheep Range recharge (-93 permil) indicate that 

recharge from the Sheep Range probably flows primarily through the basin-fill aquifer in Coyote Spring 

Valley. 

The basin-fill aquifer in Coyote Spring Valley is 

bound on the east by the carbonate rock of the northern 

Arrow Canyon Range and southern Meadow Valley 

Mountains. In this area, the carbonate rock that compose these mountains are exposed at land surface, and 

water in the basin-fill aquifer mixes with water in the 

carbonate-rock aquifers. This mixed water is observed 

at Muddy River springs. Water from a well (MX-6; 

fig. 17) completed in carbonate rock, about halfway 

between the east edge of the Coyote Spring Valley 

basin-fill aquifer and Muddy River springs, has a deuterium composition of - 97 permil (pl. 2). This isotopic 

composition is similar to Muddy River springs (-98 permil) and is more evidence supporting the conceptual 

flow and mixing model: water in the Muddy River 

springs area is probably a mixture of Sheep Range 

recharge water and water from the carbonate-rock 

aquifers beneath Coyote Spring Valley. Using the average deuterium composition of Sheep Range recharge 

water (-93 permil) and Coyote Spring Valley carbonate-rock aquifer water (-101 permil) to determine the 

sources of water at Muddy River springs (-98 permil) 

results in a mixture of 38 percent (14,000 acre-ft/yr) 

Sheep Range water and 62 percent (22 ,000 acrefeet/yr) Coyote Spring Valley water. 

Water in the carbonate-rock aquifers of Coyote 

Spring Valley (deuterium composition of -101 permil) 

can be from two sources, the White River flow system 

(deuterium composition of -109 permil) and the southern Meadow Valley Wash flow ystem (deuterium composition of - 87 permil; pls. 1 and 2, figs. 16, 17). A 

mixture of 64 percent (14,000 acre-ft/yr) White River 

flow-system water and 36 percent (8,000 acre-ft/yr) 

southern Meadow Valley Wash flow-system water 

results in water isotopically the same as water in the 

carbonate-rock aquifers in Coyote Spring Valley. 

In summary, water discharging from Muddy River 

springs is a mixture of 40 percent (14,000 acre-feet/yr) 

White River flow-system water, 38 percent (14,000 

acre-ftlyr) Sheep Range water, and 22 percent (8,000 

acre-ft/yr) outhern Meadow Valley Wash flow-system 

water. The 14,000 acre-ft/yr contribution of White 

River flow-system water to Muddy River springs is significantly less than the 35,000 acre-ft/yr proposed by 

Eakin (1966) on the basis of water-level data and 

Maxey-Eakin recharge estimates (Maxey and Eakin, 

1949) but is similar to recent estimates by A.H. Welch 

(U.S. Geological Survey, written commun., 1988) and 

Kirk and Campana (1990). Welch estimated 18,000 

acre-ft/yr of underflow from Pahranagat Valley to Coyote Spring Valley on the basis of the isotopic compositions of empirically derived Maxey-Eakin recharge 

estimates for the entire White River flow system. Kirk 

and Campana (1990) calculated a contribution of 

16,500 to 19,100 acre-ft/yr for three different flow scenarios for the White River flow system on the basis of 

Maxey-Eakin recharge estimates and water-level data 

with a discrete-state compartment model using deuterium to calibrate their models. These flow-system 

delineations are based on water-level data only, with no 

consideration of geologic or structural constraints on 

ground-water flow. 

The Sheep Range contribution of 14,000 acre-ft/yr 

is significantly higher than the estimated 2,000 

acre-ft/yr of Eakin (1966), 3,000 acre-ft/yr of A.H. 

Welch (written commun., 1988), and 5,000 to 6,000 

acre-ft/yr of Kirk and Campana (1990). The greater 

contribution of Sheep Range water compared to previous studies i balanced by not including 6,000- 9,800 

acre-ft/yr of ground-water from Dry Lake Valley, north 

of Delamar Valley, because of geologic constraints to 

ground-water flow (Dettinger and others, 1995) and 

les underflow from Pahranagat Valley to Coyote 

Spring Valley. Geologic constraints on Sheep Range 

water flowing to the west and south, as previously discussed in the section titled "Geologic Framework," indicates that most of the recharge to the Sheep Range 

probably flows to the northeast toward the Muddy 

River springs area. The calculated contribution of 

14,000 acre-ft/yr of Sheep Range water is higher than 

the empirical Maxey-Eakin recharge estimate ofll,OOO 

acre-ft/yr, but the amount is reasonable if most of the 

recharge to the Sheep Range discharges at Muddy 

River springs. Winograd and Friedman (1972) also postulated, on the basis of deuterium data, that the Sheep 

Range may be a significant source of water discharging 

from Muddy River springs. 

The 8,000 acre-ft/yr of ground water calculated to 

flow from the southern Meadow Valley Wash flow system to Muddy River springs agrees with previous estimates by Welch (8,000 acre-ft/yr) and Kirk and 

Campana (5,500-9,000 acre-ft/yr). 

·1-1 Mlv\ 1) W FLOW SYSTEM 

Springs at Ash Meadows discharge 17,000 acreft/yr at the distal end of the Ash Meadows flow system 

(Winograd and Thordarson, 1975). The average deuterium composition of the water from seven springs (the 

six largest discharging springs plus Scruggs Spring) 

is -103 permil (Winogra d an d P ea rso n , 1976 ; 
GEOCHEMISTRY AND ISOTOPE HYDROLOGY, GREAT BASIN 37 

appendix A). The sources of water discharging from the 

springs were determined on the basis of hydraulic gradients in the carbonate-rock aquifers in this area (see 

section titled "Hydrologic Framework" and pl. 1), the 

geologic and structural constraints on ground-water 

flow (see section titled "Geologic Framework" and figs. 

17, 18), and the deuterium composition of possible 

source waters. 

The first carbonate-rock aquifer sample site that is 

upgradient from Ash Meadows springs and has deuterium and water chemistry data is Army Weill (fig. 17). 

Water from Army Well 1 has an average deuterium 

composition of -104 permil (appendix A). Thus, given 

the hydrologic position of the well and the isotopic similarity of its water to Ash Meadows springs, water at 

Axmy Weill is considered representative of water that 

flows to Ash Meadows. This conclusion was previously 

reached by Winograd and Friedman (1972), but they 

also noted that the chemistry at Army Weill was more 

dilute than water discharging at Ash Meadows. At a 

carbonate-aquifer sample site about halfway between 

A.Tmy Well 1 and Ash Meadows (Amargosa Tracer Well 

2; fig. 17), deuterium data are lacking but oxygen-18 

data are similar to data from Ash Meadows springs 

(appendix B). Water chemistry also is similar, although 

slightly more dilute, so this water also is considered 

representative of flow to Ash Meadows. The water 

chemistry from these two sites and how they relate to 

flow in the Ash Meadows flow system is discussed in 

the section titled ''Water Chemistry." 

No water samples from carbonate-rock aquifer 

sites upgradient from Army Welll had deuterium compositions similar to samples from Ash Meadows. Thus, 

isotopically different waters must be mixing to produce 

the deuterium composition measured at Ash Meadows 

and Army Well 1. Given the hydrologic, geologic, and 

structural constraints (see sections titled "Hydrologic 

Framework" and "Geologic Framework"), the two nearest carbonate-rock aquifer water sources upgradient 

from Army Well 1 and Ash Meadows that could mix to 

produce their deuterium composition are in the area of 

Well C-1 in south Yucca Flat and Indian Springs 

(fig. 17, pls. 1 and 2). 

A mixture of 33 percent (6,000 acre-ft/yr) Well C-1 

water (-111 permil) and 67 percent (11,000 acre-feetJyr) 

Indian Springs water (-99 permil) is needed to produce 

the deuterium composition of water at Ash Meadows 

and Army Well 1 (-103 permil). The source of Indian 

Springs water is recharge to the Spring Mountains, on 

the basis of the hydraulic gradient (pl. 1) and deuterium composition of Indian Springs water, which is the 

same as that of average Spring Mountains recharge 

(-99 permil). The source of Well C-1 water is less obvious: three possible sources, on the basis of hydrologic, 

geologic, and structural constraints, are recharge to the 

Eleana Range (or farther to the west in Pahute Mesa), 

drainage of paleowater, or White River flow- ystem 

water. 

The Eleana Range contains 4,000 to 8,000 ft of 

Devonian to Mississippian noncarbonate rock under 

the west third of Yucca Flat (Winograd and Thordarson, 1975, "upper clastic aquitard"). Therefore, little 

precipitation that falls on the Eleana Range probably 

recharges the carbonate-rock aquifers in the Yucca Flat 

area. Winograd and Thordarson (1975) estimated the 

quantity of water flowing into the carbonate-rock aquifers beneath Yucca Flat from both the west (Eleana 

Range) and northeast (Emigrant Valley) is les than 

250 acre-ftJyr. In addition, aeromagnetic interpretations by Bath and Jahren (1984) and recent interpretations of Tertiary extensional tectonics by Guth (1988) 

indicate that little of the carbonate-rock aquifer underlies the Eleana Formation in this area; instead, the 

Eleana Formation is probably underlain by noncarbonate basement. Thus, the possibility that water in the 

volcanic rock of Pahute Mesa , west of th e El eana 

Range, flows at depth into the carbonate-rock aquifers 

and then east to Yucca Flat is unlikely. No isotope data 

exist for the carbonate aquifers beneath the Eleana 

Range , so the isotopic composition of this water i 

unknown. 

Drainage of water recharged during the last glacial 

episode is a po sible source of water at Well C-1. However, Winograd and Doty (1980) show that water levels 

in the carbonate-rock aquifers in the Nevada Test Site 

area have fluctuated less than 100 ft during Wiscon in 

time, and Jones (1982) shows fluctuations of le than 

about 150 ft in the northern Frenchman Flat area 

through most of Quaternary time. Thus, drainage of 

paleowater is not probable. 

White River flow-sy tern water in Pahranagat Valley is isotopically similar (-109 permil) to Well -1 

water (-111 permil) and, on the basis of hydraulic gradients, could be flowing southwest to Yucca Flat (pl. 1). 

Continuous, thick sequences of carbonate rock provide 

a flow path for White River flow system water to 

Frenchman Flat (fig. 17). Thus, of the three possible 

sources of Well C-1 water, the White River flow system 

is hydrologically and geologically the most likely. 

Another possibility is that little water flows from 

the Yucca Flat area to Ash Meadows. Winograd and 

Thordarson (1975, p. 94) estimated the total flow 

within the carbonate-rock aquifers beneath Yucca Flat 

to the south to be less than 350 acre-ft/yr. A likely alternative is that water from Pahranagat Valley flows 

through the Frenchman Flat area south of Well C-1 

and mixes with Spring Mountains water, producing the 

water at Ash Meadows. This interpretation is reason-
C38 REGIONAL AQUIFER-SYSTEM ANALYSIS- GREAT BASIN, NEVADA- UTAH 

able because the central core of thick, continuous carbonate rock extends from Pahranagat Valley to Ash 

Meadows (fig. 17). Using the average isotope value of 

Pahranagat Valley water (-109 permil) and Indian 

Springs water (-99 permil) to produce Ash Meadows 

water (-103 permil) results in a mixture of 40 percent 

(7,000 acre-ftJyr) Pahranagat Valley water and 60 percent (10,000 acre-ftJyr) Spring Mountains water. The 

40 percent contribution of Pahranagat Valley water to 

Ash Meadows spring discharge is in good agreement 

with the 35 percent estimated by Winograd and Friedman (1972) and Winograd and Thordarson (1975). 

The Spotted, Pintwater, Desert, and Groom Ranges 

are assumed to contribute little water to the carbonaterock aquifers (fig. 17). This assumption agrees with 

previous work by Winograd and Friedman (1972) and 

Winograd and Thordarson (1975). These mountains, 

with the exception of the Groom Range, are less than 

7,100 ft in altitude and, therefore, do not receive large 

amounts of winter precipitation that could become 

available to recharge the carbonate-rock aquifers. The 

Groom Range is composed mostly of Precambrian basement rock and is not underlain by carbonate-rock aquifers (M.D. Dettinger, U.S. Geological Survey, oral 

commun. , 1989); therefore, little precipitation in the 

Groom Range recharges the carbonate-rock aquifers. 

In addition, any potential recharge water in these 

ranges generally is isotopically heavy; median deuterium composition of 13 samples from the Pintwater 

and Groom Ranges is -90 permil (pl. 2; B.F. Lyles, 

Desert Research Institute, written commun., 1986) 

compared with recharge water in the Spring Mountains (-99 permil) and water in the White River flow 

system (-109 permil). This heavy deuterium composition severely limits the possibility that any significant 

recharge to these mountains contributes to Ash Meadows discharge. 

As previously discussed, recharge to the Sheep 

Range probably contributes little to spring discharge at 

Ash Meadows due to geologic and structural constraints. The relatively heavy deuterium composition 

of Sheep Range water (-93 permil), as compared with 

Ash Meadows spring water (-103 permil), also limits 

the percentage of Sheep Range water that could mix 

with Spring Mountains and Pahranagat Valley water 

to produce the deuterium composition measured at Ash 

Meadows. 

In summary, a mixture of 40 percent (7 ,000 acreftlyr) Pahranagat Valley water and 60 percent (10,000 

acre-ftlyr) Spring Mountains water discharging at Ash 

Meadows springs is geologically, hydrologically, and 

isotopically the most likely alternative. Previous work 

by Winograd and Friedman (1972), Winograd and 

Thordarson (1975), Winograd and Pearson (1976), 

Welch and Thomas (1984), and Kirk and Campana 

(1990) postulated a 24 to 35 percent input of Pahranagat Valley water to Ash Meadows, which is similar to 

the 40 percent proposed by this isotopic mixing model. 

The 60 percent Spring Mountains contribution also is 

reasonable, if the previous estimate of about 65 percent 

Spring Mountains plus Sheep Range water (Winograd 

and Friedman, 1972; Winograd and Thordarson, 1975; 

Winograd and Pearson, 1976) is assumed to be mostly 

Spring Mountains water. This assumption seems reasonable because the previous studies assumed that the 

Spring Mountains and Sheep Range were isotopically 

the same and no flow barriers existed between the 

Sheep Range and Ash Meadows springs. Other evidence to support the concept that recharge from the 

Spring Mountains contributes 60 percent of Ash Meadows springs discharge is as follows: 

1. A Maxey-Eakin recharge estimate , which 

assumes that only precipitation above 6,000 ft 

becomes recharge , for the part of the Spring 

Mountains that topographically drains to the Ash 

Meadows flow system is 7,000 acre-ftlyr. This estimate is lower than the 10,000 acre-ftlyr estimated 

by the isotope mixing model, but ground-water 

flow modeling studies of Las Vegas and Pahrump 

Valleys (Harrill, 1976, 1986) indicate that MaxeyEakin recharge estimates for the Spring Mountains underestimate recharge by about 20 to 35 

percent. 

2. Winograd and Thordarson (1975) suggest on the 

basis of structural disposition that some recharge 

south of the topogra phic divide in the Spring 

Mountains flows northward into Indian Springs 

Valley rather than southwestward into Pahrump 

Valley. 

3. In a recharge area such as the Spring Mountains, 

which contains well-mixed water, as indicated by 

the lack of isotopic depletion with increased altitude (fig. 21), topographic divides probably have 

less effect on the areas of recharge than in a 

recharge area that contains less well-mixed 

water. 

LA V EGA VALLEY 

Isotopic composition of ground water in the basinfill aquifers of Las Vegas Valley indicates that the aquifers are supplied almost entirely by recharge to the 

Spring Mountains. This conclusion agrees with 

ground-water flow modeling studies by Harrill (1976) 

and Morgan and Dettinger (1996). The average deuterium composition of water from 10 wells and springs in 

northern Las Vegas Valley is -98 permil, ranging from 

- 101 to - 96 permil (pl. 2). This average value is similar 
GEOCHEMISTRY AND ISOTOPE HYDROLOGY, GREAT BASIN C39 

to that of recharge to the central part of the Spring 

Mountains (-99 permil). Ground water in the central 

part of the valley has a deuterium composition that 

ranges from -106 to -94 permil, but deuterium for most 

of the water ranges from -101 to -94 permil, indicating 

this water is either from northern Las Vegas Valley or 

is upward flow from the carbonate-rock aquifers that 

originated as high-altitude recharge in the Spring 

Mountains. The lightest sample (-106 permil) may contain some isotopically light paleowater recharged during the last glacial period. 

Another possible source of recharge to northern 

Las Vegas Valley, on the basis of topographic boundaries and hydrologic data, is the Sheep Range. 

Although deuterium data indicate that ground water in 

northern Las Vegas Valley originates primarily as precipitation in the central part of the Spring Mountains, 

hydrologic data indicate that some water from the Corn 

Creek area, which originates as precipitation in the 

Sheep Range, flows into northern Las Vegas Valley. 

However, geologic flow constraints (see section titled 

"Geologic Framework") and ground-water flow modeling studies (Harrill, 1976; Morgan and Dettinger, 1996) 

indicate that only a small amount of recharge to the 

Sheep Range flows into Las Vegas Valley. 

Ground water from four wells in the southwestern 

part of Las Vegas Valley has an average deuterium 

composition of -89 permil, which is similar to that of 

recharge to the southern part of the Spring Mountains 

(table 13, pl. 2). Therefore, given the isotopic similarity 

between the recharge waters in the southern Spring 

Mountains and ground water in southwestern Las 

Vegas Valley, the hydraulic gradients in this area 

(pl. 1), and the lack of any other major recharge area 

nearby, water in southwestern Las Vegas Valley is most 

likely derived from precipitation in the southern part of 

the Spring Mountains. 

Another possible source of water for southern Las 

Vegas Valley is the McCullough Range (pl. 1, fig. 17). 

However the deuterium composition of sampled water 

in the range , -73 and -88 permil, is significantly 

heavier than that of water samples from southern Las 

Vegas Valley (pl. 2). 

PAIIR MP VALLEY 

Deuterium data combined with hydrologic and geologic information indicate water in Pahrump Valley 

originates entirely in the Spring Mountains. This 

observation is in agreement with a ground-water flow 

modeling study by Harrill (1986). Three sites in Pahrump Valley have an average deuterium composition of 

- 98 permil, which is similar to the composition (-99 

permil) of average recharge in the central part of the 

Spring Mountains. Ground water in Pahrump Valley 

flows out of the valley to the southwe t through carbonate-rock aquifers to Chicago Valley and the Amargosa 

Desert area of Shoshone and Tecopa (pl. 1). 

~t~ti\RY OF D n r rER I ~1-0F.LI . EA mo Ft.OW Y iTF. ~I 

Source areas and flow paths were delineated by 

deuterium mass-balance mixing models for the major 

carbonate-rock aquifers in southern Nevada (fig. 24). 

The volumes of flow are based on the discharge of water 

from Muddy River and Ash Meadows spring for the 

White River and Ash Meadows flow ystems (so th y 

represent minimum flow volumes) and on groundwater flow model studies of Las Vegas and Pahrump 

Valleys (Harrill, 1976, 1986; Morgan and Dettinger, 

1996). 

WATER CHEMISTRY 

Changes in water chemistry along flow paths and 

resulting from mixing different waters, as determined 

by deuterium mass-balance calculations, have to be 

accounted for by realistic geochemical proce ses for the 

flow paths and mixing to be probable. Geochemical processes can be defined by mass-balance reaction models 

on the basis of the chemical composition of the initial 

(or mixed) and final waters along a flow path. Input to 

the models must be phases (minerals and gases) that 

have been identified in the aquifers and processes 

(mineral dissolution, precipitation, and formation· gas 

dissolution or exsolution; and ion exchange) that are 

thermodynamically and physically feasible, to describe 

the inputs and outputs (mass transfers) of constituents 

between the initial and final waters. For example, calcium concentration cannot decrea e along a flow path 

unless calcium is contained in some phase in concentrations greater than saturation in the water and is 

able to precipitate, unless calcium is exchanged for 

another ion in a solid phase, or unless the water mixes 

with another water of lower calcium concentration. 

Amounts of mass transfer and mineral saturation were 

calculated using average chemical composition of samples along flow paths or, in the case of mixing, using 

samples from the different areas that also have deuterium and oxygen-18 data (appendix B). 

The mass-balance approach (Plummer and Back, 

1980; Parkhurst and others, 1982; Plummer and others, 1983; Plummer, 1984; Plummer and others, 1990) 

does not produce a unique numerical solution. Therefore, three different mass-balance models were used for 

each flow path and mixing scenario (table 14, col. 2). 

Mass transfers were calculated using the computer 

program NETPATH (Plummer and others, 1991). Flowpath sites with averaged chemistries, or mixtures of 

waters with averaged chemistries, used for flow-path 
C40 REGIO ALAQUIFER-SY TEM ANALYSIS- GREAT BASIN, NEVADA-UTAH 

0 25 50 MILES 

0 25 50 KILOMETERS 

FIGURE 24.- Deuterium-del·ived delineation of ground-water flow in the carbonate-rock aquifers of southern Nevada . 

See figure 17 for feature names. Modified from Dettinger (1 989, fig. 3). 
GEOCHEMISTRY AND ISOTOPE HYDROLOGY, GREAT BASIN C41 

calculations are numbered for reference in table 14, 

col. 1 and footnote 1. Phases used in the mass-balance 

reaction models are the prevalent minerals in the aquifers of southern Nevada (see section titled "Geologic 

Framework"). These minerals include calcite, dolomite, 

albite, kaolinite, K-feldspar, chalcedony, and clinoptilolite. Gypsum and halite are included as phases in the 

models of the White River flow system because Permian and younger rock in the Coyote Spring Valley 

area contain evaporite minerals. The Ash Meadows 

flow system, except for the Spring Mountains, consists 

of lower and middle Paleozoic carbonate rock that do 

not contain evaporite minerals. Thus, leakage of water 

from the noncarbonate Tertiary rock ("Tertiary aquitard" of Winograd and Thordarson, 1975) overlying the 

carbonate-rock aquifers is assumed to be the source of 

increased sulfate and sodium concentrations, as proposed by Winograd and Thordarson. Carbon dioxide 

gas is used as a source or sink for carbon in addition to 

calcite and dolomite. Cation exchange of calcium and 

magnesium for sodium in clay minerals also is used 

because clays are present (see section "Geologic Framework"). Calcite, dolomite, kaolinite, C02 gas, chalcedony, gypsum, and halite, or in place of gypsum, 

leakage from the Terti a ry aquitard , are u sed in all 

three mass-balance reaction models. Albite and K-feldspar are used in two reaction models, calcium and magnesium exchange for sodium is substituted for albite in 

one reaction model, and clinoptilolite is substituted for 

EXPLANATrO 

Basin-fill deposits- In areas underlain by thi ck. laterall y 

continuous carbonate rock 

V / 7J Basin-fill deposit In areas out. ide thi ck, laterall y 

1///1 

-

-

8000 ... 

(17,000) 

I' 

continuou carbonate rock 

Carbonate rock- In areas of thi ck. laterall y co nti nuous 

arbo nate rock 

a rbona te rock- In areas outside thick. latera ll y 

continuous carbonate rock 

'onca rbona te rock- In areas of thick, laterall y 

cominuous carbonate rock 

onca rbona te rock- In areas outside thick. laterall y 

c ntinuous arbonatc rock 

Boundary of la terally continuous carbonate rock 

Generalized direction a nd rate of ground-water flow 

in ca rbonate-rock aquifer umber is flow rate. in 

acre-feet per year 

prings discharging from carbona te-rock aquiferumbe r i. discharge, in acre-feet per year 

• Well ourcc of wate r is carbonate-rock aqu ifer 

K-feldspar in another reaction model (table 14). 

The zeolite mineral analcime also could be used in 

place of albite as a source of sodium, because water in 

the carbonate-rock aquifers of southern Nevada are all 

below saturation with respect to analcime (table 15) 

and analcime is common in volcanic rock that overlie 

carbonate-rock aquifers in the Nevada Test Site area 

(Hoover, 1968). 

Although many mass-balance reaction mod l 

require input of C02 gas, the source of the C02 ga is 

not apparent. Carbon dioxide gas is probably not added 

to the water. Instead, this small input may result from 

the large variability (2.9-7.1 mmol/L) of total dis olved 

inorganic carbon (TDIC) in water of springs and well 

in the Spring Mountains and Sheep Range. Average 

TDIC concentration of the water in the recharge aTea 

probably is less than actual TDIC of water recharging 

the carbonate-rock aquifers. In addition, some carbon 

dioxide gas in water in the recharge area may not 

have been measured. Exsolution of C02 gas from highaltitude springs would result in lower measured than 

actual C02 concentrations in rech arge waters. This 

exsolution is indicated by oversaturation of the pring 

waters with respect to calcite in the Spring Mountains 

and Sheep Range (table 15). The amount of carbon 

dioxide exsolution was calculated to range from 0.00 to 

0.42 mmol/L by the compute r program P HR E EQE 

(Parkhurst and others, 1980), which assumes the 

waters are at saturation with respect to calcite and 

oversaturation is the re ult of carbon dioxide exsolution (Pearson and others, 1978). 

Another explanation for higher C02 concentrations 

than those currently mea ured in recharge areas could 

be that older water in the aquifers was recharged during past cooler and wetter climatic conditions. This 

recharge would result in greater C02 concentrations in 

soil zones in recharge areas and, therefore, higher C02 

concentrations in these older waters in the flow systems (White and Chuma , 1987). 

Organic carbon is probably not a significant source 

of C02 gas in th e carbonate-rock aquifers because (1) 

organic matter was not detected in the rock during the 

carbon-13 analysis of calcite and dolomite (Davi d 

Meredith, Global Geochemistry, oral commun. , 1987); 

(2) concentrations of dis olved organic carbon in the 

water are low-average 0.7 mg/L for 14 samples in 

southern Nevada (Thomas and others, 1991)-and concentrations of total organic carbon also are low-1.0 to 

2.2 mg/L for 3 samples (Winograd and Pearson, 1976, 

p. 1133); (3) dissolved oxygen concentration is greater 

than 2.0 mg/L for all samples in so uthern Nevada 

(appendix B), which indicates the source of dissolved 

carbon is probably not oxidation of organic matter, 

because oxidation rapidly depletes dissolved oxygen in 
TABLE 14.-Mass transfer of constituents and mixing of waters along flow paths in carbonate-rock aquifers of southern Nevada 

0 

[Coefficients of mass-transfer reactions were calculated using t he computer program N ETPATH (Plummer and ot hers, 1991). Except for Ca-Mg(Na exchange, negative value indicates phase leaving ""' tv 

solution (precipitating or degassing) and positive value indicates phase entering solution (dissolving). For excha nge reaction, positive value indicates sodium entering solution and calcium a nd 

magnesium leaving solution. Symbol: --, constituent not used in mass-balance reaction[ 

Millimoles per liter 

Flow path 1 Reaction 

model2 

Calcite Dolomite Gypsum Halite Albite Kaolinite K-feldspar C02 Chal- Clinoptilolite Ca,Mg/Na 

(CaC0 3) [CaMg(COshl (CaS0.-21-1 20 ) · (NaCI) (NaAISi308)

3 1Al:.$i20 5(0H)4J (KA1Si308) gas 

cedony (Nao.sKo.4Cao.s> exchange4 

(Si02J (AISi

50 12) 

White River flow system ~ () 

...... 2 to 1 1 - 0.97 - 0.02 1.30 0.95 0.84 - 0.45 0.07 0.30 - 1.77 - - 0 

2 - .97 - .02 1.30 .95 .76 - .45 .30 - 2.06 0.14 z - -

3 - .88 .15 1.30 .95 - - .04 .07 -.12 - .10 -- 0.42 ~ 

> 

0.62 0.48 1.32 - 0.72 A) 

3 to 2A 1 --C.76 0.15 0.12 0.97 - 2.90 - - c: 

2 - .76 .15 .62 .48 1.20 - .72 - .97 - 3.36 0.23 - ~ 

3 -.66 .43 .62 .48 - - .06 .12 .31 --.27 - 0.66 tx:l 

::0 

(/} 

3A to 1 1 - 1.44 0.08 1.68 1.25 1.67 - 0.91 0.14 0.87 - 3.60 - - ><: 

(/} 

2 - 1.44 .08 1.68 1.25 1.53 - .91 -- .87 - 4.17 0.29 - >-3 

3 - 1.26 .41 1.68 1.25 - .07 .14 .04 -.26 0.83 tx:l - - ~ 

Ash Meadows flow system ~ 

5 to 4 1 0.10 - 0.12 -- 0.19 0.86 - 0.46 0.06 0.74 - 1.77 - - (/} 

~ 2 .05 - .12 - .19 .81 - .49 - 0.79 - 2.18 0.16 - en 

3 .17 .06 - .19 - - .03 .06 .31 - .05 -- 0.43 I 

() 

6 to 4 1 -0.37 0.06 - 0.51 1.15 - 0.64 0.12 0.53 - 2.37 - -

3 

2 -

-

.46 

.27 

.

.30 

06 

-

-

-

.51 

.51 -

1.06 -

- .06 

.67 -

.12 

.62 

.65 

-

-

3.11 

.08 -

0.29 -

0.57 ~ IJj 

6 to 5 1 - 0.47 0.18 0.32 0.34 - 0.19 0.05 0.47 - 0.71 - - ?;j -- _z 2 -.51 .18 - .32 .30 - .21 - .51 -1.03 0.13 - 3 - .46 .25 - .32 - - .03 .05 .30 -.03 -- 0.17 z 

tx:l 

8 to 7 1 --C.90 0.25 0.08 0.08 0.04 - .03 0.02 -0.54 - 0.02 -- - g 2 - .90 .25 .08 .08 .02 - .03 - -.54 - .09 0.03 - ;;--

3 - .90 .26 .08 .08 - -.01 .02 -.55 .05 - 0.02 c: 

>-3 

10 to 9 1 0.00 0.05 -- 0.40 1.35 - 0.67 0.00 1.03 - 2.73 - - ~ 2 .00 .05 -- .40 1.35 - .67 - 1.03 - 2.73 0.00 

3 - .13 .32 - .40 - .00 .00 .36 - .04 - 0.67 

6 to 9 1 --C.52 0.02 - 0.49 2.57 - 1.34 0.10 1.97 - 5.24 

2 - .52 .02 -- .49 2.46 -1.34 -- 1.97 -5.66 0.20 

3 -.15 .44 - .51 - -.04 .08 .60 -.01 - 0.83 

11 to 4 1 - 0.38 - 0.05 - 0.35 0.66 -0.39 0.12 0.79 -1.37 

2 - .46 -.05 - .35 .57 - .43 -- .88 - 2.12 0.29 

3 -.32 .18 - .35 - - .06 .12 .46 - .06 - 0.33 
TABLE 14.- Mass transfer of constituents and mixing of waters along flow paths in carbonate-rock aquifers of southern Nevada-Continued 

Millimoles per liter 

Flow path 1 Reaction 

model2 Chal- Calcite Dolomite Gypsum Halite Albite Kaolinite K-feldspar C02 cedony (CaC03i ]CaMg(COsi21 (CaS0.-2H20) (NaCI) (NaAJSi30 8)

3 Al~i 0H )4] (KAJSisOs) gas (Si02) 

Las Vegas Valley 

13 to 12 1 - 0.95 0.35 0.08 0.10 0.19 - 0.11 0.03 - 0.07 - 0.24 

2 - .95 .35 .08 .10 .16 - .11 -- - .07 - .35 

3 - .95 .40 .08 .10 - - .01 .03 - .16 .14 

15 to 14 1 - 3.65 1.61 4.48 0.08 0.23 - 0.13 0.04 - 0.37 - 0.49 

2 - 3.65 1.61 4.48 .08 .19 - .13 -- - .37 - .63 

3 - 3.63 1.66 4.48 .08 -- - .02 .04 - .40 - .03 

17 to 12 1 - 0.71 0.21 0.07 0.08 0.18 - 0.10 0.02 - 0.11 - 0.26 

2 - .71 .21 .07 .08 .15 - .10 -- - .11 - .35 

3 -.71 .25 .07 .08 -- - .01 .02 - .20 - .09 

Pahrump Vall ey 

13 to 16 1 --fi.77 0.30 0.15 0.03 0.09 - 0.05 0.02 - 0.12 - 0.10 

2 -.77 .30 .15 .03 .08 - .05 -- - .12 - .16 

3 -.77 .32 .15 .03 - - .01 .02 - .17 .09 

1 Flow-path numbers, and average chemistries ror waters, are: 

I Big Muddy Spring. 

2 Mixture of 62 percent Coyote Spring Valley water (MX-4, MX-5, and VF-2 wells) and 38 percent Sheep Range water (Wiregrass, Cow Camp, and Mormon Well Spring). 

2A Coyote Spring Valley (MX and VF-2 wells). 

Clinoptilolite 

(Nao.sK0.4Ca0.s> 

(AJSis012l 

0.06 

-

O.Q7 

--

0.04 

-

0.03 

-

Ca,MgfNa 

exchange4 

0.10 

0.11 

0.09 

0.05 

3 Mixture of 64 percent White River now system water from Pahranagat Valley (Crystal and Ash Springs) and 36 percent southern Meadow Valley Wash now system water (Boulder, Kane, Grapevine, and Willow 

Springs, and Bradshaw, Railroad, Randono and Jensen wells). 

3A Mixture of 40 percent White River now system water from Pahranagat Valley (Crystal and Ash Springs), 38 percent Sheep Range water (Wiregrass. Cow Camp, and Mormon Well Spring), and 22 percent southern 

Meadow Valley Wash now system water (Boulder, Kane. Grapevine, and Willow Springs, and Bradshaw, Railroad, Randono. and Jensen wells). 

4 Discharge-weighted average for springs at Ash Meadows (Winograd and Pearson, 1976, p. I 130-1131 ). 

5 Army Well I. 

6 Mixture of 60 percent central part of Spring Mountains water (Sky Mountain, Summer Homes, and Highway Maintenance wells, and Willow, Deer Creek no. I. Deer Creek no. 2, Rainbow, Trout, and Cold Creek 

Springs) and 40 percent White Rive.r now system water from Pahranagat Valley (Crystal and Ash Springs). 

7 Indian Springs. 

8 Cold Creek Spring in Spring Mountains. 

9 Test Well 3 in Frenchman !'lat. 

10 White River now system water from Pahranagat Valley (Crystal and Ash Springs). 

11 Mixture of 60 percent central part of Spring Mountains water and 40 percent Test-Well-3 water. 

12 Tule Spring area in north Las Vegas Valley (Holland, Race!, Mulder. Martin, and Tule Spring wells). 

I 3 Central part of Spring Mountains. 

14 Southwestern Las Vegas Valley (Stocks and Spanish Trail wells; water from Tenaya well is excluded because it contains twice as much chloride as sodium- in miJiiequivalents per liter). 

15 Southern part of the Spring Mountains southwest of Las Vegas Valley (BLM Visitors Center well and Sandstone, Red. and White Rock Springs). 

16 Pahrump Valley (Manse well and Pahrump Spring well). 

17 Mixture of 85 percent central part of Spring Mountains water (no. 13) and 15 percent Sheep Range water in Corn Creek Springs area (Corn Creek Springs, and Shown, Young, and Brooks wells). 2 Most constituents are involved in all three mass-balance reactions; clinoptilolite is used in place of K-feldspar in reaction 2 and calcium-magnesium exchange lor sodium is used in place ol albite in reaction 3. Seep. 41 for 

more detailed discussion. 3 Zeolite mineral analcime can be used in place ol albite; only resulting mass-transfer difference is reduction in amount of precipitating chalcedony (or other silicate mineral); see text. 

• Calcium and magnesium exchange ror sodium is based on calcium-to-magnesium ratio in final water; see text. 

0 

t".1 

0 

0 

~ ~ 

~ 

?.l 

~ -

en 

0 

>-3 

0 

'1j 

t".1 

~ ::0 

0 

t"' 

0 

0 

_><: 

~ t".1 

> >-3 

a; 

f;; 

2 

0 

ct 
C44 REGIO AL AQUIFER-SYSTEM ANALYSIS- GREAT BASIN, ~VADA UTAH 

TABLE 15.- Saturation indices for selected minerals in water from carbonate-rock aquif ers of southem Nevada1 

(Cal ula1ed usmg compmer program WATEQ4 F (Ball and others. 19 7)] 

Site Calcit e Dolomite Gypsum Ha lite Albite Kaolinite K-feldspa r Cha lcedony Analcime 

WHITE RIV ER FLOW y TEM 

Muddy Rive r springs 

Big Muddy Spring 0.0 - 0.1 - 1.4 - 6.8 - 1.4 1.9 - 0.1 0.1 - 3.2 

Coyote pring Valley 

MXwell 0.0 0.1 - 1.8 - 7.2 - 1.4 1.7 0.0 0.2 - 3.2 

VF-2 well .2 .3 - 1.8 - 7.2 - 1.3 1.6 .1 .2 - 3.2 

Sheep Range 

Wiregrass Spring 0.0 - 0.3 - 2.7 - 9.6 - 4.0 0.9 - 1.6 0.0 - 5.9 

Cow Camp Spring .1 .1 - 2.4 - 7.7 - 2.3 1.5 - 1.3 .1 - 4.2 

Mormon Well Spring .2 .2 - 2.5 - 8.2 - 2.8 1.4 - 1.6 .1 -4.8 

outhern Meadow Valley Wash 

Boulder Spring - 0.3 - 1.0 - 3.1 - 8.5 - 1.0 2.3 0.7 0.4 - 3.3 

Kane Spring - .4 - 1.2 - 2.5 - 8.0 - 1.0 2.6 .9 .6 - 3.5 Grapevine Spring .0 - .2 - 2.0 - 7.9 - 2.1 2.2 - .5 .2 -4 .1 Willow Spring - .6 - 1.9 - 2.4 - 7.4 .0 3.0 1.3 .6 - 2.5 

Bradshaw well .3 - .2 - 1.7 - 6.8 .0 2.8 1.4 .7 - 2.5 Railroad Elgin well .1 - .2 - 2.0 - 6.9 .0 2.7 1.4 .6 - 2.4 Randono well .2 .0 - 2.0 - 6.9 .1 2.8 1.4 .6 - 2.4 Jensen well .4 .3 - 1.8 -6.9 .2 2.7 1.4 .6 - 2.2 

Pahranagat Valley 

Crystal Spring 0.2 0.3 - 2.2 - 8.3 - 1.6 2.0 0.2 0.2 - 3.6 Ash Spring .0 - .2 - 2.2 - 8.2 - 2.0 1.7 - .3 .1 - 3.8 

A H MEADOWS FLOW Y TEM 

A h Meadow springs 

Ash Meadows springs 2 0.1 0.0 - 1.8 - 7.4 - 1.4 2.1 0.1 0.1 - 3.3 

Mercury Va lley 

Army Weill 0.1 0.2 - 2.0 - 7.8 - 2.2 1.4 - 0.8 0.0 - 3.9 

Indian prings Valley 

Indian Springs 0.2 0.3 - 2.5 - 9.4 - 3.5 1.2 - 1.7 - 0.2 - 5.0 

Central part of pring Mountains 

Sky Mountain well 0.1 - 0.3 - 2.1 - 9.4 - 3.6 1.4 - 2.1 - 0.1 - 5.4 Summer Homes well 

Willow - .1 - .5 -2.6 -10.2 -4.9 .4 -2.6 - .3 - 6.6 Spring .1 -.3 - 2.5 -10.0 - 4.4 .7 - 2.4 - .2 - 6.1 De r Creek Spring no. 1 .1 - .5 - 3.2 -1 0.7 - 5.1 - .3 - 3.0 - .3 -6.7 Deer Creek Spring no. 2 .9 1.2 -2.9 -10.4 - 4.4 - .1 - 2.2 - .3 - 5.9 

Highway maintenance well 0.2 - 0.2 - 2.1 - 10.2 - 4.7 0.5 - 2.7 - 0.3 -6.3 Rainbow Spring no. 2 .0 - .6 -2.8 - 9.9 - 5.0 .4 - 2.8 - .3 - 6.6 Trout Spring 

Cold .6 .6 -2.9 - 10.7 -4.9 - .3 - 2.7 .4 -6.4 reek Spring .2 - .1 - 2.6 - 10.3 - 4.6 .6 - 2.6 - .2 - 6.2 

Frenchman Flat 

Test Well3 0.2 0.3 - 1.8 - 7.3 - 2.0 1.0 - 0.8 0.0 - 3.6 
GEOCHEMISTRY AND ISOTOPE HYDROLOGY, GREAT BASIN C45 

TABLE 15.- Saturation indices for selected minerals in water from carbonate-rock aquifers of southern evada1

- Continued 

Site Calcite Dolomite Gypsum Halite Albite Kaolinite K-feldspar Chalcedony Analc.ime 

outh Yucca Flat 

C-1 Well 0.9 1.8 - 1.9 - 7.0 - 1.5 0.5 - 0.2 0.1 - 3.3 

LA VEGA VALLEY FLOW y TEM 

Tule Spring area - orth La Vegas Valley 

Martin well 0.2 0.4 - 2.6 - 8.9 - 2.6 1.4 - 0.9 0.0 -4.3 

Race! well .2 .4 - 2.5 - 9.0 - 2.5 1.5 - .9 .0 -4.3 

Tule Spring State Park well .1 .2 - 2.5 - 8.9 -2.4 1.8 - .7 .1 -4.3 

Mulder well .3 .6 -2.4 -8.6 - 2.5 1.3 - 1.1 .0 - 4.3 

Holland well - .2 - .4 - 2.5 - 9.2 - 2.9 2.1 - 1.2 .0 -4.6 

Southern part of Spring Mountains 

Sandstone Spring - 0.4 - 1.0 -2.0 - 8.8 - 3.8 1.5 - 1.9 - 0.2 - 5.5 

BLM Visitors Center well .1 .0 - 1.3 - 8.8 - 3.1 1.6 - 1.5 - .1 - 4.7 

Red Spring .2 .3 - 2.4 - 9.1 - 3.2 1.5 - 1.2 - .1 .9 

White Rock Spring - .3 - .8 -1.3 - 8.5 - 3.3 2.0 - 1.6 - .1 -4.9 

outhwe tern Las Vega Valley 

Tenaya well 0.0 0.0 - 1.1 - 7.2 - 2.2 2.0 - 0.6 0.0 - 4.0 

Spanish Trail Country Club .1 .1 - .7 -8.4 - 3.0 1.7 - 1.3 -.1 -4.6 

Stocks Mill and Supply Co. .0 .0 - .8 - 8.4 - 2.8 1.9 - 1.1 - .1 - 4.5 

Corn Creek prings area 

Corn Creek Spring 0.2 0.5 - 2.5 - 8.9 - 2.6 1.8 - 0.7 0.0 - 4.5 

Shown well -.2 - .3 - 2.6 - 8.9 - 2.1 2.4 - .2 .3 -4.2 

Brooks well .8 1.9 -2.6 -8.9 - 1.8 1.1 - .1 .3 - 3.8 

Young well -.2 .1 -2.9 - 9.0 - 1.2 2.6 .9 .5 - 3.6 

PAHR MP VALLEY FLOW SYSTEM 

Pahrump VaHey 

Manse well 0.1 0.0 - 2.3 -9.5 - 3.2 1.6 - 1.6 - 0.1 -4.9 

Pahrump Spring well .2 .4 - 2.3 - 9.4 - 3.2 1.3 - 1.4 - .1 - 4.9 

(ion-acti vi ty prod uc t) 1 Saturation index:::: log K , where K7 =equil ibrium constant at temperature T. By convention, positive value indicates mineral can precipitate 

T from solution, whereas negative value indicates mineral can dissolve if present. Data for aluminum concent-ration were not ava ilable for these sites, so a value of tO J.l g/L was 

used for all sites in calculating saturation ind.iccs. 

2 Discharge-weighted average was used. 

water; and (4) perhaps the strongest evidence of the 

lack of oxidation of organic carbon is that a large 

influx of organically derived C02 would cause a shift to 

a lighter carbon-13 composition, and this is not 

observed (see section titled "Ground-Water Age"). 

Carbon-dioxide gas from rock units overlying the 

aquifers was eliminated as a possible source of C02 gas 

in the aquifer, even though large amounts of C02 gas 

are present in some of the overlying rock units (D.C. 

Thorstenson, U.S. Geological Survey, oral commun., 

1988), because (1) partial pressures of C02 in rock units 

overlying the aquifers are less than partial pressures of 

C02 in the aquifer waters, (2) the rates of diffusion and 

dispersion for C02 gas into the aquifer waters would be 

slow, and (3) there should be a shift to lighter carbon13 values instead ofthe heavier measured values (average carbon-13 of C02 gas in rock units overlying the 

aquifers in th Nevada T t ite area of south ern 

Nevada is -16.5 permil; D.C. Thorstenson, oral commun., 1988). However, exchange of large quantities of 

dissolved carbon for carbon in calcite could balance the 

input of some C02 gas with light carbon-13. 

WHITE RIVER FLO\ Y T£M 

OYOTE. PRING AL LEY+ HEEl' Rru"\GE ~ M DDY RI ER PRING 

ATH 2-1 ) 

A deuterium mass-balance calculation to determine sources of water emanating from Muddy River 

springs, the terminus of the White River flow system, 

indicates that water discharging from the springs con-
C46 REGIO ALAQUIFER-SYSTEM ANALYSIS- GREAT BAS~, NEVADA-UTAH 

sists of 62 percent water from the carbonate-rock aquifers of Coyote Spring Valley and 38 percent water from 

the Sheep Range. Mass-balance calculations based on 

water-chemistry differences between the initial mixture of Sheep Range and Coyote Spring Valley water 

and final Muddy River springs water show that gypsum, halite, albite, and K-feldspar dissolve; calcite and 

chalcedony precipitate; and kaolinite forms (table 14). 

Dolomite dissolves if cation exchange occurs, otherwise 

dolomite does not dissolve or precipitate. The average 

chemistry of water at Muddy River springs used for 

mass balance calculations is from Big Muddy Spring. 

Big Muddy Spring is the largest spring in the Muddy 

River springs area with complete chemical and isotopic 

data and is the only spring of the Muddy River springs 

with carbon isotope data (appendix B). 

Gypsum and halite dissolution are used as sources 

of S04, Cl, and Na in this model because seven wells 

drilled in the area (Berger and others, 1988) indicate 

that the Tertiary aquitard of the Ash Meadows flow 

system does not exist in this part of the White River 

flow system. The wells generally penetrate about 20 to 

850 ft of unconsolidated sands and gravels which 

directly overlie the carbonate-rock aquifers. In addition, samples from a well about 7 mi west of and upgradient from Muddy River springs contain gypsum 

(Berger and others, 1988). Sulfur isotope data indicate 

that dissolved sulfate in Muddy River springs and Coyote Spring Valley water samples (834S of 13.4 and 

13.0 permil, respectively) could be derived from dissolution of gypsum in marine carbonates of Permian to 

lower Triassic age (Claypool and others, 1980). Upper 

Permian carbonate rock south and east of the Muddy 

River springs area contain gypsum (Longwell and others, 1965), so although gypsum has not been reported 

in exposed Permian rock in the Muddy River springsCoyote Spring Valley area, gypsum may be present in 

these rocks at depth. A more likely source of gypsum in 

this area are the Tertiary Muddy Creek and Horse 

Springs Formation units, which overlie the carbonaterock aquifers west of Muddy River springs (Longwell 

and others, 1965). These formations contain evaporite 

deposits, which include gypsum. A sample of gypsum 

from the Muddy Creek Formation in southern Nevada 

has a 834 S of 14.0 permil, which is similar to that of 

sulfate dissolved in Muddy River springs and Coyote 

Spring Valley water samples. Evaporite deposits also 

probably contain some NaCl in addition to the gypsum. 

Cation exchange of calcium and magnesium in the 

water for sodium in clay minerals also may be a source 

of odium in the water and can be used to replace albite 

in the mass-balance reaction model. Clinoptilolite also 

may be a source of potassium and can be used in place 

of K-feldspar in the mass-balance reaction model. No 

thermodynamic data were available for clinoptilolite, 

so the mineral saturation state and, therefore, the thermodynamic feasibility of this reaction could not be 

determined. 

In the mass-balance calculation that includes 

exchange of calcium and magnesium in the water for 

sodium in clay minerals, 0.12 mmol/L of carbon dioxide 

gas is lost from the water. This loss is most likely from 

degassing of the water in the spring area. Water from 

most of the springs and wells tapping the carbonate. 

rock aquifers contain gas bubbles, and because water 

supplying the springs generally flows upward from the 

rocks through unconsolidated deposits before reaching 

land surface spring waters may loose some of their 

C02 gas before being sampled. 

The mass-balance reaction models are thermodynamically feasible because gypsum, halite, albite, and 

K-feldspar are all below saturation in Coyote Spring 

Valley or Sheep Range samples (table 15), so they 

would dissolve. Calcite and chalcedony are at or above 

saturation, so they would precipitate. Kaolinite is 

above saturation in the water and, thus, could precipitate but more likely is formed by incongruent dissolution. Although dolomite is at saturation in the water, it 

would dissolve because of dedolomitization. Dedolomitization is the irreversible dissolution of gypsum 

that results in the precipitation of calcite. Calcite precipitation causes the pH to decrease and thus dolomite 

to dissolve (Back and others, 1983). 

Mixing of 62 percent Coyote Spring Valley water 

with 38 percent Sheep Range water, along with the 

mass transfer of constituents in the modeled geochemical reactions, can produce Big Muddy Spring water. 

These processes are mineralogically and thermodynamically possible using minerals identified in the 

aquifers and assuming that either C02 in rechargearea waters is higher than measured, or calcium and 

magnesium in the water is exchanging for sodium in 

clay minerals and C02 is exsolving in the Muddy River 

springs area (table 14). 

WHITE RIVER + 0 fHER:'< M EADOW VAL.LEY W t\SH ~ OYOTE 'I'RL'\;(; 

V ALLEY (PATH 3-'2 } 

A deuterium mass-balance calculation to determine the sources of water in the carbonate-rock aquifers of Coyote Spring Valley indicates that 64 percent of 

the water is from the White River flow system and 36 

percent of the water is from southern Meadow Valley 

Wash. Mass-balance calculations based on water chemistry for the initial mixture of White River flow system 

and southern Meadow Valley Wash water and final 

Coyote Spring Valley water indicate dolomite, gypsum, 

halite, albite, and K-feldspar dissolve; calcite and chalcedony precipitate; and kaolinite forms (table 14). 
GEOCHEMISTRY AND ISOTOPE HYDROLOGY, GREAT BASIN C47 

In addition, the concentration of C02 in the recharge 

area waters would have to be higher than measured. 

Calcium and magnesium exchange can be substituted 

for albite as a sodium source, and clinoptilolite can be 

substituted forK-feldspar as a potassium source, in the 

mass-balance reaction models. 

Thermodynamic calculations show that the massbalance reaction models are feasible (table 15), with 

the exception of the dissolution of K-feldspar, which is 

at saturation in the waters. Therefore, the small mass 

transfer of potassium (0.12 mmol!L) is more likely due 

to the dissolution of clinoptilolite, or perhaps, exchange 

with calcium and magnesium in the water. 

Mixing of 64 percent White River flow system 

water with 36 percent southern Meadow Valley Wash 

water, along with the mass transfer of constituents in 

the modeled geochemical reactions, can produce the 

water in the carbonate-rock aquifers of Coyote Spring 

Valley. These processes are mineralogically and thermodynamically possible using minerals identified in 

the aquifers and assuming that C02 in recharge areas 

is higher than measured. 

A H M EADOW FLO\' SY T EM 

A RMY \VEI.L I ~ ASH M EADOWS ATH 5-4) 

Deuterium data for the Ash Meadows flow system 

show that water discharging at Ash Meadows springs, 

the terminus of the Ash Meadows flow system, has the 

same deuterium composition as water from Army Well 

1, the first carbonate-rock well upgradient from the 

springs that has deuterium, carbon isotope, and chemical data. Mass-balance calculations for water chemistry, assuming the only source of sulfate and the major 

source of sodium is leakage from the Tertiary aquitard, 

for water flowing from Army Well 1 to Ash Meadows 

springs, shows that calcite, albite, K-feldspar, and clinoptilolite dissolve; chalcedony precipitates; and 

kaolinite forms (table 14). Calcite is at saturation in the 

waters and should precipitate, however because of 

changes in temperature and pressure along deep and 

tortuous flow paths (Winograd and Pearson, 1976), calcite is assumed to dissolve and precipitate. This calcite 

dissolution and precipitation is indicated by the carbon-13 composition of the waters and results of massbalance models and is discussed in the section titled 

"Ground-Water Age. " 

A small amount of dolomite dissolves in the massbalance reaction model involving cation exchange, and 

0.12 mmol/L of dolomite precipitates in the other two 

reaction models. The improbability of dolomite precipitating from these waters makes these two reaction 

models unlikely. However, the model with dolomite 

dissolution is also unlikely because both waters are saturated with respect to dolomite. Therefore, the 0.06 

mmol/L of dolomite dissolution may represent (1) analytical error, (2) dedolomitization (if not all the sulfate 

is from leakage, but a small amount of gypsum is 

present to dissolve), or (3) temperature and pressure 

differences-although dolomite would not precipitate, 

these differences could result in water becoming understated with dolomite along parts of the flow path. 

The source of all the sulfate and most of the sodium 

added to the water was assumed to be leakage from the 

Tertiary aquitard, as proposed by Winograd and Thordarson (1975). A sample from the upper part of the aturated Tertiary aquitard overlying the carbonate-rock 

aquifers in Mercury Valley (pl. 1) contained 3,600 mg/L 

sulfate and 1,230 mg/L sodium, assuming 5 percent of 

the reported sodium plus potassium is potassium 

(Winograd and Thordarson, 1975, table 11 ). Th e 

absence of gypsum or anhydrite in the Paleozoic carbonate-rock aquifers in this part of the Ash Meadows 

flow system and the extremely low sulfur concentration 

in two limestone, two dolomite, and three shale samples (table 10) also indicate the main source of sulfate 

is probably a water of higher sulfate concentration, 

rather than a result of gypsum dissolution. Most of the 

increase in sodium (70 percent) also is assumed to be 

leakage from the Tertiary aquitard. The remaining 

increase in sodium is assumed to be from NaCI and, 

thus, is equal to the increase in chloride. The NaCl may 

be from connate sea water trapped in the marine 

sediments that has been released by fracturing or from 

dissolution of NaCl in shales present in the carbonaterock aquifers. A sample from the Tertiary aquitard 

contained only 35 mg/L chloride (Winograd and Thordarson, 1975, table 11), so unless chloride is high in 

other parts of the Tertiary aquitard this is not a likely 

source of the increase in chloride. The dischargeweighted average chemistry for the Ash Meadows 

springs (Winograd and Pearson, 1976, p. 1130- 1131) 

was used for the mass-balance calculations. Thermodynamic calculations show that the mass-balance reaction models are thermodynamically feasible (table 15). 

As previously noted in the section titled "Flow System Delineation on the Basis of Deuterium," water 

from Amargosa Tracer Well 2-about halfway between 

Army Well 1 and Ash Meadows springs-lacks deuterium data, but the oxygen-18 composition ofthis water 

is similar to Ash Meadows springs and probably represents water flowing to the springs. Chemically, this 

water is similar to, although slightly more dilute than, 

Ash Meadows springs water. This water could evolve 

into Ash Meadows springs water by the same processes 

as those determined for the evolution of Army Well 1 

water, but with much smaller mass transfers of chemical constituents. Mass transfers of constituents in 
C48 REGIO AL AQUIFER-SYSTEM ANALYSIS-GREAT BASIN NEVADA- UTAH 

water are all calculated to be less than 0.10 mmol/L 

between Amargosa Tracer Well 2 and Ash Meadows 

springs, thus Amargosa Tracer Well2 i~ not included as 

a separate site in geochemical calculatwns. 

Water from Army Weill can evolve chemically into 

Ash Meadows water if calcium and magnesium are 

exchanged for sodium and C02 gas enters the water 

between the sample sites. The source of C02 gas would 

be a water that is isotopically and chemically similar to 

that of Army Weill water but contains a higher C02 

concentration. Alternatively, Army Well 1 water may 

not be entirely representative of water in this part of 

the flow system that discharges at Ash Meadows; 

instead a water containing higher C02 concentrations, 

that is ~ mixture of Spring Mountains and White River 

flow system water, may be evolving into Ash Meadows 

water. 

. PRJ:-<G l'I'I O ~'TA :--1 + WHITE R.I VER --? A II M EADOW (PATH 6-4) 

A deuterium mass-balance calculation to determine sources of water emanating from Ash Meadows 

springs (Army Well 1 water is isotopically similar to 

water emanating from springs at Ash Meadows) indicates that water discharging from the springs consists 

of 60 percent Spring Mountains water and 40 percent 

White River flow system water. Mass-balance calculations based on water chemistry of the initial mixture of 

Spring Mountains and White River flow system waters 

and final Ash Meadows springs water indicate that 

dolomite, halite, albite, and K-feldspar dissolve; calcite 

and chalcedony precipitate; kaolinite forms; and high 

sulfate and sodium water leak from the Tertiary aquitard into the carbonate-rock aquifers (table 14). Calcium and magnesium exchange can be substituted for 

albite as a sodium source, and clinoptilolite can be substituted for K-feldspar as a potassium source in the 

models. The mass-balance calculations also require 

that C02 concentration be higher than the average 

measured value in recharge-area waters. Dolomite can 

dissolve because most of the waters in the Spring 

Mountains are undersaturated with respect to dolomite (table 15) and gypsum also is present in parts of 

the Spring Mountains, so dedolomitization also may 

occur. 

Mixing 60 percent Spring Mountains water with 

40 percent White River flow system water, along with 

the mass transfer of constituents in the modeled 

geochemical reactions, can produce the water discharging at Ash Meadows springs. These processes are mineralogically and thermodynamically possible using 

minerals identified in the aquifer and assuming that 

C02 in recharge areas is higher than measured. 

The mixture of Spring Mountains and White River 

flow system waters also can produce water of the chemical composition measured at Army Well 1, using the 

same mass-balance reaction models (path 6-5 in table 

14). As discussed in the section titled "Stable Isotope 

of Ground Water," Army Well 1 water is isotopically 

similar to Ash Meadows spring water and probably 

represents mixed Spring Mountains and White River 

flow system water. Thus, the mass transfers for the 

intermediate step between the mixed water and Ash 

Meadows spring water is omitted in determining ages 

and flow rates in later sections of this report. 

Indian Springs water also can be used as the input 

chemistry for the Spring Mountains water. Similar 

models result; however, because Indian Springs water 

contains higher ion concentrations than the more 

dilute samples in the Spring Mountains, the mass 

transfers are less for models that use Indian Spring 

water chemistry to represent Spring Mountains water 

chemistry. 

C LD CREEK PRING --? I. DIAl S PRIN >ATI-I 8-7) 

Cold Creek Spring is about 12 mi directly upgradient from Indian Springs in the Spring Mountains 

(fig. 17), is isotopically similar to Indian Springs, and is 

one of two large s prings with long-term records 

(20 years) of chel)lical and isotopic data, thus it is used 

as the Spring Mountains recharge water that flows to 

Indian Springs. Mass-balance calculations, based on 

water chemistry, between these waters shows that gypsum, halite, albite, K-feldspar, and dolomite would dissolve; calcite and chalcedony (except if cation exchange 

is involved) would precipitate; kaolinite would form; 

and C02 would exsolve (table 14). Gypsum and halite, 

which are used as the sources for the small increases in 

sulfate and chloride (0.08 mmol!L), could be in Permian 

rock that the water flows through or in the Muddy 

Creek Formation in the area of spring discharge. In the 

area between Cold Creek Spring and Indian Springs, 

the existence of a water with high sulfate and chloride 

concentrations is unlikely. Calcium and magnesium 

exchange can be substituted for albite, as a sodium 

source, and clinoptilolite can be substituted for K-feldspar, as a potassium source, in the reaction models. The 

reaction models are thermodynamically feasible 

(table 15) if a small amount of chalcedony can either 

dissolve or precipitate, because both waters are near 

saturation with respect to chalcedony. 

The chemical evolution of Cold Creek Spring water 

to Indian Springs water is mineralogically and thermodynamically feasible using known minerals identified 

in the aquifers and assuming C02 is exsolving in the 

Indian Springs and Cold Creek Spring areas. The 

amount of C02 outgassing at Indian Springs and Cold 
GEOCHEMISTRY AND ISOTOPE HYDROLOGY, GREAT BASIN C49 

Creek Spring, calculated using the computer program 

PHREEQE (Parkhurst and others, 1980) and the 

method of Pearson and others (1978), was 0.16 and 

0.23 mmol!L respectively. The total C02 outgassed, 

0.39 mmol!L, is similar to the value from mass-balance 

calculations, 0.54 mmol/L. 

SI'Rii"G 1\[0 i\TAINS + TE T W ELL 3 A H M I::r\ 0 0 11' AT I-1 11 -4) 

Hydrologic, geologic, deuterium, and chemical data 

indicate the most likely sources of water discharging at 

Ash Meadows springs are the Spring Mountains and 

Pahranagat Valley. Test Well3 (a well completed in carbonate rock east of Frenchman Flat) is along the flow 

path between Pahranagat Valley and Ash Meadows 

(pl. 1, fig. 17), and water from this area may be mixing 

with Spring Mountains water to produce the water 

observed at Ash Meadows springs, or this water may 

already be a mixture of Pahranagat Valley and Spring 

Mountains waters. However, no deuterium data exist 

for Test Well 3. Mass-balance calculations based on 

water chemistry between Pahranagat Valley and Test 

Well 3 show that Test Well 3 water could evolve chemically from Pahranagat Valley water (path 10-9 in table 

14). The mass-balance calculations assume leakage 

from the Tertiary aquitard, and the model that includes 

cation exchange has 0.13 mmol/L of calcite dissolving 

(without leakage calcite would precipitate). The initial 

and final waters are both saturated with respect to calcite (table 15), but as stated previously, calcite may dissolve and precipitate because of temperature and 

pressure differences along flow paths in the carbonaterock aquifers. Therefore, Test Well 3 water could have 

a deuterium composition similar to that of Pahranagat 

Valley water. Subsequently, a mixture of 40 percent 

Test Well 3 water and 60 percent Spring Mountains 

water would be needed to produce Ash Meadows spring 

water. Mass-balance calculations for a mixture of 40 

percent Test Well3 water plus 60 percent Spring Mountains water show the chemistry observed at Ash Meadows could evolve chemically from this mixed water 

(path 11-4 in table 14, table 15). 

Winograd and Thordar on (1975) noted that the 

chemical composition of the water at Test Well3 is similar to that of water discharging at Ash Meadows 

springs and may represent already mixed water that 

changes little chemically between the well and Ash 

Meadows. This scenario, however, would require (1) 

water in Test Well 3 be isotopically similar to Ash 

Meadows water (an unknown); (2) some sodium be 

removed from Test Well 3 water before reaching Ash 

Meadows, or a more dilute water with the arne isotopic 

composition as water from Test Well 3 be mixed with 

Test Well 3 water to achieve the chemistry at Ash 

Meadows; (3) water flowing from Test Well 3 to Ash 

Meadows bypass Army Well 1 (as indica ted by their 

vast differences in chemistry), or Army Well 1 water 

does not represent most water flowing to Ash Meadow 

in this area, although it has a simila r deuterium composition; and (4) the isotopic composition of Army Well 

1 water be produced by some process other than mixing 

of Spring Mountains and Pahranagat Valley waters upgradient from the well. If Test Well 3 wa ter ha an isotopic composition similar to Ash Meadows prings 

water, then the most likely source of Test Well3 water 

would still be a mixture of 40 percent Pahranagat 

Valley water and 60 percent Spring Mountains water to 

obtain a deuterium compo ition similar to Ash Meadows springs. Mass-balance calculations ba ed on water 

chemistry, using 40 percent Pahranagat Valley water 

and 60 percent Spring Mountains wat r to produce 

Test Well 3 water, are thermodynamically fea sible 

(path 6-9 in table 14, table 15). 

As stated in (2) of the preceding paragraph, T t 

Well 3 water may mix with a more dilute water of imilar isotopic composition to produce the water discharging at Ash Meadows. Army Weill water could be such 

a water, but only if Army Weill water is entirely from 

the Spring Mountains and is not a mixture of Spring 

Mountains and Pahranagat Valley wat rs. Then the 

deuterium composition of Army Well 1 water would 

represent a 4 permil shift in the average deuterium 

composition of Spring Mountains water. 

PR ~G . [OUNTAI:-.:S + Y L : .A F'l X I' ~ 1\SII 1\ I F.AD0\1' 

Another less likely scenario for the origin of A h 

Meadows spring water (see section titl ed ' Geologic 

Framework") is the mixing of water from south Yucca 

Flat, represented by water from Well C-1, which is completed in carbonate rock, with Spring Mountains water. 

Deuterium data indicate that a mixture of 33 p rcent 

Yucca Flat water and 67 percent Spring Mountain s 

water could produce the deuterium composition of 

water sampled at Ash Meadows springs. However, on 

the basis of chemical mass-balance calculations using 

the average chemistry of water from Well C-1 and 

Indian Springs, none of the three reaction models is 

thermodynamically feasible . 

U\ VEGAS ALLEY 

Recharge to Las Vegas Valley from the Spring 

Mountains is from two different areas within the 

mountains; each area has a unique isotopic signature. 

Northern Las Vegas Valley receives an isotopically 

light component of recharge from the central part of the 

Spring Mountains, and southwestern Las Vegas Valley 

receives an isotopically heavier component of recharge 

from the southern part of the Spring Mountains. 
C50 REGIO AL AQUIFER-SYSTEM ANALYSIS- GREAT BASIN, NEVADA- UTAH 

In addition, northern Las Vegas Valley may receive as 

much as 15 percent of its water from the Sheep Range 

(see section titled "Flow System Delineation on the 

Basis of Deuterium"). 

SPRJ:'IG M OVNTAI:-.:S ~ N O RTH LAS V EGA ALLEY (PATH 13-1 2) 

Mass transfers based on water chemistry were calculated for the central part of the Spring Mountains to 

the Tule Spring area of northern Las Vegas Valley 

(table 14). Mass-balance calculations show that gypsum, halite, albite, K-feldspar, and dolomite dissolve; 

calcite and chalcedony precipitate (unless cation 

exchange is involved); kaolinite forms; and C02 

exsolves. Calcium and magnesium exchange can be 

substituted for albite as a sodium source, and clinoptilolite can be substituted forK-feldspar as a potassium 

source, in the reaction models. The mass-balance reaction models are thermodynamically feasible (table 15) 

if the ground water is degassing in the Thle Spring area 

and a small amount of chalcedony either dissolves, or 

precipitates, because both waters are near saturation 

with respect to chalcedony. 

The chemical evolution of Spring Mountains water 

to Tule Spring area water in north Las Vegas Valley is 

mineralogically and thermodynamically feasible (table 

15) using known minerals in the aquifers and assuming that C02 is exsolving in the Tule Spring area. The 

small amount of C02 outgassing (0.07 to 0.16 mmol!L) 

is within the range of calculated values for samples 

within the Tule Spring area. 

' PRI NG M O IW AI ' + HEEP RANCE~ O RT H LAS V EGAS LL Y 

(Pt\T H 17-1 2) 

Mass-balance calculations based on water chemistry for a mixture of 85 percent Spring Mountains water 

and 15 percent Sheep Range water (represented by 

samples from the Corn Creek Springs area) produce 

north Las Vegas Valley water (represented by samples 

from the Tule Spring area). Results of these calculations are similar to results of the reaction model using 

solely Spring Mountains water (tables 14 and 15). 

so rH ERN PRINt: Mo rli\IN ~ SOU11-IWEST LA V EGA V ALLEY 

(PAT H 15-1 4) 

Mass-balance calculations based on water chemistry from the southern part of the Spring Mountains to 

southwestern La Vegas Valley show that gypsum, 

halite, albite, K-feldspar, and dolomite dissolve; calcite 

and chalcedony precipitate; kaolinite forms; and C02 

exsolves (table 14). Calcium and magnesium exchange 

can be substituted for albite as a sodium source and 

clinoptilolite can be substituted for K-feldspar' as a 

potassium source, in the reaction models. The chemical 

evolution of southern Spring Mountains water to 

southwestern Las Vegas Valley water is mineralogically and thermodynamically (table 15) feasible using 

known minerals in the aquifers. 

P HR MP VALLE Y 

PRING 10 NTAINS ~ PAHR MP VALLEY (PATH 13- 16) 

Ground water in Pahrump Valley is isotopically 

similar to average recharge water in the central part of 

the Spring Mountains. Thus, ground water in Pahrump Valley should evolve chemically from recharge 

water in the Spring Mountains. Mass transfers based 

on water chemistry were calculated for water flowing 

from the central part of the Spring Mountains to Pahrump Valley (table 14). Mass-balance calculations show 

that gypsum, halite, albite, K-feldspar, and dolomite 

dissolve; calcite and chalcedony precipitate (except if 

cation exchange occurs, then chalcedony dissolves); 

kaolinite forms; and C02 exsolves. Calcium and magnesium exchange can be substituted for albite as a 

sodium source, and clinoptilolite can be substituted for 

K-feldspar as a potassium source, in the reaction models. The mass-balance reaction models are thermodynamically feasible (table 15) using known minerals in 

the aquifers, if chalcedony either dissolves or precipitates, because the waters are close to saturation with 

respect to chalcedony, and water degases C02 in the old 

spring areas of Pahrump Valley. The small amount of 

C02 outgassing is within the range of values calculated 

for the two samples in Pahrump Valley. 

Ml\1ARY OF MA -BAL 1CE R£ TIO 100£1 

Chemical mass-balance reaction models can be constructed for flow paths and mixing of water from different areas in southern Nevada that were determined by 

deuterium mass-balance calculations. The models are 

based on water chemistry and mineralogy observed in 

the flow system and leakage from the Tertiary aquitard. The models are thermodynamically feasible , 

except for flow from Yucca Flat to Ash Meadows 

springs. Geologic information in this area also indicates that flow from Yucca Flat to Ash Meadow 

springs is small (Winograd and Thordarson, 1975). The 

deuterium-derived flow paths and mixing of water from 

different areas, as shown in figure 24, are supported by 

chemical mass-balance calculations. 

GROUND-WATER AGE 

Ground-water age provides another constraint on 

flow paths and mixing in southern Nevada. Groundwater age must increase along a flow path, or be an 

average age between the ages of two initial waters that 

mix for flow paths or mixtures of waters to be probable. 

The age of mixed water has to increase along a flow 
GEOCHEMISTRY AND ISOTOPE HYDROLOGY, GREAT BASIN C51 

path; thus, the mixture has to be older than the youngest mixing water, and the final water may be older than 

both mixing waters if travel times after mixing are 

long. Ground-water ages from several thousand years 

to about 30,000 years can be determined using carbon 

isotopes. Waters less than about 60 years contain measurable tritium (Fritz and Fontes, 1980). 

Ground-water age, adjusted for the mass transfer 

of carbon into and out of the water, can be calculated 

from carbon isotope compositions of the water if(1) the 

carbon isotope composition of the recharge water when 

the water becomes isolated from atmospheric and soilzone C02 gas is known, (2) the mass and sources of carbon added to or removed from the water are known, (3) 

the isotope composition of the sources of carbon are 

known, and (4) the fractionation of the isotopes during 

removal of carbon from the water is known (Wigley and 

others, 1978). The biggest sources of error in calculating ground-water age using this approach are (1) the 

estimation of the starting, or original, carbon-14 composition of the recharge waters (A0, pre-nuclear-detonation carbon-14), (2) the accuracy of the mass-transfer 

reaction models in describing the input and output of 

carbon to the water along the flow path, and (3) the isotope composition of carbon added to the water. 

The carbon-14 composition of a recharge water (A0) 

can be calculated assuming a system is either closed or 

open to soil-zone C02 gas. Ground-water ages determined for this study assumed that ground water in 

recharge areas became closed to soil-zone gas. Initial 

carbon-14 compositions (A0) were calculated using a 

modified Tamers approach (Tamers, 1967, 1975; Tamers and Scharpenseel, 1970) with the computer program NETPATH (Plummer and others, 1991). The 

Tamers calculation used in this study is a mass-balance 

calculation including calcite, dolomite, and C02 gas, 

assuming the carbon in calcite and dolomite contains 

0 pmc (percent modern carbon) and the C02 gas contains 100 pmc. These calculated carbon-14 values for 

A0 are shown in table 18. The assumption that the system is closed to C02 gas in recharge areas may result in 

adjusted carbon-14 ages younger than actual ages, 

because almost all water samples in recharge areas are 

saturated with respect to calcite and most are saturated, or close to saturation, with respect to dolomite 

(table 15) yet water in the two main recharge areasthe central Spring Mountains and Sheep Range-contain 76 to 100 pmc (table 16). These waters contain 

post-nuclear-detonation tritium (table 16) and, thus, 

also contain carbon-14 compositions greater than the 

pre-nuclear-detonation level of 100 pmc. Therefore, Ao 

of water recharged before nuclear detonations, which 

includes all water outside the recharge areas containing little or no tritium, would have values smaller than 

those measured in recharge areas after above-ground 

nuclear detonations, so the modified Tamers values 

probably are reasonable estimates of Ao. If water was 

recharged under totally open ystem conditions, then 

the closed system ages could be in error by about one 

half-life of carbon-14 (the water would be 5,730 years 

older than calculated). However, the system is not 

totally open, as indicated by carbon-14, which is 76 to 

100 pmc in water in these areas; as compared to C02 

gas in the soil zone of Yucca Mountain, which is 110 

pmc (D.C. Thorstenson, U.S. Geological Survey, oral 

commun., 1988); and carbon-14 in plant tissue, which 

reached a maximum of about 180 pmc (Tamers and 

Scharpenseel, 1970, p. 243). Thus, the maximum error 

of the adjusted ages due to an open, rather than clo ed, 

system has to be less than 5,730 years. The amount of 

possible error depends on whether the system i closed 

partially closed, or open to C02 ga during recharge. 

Water from a well and springs in the foothills of the 

southern part of the Spring Mountains, in southwest 

Las Vegas Valley (Sandstone Bluffs area), was determined to represent recharge to southwe t Las Vegas 

Valley on the basis of hydrologic, geologic, deuterium, 

and water-chemistry data. The average carbon-13 composition in the well and spring-water samples is - 10.4 

permil, and average carbon-14 composition is 50.8 pmc 

(table 16, fig. 25). Two of the four amples contain tritium, indicating that the waters are less than 60 years 

old or are old waters that have been mixed with young 

water containing tritium. If the waters are not a mixture including young water, little decay of carbon-14 

has occurred. The low, or absent, tritium concentration 

indicates that these waters are probably pre-nucleardetonation waters, and thus their carbon-14 compositions should represent Ao values. Although the well is 

completed in, and springs discharge from, sand tone 

units, the source of thi water probably is recharge in 

carbonate rock of the southern Spring Mountains. 

Therefore, their Ao values should be similar to those of 

water in the central part of the Spring Mountains. Th 

similarity of carbon-14 compositions of these waters to 

calculated values for water in the central part of the 

Spring Mountains and Sheep Range (table 18; 53-55 

pmc) indicates that the assumption of a closed system 

in the calculations of Ao for recharge waters in southern Nevada is probably reasonable.Mass-balance calculations presented in the ection titled "Water 

Chemistry" account for the carbon inputs and outputs 

of waters along flow paths (table 14). The mass-balance 

reaction model including the exchange of calcium and 

magnesium in the water for sodium in clay minerals 

(reaction model 3 in table 14) was used for calculating 

adjusted ages. 
C52 REGIO AL AQUIFER-SYSTEM ANALYSIS- GREAT BASIN,_NEVADA- UTAH 

TABLE 16. -Carbon-13, carbon-14, and tritium compositions of ground water 

in carbonat£-rock aquifers of southern Nevada 

[Symbol: --, data not available; <, less than] 

um- Delta Carbon-14 ber 

Site of carbon- (percent 

13 modern sam- (permil) carbon) ples 1 

Central pa1·t of Spring Mountains 

Sky Mountain well 

Summer Homes well 

Willow Spring 

Deer Creek Spring 1 

Deer Creek Spring 2 

Highway maint well 

Rainbow pring 2 

Trout Spring 

Cold reek Spring 

1 - 10.1 84.1 

1 - 10.8 91.1 

1 -9.6 79.2 

2 -8.4 1 -9.6 

1 -10.1 

1 -9.8 

6 -7.9 

6 - 9.5 

100.0 

83.0 

91.7 

90.8(1) 

76.0(4) 

Tritium 

(picocuries 

per 

liter) 

34 

89 

57 

78 

73 

87 

9 

257 (3) 

92 (4 ) 

Sou thern part of Spring Mountains 

BLM Visitors Center well 1 -9.3 46.0 

Sandstone Spri ng 2 - 10.6 49.8 R~~ri. 2 ~~5 ~A 

White Rock Spri ng 2 - 11.2 44.8(1) 

Wiregrass p1; ng 

Mormon Well Spring 

MXwell 

VF-2 Well 

Crystal Spring 

Ash Spring 

Big Muddy Spring 

Indian Springs 

C-1 Well 

Army Well 1 

Average of springs3 

Corn Creek Spring 

Shown well 

Young well 

Brooks well 

Sheep Range 

1 - 10.2 96.8 

1 - 9.9 

Coyote Spring Valley 

1 7.6 

1 -6.1 7.0 

Pahranagat Valley 

3 -7.0 7.8(2) 

2 -6.7 6.3(3) 

Muddy River springs 

-6.0 6.7 

Indian Springs Valley 

3 -7.6 8.3 

Southern Yucca Flat 

-3.8 0.8 

Mercury Valley 

2 - 5.6 2.8(1) 

Ash Meadows 

11 -4.9 4.7(13) 

Corn Creek Springs area 

3 - 7.7 13.9(1) 

1 - 8.8 20.4 

1 -6.7 13.7 

1 - 6.9 35.7 

9.0 

<15 (1) 

3.0(1) 

<2.0 

90 

<2.0 

<1.0 

<2.0(1) 

0.0 

<1.0 

<2.0(2) 

<0.3 

0.6 

0.3(13) 

<1.0(2) <1.0 

<1.0 <15 

'fule Spring area - North Las Vegas Valley 

Holland well 

Mulder well 

Tule Spring well 

Martin well 

Race! well 

1 - 6.2 11.3 

1 - 7.2 23.8 1 - 7.0 13.9 

1 - 6.7 1.9 

1 - 6.7 7 

Southwest Las Vegas Valley 

<15 <15 

Stock Mill we ll 1 -7.9 11.0 <15 

Pahrump Valley 

Manse well 1 -8.3 46.9 <2.0 

Pahrump Spring well 1 - 7.6 26.0 <1.0 

Source 2 

1 

1 

1 

1 

1 

2 

2 

1,3,4 

1,3,4 

1 

1 

1 

1 

1 

4 

4 

4 

3,4 

3,4 

4 

1,3 

3,5 

3 

3 

1,3 

1 

1 

1 

2 

1 

1 

1 

4 

1 Where average is based on rewer or more samples than shown in this column, exact 

number is listed in parentheses after average constituent. value. 

2 Sources of data: 

I Thomas and others ( 1991 ). 

2 Schulke (1987. p. 78). 

3 Winograd and Pearson ( 1976). 

•I npublishcd data, U.S. Geological Survey, Garson City, ev. 

5 Boughton (1986, p. 84). 

3 Discharge-weighted average. fo r springs at. Ash Meadows {Winograd and Pearson, 

1976. table 2). 

Sources of carbon in the carbonate-rock aquifers 

outside of the recharge areas are carbonate minerals 

(calcite and dolomite), organic matter, and C02 gas in 

rock units. Atmospheric and soil-zone C02 gas are not 

considered sources of carbon outside the recharge areas 

because depths to water in the carbonate-rock aquifers 

are generally several hundred to as much as 2,000 ft 

below land surface. Mass-balance calculations (see section titled "Water Chemistry") indicate that dolomite 

dissolves by dedolomitization , and in some areas 

because dolomite is undersaturated in the water. 

Calcite also dissolves and subsequently precipitates, as 

indicated by the lighter calculated than measured carbon-13 compositions of the water (shown as cycled carbon in table 18). Calcite dissolution and precipitation 

are caused by temperature and pressure changes over 

tortuous flow paths (Winograd and Pearson, 1976) and 

possibly increased surface area of calcite due to grinding as the result of faulting. Oxidation of organic 

matter, which would produce C02 gas, and C02 gas in 

rock units overlying the aquifers do not contribute significant amounts of carbon to the water (as discussed in 

the section titled "Water Chemistry"). 

Carbon isotope fractionation factors between precipitating calcite or exsolving C02 gas and a carbonate 

solution at varJ.ing temperatures and pH's can be 

measured (Deines and others, 1974; Mook, 1980). 

V/71 

1///1 

-

-

• 

-4.9/4.7 

EXPLA ATION 

Basin-fill deposits- In areas underl ain by tPick. laterall y 

continuous carbonate rock 

Basin-fill deposit In areas outside thick, laterall y 

continuou carbonate rock 

Carbonate rock- In areas of thick, laterall y conti nuou 

carbonate rock 

Carbona te rock- [n area outside thi ck, laterally 

continuou. carbonate rock 

Noncarbonate rock- In areas of thick, laterally 

continuous carbonate rock 

oncarbonate rock- In areas out ide thi ck, laterally 

continuous carbonate rock 

Boundary of laterally continuous ca rbonate rock 

Generalized direction of ground-water flow in 

ca rbonate-rock aqujfer 

Spring- Emanate from carbonate-rock aquifers 

Well- Source of water is carbonate-rock aquifers 

Average carbon-13, in permil, a nd average carbon-14, 

in percent modern carbon 

., 
GEOCHEMISTRY AND ISOTOPE HYDROLOGY, GREAT BASIN C53 

0 25 50 MILES 

0 25 50 KILOMETERS 

F IGURE 25. - Average carbon-13 and carbon-14 compositions of ground water in ca1·bonate-rock aquifers of southern Nevada. 

See figure 18 for feature names. Modified from Dettinger (1989, fig. 3). 
C54 REGIONAL AQUIFER-SYSTEM ANALYSIS-GREAT BASIN,, NEVADA- UTAH 

These fractionations have to be accounted for in calculating the carbon-13 composition resulting from the 

mass transfer of carbon into and out of the water. 

The following assumptions were made in using carbon-13 to determine the amount of carbon moving into 

and out of the water along flow paths: 

1. Carbon is removed from the water by calcite 

precipitation and in some spring areas by exsolution of 

C02 gas (table 14). 

2. Carbon is added to the water by dissolution of 

dolomite. In all flow systems except parts of the Ash 

Meadows system, dolomite dissolution is primarily the 

result of dedolomitization (table 14), as indicated by 

the saturation of most waters with respect to calcite 

and dolomite and undersaturated with respect to gypsum (table 15). In the Ash Meadows flow system, 

except for flow paths and mixing involving Spring 

Mountains area waters, the increase in sulfate concentration was assumed to be the result ofleakage of high 

sulfate waters from the Tertiary aquitard. Dolomite 

dissolution in these parts of the aquifer may be attributed to temperature and pressure changes along deep 

and tortuous flow paths or to the presence of small 

amounts of gypsum that would cause dedolomitization 

or may represent analytical error. The carbon-13 composition of dolomite was taken as 0.0 permil on the 

basis of seven samples identified as dolomite (table 17), 

and the carbon-14 composition was assumed to be 0 

pmc. 

3. Carbon input, in addition to that from dolomite 

dissolution, along some flow paths (shown in the massbalance calculations as C02 gas in table 14) is assumed 

to be the result of the dissolution of C02 gas, calcite, or 

dolomite in the recharge areas. This carbon is added to 

the recharge water because the concentration of dissolved inorganic carbon in water circulating to depth in 

the aquifers is probably greater than measured at 

high-altitude springs and wells. For these calculations, 

the total dissolved inorganic carbon concentration of 

the recharge water was increased by the mass-balance 

calculated C02 input. This carbon is added to account 

for the sparse data for ground water from high altitudes, the large range in inorganic carbon concentration in samples from high-altitude sites (Thomas and 

others, 1991), and C02 degassing from spring water. 

4. The carbon-13 composition of dissolving calcite 

is difficult to determine because calcite veins are prevalent within the carbonate-rock aquifers (I.J. Winograd, U.S. Geological Survey, oral commun., 1988). 

Primary calcite in southern Nevada has a carbon-13 

compo ition ranging from - 0.5 to +3.7 permil, with an 

average of 1.2 permil (table 17), whereas secondary 

(vein) calcite has a carbon-13 composition ranging from 

about - 6 to - 1.5 permil (I.J. Winograd, written and oral 

communs., 1991). Thus, geochemical models using 

carbon-13 were developed for several scenarios. First 

the cycled carbon (table 18) was modeled assuming all 

dissolving calcite is primary calcite with a carbon-13 

value of 1.2 permil. Second, the cycled carbon was modeled assuming all the dissolving calcite is secondary 

(vein) calcite assumed to be precipitating from a water 

with the average carbon-13 composition of water along 

the flow path. For example, the carbon-13 composition 

of water flowing from Ash Meadows springs is -4.9 permil and the average carbon-13 composition of a mixture 

of 60 percent Spring Mountains and 40 percent Pahranagat Valley waters plus leakage from the Tertiary 

aquitard is -8.6 perrnil, so an average carbon-13 composition of the water along the flow path would be -6.75 

permil (the average of water discharging at Ash Meadows springs and the initial mixed water). Hence, using 

a fractionation factor of 3.0 (Tyler Coplen, U.S. Geological Survey, written commun., 1991), the precipitating 

calcite would have a composition of - 3.75 permil. This 

fractionation factor was used because in Devils Hole in 

southern Nevada calcite precipitating from water with 

a carbon-13 composition of -4.8 permil has a carbon-13 

composition of -1.8 permil (Tyler Coplen, written commun., 1991). Because of the sparse data on carbon-13 in 

calcite veins, a value for present-day calcite precipitation was used for vein calcite. The carbon-13 composition of calcite in vein DH-11 from Devils Hole ranges 

from -2.8 to -1.5 permil over a span of 50 ,000 to 

500,000 years before present (Tyler Coplen, written 

commun., 1991), so the carbon-13 composition of vein 

calcite probably varies little over time in different parts 

of the study area. Third, the cycled carbon was modeled 

assuming the dissolving calcite is half primary calcite 

and half vein calcite. Fourth, the cycled carbon was 

modeled as in the third model, but the fractionation 

factors of Deines and others (1974) were used for calcite 

precipitation. 

Given that most mass transfer models require the 

dissolution of dolomite (table 14), some primary calcite 

probably also dissolves, and because veins are prevalent throughout the carbonate rock, some vein calcite 

probably dissolves. Thus, adjusted carbon-14 age calculations based on mass transfers calculated using a carbon-13 value that is some proportion of primary and 

vein-calcite values probably gives the most realistic 

adjusted age (model 3 in table 18). In addition, if dissolving calcite was entirely vein calcite, then the average age of water discharging from Ash Meadows and 

Muddy River springs would be modern, which is 

unlikely given flow distances of tens of miles and the 

absence of tritium in the water (tables 16, 18). 
GEOCHEMISTRY AND ISOTOPE HYDROLOGY, GREAT BASIN C55 

T ABLE 17. -Carbon-13 composition of calcite and dolomite i 11 

southern Nevada 

Latitude Longitude Delta 

Site 1 Geologic unit or Rock type (degree, (degree, carbon-13 site sampled minute. minute, (permil) second) second) 

1 Yellowpioe Limestone Calcite 36 43 57 114 46 05 +2.5 

2 Ely Springs Dolomite Dolomite 36 29 57 115 17 20 +.6 

3 opah Dolomite Dolomite 36 34 06 115 21 34 +.4 

4 Dawn Limestone Calcite 36 56 00 114 18 50 +2.6 

5 Arcturus Limestone Calcite 39 21 32 115 20 54 +2.7 

6 Upper Cambrian Calcite 38 59 18 114 57 25 +3.4 

7 Simonson Dolomite Dolorrute 39 03 36 114 56 47 +.4 

8 Sevy Dolomite Dolomite 36 03 36 114 56 53 - 1.4 

9 Sevy Dolomite Dolomite 37 27 49 115 11 34 -. 1 

10 Sevy Dolomite (?) Dolomite 37 31 53 115 13 58 - .1 

11 Laketown Dolomite Dolomite 39 03 36 114 57 18 +.2 

12 Lower Pogonip Group Calcite 38 59 28 114 56 41 -.5 

13 Upper Cambria n Calcite 38 59 21 114 57 04 - .4 

14 Test WeB D 37 04 28 116 04 30 +3.7 

15 Well U3CN5 37 03 35 116 01 30 +.4 

16 Army Weill 36 35 30 116 02 14 +.6 

17 Test WeB 4 36 34 54 115 50 08 +2.1 

18 Test Well2 37 09 58 116 05 15 +2.3 

19 Test Well F 36 45 34 116 06 59 +.9 

20 Test Well 3 36 48 30 115 51 26 +1.0 

21 Test Weil l 37 09 29 116 13 23 +.3 

22 Well UE15D 37 12 33 116 02 29 +2.3 

23 Tracer Well3 36 32 12 116 13 47 +2.2 

24 Well C-1 36 55 07 116 00 34 +.6 

25 WellC 36 55 08 116 00 35 +1.2 

26 Blue Diamond road cut -- 36 02 05 115 23 45 +2.7 

1 Dala for sites 14-26 from Ha ns Claassen (U.S. Geological Survey, oral oommun. , 

1987). 

The four models presented for each flow path in 

table 18 demonstrate that the adjusted carbon-14 age 

is extremely sensitive to the carbon-13 composition of 

the dissolving calcite. Adjusted ages range from modern for vein-calcite dissolution to as old as 13,900 years 

for primary calcite dissolution. When only calcite veins, 

which are isotopically light compared with the primary 

calcite, are dissolved, a large amount of carbon is 

exchanged between the water and rock, resulting in 

modern adjusted ages. This large amount of exchange 

(greater than 10 mmoVL of carbon) is probably unrealistic, even in an area like southern Nevada with deep 

fracture flow. The other extreme of dissolving only primary calcite can result in ages greater than 10,000 

years in waters that are probably much younger, as 

indicated by the hydrology of the area and the distinct 

oxygen-18 record of precipitated calcite at Devils Hole, 

Nev., which suggests an age of less than 10,000 years 

for water in Devils Hole (I.J. Winograd, written commun. , 1991). In addition, the ubiquitous presence of 

calcite veins in outcrops and cores from wells in southern Nevada indicates some vein calcite should be 

exposed to ground water. Thus, the carbon-13 composition of the dissolving calcite probably is between primary calcite (1.2 permil) and vein calcite (-6.0 to -1.5 

permil). 

5. The measured carbon-13 composition of the 

final water is heavier (less negative) than the calculated composition (table 18). This difference is assumed 

to be the result of dissolution and subsequent precipitation of calcite caused by temperature and pressure 

changes along the lengthy, deep, and tortuous flow 

paths (Winograd and Pearson , 1976) and possibly 

because of increased carbon exchange resulting from 

increased calcite surface area caused by faulting. The 

increase in calcite surface area, plus the exposure of 

fresh surfaces, produced by fracturing and grinding 

associated with faulting, would increase the exchange 

rate of carbon between solution and calcite (Mozeto and 

others, 1984). This additional input of carbon was 

determined by accounting for the fractionation of carbon-13 in a hypothetical sequence of dissolving and 

precipitating calcite using the Rayleigh distillation 

equations (Plummer and others, 1991). 

6. All carbon-13 fractionation factors us d in the 

computer program NETPATH were set for the fractionation of carbon-13 during calcite precipitation for models 1-3, and calculated u sing the equatio n from 

Deines and others (1974) for model 4. All C0 2 gas and 

carbonate solution fractionations were calculated using 

the equations from Deines and others (1974; table 18). 

A carbon-13 fractionation factor of 3.01 (6.02 for carbon-14) was used for the equilibrium fractionation 

between precipitating calcite and a carbonate solution 

in models 1- 3. 

7. Mixing waters have similar histories. The carbonate-rock aquifers contain relatively homogeneous 

mineralogies, and waters in the aquifers are similar in 

chemical composition, indicating that most of the water 

in the aquifers ha s und e rgone the same major 

geochemical processes. 

WHITE R.lVER FLOW Y T EM 

Water discharging from the Muddy River springs 

area was determined to be a mixture of 40 percent Pahranagat Valley water, 38 percent Sheep Range water, 

and 22 percent southern Meadow Valley Wash water. 

To obtain the measured carbon-1 3 composition of 

Muddy River springs water (fig. 25), carbon, in addition 

to the calculated mass transfer (table 14), must be 

cycled through the water by calcite dissolution and precipitation. The amount of carbon cycled depends on the 

carbon-13 composition of the dissolving calcite 

(table 18). As previously discussed, the average traveltime (age) for the following interpretations will be for 

the model that includes half primary and half secondary (vein) calcite dissolution. 

The average traveltime from the three source areas 

to Muddy Riv er springs was calculated to be 

5,000 years (model 3 in table 18). This age was calcu-
C56 REGIONAL AQUIFER-SYSTEM ANALYSIS- GREAT BASIN, _NEVADA-UTAH 

TAStE !B.-Ground-water ages in carbonate-rock aquifers of southern Nevada 

f< f b · to and out of water on ba is of mass-balance calculations (table 14) and i otope data (table 16). [Ages are corrected for mass trans er o car on m • . . f ti t' c to f< th . . · bo -13 c m osition of ources and sinks and tak.mg mto account rae on a tOn ac rs or ese pr ocesses. Adjusted ages '~e e ca c~lated ~mg ca fC~ 0 

·/from Deines and others (1974). Carbon-13 fractionation for precipitating calcite for models 1-3 

Carbon-13 fract10nat10n or exso ut10n o 2 gas 1 . · d h (1974) Th bal t' · f 1 Co 1 (Us G 1 · 1 s ey oral commun 1991) and fo r model 4 1s from Demes an ot ers . e mass- ance reac 10n IS rom Ty er p en . . eo ogtca urv ' . . ., . (tab! 14) Abb . t' d · f 1 · d · ·

0 water for sodium in clay minerals was used for age correction e . revra tons an model usmg exchange o ca cmm an magnesmm 1 . symbols: mmol!L, millimole per liter; pmc, percent modern carbon; >, greater than; -- not determmed] 

Measured Measured Calculated Cycled Ao And Measured Age 

Flow path initial final fina l initial adj usted carbon-14 (years 

(flow-path Model

2 

o13c ol3c o13c carbon carbon-14 carbon-14 before 

terminus)1 (mmol!L)

3 

(pmd (pmc) (pmc) present)

5 

(permil) (permiJ) (permil) 

Wbite River Flow System 

3A-1 1 - 9.0 - 6.0 - 8.4 2.4 39.2 21.2 6.7 9,500 

(Muddy River 2 >10 modern 

springs)

6 3 5.2 12.3 5,000 

4 - 8.4 4.7 13.6 5,800 

2-1 1 -7.6 - 6.0 - 7.5 1.7 24.7 16.9 6.7 7,600 

(Muddy River 2 >10 modern 

springs) 3 3.5 12.0 4,800 

4 - 7.5 3.0 13.2 5,600 

3-2A 1 - 8.4 --6.1 - 7.5 1.5 31.1 19.8 7.3 ,200 

(Coyote Valley) 2 >10 modern 

3 3.0 14.8 5,800 

4 - 7.4 2.4 16.6 6,800 

Ash Meadows Flow System 

6-4 1 - 8.4 --4.9 - 7.8 3.4 34.1 16.0 4.7 10,100 

(Ash Meadows 2 >10 modern 

springs) 3 8.4 6.2 2,300 

4 - 7.1 6.7 8.6 5,000 

8-7 1 - 9.5 - 7.6 - 8.2 0.45 54 .9 44.6 8.3 13,900 

(Indian Springs) 2 >10 modern 

3 .91 40.3 13,100 

4 - 8.1 .63 42.9 13,600 

Las Vegas Valley 

13-12 1 - 9.5 - 6.8 - 8.2 1.0 53.1 34.5 11 .6 9,000 

(1\rle Spring area) 2 >10 modern 

3 2.2 25.9 6,600 

4 - 8.1 1.7 29.2 7,600 

17-12 1 - 9.2 --6.8 - 8.3 1.10 48.3 33.0 11.6 8,600 

(TuJe Spring area) 2 >10 modern 

3 2.3 24.8 6,300 

4 - 8.2 1.8 27.9 7,300 

15-14 3 - 10.4 - 7.9 - 5.8 50.8 21.3 11.0 5,500 

(Southwest Las 4 - 5.7 21.3 

Vegas Valley) 5,500 

Pahrump Valley 

13-16 1 - 9.5 - 8.0 - 8.4 0.30 53.1 42.4 36.5 1,200 

(Pahrump Va lley) 2 >10 modern 

3 0.58 39.7 680 

4 -8.3 0.40 41.4 1,000 

1 Flow·pnth designations are same as those in table 14. 2 Model I uses carbon-13 value for dissolving calcite of average primary calcite, 1.2 permil (table 17). Model2 uses carbon-13 value for dissolvi ng calcite of vein calcite, 

t.aken as carbon-13 composition of calcite that would precipitate from an average water along now path. Model 3 uses carbon-1 3 value for dissolving calcite assuming half the 

calcite is primary ca lcite (1.2 permil) a nd half the calcite is vein calcite (carbon-13 of vein calcite is that used in model 2). Model 4 uses carbon-13 value of model 3 for dissolving 

calcite. Models nrc described on p. 54. 3 Additional input of carbon, from calcite dissolution and subsequent precipitation, needed to match measured carbon-1 3 composition of water. 4 Ao was calculated using modified Tamers approach with computer model NETPATH (Plummer and ot.hers, 1991) in recharge waters that contain measurable tritium 

and as was determ ined by mixi ng for waters contai ning no tritium and less than 50 pmc. In the case of one mixing water being from a recharge area, Ao was first calculated for 

recharge water and then the mixed carbon-14 value was calculated using this value plus measured value for other water. 

6 Agc =( 5

·

1

7

2

30)(1n( C-t'\(ndju ledd) )). where C-14 (adjusted) is the carbon-14 composition ca lcul ated from mass-bala nce reaction model using carbon-L4 n - 4 measure 

compositions and fractionations of carbon inputs and outputs assuming no decay and C- 14 (measured) is ca.rbon-14 measured in water. 

6 hemistry of Wh ite Rock Spring in volcanic terrain of Nevada Test Site was used to represent carbon-isotope chemistry of southern Meadow Valley Wash water. This 

water has a cnrbon- 13 composition of -ll .2 permil and a ca rbon-14 compos'ition of91.0 pmc. 
GEOCHEMISTRY AND ISOTOPE HYDROLOGY, GREAT BASIN 57 

Jated by adjusting a volume-weighted average of the 

carbon-14 composition of the three source waters CAo in 

table 18), using the carbon mass transfers calculated 

for the mixed water to Muddy River springs, and then 

comparing the adjusted carbon-14 composition (And in 

table 18) to the measured carbon-14 composition of the 

spring water. The mass-transfer adjusted carbon-14 

composition (12.3 pmc) is larger than the measured 

composition (6.7 pmc), and the difference is assumed to 

be due to radioactive decay. The adjusted traveltime 

(age) was calculated by using the equation: 

1 = 5,730 [ In C-14(adju ted) J 

ln2 C - 14 (measured) ' (2) 

where t = adjusted carbon-14 traveltime, or 

age, of the water, in years; 

5,730 =half-life of carbon-14, in years; 

C-14 (adjusted)= carbon-14 composition adjusted for 

the mass transfer of carbon on the 

basis of carbon-13, in percent modern carbon, assuming no decay 

(And); and 

C-14 (measured)= carbon-14 composition measured in 

the water, in percent modern carbon. 

An average adjusted carbon-14 age for Ash and 

Crystal Springs, in Pahranagat Valley, was calculated 

to be 8,500 years before present. Thus, the total average age of water discharging from Muddy River springs 

is the average traveltime of the mixed water 

(5,000 years) plus the volume-weighted average of the 

starting ages of the source waters, corrected for the carbon-14 change associated with the traveltime from 

Pahranagat Valley to Muddy River springs (1,100 

years). The average age of water discharging from 

Muddy River springs, therefore, is calculated to be 

6,100 years (fig. 26). 

The mixing percentages of the three source waters 

for Muddy River springs was determined by first mixing Sheep Range and Coyote Spring Valley waters to 

produce Muddy River springs water and then mixing 

Pahranagat Valley and southern Meadow Valley Wash 

waters to produce Coyote Spring Valley water (see sections titled "Stable Isotope" and "Water Chemistry"). 

The average ages of these mixed waters also are 

included in table 18 because they are used later in the 

report for calculating flow velocities based on adjusted 

carbon-14 ages. 

AS H IE/\D0\\1. FJ.0\\1 Y.'TEM 

Water discharging from springs at Ash Meadows 

was determined to be a mixture of 60 percent Spring 

Mountains water and 40 percent Pahranagat Valley 

water. Carbon, in addition to the carbon determined 

from mass-transfer calculation (table 14), must be 

cycled through the water by calcit dissolution and precipitation to obtain the measured carbon-13 composition of the spring water (table 18). 

The average traveltime from the two sources to Ash 

Meadows springs was calculated to be 2,300 year by 

using equation 2 with volume-weighted carbon isotope 

compositions and correcting for mass transfers of carbon (table 18). Assuming that the adjusted carbon-14 

age is 8,500 years for Pahranagat Valley water the 

average age of water discharging from Ash Meadow , 

corrected for the carbon-14 change associated with the 

traveltime from Pahranagat Valley to A h Meadow 

springs is 4,100 years (fig. 26). 

\ 'EC . Vi\LLEY 

The average age of ground water in the Tule Spring 

area of northern Las Vegas Valley was calculated two 

ways. First, the age was calculated assuming that the 

central part of the Spring Mountains is the sole source 

of water for the Tule Spring area. Second, the ag wa 

calculated assuming that water in the Tule Spring area 

is a mixture of 85 percent Spring Mountains water and 

15 percent Sheep Range water (Corn Creek Spring 

area). Carbon, in addition to that determined from 

mass-transfer calculations (table 14), must be cycled 

through the water by calcite dissolution and precipitation to obtain the measured carbon-13 composition of 

the spring water (table 18). The average traveltime for 

water recharging the Spring Mountains to reach the 

Tule Spring area is 6,600 years (table 18, fig. 26). 

Because Spring Mountains water is modern, thi also 

is the average age of Tule Spring area water. 

A mass-balance reaction model was made for a mixture of 85 percent Spring Mountains water and 

15 percent Sheep Range water to evolve into Tule 

Spring area water. The model results in an average age 

of 6,300 years (table 18). 

The average age of ground water in southwest Las 

Vegas Valley was calculated using the average carbon 

isotope and chemical compositions of water in the 

Sandstone Bluffs area of the southern part of the 

Spring Mountains and water from two wells in southwest Las Vegas Valley (tables 14, 16). The average 

traveltime for water to flow from the Sandstone Bluffs 

area to the wells is 5,500 years (table 18, fig. 26). However, this age is probably younger than the actual age 

because the calculated carbon-13 composition is 

2.1 permil heavier than measured carbon-13 (table 18). 
C58 REGIO AL AQUIFER-SYSTEM ANALYSIS-GREAT BASIN, EV ADA-UTAH 

0 25 50 MILES 

0 25 50 KILOMETERS 

FIGURE 26.-Travel times and ages of ground water in carbonate-rock aquifers of southern Nevada, based on 

adj usted carbon-14 age . See figure 17 for feature names. Modified from Dettinger (1989, fig. 3). 
GEOCHEMISTRY AND ISOTOPE HYDROLOGY, GREAT BASIN 59 

PAHR MP LLEY 

The average age of ground water in the Pahrump 

and Manse Springs area of Pahrump Valley was calculated using the average chemical and carbon isotopic 

compositions of the central part of the Spring Mountains and Pahrump and Manse Springs wells 

(tables 14, 16). The average traveltime (and age) of the 

Pahrump and Manse Springs area water is 680 years 

(table 18, fig. 26). 

i\ThiAR O F GRO ID-\ ATER AGE 

Adjusted carbon-14 ages increase along flow paths 

for flow systems in southern Nevada (fig. 26). Therefore , adjusted carbon-14 ages agree with the flow paths 

delineated using deuterium data and mixing. Carbon13 composition increases along flow paths for flow systems in southern Nevada (fig. 25). The only source of 

carbon outside of recharge areas is dissolution of carbonate minerals, which have a carbon-13 composition 

heavier than that of the water (discussed earlier in this 

section); therefore carbon-13 composition should 

increase along a flow path. The increase in carbon-13 

composition along flow paths also agrees with the flow 

paths delineated using deuterium data and mixing. 

EXPLANATIO 

Basin-fill deposits- In areas underl ain by thi ck, laterally 

continuous carbonate rock 

V / /1 Basin-fill deposits- In area out ide thick, laterally 

continuou carbonate rock 

Carbonate rock- In areas of thick, laterally continuous 

carbonate rock 

1///1 Carbonate rock- In areas outside thick, laterally 

continuous carbonate rock 

-

-

-5400~ 

[modern] 

~400) 

• 

Nonca rbonate rock- In areas of thi ck. laterall y 

continuous carbonate rock 

oncarbonate rock- In areas out ide th ick. laterally 

continuou carbonate rock 

Boundary of lsterally continuous carbonate rock 

Generalized direction and traveltime of ground-water 

now in carbonate-rock aquifer- Number is adju ted 

carbon- 14 age of water, in years before present 

Age of ground water in source area 

Spring- Di charging fr m carbonate rock aquifer. 

umber i adju ted carbon- 14 age of water. 

in year before present 

Well- ourcc of water is carbonate-rock aquifers 

GROUND-WATER FLOW VELOCITIES 

Ground-water traveltimes (ages) can be u ed to 

determine flow velocities of ground water within the 

aquifers, which provide an independent estimate of 

hydraulic properties of the aquifers. Ag -determined 

flow velocities for flow path with a single ource were 

calculated by dividing the horizontal flow-path distance (l ) by the adjusted carbon-14 traveltime (t ). Agedetermined flow velocities for flow paths that involved 

mixing of two waters (labeled flow path a and flow path 

b) were calculated by using equations 15 and 16. These 

equations are derived as follows: 

The adjusted carbon-14 age of the water at the end 

of flow path a can be written as 

( 

- 1(/ J 

p = p f e 8, 270 a ad nd ' (3) 

where P a = percent modern carbon at the end of th 

flow path adjusted for geochemical reactions and decay; 

ta =adjusted carbon-14 age at the end of the 

flow path; 

8,270 = 5, 730 (half-life of carbon-14) divided by ln2 

(from eq. 2); 

fn.d =fractional change, in percent modern carbon, associated with the chemical reactions, fractionation, and carbon sources 

but not decay; and 

P ao =initial percent modern carbon of the ource 

water (Wigley and others, 1978, eqs. 23 

and 30). 

The adjusted carbon-14 age of the water at the end 

of flow path b can be written as 

(4) 

where the variables are the same as equation 3, except 

subscript a's are replaced by subscript b's. 

The amount of carbon-14 in a mixture of water 

from flow path a and flow path b that produces the 

water at cis conserved (carbon-14 does not decay during mixing and mixing occurs before the water at c is 

sampled). Thus, 

where Pc = adjusted (for geochemical reactions and 

decay) percent modern carbon at c; and 

(5) 

X= fraction of total flow at c that derives from 

source a (the percents of Pa and Pb were 

originally determined by deuterium massbalance calculations); assuming the fn.d 
C60 REGIO AL AQUIFER-SYSTEM ANALYSIS- GREAT BASIN, NEVADA- UTAH 

adjustment factor is the same for both 

flow paths (see the previous discussion of 

carbon-13 adjustments). 

The traveltime along flow path a (ta) is 

L 11 a 

'a= KI' a 

(6) 

where la =average length of flow path a; 

I a =hydraulic gradient (M/!!J.l: M is the change 

in head and !!J.l is the flow path length) 

along flow path a; 

K = hydraulic conductivity; and 

11 =effective porosity. 

A similar equation holds for flow path b (replacing 

subscript a's with subscript b's throughout eq. 6 and 

assuming-for lack of more detailed information-that 

K and n are the same along both flow paths). A corollary relates the two traveltimes and allows elimination 

of the hydraulic terms. Dividing the two equations of 

form (6) yields 

(7) 

which, upon division by -8,270 years, and exponentiation gives 

( -r J ( - rr J 

e 8, 2~0 = e 8, 2;0 , (8) 

where 

(9) 

This relation combined with equations 3 and 4 gives 

( 

-rr J 

p = p r e 8, 2;0 

b bdnd ' (10) 

= pbdnd(p p~ )r 

ad nd 

(11) 

so that equation 5 can be rewritten as 

P c = XP a + ( 1- X) Pb dn f p r ' adnd 

(12) 

Equation 12 is an implicit expression for P if p a' c, 

X, Pbo• P ao• fnd• and r are known. P a can be obtained by 

iterative solution, for example, by application of the 

Newton-Raphson method (Chapra and Canale, 1988). 

Once Pais obtained, the traveltime along path a is 

'a= - 8, 270 ln( p ~ J, 

ad nd 

and from equations 7 and 9 

(13) 

(14) 

The age-determined velocities are then estimated as 

I 

and 

v = .E 

pa r ' a 

lb 

v = - pb ' b 

where Vpa =flow velocity along path a; and 

05) 

(16) 

vpb = flow velocity along path b (table 19). 

These age-determined velocity calculations do not 

require that the hydraulic conductivity and effective 

porosity be known, but do assume they are constant for 

the entire aquifer. Ground-water flow velocities along 

each flow path 1:J.].so were calculated from estimates of 

the hydraulic properties of the aquifers using Darcy's 

equation in the form 

v = li, ha n a' 

where Vha =linear flow velocity; 

K =hydraulic conductivity; 

Ia =hydraulic gradient; and 

11 =effective porosity. 

(17) 

Hydrologic flow velocities were calculated using a 

hydraulic conductivity of 4.3 ft/d [the median value of 

39 aquifer tests for wells completed in carbonate rock 

in eastern and southern Nevada (Dettinger and others, 

1995)], horizontal flow-path distances perpendicular to 

water-level contours, hydraulic head differences measured along the flow path, and an effective porosity of 

2.0 percent. 

Hydraulic head differences were taken as difference in water-level altitudes between the initial and 

final sites along a flow path. Hydraulic head differences 

for flow paths involving the Spring Mountains were 

estimated assuming water levels in the Spring Mountains were 500 ft higher than the final site in the adjacent valley (Tule Spring area, southwest Las Vegas 

Valley, and Pahrump Valley), except for Ash Meadows. 

For Ash Meadows, the water level for the Spring Mountains was chosen as 500 ft higher than Indian Springs. 
GEOCHEMISTRY AND ISOTOPE HYDROLOGY, GREAT BASIN C61 

This approach was taken because water levels in 

springs and wells in the Spring Mountains probably do 

not represent a regional water level, but instead represent local levels. In addition, tritium in water samples 

from some wells and springs on alluvial fans of the 

Spring Mountains indicates that traveltime of ground 

water fi·om the mountains to adjacent alluvial fans is 

Jess than about 60 years. Thus, the flow of ground 

water within the Spring Mountains to adjacent alluvial 

fans is rapid, so flow in this part of the flow system is 

omitted in determining flow velocities for the carbonate-rock aquifers. 

Effective porosity was chosen as 2.0 percent on the 

basis of studies that measured or calculated porosities 

in the carbonate-rock aquifers of southern Nevada 

(Winograd and Thordarson, 1975; Berger, 1992; Kilroy, 

1992). The effective porosity used in this study is secondary fracture porosity; the intercrystalline porosity 

is minor compared with the fracture porosity of the carbonate rock (Winograd and Thordarson, 1975). Effective porosity was estimated by harmonic analysis of 

water-level fluctuations in 11 wells and Devils Hole, 

which penetrate the carbonate-rock aquifers in southern Nevada (Kilroy, 1992). Effective porosity ranged 

from 1.0 to 4.4 percent, with an average of 2.2 percent 

and a median of 1.8 percent. For 16 core samples, total 

porosity ranged from 0.4 to 12.4 percent, with a mean 

of 5.4 percent and a median of 5.5 percent (Winograd 

and Thordarson, 1975). Total porosity was e timated 

using geophysical methods for 43 zones in five wells 

completed in carbonate rock in southern Nevada 

(Berger, 1992). Total porosity ranged from 0.0 to 18.5 

percent with a mean of 4.7 percent and a median of 4.2 

percent. 

Flow velocities calculated from adjusted carbon-14 

ages range from 29 to 38 ftJyr, whereas flow velocities 

determined from hydrologic data range from 50 to 

540 ftJyr for the White River flow system (table 19). 

Flow velocities calculated from hydrologic data are 

about twice those calculated from adjusted carbon-14 

data for two flow paths that have hydraulic gradients 

of 3.3 ftlmi, and about 14 times greater for two other 

flow paths that have hydraulic gradients of about 

35 ftJmi. 

The differences in flow velocity between the age 

and hydrologic calculations could result from (1) the 

calculated median hydraulic conductivity of the carbonate aquifers being too high, (2) the assumed effecTABLE 19.-Flow velocities in the carbonate-rock aquifers of southern Nevada, calculated from adjusted carbon-14 ages and hydrologic data 

Change in 

Flow velocity (feet per year) 

Hydraulic 

Flow path Traveltime ' Distance2 hydraulic gradient 

(years) (miles) head3 (feet per From From 

(feet) mile) carbon-14 hydrol'tc 

ages4 data 

White River Flow System 

Coyote Valley to Muddy River springs 2,700 15 50 3.3 29 50 

Sheep Range to Muddy River springs 5,400 30 100 3.3 29 50 

Pahranagat Valley to Coyote Valley 6,900 50 1,800 36 38 540 

Meadow Valley Wash to Coyote Valley 5,700 40 1,400 35 37 520 

Ash Meadows Flow System 

Spring Mountains to Ash Meadows springs 2,200 60 1,400 23 140 350 

Pahranagat Valley to Ash Meadows springs 5,900 95 1,300 14 85 200 

Las Vegas Valley 

Central part of Spring Mountains to Tule Spring area 6,600 15 500 33 12 500 

Southern part of Spring Mountains to southwest La 5,500 10 500 50 9.6 740 

Vegas Valley 

Pahrump Valley 

Spring Mountains to Pahrump Valley 680 10 500 50 78 740 

1 Adjusted carbon·l4 trave.ltime between two samples along a Aow path, or for two mixing waters caJculated by using equat.ions 15 and 16. For mixing waters, traveltime is 

dependent on hydraulic gradients of two flow paths. 

2 Hori zontal flow·pat.h distance. 

3 Differences in water level between source area and end of fl ow path. 

4 Flow velocity was calculated by dividing distance by adjusted carbon-14 age. 

5 Flow velocity was ca lculated by using equation J 7. 
C62 REGIO AL AQUIFER-SYSTEM ANALYSIS - GREAT BASI , NEVADA- UTAH 

tive porosity being too low, (3) the actual flow paths 

being longer than the horizontal flow-path distances, 

(4) some combination of these factors, or (5) the 

adjusted ages being too old. For the flow paths with a 

gradient of 3.3 ft/mi, the average hydraulic conductivity used for calculating velocity may be 50 percent less 

because measurements are few and the range is large: 

hydraulic conductivity, 0.01 to 940 ftld (Dettinger and 

others, 1995). Effective porosity of2.0 percent could be 

higher because of the 1.0 to 4.4 percent range (Kilroy, 

1992). A 50-percent greater flow-path length is probable, given that the flow-path distances are horizontal 

distances and flow in the study area is fracture flow 

that is tortuous and deep (generally thousands of feet). 

Uncertainties in age calculations also can be substantial, as discussed previously in the section titled 

"Ground-Water Age." Thus, average flow velocities for 

these parts of the White River flow system probably are 

in the range of 29 to 50 ft/yr. 

The two flow paths in the White River flow system, 

with hydraulic gradients of 35 and 36 ftlmi, have agecalculated velocities of 37 and 38 ftlyr. These velocities 

are in the range of the velocities calculated from age 

and hydrologic data for the two flow paths with a 

hydraulic gradient of 3.3 ft/mi. However, velocities calculated from hydrologic data (520 and 540 ftlyr) are 

about 14 times greater than the velocities calculated 

from age determinations because of the high hydraulic 

gradients. These higher gradients probably indicate 

areas of lower hydraulic conductivity than was 

assumed as an average for the flow path. The hydraulic 

gradient is 36 ftlmi along the flow path from Pahranagat Valley to Coyote Spring Valley. However, water 

levels decline about 1,200 ft in less than 20 mi (pl. 1), 

and most of this decline could be in a shorter distance 

thus, ground-water flow apparently is restricted 

between the south end of Pahranagat Valley and the 

north end of Coyote Spring Valley. A similar high gradient also is present between Meadow Valley Wash and 

oyote pring Valley. Both of these high gradients may 

result from volcanic rock that overlie and intrude the 

carbonate-rock aquifers (pl. 1), because volcanic rock 

generally have lower hydraulic conductivity than the 

carbonate rock (Winograd and Thordarson, 1975). 

Thus, flow velocities calculated from hydrologic data 

may overestimate the average velocities along these 

flow paths. Velocities calculated from age account for 

areas of low hydraulic conductivity and hence low 

velocities, whereas velocities calculated from average 

hydrologic data do not. Therefore, the age-calculated 

v locitie may be more representative of an average 

velocity than those calculated from hydrologic data. 

The hydraulic gradient also could be high between 

the Sheep Range and Muddy River springs. However 

the gradient used to calculate flow velocity is based ~ 

the head differences between wells completed in basin 

fill and carbonate rock in Coyote Spring Valley plus the 

head differences between the wells completed in carbonate rock in Coyote Spring Valley and Muddy River 

springs. Water in the well completed in basin fill is 

assumed to represent water that recharges the carbonate-rock aquifer beneath Coyote Spring Valley from the 

Sheep Range (see the previous discussion on stable isotopes). 

Flow velocities calculated using ground-water ages 

are 140 and 85 ft/yr, as compared with 350 and 200 ftlyr 

for velocities calculated from hydrologic data for the 

Ash Meadows flow system (table 19). Flow velocities 

calculated from hydrologic data are about 2.5 times 

greater than age-estimated velocities. This difference 

is probably the result of the same five factors as discussed for the White River flow system. The velocitie 

calculated from hydrologic data are about half the minimum velocity estimated by Winograd and Thordarson 

(1975, p. 115) for the carbonate-rock aquifers beneath 

the Specter Range approximately 15 mi upgradient 

from Ash Meadows. Using their data for total discharge 

and cross-sectional area and an effective porosity of 2 

percent, a velocity of 280 ft/yr was calculated. This 

value is about the ·average of the two velocities estimated from the hydrologic data for this study. Thus, 

average flow velocities in the Ash Meadows flow system 

probably are in the range of 85 to 350 ft/yr. 

Flow velocities calculated using adjusted carbon-14 

age are significantly less than velocities calculated 

from hydrologic data for flow paths from the Spring 

Mountains to Las Vegas and Pahrump Valleys 

(table 19). This large difference is a result of the steep 

hydraulic gradient for the flow paths, as compared with 

most other flow paths in the carbonate-rock aquifers, 

and the relatively old ages of ground water in Las 

Vegas Valley. The hydraulic gradients for these flow 

paths are assumed high because recharge to the Spring 

Mountains is at altitudes greater than 10,000 ft. For 

these flow paths, the velocities calculated from hydrologic data may be more reasonable than velocities calculated from age because the amount of recharge to the 

Spring Mountains is large and ground water is 

assumed to mound beneath the mountains and adjacent alluvial fans. The velocities calculated from 

ground-water age for the flow paths that end at the 

Tule Spring area and southwestern Las Vegas Valley 

(table 19) are less than half the minimum velocity calculated from age data for other flow paths in the carbonate-rock aquifers of southern Nevada. This age 

difference indicates that the adjusted ages may be too 
GEOCHEMISTRY AND ISOTOPE HYDROLOGY, GREAT BASIN C63 

old or that ground water is not flowing directly from the 

Spring Mountains to these areas. In Pahrump Valley, 

the relatively young ground-water age results in a 

velocity of 78 ftJyr, which is in the range of other agecalculated velocities, but still about an order of magnitude less than the velocity calculated from hydrologic 

data. Thus, the average velocity for these flow paths 

ranges from 78 to 740 ftJyr and probably is closer to the 

high velocity because of the steep gradient. However, 

the lack of measurable tritium in water samples from 

these sites (table 16) indicates the velocity of 740 ftJyr 

is a maximum. 

In summary, flow velocities calculated from 

adjusted carbon-14 ages are less than velocities calculated from hydrologic data. Thus, either the adjusted 

ages are too old or the sparse hydrologic data do not 

represent average hydraulic properties of the carbonate-rock aquifers. As discussed in the section titled 

· "Ground-Water Age," the ages could be much younger 

if more vein calcite is exchanging carbon with the water 

than the 50 percent assumed. On the other hand, ageestimated flow velocities of 9.6 to 140 ftJyr are in the 

range of velocities calculated for the Madison aquifer in 

Montana, Wyoming, and South Dakota. The Madison 

aquifer is a carbonate-rock aquifer in Montana, Wyoming, and South Dakota. Flow velocities calculated 

using adjusted ages range from 7.2 to 86.7 ftJyr, and 

velocities simulated by ground-water modeling range 

from 11.2 to 74.2 ftJyr, for 22 flow paths in the Madison 

aquifer (Downey, 1984; Plummer and others, 1990, 

table 12). Thus, velocities calculated from groundwater age for the carbonate-rock aquifers of southern 

Nevada have a similar, but slightly larger, range as 

velocities for the Madison aquifer calculated from both 

age and hydrologic data. These similar velocities indicate that the adjusted ages of the ground water are 

probably reasonable. However, the Madison aquifer is 

not in an area of active extension like southern Nevada, 

so flow within the Madison aquifer may not be primarily along secondary fractures like in aquifers of southern Nevada. Thus a direct comparison of velocities in 

the aquifers may not be valid. 

The discrepancy in velocities calculated from age 

compared with those calculated from hydrologic data 

indicate that either the ages or the average hydraulic 

conductivity may be overestimated, and effective porosity and horizontal flow path lengths may be underestimated. The large discrepancy in velocities calculated 

from age and hydrologic data for flow from the Spring 

Mountains to adjacent valleys indicates the lack of 

knowledge about the recharge process for the carbonate-rock aquifers in southern Nevada. 

IMPliCATIONS OF CHEMICAL AND 

ISOTOPIC COMPOSITION OF 

GROUND WATER IN AQUIFERS 

OF THE GREAT BASIN 

Major processes affecting the chemical and i otopic 

composition of ground water in Smith Creek Valley are 

similar to those in other hydrologically closed systems 

of the Great Basin. The principal aquifers in these flow 

systems consist of unconsolidated sedimentary depo -

its underlain by less permeable con olidated rock. 

Numerous systems in which the flow is primarily in 

basin-fill deposits that culminate in a di charging 

playa area exist throughout the Great Basin (Harrill 

and others, 1988). Near recharge area , ground-water 

chemistry results from the dissolution of primary minerals and soil-zone C02. As the water moves downgradient into finer grained sediments near the center of 

the basin, ion exchange becomes an important process. 

In the discharging playa area, evaporation, transpiration, and dissolution of salts left behind by evapotranspiration are dominant processe affecting water 

chemistry. Precipitation of secondary mineral and formation of clays remove ions from water throughout the 

flow system. Deuterium and oxygen-18 become heavier 

(more positive) in the discharge area due to evaporation. 

Major processes affecting the chemical and isotopic 

composition of ground water in the carbonate-rock 

aquifers of southern Nevada should be similar to thos 

in carbonate-rock flow systems throughout the Great 

Basin. The principal aquifers in these flow systems consist of carbonate rock, but unconsolidated basin-fill 

deposits also may be hydrologically cmmected with the 

carbonate rock. Near recharge areas, ground-water 

chemistry results from dissolution of primary minerals-mainly calcite and dolomite-and soil-zone C02 

gas. Mixing of chemically and i otopically different 

waters produces ground water of chemical and i otopic 

composition different from the initial water . As the 

water circulates to depth, geothermal heating causes 

precipitation of calcite, removing calcium and bicarbonate ions from the water. Ion exchange, precipitation 

of secondary minerals, and formation of clay minerals 

removes ions from the water throughout the flow system; exchange reactions also add ions to the water. The 

carbon-isotope composition of the ground water 

changes because of (1) the dissolution of calcite, dolomite, and soil-zone C02 gas, which adds carbon of different isotopic composition to the water, and (2) the 

precipitation of calcite and outgassing of C02, which 

remove isotopically heavier (calcite precipitation) or 

lighter (C02 outgassing) carbon from the system. The 
C64 REGIONAL AQUIFER-SYSTEM ANALYSIS- GREAT BASI , NEVADA- UTAH 

chemical and isotopic compositions resulting from 

these processes can be used in conjunction with hydrologic and geologic information to determine sources, 

flow paths, and mixing of water in carbonate-rock flow 

systems. This information can be used to help determine rates and volumes of flow within the aquifers. 

Carbonate-rock aquifers and hydrologically closed 

basin-fill aquifers form the two principal types of flow 

systems in the Great Basin. Other types may (1) be a 

combination of the basin-fill and carbonate-rock systems, (2) involve ground-water flow primarily in volcanic rock, or (3) be affected by mixing with surface 

water. In the Railroad Valley flow system in central 

Nevada, for example, ground water flows in carbonaterock aquifers and volcanic rock and discharges from 

the playa area of a basin-fill aquifer. The initial chemical character of water in this flow system is a result of 

the dissolution of primary minerals and soil-zone C02 

gas. As the ground water flows into underlying carbonate-rock aquifers, dissolution of carbonate-rock minerals, followed by precipitation of calcite (where water is 

heated at greater depths), dominates. The chemical 

composition of water flowing through volcanic rock 

changes because volcanic glass and minerals dissolve. 

In the discharge area, a playa surrounded by phreatophytic vegetation, evaporation and transpiration are 

the dominant processes affecting the chemical and isotopic composition of the water. In addition, dissolution 

of any salts formed previously as the result of evapotranspiration could be a major source of ions in the 

water. Several processes, such as precipitation of secondary minerals, formation of clays, and ion exchange, 

may occur throughout the flow system. 

In the Pahute Mesa area of southern Nevada, 

ground-water flow is primarily in volcanic rock 

(Blankennagel and Weir, 1973). Processes affecting the 

chemical and isotopic compositions of the water are 

similar to those in the carbonate-rock aquifers, but the 

mineralogy is different. The water chemistry results 

from dissolution of volcanic glass and minerals (such as 

feldspars) rather than carbonate-rock minerals. Precipitation of minerals, formation of clay minerals, and 

ion exchange also are important processes affecting the 

water chemistry (White, 1979; White and others, 1980; 

Kerrisk, 1983). 

In the Humboldt River basin-fill system of northcentral Nevada, the chemical and isotopic composition 

of ground water is affected by mixing with surface 

water in parts of the aquifer. Along the river, some surface water infiltrates into the basin-fill aquifers, particularly during periods of high flow (for example see 

Cohen and others 1965, p. 79-80). Because the chemical and isotopic composition of the surface water and 

ground water are likely to be different, mixing of the 

two waters would produce a blend with a composition 

intermediate to the two end-member waters. The proportions of mixing end-member waters, along with any 

subsequent hydrologic or geochemical processes that 

affect the water chemistry, determine the chemical and 

isotopic composition of the resulting blend. Unless a 

river is a major source of recharge in such a system, 

interaction between streamflow and water in the aquifer affects the chemical and isotopic composition of the 

ground water only adjacent to the river. However, in 

areas of surface-water irrigation, water applied on the 

land surface percolates to the shallow water table 

(Loeltz and others, 1949, p. 33; Harrill and Moore, 

1970, p. 74), thus affecting the chemical and isotopic 

composition of ground water in those areas. The isotopic composition of ground water changes due to the 

infiltration of isotopically different surface water. 

SUMMARY 

This report, a product of the Great Basin Regional 

Aquifer-System Analysis and Southern Nevada Carbonate studies, briefly describes the distribution of dissolved solids and the chemical character of ground 

water in the study area; discusses the geochemical and 

hydrologic processes that result in the chemical evolution of ground wate~ in a hydrologically closed basin-fill 

aquifer; discusses the geochemical and hydrologic processes that produce the chemical and isotopic compositions of ground water in carbonate-rock aquifers of 

southern Nevada; delineates ground-water flow paths, 

source areas, and mixing of waters in the carbonaterock aquifers of southern Nevada; discusses groundwater ages calculated from mass-balance reaction 

models and carbon isotopes; and compares the resulting age-calculated flow velocities with velocities determined using hydrologic data for the carbonate-rock 

aquifers of southern Nevada. Smith Creek Valley, in 

west-central Nevada, represents hydrologically closed 

basin-fill flow systems, with ground water flowing primarily through basin-fill aquifers. Carbonate-rock 

aquifers in southern Nevada represent carbonate-rock 

flow systems, in which ground water flows through 

both basin-fill and carbonate-rock aquifers and underneath topographic divides through carbonate rock. 

Water in the principal aquifers of the Great Basin 

generally contains less than 1,000 mg/L of dissolved 

solids, except in natural-discharge and geothermal 

areas. Aquifers in industrial, mining, urban, and agricultural areas, and aquifers containing highly soluble 

evaporative salts and minerals, may have dissolvedsolid concentrations greater than 1,000 mg/L or elevated concentrations of undesirable constituents, or 

both. These areas of known higher dissolved solids, or 
GEOCHEMISTRY AND ISOTOPE HYDROLOGY, GREAT BASIN C65 

elevated constituent concentrations, are shown in a 

series of water-quality reports for States in the Great 

Basin. 

The general chemical character of water in principal aquifers ofthe Great Basin is dominated by sodium, 

calcium, and bicarbonate in basin-fill aquifers of the 

western Great Basin; calcium, sodium, magnesium, 

and bicarbonate in basin-fill aquifers of the eastern 

Great Basin; and calcium, magnesium, and bicarbonate in carbonate-rock aquifers of the eastern Great 

Basin. The chemical character of water concentrated by 

evapotranspiration in discharging playa areas is generally dominated by sodium, chloride, and sulfate. 

Geochemical and hydrologic processes that produce 

the major-ion chemistry and isotopic composition of 

water in aquifers throughout the Great Basin are identified for examples of the two principal types of flow 

systems in the Great Basin: a hydrologically closed 

basin-fill aquifer in Smith Creek Valley, west-central 

Nevada, and a regional carbonate-rock aquifer system 

in southern Nevada. 

Chemical and isotopic compositions of water in the 

basin-fill aquifer in Smith Creek Valley evolve as a 

result of (1) evapotranspirative concentration of the 

water, (2) dissolution of minerals and soil-zone C02 

gas, (3) precipitation, or formation by incongruent dissolution, of minerals, and (4) ion exchange. Water 

recharging the basin-fill aquifer originates mainly as 

precipitation in the surrounding mountains. Precipitation in the recharge areas is concentrated by evapotranspiration. The conce ntrated precipitation 

infiltrates to the soil zone where it dissolves C02 gas, 

and volcanic groundmass and phenocrysts (dominantly 

albite and anorthite), producing a sodium calcium 

bicarbonate water. In addition, small amounts of Kfeldspar, gypsum, biotite, and possibly pyrite, illite, 

and chlorite are dissolved, adding ions to the water. 

Chalcedony precipitates, removing ions from the water, 

and kaolinite (or some other clay mineral) forms, probably as the result of incongruent dissolution of the feldspars. 

Calcium and magnesium in the water exchange for 

sodium on clays in the playa area, where basin-fill 

depo sits grade to finer grained sediments. This 

exchange results in the sodium calcium bicarbonate 

water evolving into a sodium bicarbonate water. Calcium also may be removed from the water by the 

weathering of plagioclase to CaiN a-montmorillonite 

and the precipitation of a zeolite mineral. Ions are 

a dded to the wate r by the dissol ution of albite, 

anorthite, K-feldspar, C02 gas, and salts containing 

chloride. Ions are removed from the water by precipitation of chalcedony and reduction of sulfate to hydrogen 

sulfide gas. Incongruent dissolution of feldspars probably results in the formation of kaolinite. 

Evapotranspiration , dissolution of evaporative 

salts containing chloride, and precipitation of calcite 

and zeolite minerals are the main processes affecting 

ground-water chemi try in the discharge area. These 

processes result in the sodium bicarbonate water evolving into a sodium chloride water. Constituents also are 

added to the water by dissolution of albite, anorthite, 

K-feldspar, gypsum (or evaporative salts containing 

sulfate), and chlorite, and kaolinite is formed by incongruent dissolution of feldspars. Evaporation of shallow 

ground water in the discharge area a lso cau e the 

water to become heavier in deuterium and oxygen-18. 

Chemical and isotopic compositions of water in th 

carbonate-rock aquifers of southern Nevada evolve as a 

consequence of(1) dissolution of minerals and oil-zone 

C02 gas, (2) precipitation or formation of mineral (3) 

ion exchange, (4) mixing of chemically or isotopically 

different waters, and (5) geothermal heating. Water in 

the carbonate-rock aquifers originates primarily as 

precipitation in the Spring Mountains and Sh eep 

Range. This water is concentrated by evapotran piration and obtains most of its ions from dissolution of C02 

gas, calcite, and dolomite in the recharge ar as. 

Recharge waters generally are saturated with re pect 

to both calcite and dolomite and contain predominantly 

calcium, magnesium, and bicarbonate. The e water 

circulate to depth, which causes the water to heat and 

to precipitate calcite. 

Throughout the carbonate-rock aquifers, calcite 

precipitates, calcium and magnesium in the water 

exchange for sodium in clays, chalcedony precipitates, 

kaolinite forms, and in some spring areas C02 gas 

exsolves. In large areas of the carbonate-rock aquifers, 

gypsum dissolves, causing calcite to precipitate and 

dolomite to dissolve (dedolomitization). In addition, 

sodium and potassium probably are added to the water 

by the dissolution of volcanic glass and minerals (dominantly albite and K-feldspar) and zeolite minerals 

(probably clinoptilolite), which are present in parts of 

the study area. Sodium chloride salts also are present 

in some parts of the study area and dissolve. In the Ash 

Meadows flow system, downward leakage of water containing high sodium and sulfate from the Tertiary aquitard into the carbonate-rock aquifers is the primary 

source of increased sulfate and sodium concentrations. 

Thus, outside of the recharge areas of the carbonaterock aquifers in southern Nevada, sodium, sulfate, and 

chloride can be major dissolved constituents in the 

water. 
C66 REGIO AL AQUIFER-SYSTEM ANALYSIS-GREAT BASIN, ~VADA UTAH 

Waters of differing chemical and isotopic compositions mix in the carbonate-rock aquifers. This mixing 

can re ult in a water that is isotopically and chemically 

different from the source waters. However, all the 

waters generally are undergoing the same geochemical 

processes, which produce waters of similar chemical 

composition. Thus, the primary evidence of mixing in 

the carbonate-rock aquifers is the modified isotopic 

composition of the mixed water, compared to the mixing waters. The mixing waters generally originate in 

different areas, and therefore, have different isotopic 

compositions. 

The isotopic and chemical compositions of water in 

the carbonate-rock aquifers of southern Nevada were 

used to delineate flow systems. First, the deuterium 

content of water in the carbonate-rock aquifers was 

used to determine source areas, flow paths, and mixing. Second, these deuterium-delineated flow paths 

and mixing scenarios were checked for chemical feasibility using mass-balance and mineral-equilibrium 

models based on water chemistry and the geochemical 

processes that are assumed to have produced the chemical composition of the water. Third, adjusted carbon14 ages were determined from carbon-isotope data on 

the basis of the mass-balance reaction models. These 

ages provide another check on the flow path and mixing scenarios because ground-water ages increase 

along flow paths, and apparent ages change due to mixing of different age waters. 

These isotopic and geochemical models produced 

the following results: 

1. Ground water discharging at the terminus of the 

White River flow system (Muddy River springs) is 

a mixture of 40 percent (14,000 acre-ftiyr) Pahranagat Valley water, 38 percent (14,000 acreftiyr) Sheep Range water, and 22 percent (8,000 

acre-ftlyr) southern Meadow Valley Wash water. 

2. Ground water discharging at the terminus of the 

Ash Meadows flow system (Ash Meadows springs) 

is a mixture of 60 percent (10,000 acre-ft/yr) 

Spring Mountains water and 40 percent (7,000 

acre-ftlyr) Pahranagat Valley water. 

3. Las Vegas Valley receives all, or almost all, of its 

ground water from the Spring Mountains (the 

Sheep Range may supply as much as 2,500 acreftlyr to northern Las Vegas Valley). 

4. Pahrump Valley receives all its ground water 

from the Spring Mountains. 

Flow velocities calculated from adjusted carbon-14 

ages are less than velocities calculated from hydrologic 

data. This difference indicates that the ages or average 

hydraulic conductivities may be overestimated, and 

effective porosity and horizontal flow path lengths may 

be underestimated. Calculated ground-water ages are 

sensitive to the carbon-13 composition of the dissolving 

calcite. To determine ages for velocity estimates 

50 percent of the dissolving calcite was assumed to b~ 

vein calcite. Calculated ground-water ages could be 

much younger if more vein calcite, which has a lighter 

carbon-13 composition than the primary calcite, is dissolving. Knowledge about the recharge process for the 

carbonate-rock aquifers of southern Nevada is insufficient to explain the large difference in velocities calculated from age and hydrologic data for flow from the 

Spring Mountains to adjacent valleys. 

REFERENCES CITED 

Arnorsson, Stefan, Sigurdsson, Sven, and Svavarsson, Hordur, 1982, 

The chemistry of geothermal waters in Iceland, 1- Calculation 

of aqueous speciation from 0 to 370°C: Geochimica et Cosmo· 

chimica Acta, v. 47, p. 1513-1532. 

Back, W.B., Hanshaw, B., Plummer, L.N., Rahn, P.H. , Rightmire, 

C.T. , and Rubin, M., 1983i Process and rate of dedolomitiza. 

tion-Mass transfer and 4C dating in a regional carbonate 

aquifer: Geological Society of America Bulletin, v. 94, p. 1415· 

1429. 

Ball , J .W., Nordstrom, D .K. , and Zacbmann, D.W., 1987, 

WATEQ4F- A personal computer Fortran translation of the 

geochemical model WATEQ2 with revised data: U.S. Geological 

Survey Open-File Report 87-50, 108 p. 

Barrows, K.J., 1972, G~ology of the southern Desatoya Mountains, 

ChurchiiJ and Lander Counties, Nevada: University of Califor· 

nia, Los Angeles, Ph.D. dissertation, 351 p. 

Bath, G.D., and Jahren, J .E., 1984, Interpretations of magnetic 

anomalies at a potential repository site located in the Yucca 

Mountain area, Nevada Test Site: U.S. Geological Survey Open· 

File Report 84-120, 44 p. 

Bear, Jacob, 1972, Dynamics of fluids in porous media: New York, 

Dover Publications Inc., 764 p. 

Bennett, G.D., 1979, Regional ground water systems analysis: Water 

Spectrum, Fall 1979, p. 36-42. 

Benson, L.V. , and Klieforth , Harold, 1989, Stable isotopes in precipi· 

tation and ground water in the Yucca Mountain region, southern 

Nevada - Paleoclimatic implications, in Peterson, D.H., ed. , 

Aspects of climate variability in the Pacific and the western 

Americas: Geophysical MonogTaph 55, p. 41-59. 

Benson, L.V., Robison, J.H., Blankennagel, R.K. , a nd Ogard, A.E., 

1983, Chemical composition of ground water and the locations of 

permeable zones in the Yucca Mountain area, Nevada: U.S. Geo· 

logical Survey Open-File Report 83-854, 19 p. 

Benson, L.V, and Thompson, R.S., 1987, The physical record of lakes 

in the Great Basin, in Ruddiman, W.F., and Wright, H.E., Jr., 

eds., North America and adjacent oceans during the last degla· 

ciation: Geological Society of America, The Geology of North 

America, v. K-3 , p. 241-260. 

Berger, D.L., 1992, Lithologic properties of carbonate-rock aquifers 

at five test wells in the Coyote Spring Valley area, southern 

Nevada, as determined from geophysical logs: U.S. Geological 

Survey Water-Resources Investigations Report 91-4167, 27 p. 

Berger, D.L., Kilroy, K.C., and Schaefer, D.H., 1988, Geophysical logs 

and hydrologic data for eight wells in the Coyote Spring Valley 

area, Clark and Lincoln Counties, Nevada: U.S. Geological Survey Open-File Report 87-679, 59 p. 
GEOCHEMISTRY AND ISOTOPE HYDROLOGY, GREAT BASIN C67 

Blankennagel, R.K., and Weir, J .E., Jr., 1973, Geohydrology of the 

eastern part of Pahute Mesa , Nevada Test Site, Nye County, 

Nevada: U.S. Geological Survey Professional Paper 712-B, 35 p. 

Boughton, C.J., 1986, Integrated geochemical and hydraulic analyses 

of evada Test Site ground water ystems: University of 

Nevada, Reno, M.S. thesis, 135 p. 

Byers, F.M., Jr., Carr, W.J. , Orkild , P.P. , Quinlivan , W.D ., and 

Sargent, K.A. , 1976, Volcanic suites and related caldrons of 

Timber Mountain-Oasis Valley caldera complex, outhern 

Nevada: U.S. Geological Survey Professional Paper 919, 70 p. 

Chapra, S.C., and Canale, R.P., 1988, Numerical methods for engineers (2d ed.): New York, McGraw-Hill, 812 p. 

Claassen, H.C., 1973, Water quality and physical characteristics of 

Nevada Test Site water-supply wells: U.S. Geological SuTVey 

Report USGS-474-158, 145 p. Available only from National Technical Information Service, U.S. Department of Commerce, 

Springfield, VA 22161. 

---1985, Sources and mechanisms of recharge for ground water in 

the west-central Amargosa Desert, evada-A geochemical 

interpretation: U.S. Geological SuTVey Professional Paper 712-F, 

31 p. 

---1986, Late Wisconsin paleohydrology of the west-centra l 

Amargosa Desert, Nevada, U.S.A.: Chemical Geology, v. 58, p. 

311-323. 

Claypool, G.E., Holser, W.T. , Kaplan , I.R., Sakai, H. , and Zak, I., 

1980, The age curves of sulfur and oxygen isotopes in marine 

sulfate and their mutual interpretation: Chemical Geology, v. 28, 

p. 199-260. 

Cohen, Philip, and others, 1965, Water resources of the Humboldt 

River Valley near Winnemucca, Nevada: U.S. Geological Sw-vey 

Water-Supply Paper 1795, 143 p. 

Combarnos, M.A., and Bories, S.A., 1975, Hydrothermal convection 

in saturated porous media: Advanced Hydroscience, v. 10, 

p. 232-307. 

Cornwall, H.R. , 1972, Geology and mineral deposits of southern ye 

County, Nevada: Nevada Bureau of Mines and Geology Bulletin 

77,49 p. 

Craig, Harmon, 1961, Isotopic variations in meteoric waters: Science, 

V. 133, p. 1702-1703. 

Craig, R.W. , and Robinson, J .H., 1984, Geohydrology of rocks penetrated by test well UE-25p#1, Yucca Mountain area, Nye County, 

Nevada: U.S. Geological Survey Water-Resources Investigations 

Report 84-4248, 57 p. 

Dansgaard, W. , 1964, Stable isotopes in preci pitation : Tellus, v. 16, 

p. 436-467. 

Deines, P., Langmuir, D., and Harmon, R.S., 1974, Stable carbon isotope ratios and the existence of a gas pha e in the evolution of 

carbonate ground waters: Geochimica et Co mochimica Acta, 

V. 38, p. 1147-1164. 

Dettinger, M.D. , 19 9, Distribution of carbonate-rock aquifers in 

outhern Nevada and the potential for their developmentSummary of findings, 1985-88: Cru·son City, Nev., Program for 

the Study and Testing of Carbonate-Rock Aquifers in Ea tern 

and Southern Nevada, Summary Report o. 1, 37 p. 

Dettinger, M.D., Schmidt, D.L., Harrill, J.R., and Hess, J.W., 1995, 

Distribution of carbonate-rock aquife1· and the potential for 

thei1· development, southern evada and pa rts of Arizona, California, and Utah: U.S. Geological Survey Water-Re ources 

Investigations Report 91-4146, 100 p. 

Dinwiddie, G.A., and Weir, J .E., Jr., 1979, Summary of hydraulic 

tests and hydrologic data for holes UE16d and UE16f, Syncline 

Ridge area , Nevada Te t Site: U.S. Geological Survey Report 

USGS-1543-3, 25 p. 

Downey, J .S., 1984, Geohydrology of the Madison and associated 

aquifers in parts of Montana , orth Dakota, South Dakota, and 

Wyoming: U .. Geological Survey Profes ional Paper 1273-G, 

47 p. 

Drever, J.I., and Smith, C.L., 197 , Cyclic wetting and drying of the 

soil zone a an influence on the cherni try of ground water in arid 

terrains: American Journal of Science, v. 278, p. 1448-1454. 

Eakin, T.E., 1966, A regional interbasin ground-water ystem in the 

White River a rea, southeastern evada : Wa ter Re ource 

Research, v. 2, no. 2, p. 251-271. 

Eakin, T.E., and Moore, D.O., 1964, Uniformity of discharge of 

Muddy River Spring , southeastern Nevada, and relation to 

interbasin movement of ground water, in Geological Surv y 

Research 1964: U.S. Geological Survey, Profe ional Paper 501-

D, p. 171-176. 

Ekren, E.B., Orkild, P.P., Sargent, K.A. , and Dixon, G.L., 1977, 

Geologic map of Tertiary rocks, Lincoln County, vada: U .. 

Geological Survey Miscellaneous Investigations Map 1-1041, 

scale 1:250,000. 

Eugster, H.P., 1970, Chemi try and origin of the brines of Lake 

Magadi , Kenya: Minet·alogical Society of America Special Publication 3, p. 215-235. 

Eugster, H.P., and Jones, B.F., 1979, Behavior of major solutes during 

closed-basin brine evolution: American Journal of cience, 

V. 279, p. 609-631. 

Everett, D.E. , and Ru sh, F.E. , 1964, Ground-water app raisa l of 

Smith Creek a nd lone Valleys, Lander and ye ountie , 

Nevada: Nevada Department of Conservation and atura l 

Resources, Water Resources Reconnais ance Report 2 , 19 p. 

Fiero, G.W., Jr., 1986, Geology of the Great Basin: Reno, University 

of Nevada Press, Fleischmann S rie in Gr at Ba in atura l 

History, 197 p. 

Fritz, P., and Fontes, J.C., 1980, Handbook of environmental isotope 

geochemi try, v. 1, The terrestrial environment, A: w York, 

Elsevier cientific Publishing Company, 545 p. 

Frick, E.A., and Carman, R.L., 1990, evada water supply a nd 

demand, in Carr, J .E., Chase, E.B., Paul on , R.W. , and Moody, 

D.W. , comps. , National Water Summary 1987 - Hyd rologic 

events and water supply a nd use: U.S. Geologica l Survey WaterSupply Paper 2350, p. 353-360. 

Gat, J .R. , and Gonfiantini, R., 1981, Stable isotope hydrology- D uteriwn and oxygen-18 in the water cycle: International Atomic 

Energy Agency Vienna, Technical Repoli: 210, 339 p. 

Green, W.J., an d Canfield, D.E., 1984, Geoch emistry of the Onyx 

River (Wright Valley, Antarctica) and its rol in the chemical 

evolutio n of Lake Va nd a: Geochimica et o mochimica Acta, 

v. 48, p. 2457-2467. 

Guth, P.L., 1980, Geology of the Sheep Range, Clark County, evada: 

Can1bridge, Massachusetts Institute of Technology, unpublished 

Ph.D. the i , 189 p. 

---1988, Superposed Mesozoic thrusts and Tertiary extension, 

northwestern Clark County, evada [abs.]: Geological Society of 

America, Abstracts with Programs, v. 20, no. 3, p. 165. 

---1989, Tertiary extension in the Sheep Range ru·ea, northwestern Clark County, evada, in Wernicke, B.P., Snow, J.K. , Axen, 

G.J., Burchfield, B.C, Hodges, K.V. , Walker, J .D., and Guth, P.L., 

comps, Extensional tectonics in the Basin and Range Province 

between the southern Sierra Nevada and the Colorado Plateau: 

Washington, D.C., American Geophysical Union, 28th International Geological Congress Field Trip Guidebook T138, p. 33-39. 

Hardie, L.A., 1968, The origin of the recent non-marine evaporite 

depo it of Saline Valley, lnyo County, California: Geochimica et 

Cosmochimica Acta, v. 32, p. 1279-1301. 
C68 REGIONAL AQUIFER-SYSTEM ANALYSIS- GREAT BASI , NEVADA-UTAH 

Hardie, L.A., and Eugster, H.P., 1970, The evolution of closed-ba in 

brines: Mineralogical Society of America Special PublicaLion 3, 

p. 273-290. 

Harrill , J .R., 1976, Pumping and ground-water storage depletion in 

La Vega Valley, Nevada, 1955-74: Nevada Division of Water 

Resources, Bulletin 44, 70 p. 

---1986, Ground-water storage depletion in Pahrump Va lley, 

evada-California, 1962-75: U.S. Geological Survey Water-Supply Paper 2279, 53 p. 

Harrill , J .R. , Gates, J.S. , a nd Thomas, J.M. , 1988, Major groundwater flow systems in the Great Basin region of Nevada, Utah, 

and adjacent states: U.S. Geological Survey Hydrologic Investigations Atlas HA-694-C, 2 sheets, scale 1:100,000. 

Harrill, J .R., and Moore, D.O., 1970, Effects of ground-water developmen t on the water regimen of Para dise Vall ey, Humboldt 

County, Nevada, 1948-68, and hydrologic r-econnais ance of the 

tributary areas: evada Division of Water Resource , Bulletin 

39, 123 p 

Ha rrill , J .R. , Welch, A. H., Prudic, D.E., Thomas, J.M., Carman, R.L., 

Plume, R.W. , Gates, J .S., and Mason, J .L., 1983, Aquifer systems in the Great Basi11 region of Nevada, Utah, and adjacent 

states-A study plan: U.S. Geological Survey Open-File Report 

82-445, 49 p. 

Hess, J.W., and Mifflin, M.D., 1978, A feasibility study of water production from deep carbonate aquifers in Nevada: University of 

Nevada, Desert Re earch Institute Publication 41054, 125 p. 

Hintze, L.F., 1980, Geologic map of Utah: Utah Geological and Minera l Survey map, cale 1:500,000. 

Hoover, D.L. , 1968, Genesis of zeolites, evada Test Site, in Eckel, 

E. B., ed. , evada Test Site: Geological Society of America Memoir 110, p. 275-284. 

J ennings, C.W. , 1977, Geologic map of California: Californi a Division 

of Mine a nd Geology Geologic Data Map, cale 1:750,000. 

Jones, B.F., 1965, The hydrology a nd mineralogy of Deep Springs 

Lake, lnyo County, California: U.S. Geological Survey Profe -

sional Paper 502-A, 56 p. 

---1966, Geochemical evolu tion of closed basin waters in the 

westem Great Ba in, in Ran, J .L., ed., Second Symposium on 

Salt, Cleveland , Ohio,1966: orthern Ohio Geological Society, 

V. 1, p. 181-200. 

---1982, Min eralogy of fine-grained a lluvium from borehole 

U11G, ex pl. 1, northern Frenchman Flat area, evada Test Site: 

U.S. Geological Survey Open-File Report 82-765, 10 p. 

Jones, B. F., Eugster, H.P., and Rettig, S.L., 1977, Hydrochemistry of 

the Lake Magadi Basin, Kenya: Geochimica et Cosmochimica 

Acta, v. 41, p. 53-72. 

KeiTisk, J .F., 1983, Reaction-path calculations of groundwater chemistry and mineral formation at Rainier Mesa, evada: Los Alamos ational Laboratory, LA-9912-MS, 41 p. 

Kilroy, K.C., 1992, Aquifer storage cha1·acteristics of Paleozoic carbonate rocks in southea tern Nevada estimated from harmonic 

analysis of water-level fluctu ations: University of evada, Reno, 

unpublished Ph.D. the is, 77 p. 

Kirk, .T., 1987, Analy is of the White River ground-water flow system u ing a deuterium-calibrated discrete-state compartment 

model: Uni versity of Nevada, Reno, unpublished M.S. thesi , 

81 p. 

Kirk , S.T., and Campana , M.E. , 1990, A deuterium-calibrated 

gr oundwater flow model of a regional carbonate-alluvial system: 

J ournal of Hyd rology, v. 119, p. 357-388. 

Kl einhampl, F.J. , a nd Ziony, J.I., 1985, Geo logy of northern ye 

County, Nevada: Nevada Bureau of Mines and Geology Bull etin 

99A, 172 p. 

Koltermann, H.H., 19 4, Hydrogeochemica l and envu·onmental isotope investigation of ground-water recharge mechanisms in the 

Virginia ity Highlands, Nevada : Univer ity of Nevada Reno 

unpubli hed M.S. the is, 149 p. ' ' 

Lamb, C.E., and Woodwa rd, Richard, 1988, California ground-water 

quality, in Moody, D.W. , CarT, J erry, hase, E.B., and Paulson 

R.W., comps. , ation a l Wat r Summary 19 86 dr ogi~ 

events a nd ground-water quality: U.S. Geologica l urvey WaterSupply Paper 2325, p. 173-180. 

Langeheim, R.L., Carss, B.W. , Kennerly, J.B., McCutcheon, V.A., and 

Waines, R.H. , 1962, Paleozoic section in Arrow Canyon Range, 

Clark County, Nevada: American Association of Petroleum Geologists Bulletin, v. 46, no. 5, p. 592-609. 

Lerma n, Abraham, 1967, Model of chemical evolution of a chloride 

la ke - The Dead Sea: Geochimica et o mochimica Acta, v. 31, 

p. 2309-2330. 

Loeltz, O.J., Phoenix, D.A. and Robinson, T.W. , 1949, Ground water 

in Pa radise Valley, Humboldt County, Nevada: evada State 

Engineer, Nevada Water Resources Bulletin 10, 61 p. 

Longwell , C.R. , Pampeya n, E.H., Bowyer, Ben, a nd Roberts, R.J., 

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

evada Burea u of Mines Bulletin 62, 218 p. 

Lyles, B.F. , and He s, J .W. , 1988, Isotope and ion geochemi try in the 

vicinity of the Las Vega Valley hea r zo ne: Un iversity of 

evada , Desert Resear ch Institute Publication 41111, 78 p. 

Macumber, P.G., 1984, Hydrochemical processes in the regional 

ground water di chai·ge zones of the Murray Basin, southeastern Australia, in Hitchon, B., and Wallick, E.I., eds., Practical 

applications of ground water geochemistry: Worthington, Ohio, 

ational Water Well Association, p. 47-63. 

Maxey, G.B. , and Eakin, T.E., 1949, Ground wat r in White River 

Valley, White Pine, Nye, and Lincoln Counties, evada: evada 

State Engineer, Water Resou.rces Bulletin , 59 p. 

McKay, W.A. , and Zimmerman , D.E., 1983 Hydrogeochemical investigation of thermal spring in the Bl ack anyon-Hoover Dam 

area , evada a nd Arizona: University of evada , Desert 

Resear ch Institute Publication 41092, 40 p. 

McKee, E.H., 1970, Fish Creek Moun tains Tuff and volcanic center, 

Lander Coun ty, evada: U.S. Geo logical Survey Profes ional 

Pa per 681, 17 p. 

Mifflin , M.D., 1968, Delineation of ground-water flow system in 

evada: University of Nevada, Desert Research Institute Technical Report H-W 4, 89 p. 

Mifflin, M.D., and Wheat, M.M., 1979, Pluvi al lakes an d estimated 

pluvial climates of evada: evada Bureau of Mines and Geology Bulletin 94, 57 p. 

Miller, W.R. , and Drever, J .I., 1977, Chemical weathering and related 

controls on surface water chemistry in the Absa l'Oka Mountain , 

Wyoming: Geochirnica et Cosmochimica Acta , v. 41, p. 1693-

1702. 

Mook, W.G. , 1980, Carbon-14 in hydrogeological tudies, in Fritz, P. , 

and Fontes, J .C., ed ., Handbook of environme nta l isotope 

geochemistry, volume 1, The terrestrial environment, A, Chapter 2: New York, Elsevier cientific Publishing Company, p. 49-

74. 

Morgan, D.S., and Dettinger, M.D., 1996, Ground-water conditions in 

Las Vegas Valley, Clark County, evada- Part II, Hydrogeology 

a nd simulation of ground-water flow: U.S. Geological Survey 

Water-Supply Pa per 2320-B, 124 p. 

Mozeto, A.A. , Fritz, P. , and Reardon , E.J., 1984, Experimenta l ob ervations on carbon isotope exchange in carbonate-water systems: 

Geochimica et Cosmochimica Acta, v. 48, p. 495-504. 
GEOCHEMISTRY AND ISOTOPE HYDROLOGY, GREAT BASIN C69 

ichols, W.O. , and Davis, L.E., 1979, Data on grou nd-water 

resources of the Spring Mountains area, Thiyabe ational Forest, Nevada: U.S. Geological Survey Open-File Report 79-1638, 

16 p. 

oack, R.E. , 1988, Sources of ground water recharging the principal 

a lluvial aquifers in Las Vegas Valley, Nevada: University of 

Nevada, Las Vegas, unpublished M.S. thesis, 167 p. 

Palmer, C.D., and Cherry, J .A. , 1984, Geoch emical evolu tion of 

groundwater in sequences of sedimentary rocks: Journal of 

Hydrology, v. 75, p. 27-65. 

Parkhurst, D.L. , Plummer, L.N., and Thorstenson, D.C., 1980, 

PHREEQE- A computer program for geochemical calculations: 

U.S. Geological Survey Water-Resources Investigations Report 

80-96, 210 p. 

---1982, BALANCE- A computer program for calculating mass 

transfer for geochemical reactions in ground water: U.S. Geological Survey Water-Resow·ces Investigations Report 82-14, 29 p. 

Parliman, D.J., 1988, Idaho ground-water quality, in Moody, D.W., 

Carr, Jen-y, Chase, E.B., and Paulson, R.W., comps., ational 

Water Summary 1986 - Hydrologic events and ground-water 

quality: U.S. Geological Survey Water-Supply Paper 2325 , 

p. 355-362 

Pearson, F.J., Fisher, D.W., and Plummer, L.N., 1978, Correction of 

ground-water chemi try and carbon isotopic composition for 

effects of C02 outgassing: Geochimica et Cosmochimica Acta , 

V. 42, p. 1799-1807. 

Pewe, T.L., 1981, Desert dust-Origin, characteristics, and effect on 

man: Geological Society of America Special Paper 186, 303 p. 

Phillips, K.N ., and VanDenburgh A.S., 1971, Hydrology and 

geochemistry of Abert, Summer, and Goo e Lakes, a nd other 

closed-ba in lakes in south-central Oregon: U.S. Geological Survey Professional Paper 502-B, 86 p. 

Plume, R.W., 1985, Ground-water resources of Kyle a nd Lee Canyon , Spt-ing Mountains, Clark County, Nevada: U.S. Geological 

Survey Open-File Report 4-438, 47 p. 

---1996, Hydrogeologic framework of the Great Basin region of 

evada, Utah, and adjacent States: U.S. Geological Survey Professional Paper 1409-B, 64 p. 

Plume , R.W. , and CaYlton, S.M., 198 , Hydrogeology of the Great 

Basin region of Nevada, Utah, and adjacent tates: U.S. Geological Survey Hydrologic Investigations Atl as HA 694-A, scale 

1:1,000,000. 

Plummer, L. ., 1984, Geochemical modeling-A comparison of forward and inver e methods, in Hitchon, B., and Wallick, E.I. , 

eds., Fir t Canadian/American Conference on Hydrogeology, 

Practical Application of Ground Water Geochemistry: Worthington, Ohio, ational Water Well sociation, p. 149-177. 

Plummer, L. ., and Back, W., 19 0, The ma . balance a pproach -

Application to interpreti.ng the chemical evolution of hydrologic 

y tern : Am rican Journal of Science, v. 280, p. 130-142. 

Plummer, L. ., Bu by, J.F., Lee, R.W., and Han haw, B.B. , 1990, 

G ochemica l modeling of the Madison aqu ifer in pat·ts of Montana, Wyoming, a nd South Dakota: Water Resow·ce Research , 

v. 26, p. 19 1-2014. 

Plummer, L. ., Parkhurst, D.L., and Thor ten on, D.C., 19 3, Development of reaction model for groundwater sy terns: Geochimica 

et osmochimica Acta, v. 47, p. 665-6 5. 

Plummer, R.W. , Prestemon, E . . , a nd PaYkhurst, D.L., 1991, An 

interactive code (NETPATH) for modeling net geochemical reaction along a flow path: U.S. Geological u1-vey Water-Resource 

lnve tigation Report 91-407 , 227 p. 

Quad , J ay, 1986, Late Quaternary environmental change in the 

upp r La Vegas Va ll ey, evada: Quaterna ry Research, v. 26, 

p. 340-357. 

Quade, Jay, and Pratt, W.L., 1989, Late Wisconsin groundwater di -

charge environments of the southwestern Indian Springs Valley, 

southern Nevada: Quatemary Research , v. 31, p. 351-370. 

Rettig, S.L. , Jones, B.F., and Risacher, F. , 1980, Geochemical evolution of brines in the Salar of Uyuni, Bolivia: Chemical Geology, 

V. 30, p. 57-79. 

Robie, R.A., Hemingway, B.S., and Fi her, J .R. , 1978, Thermodynamic properti es of minerals and related substances at 

298.15°K and 1 bar (105 pa cals) pressure a nd at higher temperatures: U.S. Geologica l Sw·vey Bulletin 1452, 456 p. 

Schroth, B.K., 1987, Water chemistry reconnais ance and geochemical modeling in the Meadow Valley Wash area, outhern Nevada: 

University of evada, Reno, unpublished M.S. the i , 97 p. 

Schulke, D.F., 1987, Great Basin recharge studies: University of 

evada, Desert Research Institute Publication 41104, 127 p. 

Sherwood, T.K., Pigford, R.L. , and Wilke, C.R., 1975, Ma s tran fer: 

ew York, McGraw-Hill, 677 p. 

Smith, C.L. , and Drever, J.I., 1976, Controls on the chemistry of 

springs at Teels Marsh, Mineral Coun ty, Nevada: Geochimica et 

Cosmochimica Acta, v. 40, p. 1081-1093. 

Spaulding, W.G., 1985, Vegetation and climates of the !a t 45,000 

years in the vicinity of the evada Test Site, outh-central 

evada: U.S. Geological Survey Professional Paper 1329, 3 p. 

Spaulding, W.G., Robinson, S.W. , and Paillet, F.L., 1984, Preliminary 

assessment of climatic change during late Wisconsin time, 

southern Great Basin and icinity, Al"izona , alifornia, and 

evada: U.S. Geological urvey Water-Resource Inve tigations 

Report 84-4328, 40 p. 

Stewart, J .H., 1980, Geology of evada; a discussion to accompany 

the geologic map of Nevada : evada Bureau of Mine and Geology Special Publication 4, 136 p. 

Stewart, J.H. , and Carlson, J .E. , 1978, Geologic map of evada: 

evada Bureau of Mine map, scale 1:500,000. 

Stewart, J.H., and McKee, E.H., 1977, Part I. Geology and minera l 

deposits of La nder County, evada: evada Burea u of Mine 

and Geology Bulletin 8, 59 p. 

Sundquist, E.T., Plummer, L. ., a nd Wigley, T.M.L., 1979, Carbon 

dioxide in the ocean surface-The homogeneous buffer factor: 

Science, v. 204, p. 1203-1205. 

Szecsody, J.E., J acob on, R.L., and Campana, M.E., 1983 Environmental isotopic and hydrogeochemica l inve tigation of recharge 

and subsurface Dow in Eagle Valley, evada: University of 

Nevada, Desert Research Institute Publication 42037, 120 p. 

Tamers, M.A., 1967, urface-water infiltration a nd groundwater 

movement in arid zone of enezuela, in Isotope in Hyd1·ology: 

Vienna, International Atomic Energy Agency, p. 339-351. 

---1975, Validity of radiocarbon date on groundwater: Geophysical ut-veys, v. 2, p. 217-239. 

Tamer , M.A., and charpen eel, H.W. , 1970, Sequential sampling of 

radiocarbon i.n groundwater, in I otope Hydrology 1970: Vienna, 

International Atomic Energy Agency, p. 241-256. 

Thomas, J .M. , Carlton, S.M., and Hines, L.B., 1989, Ground-water 

flow and simulated respon e to selected developmental altemative in mith Creek Valley, a hydrologically closed ba in in 

Lander County, evada : U.S. Geological Survey Profes ional 

Paper 1409-E, 57 p. 

Thomas, J .M., and Hoffman, R.J. , 1988, Nevada ground-water quality in Moody, A.W., Carr, J erry, Chase, E.B., and Paulson, R.W., 

comps., ational Water Summary 1986-Hydrologic events and 

ground-water quality: U.S. Geological Survey Water-Supply 

Paper 2325, p. 355-362. 

Thoma , J .M., Lyles, B.F., and Carpenter, L.A., 1991, Chemical and 

isotopic data collected for water from well , springs, and streams 

in carbonate-rock terrain of southern evada, 1985-88: U.S. 

Geological Sw·vey Open-File Report 89-422, 24 p. 
C70 REGIONAL AQUIFER-SYSTEM ANALYSIS- GREAT BASIN, ~VADA-UTAH 

Thomas, J.M., Mason, J.L. , and Crabtree, J.D. , 1986, Ground-water 

levels in the Great Basin region of evada, Utah, and adjacent 

states: U.S.Geological Survey Hydrologic Investigations Atlas 

HA-694-B, 2 sheets, scale 1:1,000,000. 

Thomas, J.M., Welch, A.H., and Preissler, A.M. , 1989, Geochemical 

evolution of ground water in Smith Creek Valley-A hydrologically closed basin in central Nevada, USA: Applied Geochemistry, v. 4, p. 493-570. 

Thompson, T.H., and Chappell, Richard, 1984a, Maps showing distribution of dissolved solids and dominant chemical types in 

ground water, Basi n and Range Province, evada: U.S. Geological Survey Water-Resources Investigations Report 83-4119-C, 

11 p. 

--- 1984b, Maps showing distribution of dissolved solids and dominant chemical types in ground water, Basin and Range Province , Idaho: U.S .Geological Survey Water-Resourc es 

Investigations Report 83-4117-C, 5 p. 

Thompson, T.H., and utter, Janet, 1984, Maps showing distribution 

of dissolved solids and dominant chemica l types in ground 

water, Basin and Range Province, Utah: U.S. Geological Sur-vey 

Water-Resources Investigations Report 83-4122-C, 7 p. 

Thomp on, T.H., Nutter, Janet, Moyle, W.R. , Jr. , and Woolfenden, 

L.R., 1984, Maps showing distribution of dissolved solids and 

dominant chemical types in ground water, Basin and Range 

Province, southern California: U.S. Geological Survey WaterResources Investigations Report 83-4116-C, 7 p. 

Tschanz , C.M., and Pampeyan, E.H. , 1970, Geology and minera l 

deposits of Lincoln County, Nevada : Nevada Bureau of Mines 

and Geology Bulletin 73, 187 p. 

Turner, J.V., Arad, Arnon, and Johnston, C.D., 1987, Environmental 

isotope hydrology ofsalinized experimental catchments: Journal 

of Hydrology, v. 94, p. 89-107. 

U.S. Department of the Interior, 1985, A proposed program to study 

the water resources of the carbonate-rock system of eastern and 

·outhern Nevada: U.S. Department of the Interior, 14 p. 

Van Denburgh, A.S., 1975, Solute balance at Abert and Summer 

Lakes, south-central Oregon: U.S. Geological Survey Professional Paper 502-C, 29 p. 

Waddell, K.M., a nd Maxell, M.H., 1988, Utah ground-water quality, 

in Moody, D.W., Carr, Jerry, Chase, E.B. , and Paul on, R.W. , 

comps., National Water Summary 1986-Hydrologic events and 

ground-water quality: U.S. Geological Survey Water-Supply 

Paper 2325, p. 355-362. 

Waddell, R.K., Robison, J.H., and Blankennagel, R.K. , 1984, Hydrology of Yucca Mountain and vicinity, Nevada-California - Investigative results through mid-1983: U.S. Geological Survey 

Water-Resources Investigations Report 84-4267, 72 p. 

Wang, J.H., Robinson, C.V. , and Edelman, I.S., 1953, Self-diffusion 

a nd structure of liquid water III- Measurement of self-diffusion 

of liquid water with H2, H3, and 0 18 as tracers: Journal of the 

American Chemical Society, v. 75, p. 66-470. 

Welch, A. H., a nd Preissler, A.M., 1990, Geothermal resources of the 

western arm of the Black Rock Desert, northwestern NevadaPart n, aqueous geochemistry a nd hydrology: U.S. Geological 

Survey Water-Resources Investigations Report 87-4062, 91 p. 

Welch, A.H., and Thomas, J.M. , 1984, Aqueous geochemistry and isotope hydrol ogy of the White River System, eastern Nevada 

[abs.]: Geological Society of America, Abstracts with Programs, 

v. 16, no. 6, p. 689. 

Welch, A.H., and Williams, R.P., 1986a, Data on ground-water quality for the Millett 1° x 2° quadrangle, central Nevada: U.S. Geologica l Survey Open-File Report 85-648-A, scale 1:250,000. 

--- 1986b, Data on ground-water quality for the Elko 1° x 2° quadrangle, eastern evada : U.S. Geologica l Survey Open-File 

Report 85-648-B, cale 1:250,000. 

---1986c, Data on ground-water quality for the Ely 1 °x 2° quadrangle , eastern Nevada: U.S. Geological Survey Open-File 

Report 85-648-C, scale 1:250,000. 

---1986d, Data on ground-water quality for the Lund 1° x 2o 

quadrangle, eastern Nevada: U.S. Geological Survey Open-File 

Report 85-648-D, scale 1:250,000. 

---1987a, Data on ground-water quality for the McDermitt 1° x 

2° quadrangle, northern Nevada: U.S. Geological Survey OpenFile Report 85-648-E, scale 1:250,000. 

---1987b, Data on ground-water quality for the Lovelock 1° x 2o 

quadrangle, western Nevada: U.S. Geological Survey Open-File 

Report 85-648-F, scale 1:250,000. 

--- 1987c, Data on ground-water quality for the Winnemucca 1° x 

2° quadrangle, central Nevada: U.S. Geological Survey OpenFile Report 85-648-G, scale 1:250,000. 

---1987d, Data on ground-water quality for the Reno 1° x 2o 

quadrangle, western Nevada: U.S. Geological Survey Open-File 

Report 85-648-H, scale 1:250,000. 

--- 1987e, Data on ground-water quality for the Walker Lake 1° x 

2° quadrangle, western Nevada and eastern California: U.S. 

Geological Survey Open-File Report 85-648-I, scale 1:250,000. 

---1987f, Data on ground-water quality for the Thnopah 1° x 2° 

quadrangle, central Nevada: U.S. Geological Survey Open-File 

Report 85-648-J, scale 1:250,000. 

---1987g, Data on ground-water quality for the western Nevada 

part of the Goldfield 1° x 2° quadrangle: U.S. Geological Survey 

Open-File Report 85-648-K, scale 1:250,000. 

--- 1987h, Data on ground-water quality for the Caliente 1° x 2° 

quadrangle, eastern Nevada: U.S. Geological Survey Open-File 

Report 85-648-L, scale 1:250,000. 

---1987i, Data on ground-water quality for the western Nevada 

part of the Death Valley 1° x 2° quadrangle: U.S. Geological Survey Open-File Report 85-648-M, scale 1:250,000. 

---1987j, Data on ground-water quality for the southern Nevada 

part of the Kingman 1° x 2° quadrangle: U.S. Geological Sm-vey 

Open-File Report 85-648-N, scale 1:250,000. 

Wershaw, R.L. , Friedman, Irving, Heller, S.J., and Frank, P.A. , 1966, 

Hydrogen isotopic fractionation of water passing through trees, 

in Hobson, G.D., and Speers, G.C., eds., Advances in organic 

geochemistry: Proceedings of the Third International Geological 

Congress, p. 55-67. 

White, A. F., 1979, Geochemistry of ground water associated with tuffaceous rocks, Oasis Valley, Nevada: U.S. Geological Survey Professional Paper 712-E, 25 p. 

White, A.F., and Chuma, N.J., 1987, Carbon and isotopic mass balance models of Oasis Valley-Fortymile Canyon groundwater 

basin, southern Nevada: Water Resources Research, v. 23, no. 4, 

p. 571-582. 

White, A. F., Claassen, H.C., and Benson, L.V. , 1980, The effect of dissolution of volcanic glass on the water chemistry in a tuffaceous 

aquifer, Rainier Mesa, Nevada: U.S. Geological Survey WaterSupply Paper 1535-Q, 34 p. 

White, J.W.C., Cook, E.R. , Lawrence, J.R., and Broecker, W.S., 1985, 

The D/H ratios of sap in trees-Implications for water sow·ces 

and tree ring D/H ratios: Geochimica et Cosmochimica Acta, 

V. 49, p. 237-246. 

Wigley, T.M.L., Plummer, L.N., and Pearson, F.J., Jr., 1978, Mass 

transfer and carbon isotope evolution in natural water systems: 

Geochimica et Cosmochimica Acta, v. 42, p. 1117-1139. 

Winograd, I.J., and Doty, G.C., 1980, Paleohydrology of the southern 

Great Basin, with special reference to water table fluctuations 

beneath the Nevada Test Site during the late(?) Pleistocene: U.S. 

Geological Survey Open-File Report 80-569, 91 p. 
GEOCHEMISTRY AND ISOTOPE HYDROLOGY, GREAT BASIN C71 

Winograd, I.J., and Friedman, Irving, 1972, Deuterium as a tracer of 

regional ground-water flow, southern Great Basin, Nevada and 

California: Geological Society of America Bulletin, v. 83, p. 3691-

3708. 

Winograd, I.J., and Pearson, F.J., Jr., 1976, Major carbon-14 anomaly 

in a regional carbonate aquifer- Possible evidence for megascale 

channeling, south central Great Basin: Water Reso urces 

Research, v. 12, no. 6, p. 1125-1143. 

Winograd, I.J., and Riggs, A. C., 1984, Recharge to the Spring Mountains, Nevada - Isotopic evidence [abs.]: Geological Society of 

America, Abstracts with Programs, v. 16, no. 6, p. 698. 

Winograd, I.J., and Thordarson, William, 1968, Structural control of 

ground-water movement in miogeosynclinal rocks of south-central Nevada: Geological Society of America Memoir l10, p. 35-48. 

__ - 1975, Hydrogeologic and hydrochemical framework, southcentral Great Basin, Nevada-California, with special reference 

to the Nevada Test Site: U.S. Geological Survey Professional 

Paper 712-C, 126 p. 

Wood, W.W., 1976, Guidelines for collection a nd fi eld analy is of 

ground-water samples for selected unstable constituents: U.S. 

Geological Survey Techniques of Water-Resources Investigations, Book 1, Chap. D2, 24 p. 

---1978, Use of laboratory data to predict sulfate orption during 

artificial ground-water recharge: Ground Water, v. 16 p. 22-31. 

Yuretich, R.F., and Cerling, T.E., 1983, Hydrogeochemistry of Lake 

Turkana, Kenya-Mass balance and mineral reaction in an 

alkaline lake: Geochimica et Cosmochimica Acta, v. 47, p. 1099-

1109. 

Ziegler, H. , Osmond, C.B. , Stichler W. , and Trimborn , P., 1976, 

Hydrogen isotope di crimination in higher plants- Correlations 

with photosynthetic pathway and environment: Planta, v. 128, 

p. 85-92. 

Zimmerman, U., Ehhalt, D., and Munnich, K.O., 1967, Soil-water 

movement and evapotranspiration - Changes in the isotopic 

composition of the water, in Symposium on Isotope in HydYology, 1966, Proceedings: Vienna, International Atomic Energy 

Agency, p. 567-584. 

GEO HEMlSTRY A D I OTOPE HYDROLOGY, GREAT BA I 73 

APPENDIXES 
C74 REGIO AL AQUWER-SYSTEM ANALY IS-GREAT BASIN, EVADA-UTA H 

APPENDIX A.- Deuterium and oxygen-18 compositions of water from wells and springs in southern Nevada m1d 

southeastern California between latitudes 95 and 98 degrees north, and longitudes 114 and 117 degrees east 

(A\ erage deuterium composiuon for each site is ploued on plate 2. Penni! values of deuterium and oxygen· IS nrc reported relative to V- MOW( 

Latitude Longitude 

(degree, (degree, Deuterium Oxygen-I Date Source 1 Site name minute, minute, (permit) (permit) 

second ) second) 

Cresent Spring 35 28 43 11510 47 -73.0 -9.4 06-22-85 2 

Pine Spring 35 34 25 115 09 23 -88.0 -11.9 06-22-85 2 

Ora Hana Spring 35 37 25 115 04 07 -72.0 -8.4 06-22-85 2 

Saratoga Spring 35 40 53 116 2518 -90.5 -10.8 04-23-82 1 

McClanahan Spring 35 4142 115 11 05 -67.0 -7.2 06-21-85 2 

Test Hole Al-l (505 feet) 35 45 28 115 15 05 -91.0 -9.3 2 

Test Hole Al-l (625 feet) 35 45 28 11515 05 -94.0 -10.9 2 

Test Hole Al-2 (408 feet) 35 46 04 115 15 46 -94.0 -12.4 2 

Test Hole A1-2 (485 feet) 35 46 04 11515 46 -95.0 -11.0 2 

Test Hole A3-3 (580 feet) 35 47 16 115 20 39 -90.0 -10.7 2 

Test Hole A3-3 (600 feet) 35 47 16 115 20 39 -87.0 -10.5 2 

Test Hole A3-3 (740 feet) 35 47 16 115 20 39 -97.0 -13.6 2 

Test Hole A3-3 (855 feet) 35 47 16 115 20 39 -89.0 -10.2 2 

Test Hole A3-3 (890 feet) 35 47 16 115 20 39 -94.0 -11.2 2 

Jean Prison Well 35 47 18 115 20 43 -94.0 -10.4 2 

Jean Prison Well 35 47 18 115 20 43 -95.0 -12.1 06-21-85 2 

Test Hole A3-2 (740 feet) 35 47 43 115 21 34 -93.0 -10.8 2 

Test Hole A3-2 (840 feet) 35 47 43 115 21 34 -91.0 -11.5 2 

Test Hole A3-l (833 feet) 35 48 13 115 22 38 -89.0 -1 0.8 2 

Test Hole A3-1 (903 feet) 35 48 13 115 22 38 -88.0 -10.5 2 

Rosechrist Well 35 4818 115 4141 -94.0 -13.20 09-27-86 1 

Castillo Well 35 50 02 115 26 09 -94.0 -12.8 06-21-85 2 

Tecopa Hot Spring 35 5219 11613 50 -98.0 -12.85 06-30-85 1 

Bird Spring 35 53 20 115 2212 -88.0 -11.7 06-23-85 2 

Arizona Seep Spring (Black Canyon # 13) 35 55 42 11442 20 -82.0 -10.0 01-00-81 9 

Wilson's Tank 35 56 02 115 25 28 -87.5 -10.9 06-22-85 2 

Bighorn Sheep Spring (Black Canyon # 12) 35 56 22 114 44 06 -80.5 -1 0.2 01-00-81 9 

Ringbolt Rapids Spring (Black Canyon #10 ) 35 57 39 114 43 26 -83.5 -11.1 03-00-82 9 

Sky Harbor Airport 35 5816 115 08 50 -95 -13.1 02-28-86 16 

Shoshone Spring 35 58 48 11616 23 -94.5 -12.9 04-25-82 1 

Palm Tree Cold Spring (Black Canyon #7) 35 59 42 114 4415 -82.0 -10.5 03-00-82 9 

Tenaya Well 36 00 42 11515 05 -92.0 -12.3 05-10-83 1 

Showboat Country Club #2 36 02 51 115 04 48 -97 -13.3 02-27-86 16 

Genstar Gypsum Plant 36 03 04 115 23 43 -86 -12.3 07-11-86 16 

Flowing Well (DRI LG153) 36 03 22 115 03 08 -100.0 -12.9 05-11-83 1 

andstone Spring # 1 36 03 47 115 28 09 -89.0 -12.20 06-25-85 1 

Sandstone Spring #1 36 03 47 115 28 09 -90.0 -12.7 06-25-85 2 

Sunset Park Well 36 03 49 115 06 49 -94.0 -12.7 05-09-83 1 

Gravel Pit Well 36 0517 114 56 32 -76.0 -7.8 05-12-83 1 

Spanish Trail Cou ntry Club Well 36 05 56 115 15 38 -89 -12.2 03-13-86 16 

Stocks Mill & Supply Co. Well 36 06 07 115 15 46 -86 -12.4 03-13-86 16 'frop icana Country Club South #1 36 06 22 115 10 09 -95 -13.2 05-16-86 16 

Sands Hotel And Casino #3 36 07 28 11510 09 -98 -13.5 05-16-86 16 

Sparklettes Drinking Water Co. 36 07 41 115 1145 -99 -13.6 04-22-86 16 

BLM Visitors Center 36 07 44 115 26 03 -89.0 -12.25 06-30-85 1 

Las Vegas Country Club 36 08 20 115 08 49 -100 -13.7 07-08-86 16 

Hartzski Well 36 08 36 115 15 47 -90 -12.4 03-04-86 16 

Red Spring 36 08 40 115 25 10 -89.0 -12.25 06-26-85 1 

Red Spring 36 08 40 115 2510 -93.0 -12.2 06-26-85 2 

Manse Well 36 09 17 115 53 42 -99.0 -13.55 06-27-85 1 

Manse Spring 36 09 21 115 5410 -97.0 08-00-68 3 
GEOCHEMISTRY A D ISOTOPE HYDROLOGY, GREAT BASI C75 

APPE DIX A.- Deuterium and oxygen-1 8 compositions of water from wells and springs in southern evada and 

southeastern California between latitudes 35 and 38 degrees north, and longitude 11.4 and 11 7 degrees east- ontinued 

Latitude Longitude 

Site name (degree, (degree, Deuterium Oxygen-IS Date Source1 minute, minute, (perm ill (permil) 

seeond) seeond) 

Manse Spring 36 09 21 115 5410 -101.0 03-00-70 3 

DRI Well LG047 36 09 33 115 05 51 -lOLO -13.6 05-11-83 1 

Shetland Mutual Water Users Association 36 09 39 115 10 33 -100 -13.5 03-06-86 16 

LVVWD #lA 36 09 39 115 13 32 -94 -13.2 05-14-86 16 

Willow Spring 36 09 41 115 29 51 -90.5 -12.3 06-26-85 1 

LVVWD #11A 36 09 52 1151122 -97 -13.4 06-13- 6 16 

Kiup Spring 36 09 56 115 43 28 -93.0 -12.7 06-28- 5 1 

Cave Spring 36 09 58 115 35 52 -93.0 -12. 06-28-85 1 

Union Pacific Railroad Well #3 36 10 05 115 0913 -100 -13.8 04-09-86 16 

LVVWD#7A 36 10 06 1151123 -96 -13.2 06-17-86 16 

Sky Mt. Resort 36 10 13 115 34 44 -96.5 -13.25 06-28-85 1 

LVVWD #14 36 10 18 115 11 22 -97 -13.2 05-06- 6 16 

White Rock Spring 3610 27 115 28 43 -91.0 -12.5 06-26- 5 1 

LVVWD #15A 36 10 31 1151123 -97 -13.8 05-14- 6 16 

LVVWD #34 36 10 31 115 11 06 -99 -13.6 05-16-86 16 

LVVWD #16 36 10 31 115 11 39 -97 -13.6 06-04- 6 16 

LVVWD #17 36 10 31 115 1139 -97 -13.5 06-04-86 16 

LVVWD #18A 361112 115 14 38 -94 -13.4 06-06- 6 16 

LVVWD #45 36 11 50 115 12 13 -101 -14.0 05-13-86 16 

LVVWD #22A 3612 05 11515 43 -100 -14 03-27-79 2 

NLVWD Robinson Well 36 1217 115 1141 -100 -14.1 06-03- 6 16 

Pahrump Spring Well 36 12 27 115 59 01 -97.0 -13.55 06-27- 5 1 

NLVWD West Cheyenne Well 36 12 38 115 11 21 -104.0 -13.5 05-10- 3 1 

NLVWD West Cheyenne Well 36 12 38 115 1121 -100 -13.8 06-12-86 16 

ellis AFB #13 36 12 44 115 03 00 -98 -13.8 04-03-86 16 

Trout Spring 3613 22 115 40 59 -99 03-28-70 3 

Trout Spring 36 13 22 1154059 -99.1 -14 .1 06-04-73 4 

Trout Spring 36 13 22 115 40 59 -13.8 09-07-73 4 

Trout Spring 36 13 22 115 40 59 -13.8 11-14-73 4 

Trout Spring 3613 22 115 40 59 -13.7 03-25-74 4 

Trout Spring 3613 22 115 40 59 -98.4 -13.85 12-08-74 4 

Trout Spring 3613 22 115 40 59 -97.6 -13.30 05-01-75 4 

Trout Spring 3613 22 115 40 59 -96.2 -13.35 11-11-75 4 

Trout Spring 3613 22 115 40 59 -99.8 -14.02 02-16-76 4 

Trout Spring 3613 22 115 40 59 -98.6 -13.90 11-17-76 4 

Trout Spring 3613 22 115 40 59 -98.8 -14.10 03-08-77 4 

Trout Spring 3613 22 115 40 59 -99.0 -14.10 05-13-77 4 

Trout Spring 36 13 22 115 40 59 -9 .6 -13.45 11-19-77 4 

Trout Spring 36 13 22 115 40 59 -96.0 -12.85 03-21-78 4 

Trout Spring 36 13 22 115 40 59 -97.0 -12.90 05-08-78 4 

Trout Spring 36 13 22 115 40 59 -96.0 -13.20 05-04-83 4 

Trout Spring 3613 22 115 40 59 -95.5 -13.05 05-16-83 4 

Trout Spring 3613 22 115 40 59 -99.5 -13.65 11-30-83 4 

Trout Spring 36 13 22 115 40 59 -96.5 -13.65 03-19-84 4 

Trout pring 36 13 22 115 40 59 -97.0 -13.7 06-30-87 2 

Trout Spring 3613 22 115 40 59 -96.5 -13.70 03-24-88 4 

Trout Spring 36 13 22 115 40 59 -97.0 -13.70 04-04-88 1 

Trout Spring 3613 22 115 40 59 -98.5 -13.70 12-11-88 1 

Trout Spring 3613 22 115 40 59 -97.0 -13.60 06-21-89 4 

Well 5 Franklin Lake r Death Valley 36 14 06 11617 32 -93.5 -11.1 11-21-83 1 

Well10 Franklin Lake r Death Valley 36 14 06 11617 39 -91.0 -10.0 11-21-83 1 

NLVWD Desert Aire Well 36 1415 115 1216 -102 -14.0 03-06-86 16 

Lake Mead Base Well #3 36 14 21 115 00 16 -101.5 -13.80 09-29-86 1 

Lake Mead Base Well #3 36 14 21 115 00 16 -103.0 -13.8 09-29-86 2 
C76 REGIO AL AQ !FER-SYSTEM ANALYSIS-GREAT BASI EVAQA- TAH 

APPE DIX A.- Deuterium and oxygen-18 compositions of water from wells and springs in southern Nevada and 

southeastern California between latitudes 35 and 38 degrees north, and longitudes 111, and 117 degrees east-Continued 

Latitude Longitude 

(degree. (degree, Deuterium Oxygen-! Date Source1 ite name minute, minute, (permill (permil) 

second ) second ) 

Craig Ranch Country Club #2 :!614 29 115 09 00 -106 -14.5 03-04-86 16 

Rainbow Spring #2 3614 36 115 37 55 -96.0 -12.4 0 -19-82 2 

Peak Spring Canyon Creek 36 14 40 115 43 09 -92.5 -13.10 09-27-86 1 

Peak Spring Canyon Creek 3614 40 115 43 09 -93.5 -13.4 04-07-87 1 

Peak Spring Canyon Creek 36 14 40 115 43 09 -92.0 -13.0 06-09-87 1 

Peak Spring Canyon Creek 36 14 40 115 43 09 -92.5 -12.95 08-03-87 1 

Peak Spring Canyon Creek 36 14 40 115 43 09 -97.5 -13.5 11-10-87 1 

Peak Spring Canyon Creek 36 14 40 115 43 09 -98.0 -13.70 03-08-88 1 

Peak Spring Canyon Creek 36 14 40 115 43 09 -101.0 -13.85 04-05-88 1 

Peak Spring Canyon Creek 3614 40 115 43 09 -98.5 -13.85 05-17-88 1 

Peak Spring Canyon Creek 3614 40 1"15 43 09 -95.5 -13.60 06-23-88 1 

Peak Spring Canyon Creek 36 14 40 115 43 09 -95.5 -13.25 09-06-88 1 

Peak Spring Canyon Creek 36 14 40 115 43 09 -94.5 -13.30 10-18-88 1 

Peak Spring Canyon Creek 36 14 40 115 43 09 -94.5 -13.45 11-25- 8 1 

GS-18 Franklin Lake r Death Valley 36 14 51 11617 08 -66.5 -2.5 11-18-83 1 

ellis AFB Well #4 36 14 56 115 00 15 -95 -13.2 04-03-86 16 

Well13 Franklin Lake r Death Valley 3614 57 116 18 34 -92.0 -11.3 11-17-83 1 

alnev Pipeline Well 3614 59 115 02 39 -98.0 -13.1 00-00-86 1 

GS-15 Franklin Lake r Death Valley 3615 27 1161713 -66.0 -2.1 11-14-83 1 

GS-15 Franklin Lake r Death Valley 3615 27 11617 13 -62.0 -1.5 10-20-84 1 

Pat Well 3615 45 11519 37 -92.0 -12.9 03-31-87 2 

Echo Spring 3615 55 115 39 29 -94.5 -12.8 04-16-80 2 

GS-4 Franklin Lake r Death Valley 3616 00 116 16 22 -93.5 -10.4 11-16-83 1 

GS-4 Franklin Lake r Death Valley 3616 00 11616 22 -93.5 -10.3 10-18-84 1 

Highway Maintenance Well 36 16 17 115 35 38 -96.0 -12.2 08-19-82 2 

GS-12 Franklin Lake r Death Valley 3616 35 11617 21 -76.0 -6.6 11-14-83 1 

GS-12 Franklin Lake r Death Valley 3616 35 11617 21 -77.0 -6.7 10-27-84 1 

Taylor's Steak House Rest. 3617 08 115 14 41 -101 -13.7 11-03-86 16 

Martin Well 3617 25 115 14 35 -100.0 -13.4 06-30-85 2 

GS-8 Franklin Lake r Death Valley 3617 27 11617 09 -100.0 -12.9 11-19-83 1 

Grapevine Springs 3618 03 115 29 25 -91.0 -11.6 06-28-85 2 

Grapevine Springs 3618 03 115 29 25 -92.0 -13.2 07-09-87 2 

Deer Creek Spring 1#1 3618 27 115 3813 -97.0 -14.1 06-28-85 2 

Deer Creek Spring #1 3618 27 115 3813 -100.0 -14.0 03-30-87 2 

Deer Creek Spring #2 3618 27 115 37 37 -98.0 -13.45 06-28-85 2 

Race! Well 3618 40 115 15 39 -99.0 -13.3 05-10-83 1 

Gilbert Well 36 18 45 115 25 06 -98.0 -12.7 0 -20-82 2 

Well15 Franklin Lake Nr Death Valley 36 18 51 11616 60 -98.0 -12.7 11-21-83 1 

St.ewart Well 36 19 10 115 40 20 -100 -13.4 06-24- 6 2 

Tule Spring State Park Well 36 19 14 11516 00 -100.0 01-00-69 3 

Tule Spring State Park Well 36 19 14 115 16 00 -100.0 -11.5 08-20-82 2 

Tule Spring State Park Well 36 19 14 115 16 00 -99.0 -13.4 06-30-85 2 

Clark Spring 3619 14 115 4315 -93.5 -12.9 06-29-85 1 

lark Spring 361914 115 4315 -99.0 -13.7 06-24-87 1 

Mulder Well 3619 25 11513 22 -97.0 -13.2 06-25-86 2 

Mifflin Well 36 19 32 115 25 23 -100 -12.6 08-20-82 2 

Lee's Oasis Well 36 19 48 115 18 55 -98.0 -13.4 06-24-86 2 

Holland Well 36 20 00 115 17 00 -98.0 -12.6 08-20-82 2 ummer Homes Well 36 20 06 115 3918 -99.5 -13.80 09-26-86 1 ummer Homes Well 36 20 06 115 3918 -101.0 -13.5 09-26-86 2 
GEOCHEMI TRY A D ISOTOPE HYDROLOGY, GREAT B IN C77 

APPE DIX A.- Deuterium and oxygen-18 compositions of water from wells and springs in southern Nevada and 

southeastern California between latitudes 35 and 3 degrees north, and longitudes 114 and 11 7 degrees east- Continued 

Latitude Longitude 

Site name (degree. (degree. Deuterium Oxygen-! Date Source1 mjnute, minute, (permit) (J>ermil) 

second ) second) 

G.P. Apex Well 36 20 28 114 55 36 -97.5 -13.35 09-29-86 1 

G.P. Apex Well 36 20 28 114 55 36 -98.0 -13.45 09-30- 6 1 

G.P. Apex Well 36 20 28 114 55 36 -96.0 -13.8 09-30-86 2 

Gortney Well 36 20 42 115 20 52 -96.0 -12.1 0 -21- 2 2 

Adams Well 36 20 47 115 19 50 -98.0 -12.7 08-20- 2 2 

Paiute Indian Reservation Well 36 21 02 115 20 33 -9 .0 -14.0 08-21- 6 2 

Big Spring 36 22 30 116 16 25 -104.0 01-00-69 3 

Big Spring 36 22 30 116 16 25 -104.0 03-00-70 3 

Big Spring 36 22 30 11616 25 -102.0 -13.4 05-24-73 6 

Big Spring 36 22 30 11616 25 -102.0 03-09-75 6 

Rogers Spring 36 22 39 114 26 38 -92.0 -12.2 07-21- 1 1 

Grace Petroleum Arrow Canyon Water Well 36 22 58 114 54 60 -96.0 -13.7 04-26- 2 1 

Blue Point Spring 36 23 21 114 25 26 -93.5 -12.50 07-01- 5 1 

Blue Point Spring (Duplicate Sample) 36 23 21 114 25 26 -92.5 -12.35 07-01-85 1 

Blue Point Spring 36 23 21 114 25 26 -93.0 -12.4 06-24-85 2 

Genstar Well 36 23 29 114 5414 -97.0 -13.05 03-31- 6 1 

Point of Rocks (King) Spring 36 24 05 116 16 14 -106.5 08-00-68 3 

Point of Rocks (King) Spring 36 24 05 1161614 -101.0 01-00-69 3 

Point of Rocks (King) Spring 36 24 05 11616 14 -104.0 03-00-70 3 

Point of Rocks (King) Spring 36 24 05 116 16 14 -104.0 03-03-75 6 

Point Of Rocks (King) Spring 36 24 05 11616 14 -102.0 -13.6 03-09- 1 1 

Cold Creek Spring 36 24 50 115 44 20 -97 08-24-68 3 

Cold Creek Spring 36 24 50 115 44 20 -102 01-27-69 3 

Cold Creek Spring 36 24 50 115 44 20 -103 03-30-70 3 

Cold Creek Spring 36 24 50 115 44 20 -99.1 -14.1 05-31-73 4 

Cold Creek Spring 36 24 50 115 44 20 -98.4 -14.2 08-29-73 4 

Cold Creek Spring 36 24 50 115 44 20 -13.8 11-13-73 4 

old Creek Spring 36 24 50 115 44 20 -13.9 04-04-74 4 

Cold Creek Spring 36 24 50 115 44 20 -100.4 -13.80 12-09-74 4 

Cold Creek Spring 36 24 50 115 44 20 -100.0 -13.75 04-28-75 4 

Cold Creek Spring 36 24 50 115 44 20 -98.0 -13.30 11-10-75 4 

Cold Creek Spring 36 24 50 115 44 20 -10Q.4 -13.95 11-16-76 4 

Cold Creek Spring 36 24 50 115 44 20 -100.7 -14.20 02-17-77 4 

Cold Creek Spring 36 24 50 115 44 20 -101.8 -14.15 05-12-77 4 

Cold Creek Spring 36 24 50 115 44 20 -101.5 -13.85 11-18-77 4 

Cold Creek Spring 36 24 50 115 44 20 -99.5 -13.15 03-20-78 4 

Cold Creek Spring 36 24 50 115 44 20 -98.5 -13.15 05-06-78 4 

Cold Creek Spring 36 24 50 115 44 20 -102.5 -14.00 12-04-82 4 

Cold Creek Spring 36 24 50 115 44 20 -100.5 -13.75 05-02-83 4 

Cold reek Spring 36 24 50 115 44 20 -100.5 -13.65 05-15- 3 4 

Cold Creek Spring 36 24 50 115 44 20 -99.5 -13.85 12-12-83 4 

Cold Creek pring 36 24 50 115 44 20 -99.0 -13.8 03-31-87 2 

Cold Creek Spring 36 24 50 115 4.4 20 -100.0 -13.75 04-05-88 1 

Willow Spring 36 25 00 115 45 47 -97.0 -13.9 06-02-73 5 

Willow Spring 36 25 00 115 4.5 47 -98.0 -13.4 06-26-85 2 

Willow Spring 36 25 00 115 45 47 -98.0 -13.60 04-05-88 1 

Young Well 36 2511 115 22 58 -93.0 -12.80 09-25-86 1 

Crystal Pool Spring 36 25 14 116 19 21 -106.5 08-00-68 3 

Crystal Pool Spring 36 25 14 116 19 21 -103.0 01-00-69 3 

Crystal Pool Spring 36 25 14 11619 21 -104.0 03-00-70 3 
C78 R GIONAL AQUfFER- YST M ALYSIS REAT BASIN. EVADA-UTAH 

APPE DIX A.- Deuterium and oxygen-18 compositions of water from wells and springs in southern Nevada and 

southeastern Califomia between latitudes 35 and 38 degrees north, and longitudes 111, and 117 degrees east- Continued 

Latitude Longitude 

(degree, (degree, Deuterium Oxygen-IS Dale Source1 Site name minute, minute, (permil) (penni!) 

second ) second ) 

Crystal Pool Spring 36 2514 11619 21 -102.0 -13.7 05-24-73 6 

Crystal Pool Spring 36 25 14 116 19 21 -104.0 03-04-75 6 

Brooks Well 36 25 20 115 22 40 -93.0 -12.7 06-24-86 2 

Valley of Fire Well 36 25 21 114 32 52 -82.0 -10.6 06-24-85 2 

Shown Well 36 25 31 115 22 44 -94.0 -13.00 09-25-86 1 

Amargosa Well #20 (Ash Tree Spring) 36 25 35 116 24 32 -1 02.0 -12.4 03-06-74 8 

Scruggs Spring 36 25 59 11618 28 -103.0 03-10-75 6 

Corn Creek Spring Well 36 26 20 115 21 26 -95.0 01-00-69 3 

Corn Creek Spring Well 36 26 20 115 2126 -94.0 03-00-70 3 

Corn Creek Spring 36 26 20 115 2126 -96.0 -13.0 06-29-85 2 

Corn Creek Spring 36 26 20 115 2126 -93.0 -12.85 09-25-86 1 

Corn Creek Spring 36 26 20 115 2126 -93.0 -12.9 06-17-87 1 

Corn Creek Spring 36 26 20 115 2126 -93.5 -12.9 01-05-88 1 

Travertine Spring 36 26 27 116 49 49 -105.5 03-00-70 3 

Travertine Spring 36 26 27 116 49 49 -1 02.0 -13.7 04-22-82 1 

Big Timber Spring 36 26 42 115 55 37 -93.0 -13.3 06-27-85 2 

Dry Lake Valley Well 36 27 18 114 50 38 -97.5 -13.30 07-01-85 1 

Grapevine Springs 36 27 27 116 01 35 -92.5 -12.75 06-2 - 5 1 

Texas Spring 36 27 28 116 50 11 -105.0 03-00-70 3 

Texas Spring 36 27 28 116 50 11 -102.0 -13.7 04 -22- 2 1 

Corn Creek Well 36 27 53 115 23 54 -95.5 -13.55 12-02-86 2 

Longstreet Spring 36 28 03 116 19 31 -103.0 03-10-75 6 

Silver Flag Alpha Well 36 28 34 115 26 45 -99.0 . -13.7 12-18-87 2 

Rogers Spring 36 28 46 116 19 31 -102.0 03-09-75 6 

Amargosa Well #18 36 29 04 116 28 08 -102.0 -13.0 03-06-74 8 

Fairbanks Spring 36 29 25 116 20 29 -103.0 08-00-68 3 

Fairbanks Spring 36 29 25 116 20 29 -103.0 01-00-69 3 

Fairbanks Spring 36 29 25 116 20 29 -104.0 03-00-70 3 

Fairbanks Spring 36 29 25 116 20 29 -103.0 -13.6 05-23-73 6 

Amargosa Well #17 36 29 38 116 27 00 -105.0 -12.8 03-01-74 

Amargosa Well #16 36 29 38 116 30 01 -1 04.0 -12.7 03-01-74 

Amargosa Well #15 36 30 28 116 30 25 -104.0 -13.0 03-05-74 

evares Spring 36 30 44 116 4914 -105.5 03-00-70 3 evares Spring 36 30 44 116 49 14 -104.0 -13.6 04-22-82 1 

Divide Well 36 30 45 115 28 05 -98.0 -13.7 07-26-87 2 

Indian Springs Prison Well #1 36 30 52 115 33 15 -1 02.0 -13.7 06-26-85 2 

Amargosa Well #30 36 31 24 116 24 02 -104.0 -13.7 06-24-79 8 

Amargosa Well #14 36 31 28 116 30 24 -9 .5 -12.6 03-04-74 

Mathew's Well 36 3132 116 24 00 -104.0 -13.7 05-11-81 1 

Old Dry Well 36 31 35 115 2813 -95.0 -13.2 12-19-87 2 

Alpha Post Well 36 32 06 115 33 55 -98.0 -13.2 06-23-86 2 

South Black Hills Well 36 3212 115 24 03 -87.0 -12. 10 08-05-87 1 

South Black Hills Well 36 3212 115 24 03 -88 -11.9 08-05-87 2 

Amargosa Well # 13 36 3219 116 30 24 -102.0 -13.0 03-05-74 8 

Amargosa Well #21 36 32 48 116 25 07 -99.0 -13.2 06-25-79 8 

Amargosa Well #11 36 32 49 116 29 19 -101.0 -13.1 03-05-74 8 

Rancho Amargosa Well 36 32 52 116 32 30 -99.0 -11.9 05-12-81 1 

South Hidden Valley Well 36 33 08 114 55 30 -90.5 -11.20 03-28-86 1 

Amargosa Well #10 36 33 13 116 2812 -97.5 -13.2 06-26-79 8 

Amargosa Well #9 36 33 16 116 29 45 -102.0 -12.6 03-01-74 8 
GEO HEMISTRY AND I OTOPE HYDROLOGY, GREAT BASIN C79 

APPE DIX A.- Deuterium and oxygen-18 compositions of water from wells and springs i11 southem evada and 

southeastem Califomia between latitudes 35 and 38 degrees north, and longitudes 114 and 117 degrees east-Continued 

Latitude Longitude 

Site name (degree. (degree. Deuterium Oxygen-IS Date Source1 

minute, minute, (permil) (permil) 

second) second ) 

Albitre Well (Formerly Thiede's Well) 36 33 20 116 28 09 -97.5 -11 .6 05-06-81 1 

Amargosa Well #50 36 33 25 116 35 50 -104.0 -13.6 06-25-79 8 

Indian Springs #2 36 33 54 115 40 06 -98.0 08-00-6 3 

Indian Springs #2 36 33 54 115 40 06 -100.0 01-00-69 3 

Indian Springs #2 36 33 54 115 40 06 -101.0 03-00-70 3 

Indian Springs #2 36 33 54 115 40 06 -93.0 -11.9 06-23-86 2 

Indian Springs #2 36 33 54 115 40 06 -97.0 -12.9 06-18-87 1 

Indian Springs #2 36 33 54 115 40 06 -101.5 -13.7 01-04-88 1 

Indian Springs #1 36 33 56 115 40 06 -96.5 -12.7 06-18-87 1 

Indian Springs #1 36 33 56 115 40 06 -101.0 -13.7 01-04-88 1 

Indian Springs #3 36 33 56 115 40 05 -93.5 -12.6 06-18-87 1 

Indian Springs #3 36 33 56 115 40 05 -100.0 -13.5 01-04-88 1 

Amargosa Well #23 36 33 58 116 32 37 -103.0 -13.4 03-31-71 8 

Amargosa Well #29 36 33 59 116 26 12 -105.0 -13.8 03-31-71 8 

ichols' Well 36 34 05 116 32 40 -103.0 -13.0 05-06-81 1 

Amargosa Well #8 36 3410 116 27 35 -103.0 -13.4 03-01-74 8 

Amargosa Well #25 36 34 24 116 33 25 -102.0 -13.4 03-31-71 8 

Cook's Well 36 34 25 116 23 50 -104.0 -13.4 05-08-81 1 

Fox Well (Formerly Kirker's Well) 36 34 25 116 33 20 -101.0 -12.2 05-10-81 1 

Amargosa Well #27 36 34 37 116 25 19 -105.0 -13.8 04-01-71 8 

Indian Springs AFB Well #1 36 34 47 115 40 47 -96.0 -13.0 06-27-85 2 

Amargosa Well #4 7 36 34 49 116 36 38 -102.0 -13.1 03-31-71 8 

Amargosa Well #5 36 34 56 116 28 41 -99.5 -13.2 11-17-72 8 

Cow Camp Spring 36 35 01 11518 26 -90.5 -12.6 10-28-81 1 

Cow Camp Spring 36 35 01 115 18 26 -93.0 -12.6 05-10-83 1 

Amargosa Well #4 36 35 28 116 28 42 -103.0 -13.2 03-04-74 8 

Army Well 0. 1 36 35 30 116 02 14 -104.0 01-00-69 3 

Army Well o. 1 36 35 30 116 0214 -103.0 03-00-70 3 

Amargosa Well #3 36 37 18 116 26 32 -102.0 -12.8 11-20-72 8 

Wiregrass Spring 36 38 00 115 12 29 -94.0 -12.8 10-28-81 1 

Wiregrass Spring 36 38 00 115 12 29 -96.0 -12.7 05-11-83 1 

Wiregrass Spring 36 38 00 115 12 29 -94.0 -12.85 10-09-86 1 

Wiregrass Spring 36 38 00 11512 29 -94.0 -12.9 10-09-86 2 

Wiregrass Spring 36 38 00 115 12 29 -91.5 -12.80 03-20-87 1 

Wiregrass Spring 36 38 00 11512 29 -92.0 -12.50 06-17- 7 1 

Wiregrass Spring 36 38 00 11512 29 -94.0 -12.8 08-04-87 1 

Wiregrass Spring 36 38 00 11512 29 -97.0 -12. 01-05-88 1 

Wir grass pring 36 38 00 11512 29 -95.5 -12.95 04-06-88 1 

Wiregrass pring 363 00 115 12 29 -94.5 -12. 5 12-12- 1 

Juanita pring 36 3 13 114 14 51 - 7.0 -11.65 01-25-86 1 

Wamp pring 115 0412 -81.0 -10.60 03-20-87 1 

Mormon Well pring 115 05 52 -92.5 -12.9 10-27-81 1 

Mormon Well Spring 115 05 52 -91.0 -12.5 05-09- 3 1 

Mormon Well Spring 115 05 52 -92.0 -12.6 10-07-87 1 

Weiser Wash EH-2 (235 reet) 1143 55 -70.0 -6.7 10-05-85 13 

Weiser Wash EH-2 (255 reet) 36 3 50 114 3 55 -69.0 10-05- 5 13 

Weiser Wash EH-2 (295 reet) 36 3 50 114 3 55 -71.0 10-05-85 13 

Weiser Wash EH-2 (335 reet) 363 50 114 3 55 -79.0 -9.3 10-05-85 13 

W iser Wash EH-2 (375 reet) 36 3 50 114 3 55 -86.0 10-05-85 13 

Weiser Wash EH-2 (395 reet) 36 38 50 114 38 55 -97.0 10-05-85 13 
C80 REG IO AL AQUTFER-SY TEM ANALYS IS R AT BA I , NEVADA- TAH 

APPENDIX A.- Deuterium and oxygen-18 compositions of water from wells and springs in sot~thern Nevada and 

outheastem California between latitudes 35 and 3 degrees north, and longitudes 114 and 117 degrees east- Continued 

Latitude Longitude 

(degree, (degree. Deulerium Oxygen- IS Date Sourcc1 Sile name minute, minute, (permil) (pcrmil ) 

second ) second ) 

Weiser Wash EH-2 {415 feet) 36 38 50 114 38 55 -101.0 10-05- 5 13 

Weiser Wash EH-2 (495 feet) 36 38 50 11 4 38 55 -97.0 10-05-85 13 

Weiser Wash EH-2 (535 feet ) 36 38 50 114 38 55 -99.0 -12.9 10-06-85 13 

Weiser Wash EH-2 (555 feet) 36 38 50 114 38 55 -100.0 10-06-85 13 

Weiser Wash EH-2 (655 feet) 36 38 50 114 38 55 -1 03.0 -13.0 10-06-85 13 

Weiser Wash EH-2 (675 feet) 36 38 50 114 3 55 -105.0 -14.3 10-06- 5 13 

Wei er Wash EH-2 (715 feet) 36 38 50 114 38 55 -102.0 10-00- 5 13 

Weiser Wash EH-2 (735 feet) 36 38 50 114 38 55 -102.0 10-00- 5 13 

Weiser Wash EH-2 (755 feet) 36 38 50 1143 55 -96.5 10-00- 5 13 

Weiser Wash EH-2 (775 feet) 36 38 50 114 38 55 -102.0 10-00- 5 13 

Wei er Wash EH-2 (795 feet) 36 3 50 114 3 55 -101.0 10-00- 5 13 

Weiser Wash EH-2 (815 feet) 36 38 50 114 38 55 -99.5 10-00- 5 13 

Weiser Wash EH-2 (835 feet) 36 38 50 114 38 55 -92.0 10-00-85 13 

Weiser Wash EH-2 (875 feet) 36 38 50 114 38 55 -101.5 -13.4 10-08-85 13 

Weiser Wash EH-2 (895 feet) 36 38 50 114 38 55 -99.0 10-00-85 13 

Weiser Wash EH-2 (955 feet) 36 38 50 114 3 55 -102.0 10-00- 5 13 

Weiser Wash EH-2 (981 feet) 36 3 50 114 38 55 -9 .0 10-00-85 13 

Weiser Wash E.H-2 (997 feet) 36 38 50 114 38 55 -104.0 10-00-85 13 

Weiser Wash EH-2 (1,017 feet) 36 38 50 114 38 55 -90.0 10-00-85 13 

Weiser Wash EH-2 (1,055 feet) 36 38 50 114 38 55 -96.5 10-00- 5 13 

Weiser Wash EH-2 (1,075 feet) 36 38 50 114 38 55 -92.0 10-00-85 13 

Weiser Wash EH-2 (1,095 feet) 36 38 50 114 38 55 -99.0 -12.1 10-14-85 13 

Weiser Wash EH-1 (drilling water) 36 39 37 114 37 52 -97.0 -13.0 13 

Weiser Wash EH-1 (105 feet) 36 39 37 114 37 52 -95.0 10-00- 5 13 

Weiser Wash EH-1 (135 feet) 36 39 37 114 37 52 -98.0 -13.0 10-02-85 13 

Weiser Wash EH-1 (175 feet) 36 39 37 114 37 52 -95.0 10-00- 5 13 

Weiser Wash EH-1 (215 feet) 36 39 37 114 37 52 -95.0 10-00- 5 13 

Weiser Wash EH-1 (235 feet) 36 39 37 114 37 52 -94.0 10-00-85 13 

Weiser Wash EH-1 (255 feet) 36 39 37 114 37 52 -96.0 10-00- 5 13 

Weiser Wash EH-1 (295 feet) 36 39 37 114 37 52 -96.0 -13.4 10-03- 5 13 

Weiser Wash EH-7 (175 feet) 36 40 14 114 31 53 -91.5 -12.3 13 

Weiser Wash EH-7 (305 feet) 36 40 14 114 31 53 -90.0 -13.5 13 

Weiser Wash EH-7 (405 feet) 36 40 14 114 31 53 -92.0 -12.5 13 

Weiser Wash EH-7 (505 feet) 36 40 14 114 31 53 -93.5 -12.2 13 

Wei er Wash EH-7 (615 feet) 36 40 14 114 31 53 -96.0 -13.1 13 

Weiser Wash EH-7 (USGS composite sample) 36 40 14 114 31 53 -91.0 -12.45 03-19- 7 1 

Keane Wonder Spring 36 40 25 116 55 11 -99.5 -13.0 04-23-82 1 

Weiser Wash EH-8 (drilling water) 36 40 26 114 34 33 -94.0 -12.1 05-10- 6 13 

Weiser Wash EH-8 (1 15 feet) 36 40 26 114 34 33 -90.0 -12.5 05-10- 6 13 

Weiser Wash EH-8 (175 feet) 36 40 26 114 34 33 -92.0 -12.5 05-10- 6 13 

Weiser Wash EH-8 (195 feet) 36 40 26 114 34 33 -97.0 -13.7 05-10- 6 13 

Weiser Wash EH-8 (225 feet) 36 40 26 114 34 33 -97.0 -13. 05-10- 6 13 

Weiser Wash EH-8 (244 feet) 36 40 26 114 34 33 -96.0 -13.6 05-10-86 13 

awmill Spring (Sheep Range) 36 40 50 115 10 34 -92.0 -12.85 05-19-88 1 

Weiser Wash EH-6 (85 feet) 36 40 54 114 34 12 -86.0 -11.3 03-24-86 13 

Weiser Wash EH-6 {145 feet) 36 40 54 114 34 12 -94.5 -12.8 03-24-86 13 

Weiser Wash EH-6 (295 feet) 36 40 54 114 3412 -105.0 -14.3 03-25-86 13 

Weiser Wash EH-6 (304 feet) 36 40 54 114 3412 -99.0 -12.3 03-25-86 13 

Weiser Wash EH-6 (335 feet) 36 40 54 114 3412 -99.0 -14.6 03-26-86 13 

Weiser Wash EH-6 {455 feet) 36 40 54 114 34 12 -100.0 -13.1 03-26-86 13 
GEOCHEMISTRY A D ISOTOPE HYDROLOGY. GREAT BASI C81 

APPE DIX A .- Deuterium and oxygen-18 compositions of water from wells and springs in southern evada and 

southeastern California between latitudes 35 and 38 degrees north, and longitudes llJ. and 117 degrees east- Continued 

Latitude Longitude 

Site name (degree, (degree, Deuterium Oxygen-! Date Source1 

minute, minute, (permil) (perm ill 

second ) second ) 

CSV-3 Well 36 41 27 114 55 30 -75.0 -10.3 10-07-87 1 

Weiser Wash EH-3 (295 feet) 36 41 32 114 3132 -92.0 -12.1 02-02- 6 13 

Weiser Wash EH-3 (355 feet) 36 41 32 114 3132 -90.0 -12.7 02-02-86 13 

Wei er Wash EH-3 (455 feet) 36 4132 114 31 32 -90.0 -12.2 02-02-86 13 

Wei er Wash EH-3 (545 feet) 36 41 32 114 31 32 -93.0 -13.4 02-02-86 13 

Weiser Wash EH-3 (795 feet) 36 41 32 114 3132 -91.0 -13.2 02-05-86 13 

Weiser Wash EH-4 (165 feet) 36 42 23 114 42 58 -100.0 -13.2 03-18-86 13 

Weiser Wash EH-4 (285 feet) 36 42 23 114 42 58 -96.0 -12. 03-18-86 13 

White Rock Spring 36 42 30 115 14 20 -82.0 -9.9 10-29-81 1 

White Rock Spring 36 42 30 115 14 20 -85.0 -9.8 05-10- 3 1 

Pederson's Warm Spring (M-13 ) 36 42 36 114 42 54 -98.0 01-00-69 3 

Pederson's Warm Spring (M-13) 36 42 36 114 42 54 -97.0 03-00-70 3 

Pederson's Warm Spring (M-13) 36 42 36 114 42 54 -97.0 -12.75 10-30- 5 1 

Iverson's pring 36 42 37 11442 43 -97.0 03-00-70 3 

pring Feeding Moapa 36 42 53 114 43 05 -97.0 03-00-70 3 

Big Muddy Spring Area (M-8) 36 43 15 114 43 39 -99.0 -12.75 10-30- 5 1 

Big Muddy Spring 36 43 20 114 42 48 -98.0 03-00-70 3 

Big Muddy Spring 36 43 20 114 42 48 -96.5 -12.9 07-22-81 1 

Big Muddy Spring 36 43 20 114 42 48 -98.0 -12.75 10-30-85 1 

Big Muddy Spring 36 43 20 114 42 4 -99.0 -13.0 01-07- 1 

Big Muddy Spring 36 43 20 114 42 48 -98.0 -14.0 2 

Big Muddy Spring Area (M-9) 36 43 33 114 43 38 -96.5 -12.45 10-30- 5 1 

Weiser Wash EH-5A (65 feet) 36 43 58 114 44 36 -99.0 -13.1 03-05-86 13 

Weiser Wash EH-5A (205 feet) 36 43 58 114 44 36 -98.0 -12.9 03-05- 6 13 

Weiser Wash EH-5A (265 feet) 36 43 58 114 44 36 -107.0 -13.7 03-12-86 13 

Well J-12 ( TS) 36 45 54 116 23 24 -99.0 01-00-69 3 

Well J-12 ( TS) 36 45 54 116 23 24 -97.5 -12.8 03-26-71 10 

uclear Engr. Co. Well 36 45 58 116 4110 -10 .5 12-00-6 3 

ERTEC MX-6 Well 36 46 04 114 47 13 -97.0 -12.95 09-28-86 1 

ERTEC MX-6 Well 36 46 04 114 47 13 -99.0 -13.1 09-2 - 6 2 

CSV-2 Well 36 46 50 114 43 20 -98.0 -12. 5 01-26- 6 1 

USW VH-1 (Amargosa Well #55 ) 36 47 32 116 33 07 -10 .0 -14.2 02-11- 1 10 

ERTEC MX-4 Well 36 47 44 114 53 32 -102.5 -13.0 12-23-80 1 

ERTEC MX-5 Well 36 47 44 114 53 32 -99.5 -12.9 07-22- 1 1 

Well5B 36 48 05 115 58 0 -106.5 01-00-69 3 

Well J-13 36 48 29 116 23 40 -97.5 -13.0 03-26-71 10 

Railroad Well Farrier 36 48 49 114 39 14 -97.5 -12.5 02-04-84 1 

Sand pring 36 49 30 115 34 05 - 8 -11.9 01-03-88 2 

E-25P-l 36 49 3 116 25 21 -107.5 -13.7 02-11- 3 11 

E-25P-1 36 49 3 116 25 21 -106.0 -13. 05-12- 3 11 

36 49 42 116 27 60 -101.0 -13.9 03-13-84 1 

36 49 47 116 25 43 -102.0 -13.5 09-30-83 1 

36 49 47 116 25 43 -101.0 -13.4 03-13-84 1 

36 49 47 116 25 43 -103.0 -13.5 05-09-84 1 

36 50 32 116 26 54 -104.0 -14.0 05-17- 2 10 

W H-6 36 50 49 116 28 55 -106.0 -13. 10-16- 2 10 

Tim pring 36 50 5 115 34 10 -99 -13.2 01-02-88 2 

E-25B-1 (Amargosa Well #57 ) 36 51 0 116 26 23 -99.5 -13.4 08-07- 1 10 

E-25B-1 (Amargosa Well #57 ) 36 51 0 116 26 23 -101.0 -13.4 09-01-81 10 

E-25B-l (Amargosa Well #57 ) 36 51 08 116 26 23 -99.5 -13.5 07-20-82 10 
82 REGIO AL Q IFER-SY TEM ANALYSI -GREAT BASI . EVADA-UTAH 

APPENDIX A.- Deuterium and oxygen-1 compositions of water from wells and springs in southern Nevada and 

southeastern California between latitudes 95 and 98 degrees north, and longitudes 111, m1d 117 degrees east- Continued 

Latitude Longitude 

ite name (degree, (degree. Deuterium Oxygen-18 Date Source 1 

minute, minute, (permi)) (penni!) 

second) second ) 

SW G-4 36 5114 116 27 04 -103.0 -13.8 12-09-82 10 

USW H-5 36 51 22 116 27 55 -102.0 -13.6 07-03- 2 10 

USW H-5 36 51 22 116 27 55 -102.0 -13.6 07-26-82 10 

USW H-1 (Amargosa Well #56) 36 51 58 116 27 12 -102.0 -13.4 10-01-80 8 

USW H-1 (Amargosa Well #56) 36 51 5 116 27 12 -103.0 -13.4 10-20-80 10 

USW H-1 (Amargosa Well #56) 36 51 58 116 27 12 -101.0 -13.5 12-08-80 10 

Dejesus Spring 36 52 28 115 34 45 -100 -13.1 05-09-87 2 

VF-2 Well 36 52 30 114 56 44 -101.0 -12.95 02-05- 6 1 

VF-2 Well 36 52 30 114 56 44 -101.0 -13.1 01-06- 1 

VF-1 Well 36 52 32 114 55 44 -94.0 -12.6 01-06-88 1 

Well12S/47E{19ADC 36 52 41 116 45 19 -1 04.0 -13.3 7 

Well12S/47E/20BBB 36 53 01 116 45 02 -1 06.0 -13.6 7 

Litt lefield Road-Cut Spring 36 53 42 113 54 54 -97.5 -12.8 07-01-88 1 

heep Spring (Sheep Range) 36 53 42 115 06 53 -96.0 -13.35 05-19- 1 

Well12S/47E/7DBA 36 54 19 116 45 26 -1 08.0 -13.9 7 

Well12S/47E/6CDD 36 54 52 116 45 42 -102.0 -13.3 7 

Hackberry Spring 36 55 04 114 2616 -87.0 -12.3 02-05-84 1 

Well C-1 36 55 07 116 00 34 -110.5 01-00-69 3 

Well11S/47E/32DDA 36 55 52 116 44 03 -102.0 -13.4 7 

Horse Spring 36 56 29 114 26 47 -89.0 -12.7 02-05-84 1 

UE-29A-2 36 56 29 116 22 26 -93.5 -12.8 01-08-82 10 

UE-29A-2 36 56 29 116 22 26 -93.0 -12.8 01-15-82 10 

UE-29A-1 36 56 29 116 22 26 -92.0 . -12.1 01-29-82 1 

Lamb Spring (Sheep Range ) 36 56 42 115 06 21 -92.5 -13.15 05-19- 8 1 

Well11 S/47E/28DAC 36 56 53 116 43 06 -109.0 -14.1 7 

Well11S/47E/28ACC 36 57 07 116 43 22 -108.0 -14.1 7 

Desert Dry Lake Well 36 57 11 115 11 51 -98.0 -13.10 03-18-87 1 

Peach Spring 36 57 16 114 17 23 -76.5 -1 0.4 02-06-84 1 

Gourd Spring 36 57 31 11417 30 -77.5 -10.6 02-06-84 1 

Well11S/47E/21DBB 36 57 55 116 43 22 -10 .0 -14.0 7 

Davies Spring 36 57 56 114 30 07 -89.0 -12.5 02-06- 4 1 

Well11S/47E/16DCA · 36 58 36 116 4313 -110.0 7 

Quartz Spring 36 59 10 115 36 00 -88 -11 .6 01-02-88 2 

Well11S/47E/5CDA 37 00 25 116 44 35 -108.0 -14.1 7 

Well 11S/47E/4CAD 37 00 32 116 43 29 -108.0 -14.0 7 

Well1 0S/47E/33AAB 37 0159 116 42 29 -108.0 -14.0 7 

Well10S/47E{31AAB 37 01 59 116 45 06 -102.0 -13.3 7 

UE-16F 37 02 09 116 09 25 -105.0 -14.9 09-25-77 12 

Well10S/47E/27CBA 37 02 26 116 4139 -110.0 -14.3 7 

Well10S/47E/30BBC 37 02 45 116 46 05 -1 02.0 -13.4 7 

Well10Sf47E/14BAB 37 04 37 116 37 40 -112.0 -14.5 7 

Willow pring KSV-1 37 05 34 114 49 52 -88.0 -11.6 02-03-84 1 

Grapevine Spring KSV-2 37 08 08 114 42 02 -87.5 -12.0 02-03-84 1 

Well#8 ( TS) (Amargosa Well #64 ) 37 09 56 1161721 -104. 0 -13.0 03-24-71 8 

Snow Spring 37 10 49 114 07 53 -79.5 -10.0 11-13-86 1 

Jensen Well 37 11 03 114 27 52 -88.5 -11.6 04-10-85 1 

Maynard Lake Spring 37 1130 115 02 02 -94.0 -12.3 01-14-85 2 

Lone Tree Spring 37 12 07 115 03 32 -89.5 -10.9 01-14-85 2 

U-20A2 37 14 34 116 25 51 -114.0 -14.8 7,14 

Kane Spring KSV-3 37 14 46 114 42 21 -86.5 -11.9 02-02-84 1 

Boulder Spring KSV-4 37 16 12 114 38 44 -87.0 -12.6 02-02-84 1 

Irrigation Well 37 16 46 115 07 11 -91 15 

UE-19E 37 17 50 11619 59 -109.5 -14.0 7,14 

UE-19GS 37 18 30 116 21 53 -113.5 -14.5 7,14 

Randono Well 37 19 26 114 30 08 -87.5 -11.7 02-03-84 1 
GEOCHEMISTRY AND ISOTOPE HYDROLOGY. GREAT BASI C83 

APPE DIX A.- Deuterium and oxygen-18 compositions of water from wells and springs in outhern evada and 

southeastern California between latitudes 35 and 38 degrees north, and longitudes 114 and 117 degrees east- Continued 

Latitude Longitude 

Site name (degree. (degree. Deuterium Oxygen-! Date Source1 

minute. minut.e. (permil) (permil) 

second ) second ) 

Cane Spring 37 20 27 115 44 50 -88 -9.5 05-15-85 2 

Bradshaw Well 37 20 57 114 32 38 -88.5 -11.4 02-01- 4 1 

Stock Well 37 20 58 114 45 30 -88 15 

Railroad Well 37 21 04 114 32 02 -86.0 -11.6 01-31-84 1 

Upper Riggs Spring 37 22 06 114 38 52 -88.0 -1 1.9 02-02-84 1 

Sheep Spring 37 24 02 11416 37 -87.0 -12.0 06-03- 5 1 

Cattle Spring 37 24 57 115 45 05 -85 -9.4 05-15-85 2 

Bishop Spring 37 25 07 114 38 26 -85.5 -11.7 02-02-84 1 

Rock Spring 37 25 53 115 41 23 -86 -10.9 05-15-85 2 

Quail Spring 37 26 29 115 41 01 -92 -11.9 05-15-85 2 

Hells Acre Gulch Spring 37 27 37 115 07 29 -93.0 -12.3 01-14-85 2 

Ash Spring 37 27 49 1151134 -107.0 08-00-68 3 

Ash Spring 37 27 49 115 11 34 -109.0 01-00-69 3 

Ash Spring 37 27 49 115 1134 -112.0 03-00-70 3 

Ash Spring 37 27 49 1151134 -108.0 -14.1 07-20-81 1 

Ash Spring 37 27 49 11511 34 -108 -12.3 2 

Indian Spring 37 27 50 115 44 28 -88 -10.4 05-15-85 2 

Rabbitbrush Spring 37 28 56 115 41 28 -89 -11.2 05-14- 5 2 

Bullwhack Spring 37 29 45 115 45 47 -88 -10.2 05-17-85 2 

orth Ella Spring 37 29 57 114 27 09 -86.5 -11.6 06-03-85 1 

Ramone Mathews Well 37 31 36 114 14 39 -92.0 -12.3 06-03-85 1 

Crystal Spring 37 31 53 115 13 58 -109.0 0 -00-68 3 

Crystal Spring 37 31 53 115 13 58 -110.0 01-00-69 3 

Crystal Spring 37 31 53 115 13 58 -109.0 03-00-70 3 

Crystal Spring 37 31 53 115 13 58 -109.0 -14.3 07-20- 1 1 

Crystal Spring 37 31 53 115 13 5 -110 2 

April Fool Spring 37 32 14 115 44 19 - 9 -10.7 05-16- 5 2 

Grassy Spring 37 32 28 114 47 27 -85.0 -10.9 01-14-85 2 

Acoma Well 37 32 55 114 10 23 -95.0 -12.6 06-03-85 1 

Meadow V. Wash Below Caliente 37 33 27 114 33 54 -93.5 -12.3 11-13-86 1 

Hiko Spring 37 36 34 115 12 51 -111.0 0 -00-68 3 

Hiko Spring 37 36 34 115 12 51 -110.0 01-00-69 3 

Hiko Spring 37 36 34 115 12 51 -110.0 03-00-70 3 

Hiko Spring 37 36 34 115 12 51 -110.0 -15.3 01-14-85 2 

Hiko Spring (Duplicate Sample) 37 36 34 115 12 51 -105.0 -14.0 01-14- 5 2 

Clover reek 37 36 47 114 28 21 -87.5 -11.8 11-13- 6 1 

Caliente City Well 37 36 57 114 30 48 -89.0 -12.4 01-31-84 1 

Cali nte Hot Spring 37 37 16 114 30 34 -109.0 -14.5 04-10- 5 1 

Irrigation Well 37 3 10 115 12 54 -109 15 

Meadow V. Wash At Cove Canyon 37 39 15 114 29 45 -9 .0 -12.6 11-13-86 1 

Pahroc pring 37 39 52 114 5 47 - 9.0 -12.5 01-14-85 2 

SK-1 (MX 10" Well) 37 4215 114 45 31 -95 15 

Mustang Spring 37 44 09 114 55 14 -91.0 -12.6 01-14-85 2 

The Seeps 37 44 22 115 34 32 -9 .0 -13.3 01-15-85 2 

Weaver Well 37 44 41 114 25 28 -101.0 -13.1 06-04-85 1 

Cedar pring 37 45 05 11616 25 -101.0 -13.6 01-15- 5 2 

Well B-1 Tonopah Test Range ellis B&G RG 37 45 06 116 29 23 -110.0 -14.0 09-10-80 1 

Cedar Pass Well 37 45 07 116 28 57 -110.0 -14.0 2 

John Wadsworth Well 37 46 07 114 24 25 -101.0 -12.9 06-04-85 1 

Bennett pring 37 47 03 114 31 41 -103.0 -13.7 04-10-85 1 

Sandia 6 37 47 03 116 45 05 -124.0 -15.2 2 

Lester Math ws Well 37 47 37 114 23 59 -103.0 -13.3 06-04-85 1 

Panaca Town Well 37 47 50 114 23 57 -106.0 -14.0 06-04-85 1 

Panaca pring 37 48 24 114 22 47 -106.0 -13.9 04-26-84 1 

Panaca pring 37 4 24 114 22 47 -108.0 -14.0 04-08-85 1 
C84 REGIO AL AQUIFER-S YSTEM A ALYS IS-GREAT BASI . EVAD -VTA H 

APPE DlX A.- Deuterium and oxygen-1 8 compositions of water from wells and springs in southern Nevada and 

southeastern Califonlia between latitudes 35 and 38 degrees north, and longitudes 111; and 117 degrees east- Continued 

Latitude Longitude 

ite name (degree. (degree. Deuterium Oxygen- 18 I ate Source 1 

mmute, minute, (permil) (pcrmil) 

second ) second ) 

Panaca Spring 37 48 24 114 22 47 -106.5 -14.2 11-11-86 1 

Panaca Spring 37 48 24 114 22 47 -1 07 -14.4 2 

orth Lee Well 37 49 28 114 23 04 -101.0 -13.3 06-04-85 1 

Well9 37 5115 116 43 06 -113.0 -14.3 2 

Delmues Spring 37 5136 11419 20 -104.0 -13.4 04-08-85 1 

Georges Spring 37 5137 116 20 57 -98.0 -13.6 01-15-85 2 

Meadow Valley Wash Above Delmues Spring 37 5140 114 19 18 -98.0 -12.8 04-08-85 1 

WelJ 1A 37 53 00 116 46 53 -118.0 -14.5 2 

Oxborrow Well 37 53 10 114 1817 -92.0 -11.8 06-05-85 1 

F latnose Spring 37 53 46 11413 33 -101.0 -13.4 04-08-85 1 

White Rock Spring 37 53 46 115 0111 -90.0 -12.1 01-13-85 2 

Upper Conners Spring 37 54 10 114 33 38 -100.0 ,13.9 11-11-86 1 

Runoff At Pine Spri ng 37 54 29 114 32 56 -99.0 -13.4 04-07-85 1 

Lime Spring 37 54 52 114 32 25 -97.0 -12.9 04-07-85 1 

Deadman Spring 37 55 07 114 32 29 -99.0 -1 3.3 04-07-85 1 

Oceana Spring 37 55 07 115 09 26 - 7 15 

Highland Spring 37 55 16 114 32 56 -98.5 -13.3 04-07-85 1 

Highland Spring 37 55 16 114 32 56 -98.0 -13.2 11-11-86 1 

Pioche Municipal WeU 37 57 33 114 24 51 -108.5 -14.4 11-10- 6 1 

Edan Creek Ranch Spring 37 58 12 116 22 53 -99.0 -13.9 01-15- 5 2 

1 Sources of data: 

l .S. Geological urvcy (unpublished ). 

2 Desert Research Institute (unpublished ). 

3 Winograd and Friedman (1972). Deuterium values were multiplied by 0.97 to make comparable with deuterium data from the U . . Geological urvey 

l..aboratory, Reston, Va. (l.J. Winograd, U.S. Geological urvey, written commun., 1985). 

4 J.J. Winograd, (U.S. Geological urvey, written commun .. 19 9). 

5 I.J. Winograd , (U.S. Geological Survey, written commun. , 1986). 

6 Winograd and Pearson (1976). 

7 Waddell and others ( 1984 ). 

8 Claassen (1985). 

9 McKay and Zimmerman (1983 ). 

10 Benson and others (1983). 

I I Craig and Robison (1984 ). 

12 Dinwiddie and Weir(1979). 

13 Schroth (19 7). 

14 White and Chuma (19 7). 

15 Kirk (1987). 

16 oack (19 ). 
APPENDIX B.- Average chemical and isotopic compositions of wat.er from wells and springs in southern Nevada and southeastern California, 

between latitudes 35 and 38 degrees north, and longitudes 114 and 117 degrees east 

!For Las Vegas Valley. chem.Jcal data are included only for sites that also h:we deuterium and oxygen-IS data. Deuterium and oxygen- IS are reponed relative to V-SMO\V. carbon- 13 is reported relative to pcedce belemnite, and 

carbon- 14 IS reponed as percent modem of Nnuonal Bureau of Standards 1950 oxalic acid. Units of measure: milligrams per liter. except as ind icated. Number in parentheses indicates number of samples if different from total 

number of samples Abbreviations· °C. degree~ Celsius; J.i.Sicm. microsiemcns per centimeter at 25°Cclsius: pmc. percent modem carbon: pCiiL. picocuries per liter: L. measured in Jabomtoryj 

Latitude Longitude Number Tern- Specific 

Site Site name (degree, (degree, or pera- pH conduc- Cal- Magne- Sodium Po lasminute. minute. ture tance cium siurn sium 

second ) second) samples <"CJ (!lS/cm) 

1 Big Bend Weill Area 2 35 07 21 114 38 03 4 23.0 7.7 1,400 120 36 132 4.8 

2 B. Laughlin (Knight) Well 35 07 23 114 36 42 22 18.3 7.8 1,300 114 33 112 4.5 

3 Cromer Well 35 07 26 114 37 55 23 19.1 7.8 1,200 98 32 115 3.6 

4 Sundance Shores Well 35 09 10 114 34 40 30 22.9 7.8 1,200 76 18 151 3.8 Cl 5 Nevada Club Well 35 09 20 114 34 19 22 18.8 7.8 1,400 113 30 146 4.9 rn 

0 

0 6 Big Bend Weill Area 1 35 09 31 114 34 16 5 16.0 7.8 1,200 97 25 106 4.0 :r 

7 Riverside Trailer Court 35 09 37 114 34 15 24 20.6 7.8 1,300 112 31 125 4.9 rn 

~ 

8 Cresent Spring 35 28 43 115 10 47 1 20.5 7.8 990 108 25 37 5.0 c;; 

9 Pine Spring 35 34 25 115 09 23 1 30.0 7.6 980 99 31 81 2.2 ..., 

;Q 

10 Ora Hana Spring 35 37 25 115 04 07 1 20.5 7.2 760 55 31 43 4.8 -< 

> 

11 Saratoga Spring 35 40 53 1162517 1 28.5 8.0 4,700 30 37 

z 

980 32 0 

12 McClanahan Spring 35 41 42 115 11 05 1 25.0 8.0 620 58 22 48 7.6 c;; 

13 Jean Prison Well 35 47 18 115 20 43 1 22.0 6.8 850 60 41 30 3.8 0 

..., 14 Rosechrist Well 35 48 18 115 41 41 1 20.0 7.3 490 53 38 17 1.6 0 

"'0 15 Castillo Well 35 50 02 115 26 09 1 24.0 7.3 1,400 97 68 86 4.1 rn 

J: 

16 Tecopa Hot Spring -< 35 52 19 11613 50 1 42.0 8.2 3,600 4.0 1.5 850 16 0 

17 Bird Spring 35 53 20 115 2212 1 29.0 7.6 640 35 39 36 3.0 ;Q 

0 18 Wilson's Tank 35 56 02 115 25 28 1 29.0 7.4 830 68 57 36 1.7 r 

0 19 Bighorn Sheep Spring (Black Canyon # 12) 35 56 22 114 44 06 1 36.0 8.7 - 4.2 .2 156 1.1 Cl 

20 Ringbolt Rapid Spring (Black Canyon # 10) 35 57 39 114 43 26 1 50.0 7.8 -- 239 14 592 12 ;-< 

Cl 

21 Sky Harbor Airport 35 5816 115 08 50 10 ;Q 1 25.6 7.8 1,200 64 31 130 rn 

22 Palm Tree Cold Springs (Black Canyon#'/) 35 59 42 114 4415 1 24.0 7.8 389 39 986 16 > - ..., 23 Tenaya Well 36 00 42 115 15 05 1 23.0 7.3 1,300 110 56 31 4.6 Ct) 

24 Showboat Country Club #2 36 02 51 115 04 48 1 26.7 7.9 1,100 74 38 98 14 > 

en 25 Genstar Gypsum Plant Well 36 03 04 115 23 43 1 23.7 7.0 710 89 38 9.9 1.6 ~ 

26 Flowing Well (DRI LG153) 36 03 22 115 03 08 1 24.0 8.3 1,100 40 22 130 14 

27 Sandstone Spring #1 36 03 47 115 28 09 1 17.0 7.0 460 53 29 5.9 2.0 

28 Sunset Park Well 36 03 49 115 05 51 1 26.0 7.3 1,700 160 58 50 15 

29 Spanish Trail Country Club Well 36 05 56 11515 38 1 28.0 7.2 1,300 175 66 14 3.4 

30 Stocks Mill & Supply Co. Well 36 06 07 115 15 46 1 26.2 7.2 1,100 161 69 14 3.1 

0 

"" 
APPENDIX B.- A verage chemical and isotopic compositions of water from wells and springs in southern Nevada and southeastern California, () 

00 

between latitudes 35 and 38 degrees north, and longitudes 114 and 117 degrees east- Continued aLatitude Longitude Number Tern- Specific 

Site Site name (degre<!, (degre<!, or pera- pR con due- Cal- Magne- Sodium Potasminute, minute. lure iance cium sium sium 

second ) second ) samples (OC) ~S cm ) 

31 Tropicana Country Club South Well #1 36 06 22 115 10 09 1 23.0 7.6 760 78 38 18 3.2 

32 Sands Hotel And Casino #3 36 07 28 115 10 09 1 22.5 7.7 510 57 29 7.5 2.5 

33 Sparklettes Drinking Water Co. 36 07 41 115 1145 1 22.7 7.7 460 51 27 5.9 2.5 

34 BLM Visitors Center 36 07 44 115 26 03 1 25.0 7.4 600 85 30 8.3 1.6 ;:o 

35 Las Vegas Country Club 36 08 20 115 08 49 1 22.5 7.4 520 54 27 8.7 3.2 {TI 

0 

36 Hartzski Well 36 08 36 115 15 47 1 21.3 7.6 860 103 42 8.2 2.2 0 

z 37 Red Spring 36 08 40 115 25 10 1 20.0 7.6 430 51 25 5.2 2.0 ;J> 

38 Manse Well 36 0917 115 53 42 1 22.5 7.5 400 48 22 4.7 .9 r 

)> 

39 DRI Well LG047 36 09 33 115 05 51 1 21.5 8.1 440 26 32 7.8 3.5 0 

40 Shetland Mutual Water Users Association 36 09 39 11510 33 1 22.3 7.7 470 49 27 7.3 2.6 c 

:::;:; 

41 LVVWD #1A 36 09 39 115 13 32 1 25.1 7.6 480 62 31 8.0 2.9 {TI 

;:o 

c:, 

42 LVVWD #11A 36 09 52 115 11 22 1 26.0 6.9 460 50 27 6.9 3.4 -< 

43 Union Pacific Railroad #3 36 10 05 115 09 13 1 24.8 7.6 350 41 21 2.7 en 7. -l 

44 LVVWD #7A 36 10 06 115 1123 1 25.6 7.5 420 54 26 6.8 3.2 {TI 

s: 

45 Sky Mt. Resort 36 10 13 115 34 44 1 14.0 7.3 470 80 22 4.8 .6 )> 

46 LVVWD #14 3610 18 1151122 1 24.5 7.3 460 54 28 6.3 2.7 z 

)> 

r 

47 White Rock Spring 36 10 27 115 28 43 1 25.0 7.0 720 94 29 8.4 1.8 -< en 

48 LVVWD#15A 36 10 31 115 11 23 1 24.9 7.0 410 50 25 5.6 2.3 u; 

49 LVVWD#34 3610 31 115 11 06 1 24.0 7.5 440 46 24 7.1 3.1 

50 LVVWD #16 36 10 31 115 11 39 1 24.8 7.5 400 55 25 6. 2.9 ;:o 

51 LVVWD#l7 36 10 31 115 1139 1 23.8 7.4 410 53 25 5.8 2.0 {TI 

)> 

-l 

52 LVVWD#l8A 361112 115 14 38 1 23.0 7.4 500 56 2.8 6.0 2.0 OJ 

)> 

53 LVVWD #45 36 1150 115 12 13 1 25.4 7.0 410 49 25 5.8 1.6 en 

54 LVVWD#22A 3612 05 115 15 43 1 24.0 7.5 450 48 26 5.9 2.6 z 

55 NLVWD Robinson Well 361217 115 11 41 1 25.7 7.3 400 45 23 6.7 1.6 {TI 

56 Pahrump Spring Well 3612 27 115 59 01 1 25.0 7.6 420 47 24 4.7 1.3 < 

)> 

0 

57 NLVWD West Cheyenne Well 3612 38 115 1121 2 25.0 7.2 450 45 22 6.7 1.4 >' 

58 Pahrump Community Church 3612 42 115 5918 1 27.0 - - 47 23 5.7 1.2 C: 

-l 

59 Nellis AFB #13 3612 44 115 03 00 1 24.5 7.8 600 27 27 44 6.5 )> 

60 Trout Spring 3613 22 115 40 59 8 7.5 8.4 - 45 10 .9 .4 :r 

61 Well 5 Franklin Lake Nr Death Valley 36 14 06 1161732 1 20.2 9.3 27,000 2.6 2.0 4,500 87 

62 Well10 Franklin Lake Nr Death Valley 36 14 06 11617 39 1 19.5 9.3 22,000 4.0 4.4 6,200 230 

63 NLVWD Desert Aire Well 36 14 15 115 12 16 1 26.4 7.4 370 44 22 6.8 1.3 

64 Lake Mead Base Well #3 36 14 21 115 00 16 1 25.0 7.6 700 36 25 76 7.5 

65 Mazie Spring 36 14 26 115 3819 1 3.0 - 120 37 7.8 .7 .2 
APPENDIX B.- Average chemical and isotopic compositions of water from wells and springs in southern Nevada and southeastern California, 

between latitudes 35 and 38 degrees north, and longitudes 114 and 117 degrees east-Continued 

Latitude Longitude Number Tern- Specific 

Site Site name (degree, (degree, or pera- pH conduc- Cal- Magne- Sodium Potasminute, minute. ture tance cium sium sium 

second) second ) samples (oC) (IJ,S/cm) 

66 Craig Ranch Country Club # 2 36 14 29 115 09 00 1 23.1 7.8 360 30 19 16 3. 

67 Rainbow Spring #2 36 14 36 115 37 55 1 9.8 7.5 360 61 13 1.1 .5 

68 Peak Spring Canyon Creek 3614 40 115 43 09 1 7.0 8.7 400 64 13 1.4 .4 

69 East Spring #2 36 14 45 115 39 07 1 4. 0 - 100 40 8.0 .9 .2 

70 GS-18 Franklin Lake Nr Death Valley 36 14 51 11617 08 1 17.0 9.8 65,000 4.0 6.6 28,000 830 

71 NellisAFB #4 36 14 56 115 00 15 1 25.9 8.04 550 31 32 41 5.0 0 

72 GS-13 FrankJin Lake Nr Death Valley 36 14 57 11618 34 1 20.9 8.4 3,300 9.3 5.2 750 21 rn 

0 73 West Spring 36 15 11 115 39 42 1 5.5 - - 56 8.9 .7 .3 n 

74 Rainbow Spring #1 3615 14 115 39 23 1 5.0 160 53 7.4 .7 .3 :r: - rn 75 Mt Charleston Lodge 36 15 24 115 38 50 5 - - 290 50 8.8 1.0 .4 s:: 

Vi 

-'1 76 Rainbow Well 3615 34 115 37 47 4 8.7 - 370 61 13 1.5 .5 AI 

77 Pat Well 3615 45 115 19 37 1 17.5 8.1 600 50 28 6.1 2.1 -< 

>- 78 Echo #3 36 15 55 115 39 29 4 8.6 -- 350 59 11 1.4 .5 

79 Echo Spring a 3615 55 115 39 29 1 8.0 - 360 60 11 1.3 .5 Vi 80 Daines 36 16 12 115 35 33 4 - - 390 58 16 2.3 .5 0 

-'1 

81 Highway Maintenance Well 36 16 17 115 35 38 5 10.5 7.6 410 65 16 1.7 .5 0 

-o 

82 Lower Stanley B Spring 36 16 14 115 3818 1 10.0 430 81 41 1.4 .4 rn - :r: 83 Fletcher Spring 3616 26 115 37 33 1 11.5 - 380 84 24 2.5 .7 -< 

84 Taylor's Steak House Rest. 3617 08 115 14 41 1 21.2 7.6 390 42 24 6.4 1.3 0 

AI 

85 Martin Well 3617 25 115 14 35 1 22.0 7.8 450 35 23 9.2 1.8 0 

r 

0 

86 GS-8 FrankJin Lake Nr Death Valley 3617 27 116 17 09 1 18.9 8.5 3,600 3.9 5.2 760 71 0 

-< 87 T-Bar Spring 36 17 38 115 40 60 1 6.0 - 240 41 8.3 .8 .4 0 88 Cave Spring #1 36 17 40 115 39 55 2 5.3 - 240 51 10 1.0 .4 ;:o 

89 Grapevine Springs 36 18 03 115 29 25 2 18.5 7.5 630 62 28 20 2.2 rn 

>-

90 Ski Lodge Well 36 1811 115 40 44 1 8.0 - 340 47 14 .9 .4 -'1 

o:l 

>- 91 Youth Camp 3618 26 115 40 28 4 7.3 - 400 56 21 1.6 .5 ~ 

92 Deer Creek Spring #1 3618 27 115 3813 1 4.3 7.9 270 45 10 1.3 .3 

93 Deer Creek Spring #2 36 18 27 115 37 37 1 8.0 8.5 670 56 13 1.4 .5 

94 Deer Cr Picnic Area Spg 3618 33 115 37 25 2 7.5 - 290 56 16 1.1 .4 

95 Race! Well 36 18 40 115 15 39 1 24.0 7.7 430 37 24 8.6 1.6 

96 Gilbert Well 3618 45 115 25 06 1 15.5 7.2 410 60 20 2.6 0.5 

97 Lee's Crest 36 19 07 115 40 22 4 9.0 - 470 45 31 2.8 .8 

98 Stewart Well 36 19 10 115 40 20 1 9.7 8.6 570 44 32 2.0 .9 

99 Tule Spring State Park Well 361914 115 16 00 1 21.0 7.6 520 40 26 8.6 1.8 

100 Clark Spring 36 19 14 115 43 15 1 10.0 7.5 480 75 38 2.0 .6 

n 

00 

_, 
APPENDIX B.- Average chemical and isotopic compositions of water from wells and springs in southern Nevada and southeastern California, n 

00 

between latitudes 35 and 38 degrees north, and longitudes 11;, and 117 degrees east- Continued 

Latitude Longitude Number Tern- Specific 

Site Site name (degree, (degree, or per a- pH conduc- Cal- Magne- Sodium Pot.asminute, minute, lure tance cium sium sium 

second ) second) samples {•C) ~S cm ) 

101 Mulder Well 36 19 25 115 13 22 1 24.0 7.8 400 42 23 10 1.3 

102 Mifflin Well 36 19 32 115 25 23 1 18.0 7.5 400 50 23 3.0 1.2 

103 Lee's Oasis Well 36 19 48 115 18 55 1 20.0 8.2 530 63 26 4.6 .7 

104 Holland Well 36 20 00 11517 00 1 26.0 7.2 400 44 25 6.2 1.5 ;;o 105 Summer Homes Well . 36 20 06 115 3918 3 9.0 7.4 390 51 26 1.5 .9 {T) 

0 

106 G.P. Apex Well 36 20 28 114 55 36 1 31.0 7.0 1,570 120 46 129 12 0 

z 

107 Gortney Well 36 20 42 115 20 52 1 20.5 7.2 510 67 25 4.8 .7 )> 

r 108 Adams Well 36 20 47 115 19 50 1 22.5 7.3 490 64 25 4.6 .7 )> 

109 Paiute Indian Reservation Well 36 21 02 115 20 33 1 18.7 7.0 460 60 22 3.5 .6 0 

110 Big Spring 36 22 30 116 16 25 6 27.0 7.4 - 43 19 97 9.4 s 

., 

{T) 

111 Rogers Spring 36 22 39 114 26 38 3 30.0 7.4 3,800 430 136 290 20 ;;o 

v, 

112 Grace Petroleum Arrow Canyon Water Weill 36 22 58 114 55 00 1 26.5 7.3 1,600 120 46 140 16 -< 

en 113 Blue Point Spring 36 23 21 114 25 26 1 30.0 7.0 3,800 510 170 360 23 -l 

114 Genstar Well 36 23 29 114 54 14 1 24.0 7.4 1,500 120 47 140 1.3 {T) 

~ 

115 Cold Creek Spring 36 24 50 115 44 20 9 10.0 7.6 - 69 16 1.6 .4 )> 

z 

116 Amargosa Well #41 36 24 51 116 25 41 1 24.0 7.4 730 29 12 120 9.7 )> 

r 

117 Willow Sring 36 25 00 115 45 47 1 10.5 7.5 720 72 15 2.1 .6 -< 

en 

118 Young Well 36 2511 115 22 58 1 17.0 7.7 380 20 38 7.1 2.7 Vi 

119 Crystal Pool Spring 36 25 14 116 19 21 6 31.0 7.4 -- 47 21 74 9.4 6 120 Brooks Well 36 25 20 115 22 40 1 24.6 8.2 490 40 43 7.1 1.4 ;;o 

{T) 

)> 

121 Valley of Fire Well 36 25 21 114 32 52 1 28.0 7.4 1,100 118 53 39 8.2 -l 

122 Shown Well 36 25 31 115 22 44 1 17.0 7.3 380 38 40 7.2 2.0 c:o 

)> 

123 Amargosa Well #20 36 25 35 116 24 42 1 - 7.9 370 14 4.4 46 8.0 

124 Corn Creek Spring 36 26 20 115 21 26 4 21.0 7.4 540 46 33 6.2 2.0 

125 Travertine Spring 36 26 27 116 49 49 1 30.5 7.8 1,000 39 20 160 11 {T) 

< 

126 Big Timber Spring 36 26 42 115 55 37 1 11.0 7.7 580 50 20 4.2 0.6 )> 

0 

127 Dry Lake Valley Well 36 27 18 114 50 38 1 29.0 7.3 1,400 110 48 120 13 :;:-· 128 Grapevine Spring 36 27 27 116 01 35 1 20.0 7.7 670 57 40 27 1.5 c 

-l 

129 Texas Spring 36 27 28 116 50 11 1 31.0 7.9 950 36 19 150 11 )> 

130 Corn Creek Well 36 27 53 115 23 54 1 18.5 8.0 380 17 27 13 2.5 :r: 

131 Silver Flag Alpha Well 36 28 34 115 26 45 1 - 7.8 360 32 21 5.8 1.5 

132 Amargosa Well #19 36 28 39 116 26 37 1 - 8.1 320 21 4.0 32 8.2 

133 Amargosa Well #18 36 29 04 116 28 08 1 - 8.0 300 21 2.7 36 7.5 

134 S17 E4812 BC 36 29 20 116 3110 1 - 7.7 1,300 74 24 160 16 

135 Fairbanks Spring 36 29 25 116 20 29 8 27.0 7.4 - 48 20 69 8.2 
APPENDIX B.- Average chemical and isotopic compositions of water from wells and springs in southern Nevada and southeastern California, 

between latitudes 35 and 38 deg rees north, and longitudes 11.4 and 117 degrees east- Continued 

Latitude Longitude Numb<!r Tern- Specific 

Site Site name (degree, (degree. of pera- pH con due- Cal- Magne- Sodium Po lasminute. minute, ture tance cium sium sium 

second ) second ) samples (•C) ~S ) 

136 Amargosa Well #36 36 29 36 116 25 15 1 - 8.1 800 40 14 97 14 

137 Amargosa Well # 16 36 29 38 116 30 01 1 -- 8.0 360 24 1.8 48 7.3 

138 Amargosa Well #17 36 29 40 116 26 58 1 - 7.9 420 25 3.6 48 9.7 

139 Amargosa Well #15 36 30 28 116 30 25 1 - 8.0 310 19 1.5 40 7.1 

140 Nevares Spring 36 30 44 116 4914 1 36.5 7.7 980 43 20 140 11 

141 Divide Well 36 30 45 115 28 05 1 19.0 8.1 370 22 21 18 3.4 Cl 

142 Indian Springs Prison Well #1 36 30 52 115 3315 1 23.0 7.8 410 39 21 3.6 1. rn 

0 143 Amargosa Well #30 36 31 24 116 24 02 1 - 7.8 - 52 22 120 18 () 

144 Amargosa Well #14 36 3128 116 30 24 1 -- 7.9 300 17 2.0 40 6.1 ;r: 

rn 145 Mathew's Well 36 31 32 116 24 00 1 24.5 7.6 940 50 20 110 1.2 3:: 

c.n 

-l 146 Old Dry Well 36 31 35 115 28 13 1 23.0 8.1 390 22 22 15 2.2 ::0 

147 Alpha Post 36 32 06 115 33 55 1 25.1 8.7 330 35 22 4.9 1. -< 

148 South Black Hills Well 36 32 12 115 24 03 1 29.0 7.5 400 39 21 7.3 4. 

149 Amargosa Tracer Well 2 36 3212 116 13 47 4 31.0 7.4 - 44 20 65 7.8 ~ c.n 150 Amargosa Well #13 36 32 19 116 30 24 1 -- 7.9 320 19 .8 43 7.3 0 

-l 

151 Amargosa Well #21 36 32 48 116 25 07 1 8.2 16 1.7 56 6.4 0 -- - ., 152 Amargosa Well #11 36 32 49 116 2919 1 7.9 320 24 1.1 36 8.2 rn - :I: 153 South Hidden Valley Well 36 33 08 114 55 30 1 25.0 7.8 820 33 30 86 12 -< 

154 Amargosa Well # 12 36 3313 116 30 25 1 27.0 7.0 320 18 .7 54 6.9 0 

::0 155 Amargosa Well #10 36 3313 116 2812 1 -- 7.9 - 30 1.9 40 4.3 0 

r 

0 

156 Amargosa Well #9 36 33 23 116 29 44 1 - 8.0 340 20 2.7 42 8.8 Cl 

-< 157 Amargosa Well #50 36 33 25 116 35 50 1 - 7.7 - 53 8.5 150 11 Cl 158 Indian Springs #2 36 33 54 115 40 06 5 25.5 7.6 400 46 22 4.2 1. ;o 

159 Amargosa Well #23 36 33 58 116 32 37 1 25.5 8.1 9.6 3.2 58 5.9 rn - > 160 Amargosa Well #29 36 33 59 116 2612 1 23.8 7.7 - 41 7.5 80 9.8 -l 

co 

161 Amargosa Well #8 36 34 10 116 27 35 1 - 7.6 

> 

430 23 2.6 56 9.0 ~ 

162 Amargosa Well #25 36 34 24 116 33 25 1 24.5 8.3 - 9.2 3.9 61 5.5 

163 Amargosa Well #27 36 34 37 116 25 19 1 30.6 7.6 - 48 17 111 13 

164 Indian Springs AFB Well # 1 36 34 47 115 40 47 1 23.5 7.3 1,300 126 66 43 4.5 

165 Amargosa Well #47 36 34 49 116 36 38 1 24.2 7.7 - 47 16 130 9.4 

166 Amargosa WeU #5 36 34 56 116 28 41 1 23.0 7.0 310 30 2.6 37 5.6 

167 Cow Camp Spring 36 35 01 115 18 26 2 12.3 7.6 540 49 33 23 .6 

168 Amargosa Well #4 36 35 28 116 28 42 1 - 7.8 310 29 2.2 35 5.2 

169 Army Well No. 1 36 35 30 116 0214 3 31.0 7.4 -- 45 22 38 5.5 

170 Test WelllO 36 35 31 115 51 04 2 27.0 7.4 - 39 18 7.4 2.0 

() 

00 

"' 
APPENDIX B.-Average chemical and isotopic compositions of water from wells and springs in southern Nevada and southeastern California, (") 

-a 

between latitudes 35 and 38 degrees north, and longitudes 114 and 117 degrees east- Continued 0 

Latitude Longitude Number Tern- Specific 

Site Site name (degree, (degree, or pera- pi! conduc- Cal- Magne- Sodium Potasminute. minute, samples ture tanee cium sium sium 

second ) second ) (oC ) CI!S/cm) 

171 S15 E50 25BD 1 36 37 15 116 24 45 2 44.0 7.9 340 22 1.3 49 2.5 

172 S15 E49 22DC 1 (BR supply ) 36 37 40 116 26 39 1 - 7.8 340 28 2.1 39 4.9 

173 Amargosa Well #3 36 37 50 116 20 00 1 - 6.7 330 27 2.0 43 4.6 

174 Wiregrass Spring 36 38 00 11512 29 8 8.6 7.3 560 70 33 3.0 1.7 ::0 

175 Juanita Spring 36 38 13 114 14 51 1 26.0 7.3 940 130 43 25 5.3 rn 

0 

176 Wamp Spring 36 38 30 115 04 12 1 7.0 8.1 320 71 13 10 2.1 5 

z 

177 Moorman Well ' 36 38 38 115 05 52 3 11.2 7.4 670 77 42 12 .6 ;l> 

178 Weiser Wash EH-2 36 38 50 114 38 55 3 24.0 8.2 890 38 26 101 15.6 r 

)> 

179 Weiser Wash EH-1 36 39 37 114 37 52 2 - 8.2 3,000 262 116 278 26 0 

180 Weiser Wash EH-7 36 40 14 114 3153 5 23.2 7.7 3,900 481 198 163 24 c 

"T1 

rn 

181 Weiser Wash EH-8 36 40 26 114 34 33 3 7.6 3,800 375 104 416 22 ::0 - v, 

182 Weiser Wash EH-6 36 40 54 114 34 12 3 24.8 7.7 3,000 341 131 274 31 -< 

(I) 

183 CSV-3 Well 36 4127 114 55 30 1 41.0 7.4 650 51 25 38 10 -l 

184 Weiser Wash EH-3 36 41 32 114 31 32 4 24.1 7.8 3,700 511 201 170 22 rn 

s:: 

185 TH20 Nevada Power 36 41 49 114 35 33 1 24.0 7.1 3,500 195 147 497 13 )> 

z 

186 Weiser Wash EH-4 36 42 23 114 42 58 2 22.8 8.3 920 49 30 90 12 ~ 

187 White Rock Spring 36 42 30 115 14 20 2 12.5 7.5 420 37 30 14 7.2 -< 

(I) 

188 B. Lewis Well 36 42 40 114 36 00 1 22.0 7.6 1,800 107 76 203 12 en 

189 Pederson Warm Springs (M-13 ) 36 42 36 114 42 54 1 32.2 - 1,000 75 26 110 8.8 

190 Big Muddy Spring 36 43 20 114 42 48 1 32.5 7.2 930 66 26 96 10 ::0 

rn 

)> 

191 Weiser Wash EH-5A 36 43 58 114 44 36 2 28.0 8.2 890 49 26 96 12 -l 

192 Test Well F 36 45 34 116 06 59 2 64.5 7.4 650 45 16 62 9.0 co 

)> 

193 J-12 Well 36 45 54 116 23 24 1 26.8 7.1 290 14 2.1 38 5.1 

194 ERTEC MX-6 Well 36 46 04 114 47 13 1 33.5 7.2 980 58 25 87 10 

195 CSV-2 Well 36 46 50 114 43 20 1 27.0 7.4 1,000 60 27 100 10 rrl 

< 

196 USW VH-1 (Amargosa Well #55) 36 47 32 116 33 07 3 35.4 7.6 10 1.5 79 1.9 )> 

- 0 

197 ERTEC MX-4 anD MX-5 Wells 36 47 44 114 53 32 2 34.7 7.3 750 46 20 81 11 :;--

198 Well J-13 36 48 29 116 23 40 1 31.0 7.2 250 12 2.1 42 5.0 c 

-l 

199 Test Well3 36 48 30 115 51 26 1 38.0 7.3L - 51 21 83 7.4 )> 

200 Railroad Well Farrier 36 48 49 114 3914 1 22.8 8.0 1,300 84 31 150 19 ;r: 

201 Sand Spring 36 49 30 115 34 05 1 15.0 8.7L 450 19 44 19 4.6 

202 UE-25P-1 36 49 38 116 25 21 1 57.0 6.7 1,200 94 31 150 12 

203 UE-25C-2 36 49 45 116 25 43 1 40.5 7.7 300 12 .3 54 2.0 

204 UE-25C-3 36 49 47 116 25 43 1 40.8 7.7 300 11 .4 55 1.9 

205 USW H-4 36 50 32 116 26 54 1 34.8 7.4 - 17 .3 73 2.6 
APPEND IX A~erage chemical and isotopic compositions of water from wells and springs in southern Nevada and southeastern California, 

between latitudes 35 and 38 degrees north, and longitudes 114 and 117 degrees east-Continued 

Latitude Longitude Number Tern- Specific 

Site Site name (degree, (degree. of pera- pH con due- Cal- Magne- Sodium Pot.asminute, minute, samples ture lance cium sium sium 

second ) second ) ( oC) ~S em ) 

206 USW H-6 36 50 49 116 28 55 1 37.8 8.1 - 4.1 0.1 86 1.3 

207 Tim Spring 36 50 58 115 34 10 1 14.0 8.4 340 19 28 13 2.9 

208 UE-25B-1 (Amargosa Well #57) 36 51 08 116 26 23 3 36.4 7.3 - 18 0.7 48 3.3 

209 USW G-4 36 5114 116 27 04 1 35.6 7.7 - 13 0.2 57 2.1 

210 USW H-5 36 51 22 116 27 55 2 36.0 7.8 - 1.9 0.01 60 2.1 

211 USW H-1 (Amargosa Well #56) 36 5158 116 27 12 2 33.8 7.6 - 5.3 <.1 51 2.0 0 

212 Dejesus Spring 36 52 28 115 34 45 1 15 7.5 590 41 45 18 3.7 (T1 

0 213 VF-2 Well 36 52 30 114 56 44 1 34.0 7.4 800 47 21 81 11 n 

214 VF-1 Well 36 52 32 116 55 44 1 28.0 7.0 460 41 7.5 34 1.2 ;r; 

(T1 

215 C-1 Well 36 55 07 116 00 34 4 37.0 7.7 - 74 30 123 14 3:: 

Vi 

~ 216 UE-29A-2 36 56 29 116 22 26 2 24.0 7.1 - 10 .2 44 1.2 ;<:> 

217 Desert Dry Lake Well 36 57 11 115 11 51 1 19.0 8.0 400 22 27 35 5.7 -< 

;l> 218 Quartz Spring 36 59 10 115 36 00 1 18.0 8.0 800 67 39 54 2.2 z 

219 UE-16F 37 02 09 116 09 25 1 23.3 8.4 1,600 4.7 1.3 425 2.2 Ci 

220 Tippipah Spring 37 02 36 11612 26 3 18.0 7.4 340 23 1.7 49 2.3 Vi 

0 

~ 

221 WellU3CN5 37 03 34 116 01 20 1 590 41 17 54 9.7 0 - - "0 

222 Willow Spring KSV-1 37 05 34 114 49 52 1 17.4 7.5 20 2.7 56 4.6 (T1 

- ::t. 223 Grapevine Spring KSV-2 37 08 08 114 42 02 1 18.5 7.3 - 75 22 17 2.3 -< 

224 Well #8 (NTS) (Amargosa Well #64) 37 09 56 11617 21 1 26.5 7.4 - 8.4 1.2 31 3.5 cJ 

;<:> 

225 Jensen Well 37 11 03 114 27 52 1 18.0 7.7 840 55 14 100 7.2 0 

r 

0 

226 Maynard Lake Spring 37 11 30 115 02 02 1 9.6 7.9 910 43 23 114 14 0 

-< 227 Lone Tree Spring 37 12 07 115 03 32 1 11.0 7.5 1,300 45 43 164 20 0 228 Whiterock Spring 37 12 09 116 07 52 1 - 6.2 120 6.2 .2 17 3.0 

229 Kane Spring KSV-3 37 14 46 114 42 21 1 16.4. 7.2 - ~ 44 13 20 5.9 ;l> 

230 Boulder Spring KSV-4 37 16 12 114 38 44 1 16.8 7.9 - 21 4.9 12 2.3 ~ 

a:1 

;l> 

231 Randono Well 37 19 26 114 30 08 1 17.2 7.6 760 46 14 100 8.4 

232 Cane Spring 37 20 27 115 44 50 1 -- 7.6 810 84 48 24 2.4 

233 Bradshaw Well 37 20 57 114 32 38 1 14.8 7.3 1,100 85 28 120 11 

234 Railroad Well 37 21 04 114 32 02 1 16.0 7.6 730 42 14 98 8.8 

235 Sheep Spring 37 24 02 114 16 37 1 10.0 6.8 140 24 5.0 9.8 1.3 

236 Cattle Spring 37 24 57 115 45 05 1 - 8.0 530 56 11 41 5.3 

237 Rock Spring 37 25 53 115 4123 1 - 7.8 580 87 19 13 1.7 

238 Qua il Spring 37 26 29 115 41 01 1 - 7.8 670 86 19 29 1.9 

239 Hells Acre Gulch Spring 37 27 37 115 07 29 1 13.0 8.0 380 45 9.0 21 2.4 

240 Ash Spring 37 27 49 1151134 3 35.3 7.2 460 46 15 29 7.7 

n 

v::> 
APPEND IX B.- Average chemical and isotopic compositions of water from wells and springs in southern Nevada and southeastern California, 'Jj 

between latitudes 35 and 38 degrees north, and longitudes 114 and 117 degrees east- Continued "' 

Latitude Longitude Number Tern- Specific 

Site Sile name (degree. (degree, of pera- pH con due- Cal- Magne- Sodium Po lasminute, minute, lure lance cium sium sium 

second ) second ) samples <•C) (!iS/em ) 

241 Little Ash 37 27 50 115 1130 1 36.0 7.6L 500 56 14 31 5.6 

242 Indian Spring 37 27 50 115 44 28 1 -- 8.1 360 30 7.1 39 .9 

243 Rabbitbrush Spring 37 28 56 115 4128 1 - 7.9 380 42 8.9 25 3.5 

244 Savio Spring 37 29 42 115 42 04 1 - 8.3 470 55 14 24 6.2 ;o 245 Rose Bud Spring . 37 30 32 115 46 25 1 - 7.3 850 89 60 18 2.0 m 

0 

246 Ramone Mathews Well 37 31 36 11414 39 1 18.5 7.8 270 42 6.3 20 5.9 0 

z 

247 Crystal Spring 37 3153 115 13 58 2 27.5 7.3 410 44 22 22 5.3 )> 

r 248 Acoma Well 37 32 55 114 10 23 1 17.0 7.7 260 38 5.3 21 7.0 )> 

249 Hiko Spring 37 36 34 115 12 51 2 26.0 7.4 - 49 23 26 7.4 0 

250 Walis Health Well 37 37 13 114 30 44 1 63.0 7.8L 440 41 4.4 40 11 c 

~ 251 Caliente Hot Spring 37 37 16 114 30 34 1 45 480 37 7.3 49 19 ;o - c:, 

252 Weaver Well 37 44 41 114 25 28 1 17.0 7.7 980 100 42 110 14 -< 

Well B-1 Tonopah Test Range Nellis B&G Rg 37 45 06 116 29 23 1 26.7 7.9 280 9.6 en 253 19 .6 34 -'j 

254 John Wadsworth Well 37 46 07 114 24 25 1 14.5 7.5 1,100 120 47 150 9.5 m 

~ 

255 Bennett Spring 37 47 03 114 3141 1 24.0 7.5 580 56 26 6.5 1.5 )> 

z 

256 Lester Mathews Well 37 47 37 114 23 59 1 20.0 8.1 1,000 73 21 140 10 )> 

r 

257 Panaca Town Well 37 47 50 114 23 57 1 29.5 7.9 500 45 13 47 8.3 -< en 

258 Panaca Spring 37 48 24 114 22 47 2 29.0 7.8 460 33 10 37 7.0 ;;; 

259 North Lee Well 37 49 28 114 23 04 1 22.0 8.0 580 59 12 44 9.9 

260 SOl E47 15 CC 37 50 40 116 42 40 1 17.5 7.7 320 14 1.1 49 6.7 ;:o 

m 

)> 

261 SOlE 5121BA 37 50 45 116 20 55 1 15.0 7.4 290 27 3.2 26 6.9 -'j 

262 Delmues Spring 37 51 36 114 19 20 1 18.0 7.7 560 47 6.7 30 6.3 co 

)> 

263 Oxborrow Well 37 53 10 114 1817 1 11 .5 7.9 800 130 22 65 11 

264 Flatnose Spring 37 53 46 114 13 33 1 25.0 8.0 400 26 3.5 34 5.6 

265 NOl E53 31CD 37 54 03 116 03 51 1 17.0 7.8 270 17 1.8 39 5.0 

266 Upper Conners Spring 37 54 10 114 33 38 1 8.0 7.4 490 73 26 2.2 0.5 

267 N01 E53 32CAA 37 54 15 116 02 20 1 - 7.8 360 25 1.8 42 7.8 

268 Lime Spring 37 54 52 114 32 25 1 21.0 8.3 330 55 31 3.8 0.9 -'j 

269 NOl E47 30ABB 37 54 55 116 45 08 1 17.0 7.7 400 23 3.5 53 7.7 )> 

270 Deadman Spring 37 55 07 114 32 29 1 9.5 7.1 370 98 41 5.0 0.9 :I: 

271 Highland Spring 37 55 16 114 32 56 1 10.0 7.2 380 86 36 4.7 1.0 

272 S02 E47 07AA 37 57 20 116 45 00 1 25.0 8.5 450 1.4 .1 96 5.6 

273 Pioche Municipal Well 37 57 33 114 24 51 1 20.5 7.7 300 31 4.4 17 5.5 

274 NOl E53 07AD 37 57 50 116 02 60 1 17.0 9.9 4,100 .7 .1 980 9.6 

275 NOl E47 02BAB 37 5818 116 41 04 1 16.0 7.5 350 23 1.5 47 7.2 
APPENDI X B.- A verage chemical and isotopic compositions of water from wells and springs in southern Nevada and southeastern California, 

between latitudes 35 and 38 grees north, and long tt~des 114 and 11 7 degrees east- Continued 

Bicar- Car- rluor- Sum or Dis- Deuterium Oxygen-18 Carbon-1 3 Carbon-14 Tritium Site bonate Chloride Sulfate ide Silica consti- solved (permil) (perm ill (permil) (pmc) (pCi{L) Date Source2 

bonate tuent.s 1 oxygen 

1 262 - 118 362 0.4 20 920 - - - -- - - -- 1 

2 194 - 114 344 - 16 830 - -- -- - -- - -- 1 

3 209 - 95 313 - 19 780 -- - -- -- - -- -- 1 

4 160 - 188 195 - 28 740 - - -- -- - - -- 1 

5 194 - 157 341 - 17 910 -- - -- -- -- -- -- 1 Cl 

(T1 

6 183 94 288 .3 16 720 1 0 -- - - - -- -- - - () 

7 184 -- 142 320 - 15 840 - - -- -- -- -- -- 1 :r: 

rn 8 168L - 66 235 .6 55 610 - -73.0 -9.4 -- -- - 06-22-85 2 ~ 9 300 L - 76 208 .6 18 650 - -88.0 -11.9 -9.9 -- -- 06-22-85 2 Vl 

-l 10 368L - 30 26 .5 80 450 - -72.0 -8.4 - - - 06-22-85 2 ;;o 

-< 

11 410 730 1,000 2.6 41 3,100 -90.5 -10.8 04-23-82 1 )> 

- - -- - - z 

12 169 L - 112 53 1.3 29 410 - -67.0 -7.2 -7 68.1 - 06-21-85 2 0 

13 230 - 55 550 1.5 34 1,100 - -95 -12.1 -7.6 2.4 - 06-21-85 2 c:;; 

0 14 242 - 7.6 109 .4 25 370 - -94.0 -13.2 - -- -- 09-27-86 1 -l 

15 315L 126 263 .3 18 820 -94 -12.5 -9.3 39.4 06-21-85 2 0 - -- -- "0 

(T1 

16 730 -- 460 500 3.1 91 2,300 2.0 -98.0 -12.85 -4.3 -- <1.0 06-30-85 1 

17 168 L - 51 98 .2 15 360 - -88.0 -1 1.7 -7.8 67.5 - 06-23-85 2 ;;o 

~ 18 366 L - 59 101 .5 29 530 -- -87.5 -10.9 -9.4 60.4 - 06-22-85 2 0 

19 89 82 141 1.0 24 450 -80.5 -10.2 01-00-81 3 r - - - - - 0 

20 38 - 980 575 4.2 40 2,500 - -83.5 -11.2 - - - 03-00-82 3 Cl 

_-< 

21 154 198 177 .9 31 720 -95 -13.1 -6.8 02-28-86 4 Cl -- - - -- ;;o 

22 141 - 1,530 1,030 4.2 45 4,100 - -82.0 -10.5 - - - 03-00-82 3 rn 

)> 

23 210 - 88 310 .4 17 720 3.8 -92.0 -12.3 -7.4 4 - 05-10-83 1 -l 

24 152L - 95 292 .6 39 730 - -97 -13.3 02-27-86 4 c:o -- - - )> 

25 249 - 7.4 171 -- 9.7 450 - -86 -12.3 -9.7 59 - 07-11-86 4 ~ 

z 

26 150 -- 97 250 0.7 53 680 3.6 -100.0 -12.9 -6.4 1 -- 05-11-83 1 

27 260 - 10 42 .2 10 290 6.0 -89.0 -12.2 -10.6(2) 49.8(2) <15 (1) 06-25-85 1 

28 210 - 110 450 .8 26 690 3.4 -94.0 -12.7 -6.7 4 - 05-09-83 1 

29 192 - 12 548 .3 14 930 - -89 -12.2 - -- - 05-18-79 4 

30 192 - 13 518 .3 15 890 - -86 -12.4 -7.9 11.0 <15 03-13-86 4 

31 215 - 21 176 .3 15 320 - -95 -13.2 -7.9 - - 05-10-79 4 

32 223 - 8.0 80 .2 16 310 - -98 -13.5 -8.0 -- -- 05-08-79 4 

33 228L -- 4.8 59 .2 15 280 - -99 -13.6 -9.3 39.4 - 03-21-79 4 

34 210 - 7.3 170 .2 13 430 6.0 -89.0 -12.25 -9.3 46.0 9.0 06-30-85 1 

35 223 - 7.8 73 .2 16 300 - -100 -13.7 -7.6 - - 05-15-79 4 i.O 

<..J 
APPENDIX B.-Average chemical and isotopic compositions of water from wells and springs in southern Nevada and southeastern California, () 

..0 

between latitudes 35 and 38 degrees north, and longitudes 114 and 117 degrees east-Continued ... 

Bicar- Car- Fluor- Sum or Dis- Deuterium Oxygen-IS Carbon-13 Carbon-14 Tritium Site Chloride Sulfate Silica consti- solved Date Source2 

bonate bonate ide tuents1 (permil) (permil) (permil) (pmc) (pCi(L) oxygen 

36 206 -- 7.0 244 0.2 13 520 - -90 -12.4 -8.5 - -- 03-28-79 4 

37 260 - 6.0 21 .2 12 260 6.4 -89.0 -12.25 -10.5(2) 62.4(2) 3.0 06-26-85 1 

38 230 - 2.4 23 .1 13 230 8.8 -99.0 -13.55 -8.3 46.9 <2.0 06-27-85 1 

39 200 - 4.5 49 .5 35 260 7.1 -101.0 -13.6 -7.9 9 - 05-11-83 1 

40 230 - 5.8 54 .2 .18 280 - -100 -13.5 -7.2 - - 03-29-79 4 

41 223 - 6.5 116 .2 13 340 - -94 -1 3.2 -8.3 - - 06-26-79 4 ~ a 

0 

42 226 -- 4.8 65 .2 14 280 -- -97 -13.4 -7.3 14 - 06-13-86 4 z 

43 207 - 3.5 33 .2 15 230 - -100 -13.8 -7.7 -- - 06-28-79 4 ~ 44 227 - 7 67 .2 14 290 - -96 -13.2 -7.7 -- - 06-26-79 4 )> 

45 330 - 3.3 25 .2 11 320 7.7 -96.5 -13.25 -10.1 84.1 34 06-28-85 1 .0 

s 46 229 - 5.0 72 - 14 290 - -97 -13.2 -7.8 -- - 05-06-86 4 ri1 

::0 

47 200 - 16 180 .2 13 450 5.4 -91.0 -12.5 -12.0 - <2.0 06-26-85 1 u, 

48 235 - 3.7 48 .2 14 250 - -97 -13.8 -7.2 - - 05-14-86 4 -< (/) 

49 230 - 4.5 43 .2 15 260 - -99 -13.6 -7.3 -- - 03-27-79 4 -l (T) 

50 236 - 4.5 50 .2 13 270 -- -97 -13.6 -8.0 - - 06-26-79 4 3:: 

51 238 - 5 52 .2 13 280 -- -97 -13.5 -8.0 - - 06-26-79 4 )> 

z 

)> 

52 229 - 4.8 73 .2 14 270 -- -94 -13.4 -8.3 -- -- 03-27-79 4 r 

-< 

53 239 - 4. 0 36 .2 14 530 - -101 -14.0 -7.3 -- -- 05-13-86 4 (/) 

54 233 - 3.5 48 .2 14 260 - -100 -14 -8.2 - - 03-27-79 2 Ui 

55 234 -- 3.1 33 .2 14 240 - -100 -14.1 -7.0 - - 06-03-86 4 6 

56 240 - 3.4 28 .2 14 240 6.9 -97.0 -13.55 -7.6 26.0 <1.0 06-27-85 1 ~ )> 

57 231 3.5 31 0.2 14 240 6.0 -104.0 -13.5 -6.8 13 1,4 -l - - - o:l 

58 240 - 4.5 35 .2 13 250 - - -- - - - 01-09-76 1 )> 

59 256 8.0 68 .4 80 390 -98 -13.8 -8.0 05-15-79 4 (/) 

-- - - - _2 

60 178 -- .7 6.0 .2 4 160 9.4 -97.7(19) -13.6(22) -8.1(5) 90.8(1) 257 (3) - 5 z 

(T) 

61 2,350 720 3,800 2,800 15 8.7 72,000 0.8 -93.5 -11.1 - - - 11-21-83 1 < 

)> 

62 2,450 590 6,700 3,400 12 20 8,000 1.5 -91.0 -10.0 - - - 11-21-83 1 0 · 

63 231 - 2.8 29 .2 15 240 - -102 -14.0 -7.2 - - 03-06-86 4 :;-

64 192 41 150 2.1 55 490 3.4 -101.5 -13.8 -5.3 5.6 <.3 09-29-86 1 c - -l 

65 150 - .7 3.7 .1 3.2 130 - - - - - - 08-25-78 6 5: 

66 197 - 3.5 27 .3 34 230 - -106 -14.5 -8.2 3 - 05-11-79 4 

67 235 -- 4.1 5.7 - 6.0 210 - -96.0 -12.4 -9.8 91.7 98 08-19-82 2 

68 242 8.3 1.9 6.7 .2 5.1 220 - -95.5 -13.4(12) - - - 04-05-88 1 

69 150 - .8 4.6 .1 3.8 130 - - - - - - 08-24-78 6 

70 15,980 10,200 23,000 19,000 30 28 9,000 6.5 -66.5 -2.5 - - - 11-18-83 1 
APPENDIX B.- Average chemical and isotopic compositions of water from wells and springs in southern Nevada and southeastern California, 

between latitudes 35 and 38 degrees north, and longitudes 111, and 117 degrees east- Continued 

Biear- Car- Fluor- Sum or Dis- Deuterium Oxygen-IS Carbon-1 3 Carbon-14 Tritium Site bonate Chloride Sulfate ide Silica consti- solved (permil) (permil) (permil) (pmc) (pCifL) Date Source2 

bonate tuents1 oxygen 

71 234 - 20 78 .5 41 0 360 - -95 -13.2 -6.3 21 - 04-03-86 4 

72 600 - 480 550 3.4 67 2,200 5.8 -92.0 -11.3 - -- - 11-17-83 1 

73 210 - 3.7 5.9 .2 4.6 180 -- - - - - - 08-24-78 6 

74 180 - .7 5.1 .1 4.1 160 - - - - -- - 08-24-78 6 

75 185 - .7 3.8 .1 4.8 160 - - -- -- - - - 6,7 

76 235 - 2.4 6.2 .1 5.6 210 - - - - - - -- 6,7 

77 252 - 6.3 34 .2 13 260 - -92.0 -12.9 - - <15 03-31-87 2 0 

78 225 .8 6.4 .1 5.6 200 6,7 en - - - - - - - - 0 

79 232 - 1.2 6.5 .2 6.3 200 - -94.5 -12.8 -7.4 -- .3 04-16-80 2,7 () 

:r: 80 244 - 1.4 9.9 .1 6.5 220 - - - - - - - 7 en 

s:: 

81 257 1.3 26 .2 6.1 240 -96.0 -12.2 -10.1 83 87 2,6,7 en - - - -l 

82 2.5 14 7.1 - - 08-18-78 6 ;;o - - - - - - - - -< 83 340 -- 2.9 19 .1 7.7 310 - -- - -- -- -- 08-23-78 6 > 

84 224 - 3.3 25 .2 17 230 - -101 -13.7 -7.1 - - 11-03-86 4 z 

t:? 85 213 L - 4.6 16 .2 20 210 - -100.0 -13.4 -6.7 1.9 - 06-30-85 2 en 

0 

86 720 25 690 280 6.1 35 2,200 0.2 -100.0 -12.9 11-19-83 1 -l - - - 0 87 170 - .3 3.4 .2 3.1 140 - - - - - - 07-24-80 1 -o 

tn 88 200 - .6 3.4 .2 3.9 170 - - - - - - - 1,6 

89 292 - 16 53 .2 22 340 - -91.5 -12.4 -9.1 46 <15 - 2 ~ 0 90 207 - 1.4 9.9 .1 4.9 180 - - - - - - 08-23-78 6 ;;o 

0 

r 91 260 - .9 11 .1 6.1 230 - - - - - - - 7 0 

92 181 L .5 2.8 .1 5.0 160 -98.5{2) -14.1(2) -8.4{2) 78.4(2) 06-28-85 2 0 - - - _-< 

93 238L - .9 4.3 .1 5.1 200 8.3 -98.0 -13.45 -9.6 100 73.2 06-28-85 2 0 

94 245 - .9 3.1 .1 5.2 210 - - - - - - - 2 ;;o 

tn 95 240 -- 4.1 19 .3 18 230 5.6 -99.0 -13.3 -6.7 7 - 05-10-83 1 > -l 

Cll 96 244 - 1.8 30 - 7.0 240 - -98 -12.7 -8.8 61.4 - 08-21-85 2 > 

97 277 1.5 21 .8 7.9 240 6,7 en - - - - - - - - z 98 244 - 1.6 20 .01 8 230 2.0 -100 -13.4 -8.0 31.6 <15 06-24-86 2 

99 251 L - 4.7 18 .2 19 240 - -99.7(3) -12.5(2) -7.0 13.9 <15 06-30-85 2 

100 440 - 1.5 5.8 .1 7.2 360 - -93.5 -12.9 - - - 06-29-85 1 

101 226 - 9.2 22 .3 17 240 -- -97.0 -13.2 -7.2 23.8 <15 06-25-86 2 

102 223 - 1.5 39 - 11 240 - -100 -12.6 -7.7 16.4 -- 08-20-85 2 

103 257 - 3.4 59 .2 9.0 290 - -98.0 -13.4 -8.6 49.6 <15 06-24-85 2 

104 247 - 3.7 18 - 18 220 - -98.0 -12.6 -6.2 11.3 - 08-20-82 2 

105 278 - 1.3 11 .7 6.5 220 - -99.5 -13.8 -1 0.8 91.1 89 - 1,6,7 

() 

\0 

V> 
APPENDfX B.-Average chemical and isotopic compositions of water from wells and springs in southern Nevada and southeastern California, () 

\0 

between latitudes 35 and 38 degrees north, and longitudes 111, and 117 degrees east- Continued a, 

Bicar- Car- Fluor- Sum of Dis· Deuterium Oxygen-I S Carbon-1 3 Carbon-14 'l'ritium Site Chloride Sulfate Silica consti- solved Date Source2 

bonate bonale ide tuents1 (permil) (permil) (permil) (pmc ) (pCi{L) oxygen 

106 226 - 200 380 1.4 23 1,000 5.5 -98.0 -13.45 -5.5 2.7 <.3 09-30-86 1 

107 255 L -- 3.5 67 - 10 300 - -96.0 -12.1 -7.9 48.4 -- 08-21-82 2 

108 255 -- 3.3 64 -- 10 300 - -98.0 -12.7 -8.2 50.1 - 08-20-82 2 

109 243 -- 2.5 43 .7 9.7 260 -- -98.0 -14.0 -8.2 57 32 08-21-82 2 

110 318 -- 27 111 1.3 28 490 4.5 -103.0(4) -13.4(1 ) -4.6(1 ) 3.2(3) .5(2) - 5 m "' 

111 163 333 1,633 1.4 18 2,900 2.3 -92.0 -12.2 1 0 -- -4.05 1.6 -- - 0 

112 230 - 190 360 1.6 21 1,000 .5 -96.0 -13.7 -- - -- 04-26-82 1 z 

113 160 - 500 2,300 1.4 18 4,000 3.4 -93.0(2) -12.4(2) -5.3 7.2 - 07-01-85 1 ~ r 

114 226 -- 180 370 1.6 23 1,000 4.8 -97.0 -13.05 -4.9 1.5 <1.0 03-31-86 1 ~ 

115 292 -- 1.1 9.0 .2 7 250 8.2 -100.1 (16) -13.8(18) -9.6(5) 76.0(4) 92 (4) - 5 0 

c 

'Ti 

116 350 -- 20 74 3.7 59 500 -- - - -- - - 11-18-72 1 m 

117 289L - 1.8 9.9 .2 7.6 250 -- -97.5(3) -13.75(3) -9.6 79.2 57 06-26-85 2 v, "' 

118 242 - 5.5 15 .5 46 260 6.1 -93.0 -12.8 -6.7 13.7 1.0 09-25-86 1 -< tn 

119 312 - 26 89 1.7 26 450 3.7 -104.0(5) -13.7(1) -5.0(1) 11.1(2) 1.6(2) - 5 -l 

m 120 320 - 5.9 16 .4 35 310 - -93.0 -12.7 -6.9 35.7 <15 06-24-86 2 ~ 

121 164 L 21 449 .2 8.3 780 -82.0 -10.6 -8.5 18.7 06-24-85 2 ~ - -- --

122 294 -- 6.5 17 .4 30 290 - -94.0 -13.0 -8.8 20.4 1.0 09-25-86 1 ~ -< 

123 160 - 6.5 40 2.3 82 280 - -102.0 -12.4 -- - -- 03-06-74 8 tn 

124 284L -- 7.1 18 .2 18 300 - -93.2(3) -12.9(3) -7.7(3) 13.9(1) 1.0(2) - 1,5 v; 

I 125 350 -- 41 190 6.9 31 660 - -102.0 -13.7 -- -- -- 04-22-82 1 0 

"' 126 243L 2.7 11 .1 8.7 220 8.2 -93.0 -13.3 -8.8 2 en -- 87.3 46 06-27-85 )> 

127 210 - 170 360 2.1 21 960 2.0 -97.5 -13.3 -4.2 3.0 7.0 07-01-85 1 -l 

CP 

128 270 - 12 130 .2 21 430 6.4 -92.5 -12.75 -7.2 - 10 06-28-85 1 )> 

129 340 - 37 160 7.1 31 610 - -102.0 -13.7 - -- -- 04-22-82 1 ~ 

130 195 -- 4.6 12 .4 24 200 - -95.5 -13.55 -7.7 7.0 <15 12-02-86 2 

rct 

131 197 -- 3.3 13 .2 15 190 8.7 -99 -13.7 -8.0 -- - 12-18-87 2 < 

)> 

132 120 - 10 35 1.4 73 240 - - - - - - 03-06-74 8 0 

133 120 - 6.4 27 1.4 81 240 - -102.0 -13.0 - - - 03-06-74 8 

134 400 78 180 6.8 46 770 03-03-74 8 c - - -- - - - - -l 

135 306 - 21 80 1.7 22 420 3.2 -103.2(4) -13.6(1) -5.1(2) 1.9(3) .5(3) - 5 )> 

::t 

136 210 - 28 160 2.9 53 510 - - - - - - 03-07-74 8 

137 150 -- 9.5 31 1.7 80 280 - -104.0 -12.7 - - - 03-01-74 8 

138 130 - 10 69 1.2 70 300 - -- - - - - 03-01-74 8 

139 140 - 6.3 25 1.7 79 250 - -104.0 -13.0 - - - 03-05-74 8 

140 350 - 38 180 6.4 25 630 - -104.0 -13.6 - - - 04-22-82 1 
APPENDI X B.- Average chemical and isotopic compositions of water from wells and springs in southern Nevada and southeastern California, 

between latitudes 35 and 38 degrees north, and longitudes 114 and 11 7 degrees east- Continued 

Bicar- Car- lu Sum or Dis- Deuterium Oxygen-I S Carbon-13 Carbon-14 Tritium Site Chloride Sulfate Silica consti- solved Date Source2 

bonate bonate ide tuents1 (permil) (permil) (perm ill (pmc) (pCi{L) oxygen 

141 202 - 3.4 11 .6 26 200 9.3 -98.0 -13.7 -6.9 - - 12-19-87 2 

14.2 219L - 3.1 11 .1 13 200 7.0 -102.0 -13.7 -6.6 4.9 - 06-26-85 2 

143 314 - 27 168 - 38 600 - -104.0 -13.7 - -- - 06-24-79 8 

144 130 - 6.9 25 1.6 79 240 - -98.5 -12.6 -- -- -- 03-04-74 8 

145 320 - 29 170 4.4 33 570 - -104.0 -13.7 -- -- - 05-11-81 1 

146 195 - 5.3 13 0.5 26 200 9.2 -95.0 -13.2 -7.2 -- -- 12-19-87 2 

147 203 - 4.2 12 .1 13 200 7.2 -98.0 -13.2 -7.1 6.1 <15 06-23-86 2 0 

148 197 6.7 32 .5 22 230 -87.0 -12.1 -6.2 9.2 08-05-87 1 lTl - -- - 0 

149 291 - 20 70 1.7 22 400 - -- -13.6(1) -4.6(1) 1.8(1) - - 5 () 

::r: 150 130 - 9.3 28 1.3 72 240 -- -102.0 -13.0 -- -- - 03-05-74 8 lTl 

3:: 

151 127 8.9 35 76 260 -99.0 -13.2 06-25-79 8 (/) 

- - -- -- -- - -l 

152 130 6.6 33 1.0 75 250 -101.0 -13.1 - 03-05-74 8 ;;<l - - - - -< 153 245 - 64 90 1.2 27 470 3.8 -90.5 -11.2 - - <1.0 03-28-86 1 )> 

154 150 - 7.8 30 1.5 79 270 - - - -- - -- 11-17-72 8 z 

0 155 132 - 8.2 51 - 77 280 - -97.5 -13.2 -- - - 06-26-79 8 Vi 

0 

156 150 - 7.4 28 1.2 59 240 - - -- - 03-01-74 8 -l - - 0 157 236 -- 63 187 - 77 670 - -104.0 -13.6 -- - - 06-25-79 8 -c 

lTl 158 242 - 3.8 16 .2 12 220 4.8 -99.3 -13.3 -7.6(3) 8.3(3) <2.0(2) - 1,5 ::r: 159 153 -- 7.4 29 - 68 260 - -103.0 -13.4 -- - -- 03-31-71 8 -< 0 160 195 - 23 130 -- 46 430 - -105.0 -13.8 - - - 03-31-71 8 ;;<l 

0 

r' 161 140 - 10 67 .9 72 310 -- -103.0 -13.4 - - - 03-01-74 8 0 

162 166 8.2 33 64 270 -102.0 -13.4 03-31-71 8 0 - - - -- - -- :< 163 291 - 29 152 -- 29 540 -- -105.0 -13.8 -- - - 04-01-71 8 0 

164 222 - 76 398 .3 18 840 3.2 -96.0 -13.0 -6.9 7.3 <15 06-27-85 2 ;:o 

lTl 165 239 - 62 180 - 64 630 -- -102.0 -13.1 -- - -- 03-31-71 8 )> 

-l 

166 150 - 7.7 30 .7 54 240 - -99.5 -13.2 -- - - 11-17-72 8 co 

)> 

167 290 29 19 .2 16 310 5.9 -92.0 -12.6 1 (/) 

- -- -- -- - 168 140 - 6.0 26 1.0 62 230 - -103.0 -13.2 -- -- -- 03-04-74 8 

169 275 - 16 54 .9 19 340 2.8 -103.5(2) -- -5.6(2) 2.8(1) .6(2) - 5,14 

170 197L - 6.0 14 .2 14 200 - - - - - - -- 5 

171 150 - 7.4 38 .9 20 220 - - - - - - - 1 

172 150 -- 6.7 33 1.0 49 240 - -- - -- -- -- 03-04-74 8 

173 150 - 8.5 33 0.9 49 240 - -102.0 -12.8 - -- - 11-20-72 8 

174 370 - 3.1 7.0 .1 12 310 5.4 -94.3(9) -12.8(9) -10.2 96.8 89.6 - 1 

175 - -- 15 370 1.0 29 - - -87.0 -11.65 -- - -- 01-25-85 1 

() 

"' _, 
APPENDIX B.- Average chemical and isotopic compositions of water from wells and springs in southern Nevada and southeastern California, () 

'D 

between latitudes 35 and 38 degrees north, and longitudes 114 and 117 degrees east- Continued 00 

Bicar· Car- Fluor- Sum of Dis- Deuterium Oxygen-IS Carbon-13 Carbon-14 Tritium Site Chloride SuUate Silica consti- solved Date Source2 

bonate bonate ide tuents1 (permil) (permil) (permil) (pmc) (pCi/L) oxygen 

176 293 - 4.9 8.4 0.2 24 420 - -81.0 -10.6 -- - - 03-20-87 1 

177 395 - 18 13 .1 16 370 5.1 -91.8 -12.7 -9.9 -- - - 1 

178 250 - 55 149 - 15 660 - -99.0 -13.1 -- -- - - 9 

179 270 - 294 1,094 -- 18 2,200 - -95.5 -13.2 - -- - - 9 

180 124 - 184 1,954 - 13 3,100 - -92.5 -12.7 -- - - - 9 ?J 

9 

25 

181 162 - 233 1,780 - 26 3,000 - -96.5 -13.7 - - - - 0 

182 178 - 41 1,800 - 13 2,700 - -99.5 -13.9 - - - - 9 z 

183 299 26 54 1.2 24 380 10-07-87 1 )> 

- - - - -- - - r 

184 123 - 194 2,100 - 15 3,300 - -91.0 -12.7 - - - - 9 )> 

185 475 - 335 1,240 - 65 2,700 - - - - - - 01-16-81 2 tO 

s 

-n 

186 245 - 57 171 - 28 560 - -98.0 -13.0 - -- - 9 (T! 

- ;:o 

187 275 -- 10 8.5 .2 46 290 5.7 -83.5 -9.8 -8.3 - - - 1 c:, 

188 321 - 121 560 -- 66 1,300 - - - - -- - 07-09-81 1 -< (I) 

189 280 - 59 190 2.1 25 640 -- -97.0 -12.75 -- - - 03-00-70 1 -l 

(T! 

190 270 - 61 190 2.1 29 610 3.0 -97.8(3) -12.9(3) -6.0 6.7 <1.0 07-22-81 1 3:: 

)> 

191 255 54 154 30 550 -101.5 -13.2 9 z - - - - - - - )> 

192 250 - 15 82 3.2 38 390 - - - - - - - 1 r 

-< 

193 119 - 7.3 22 2.1 54 210 - -97.5 -12.8 - - - 03-26-71 10 VJ 

194 271 - 53 159 2.1 30 560 3.7 -97.0 -12.95 -8.0 8.4 1.8 01-26-86 1 Ci'i 

I 195 276 - 61 160 2.3 30 590 4.0 -98.0 -12.85 -5.5 8.4 4.0 01-26-86 1 0 

;:o 

1,8 (T! 

196 165 - 10 44 2.7 50 280 - -108.0(1) -14.2(1) -8.5 12.2 - - )> 

197 295 34 105 1.9 33 480 2.9 -101.0 -13.0 7.6 <2.0(1) 1 -l - - - co 198 124 - 7.1 17 2.4 57 210 - -97.5 -13.0 - - - 03-26-71 10 )> 

199 328L - 23 84 1.5 24 480 - - - -- - - 05-10-62 5 ~ 

200 64 - 52 550 1.6 23 940 - -97.5 -12.5 - - - 02-04-84 1 

~ 

201 220 - 16 24 .2 - 240 - -88.0 -11.9 -5.3 -- - 01-03-88 2 < 

202 890 - 26 78 4.9 44 870 - -107.0 -13.8 - - - 02-11-83 11 ~ 203 140 - 7.0 22 2.1 54 220 - -101.0 -13.4 -7.0 15.3 - 03-13-84 1 :;- . 

204 170 7.2 22 2.0 53 230 -103.0 -13.5 05-19-84 1 c - - - - - -l 

205 173 - 6.9 26 4.8 46 260 - -104.0 -14.0 - - - 05-17-82 12 )> 

:r: 

206 182 - 7.6 29 4.7 48 270 - -106.0 -13.8 - - - 10-16-82 12 

207 143 - 11 37 .2 - 180 - -99.0 -13.2 -8.9 - - 01-02-88 2 

208 143 - 9.7 22 1.6 52 230 - -100.0 -13.4 - - - - 10,12 

209 139 - 5.9 19 2.5 45 220 - -103.0 -13.8 - - - 12-09-82 12 

210 126 - 6.1 16 1.4 48 200 - -102.0 -13.6 -10.3 19.8 - - 12 
APPENDI X B.- Average chemical and isotopic compositions of water from wells and springs in southern Nevada and southea.stern California, 

between latitudes 35 and 38 degrees north, and longitudes 114 and 117 degrees east-Continued 

Bicar- Car- Fluor- Sum or Dis- Deuterium Oxygen-IS Carbon-1 3 Carbon-14 Tritium Site Chloride Sulfate Silica consti- solved Date Source2 bonate bonate ide tuents1 (permil) (permil) (permil) (pmc) (pCifL) oxygen 

211 118 - 5.7 18 1.1 44 190 - -102.0 -13.4 -11.4 21.9 - - 10,12 

212 287 - 14 64 .5 16 340 - -100 -13.1 -12.0 -- 51.2 05-09-87 2 

213 303 - 34 90 1.7 34 470 2.9 -101.0(2) -13.0(2) -6.1 7.0 <1.0 02-05-86 1 

214 156 - 42 20 .5 14 230 - -94.0 -12.6 -- - -- 01-06-88 1 

215 584 - 32 67 1.1 29 660 -- -110.5 - -3.8(1) .8(1) <.3(1) - 5,14 

216 107 - 9.9 21 .9 44 180 - -93.2 -12.8 -12.9 61 - - 12 

217 207 - 8.9 48 .6 49 300 - -98.0 -13.1 -5.3 1.3 <.6 03-18-87 1 0 

218 383 31 80 .6 52 520 11.0 -88.0 -11.6 -11.3 01-02-88 2 en - -- -- 0 

219 930 33 26 120 4.4 4.7 1,100 - -105.0 -14.9 - -- - 09-25-77 13 () 

:r 220 160 - 8.9 18 .3 53 240 - - - - - 58 - 1 en 

3:: 

221 270 32 41 0.8 38 370 11-15-74 1 ;;; - - - - -- -- - -:1 

222 140 L - 22 34 1.1 65 270 - -88.0 -11.6 02-03-84 1 ;;o - - - -< 

223 280 L - 27 40 .9 22 340 - -87.5 -12.0 -- -- - 02-03-84 1 )> 

224 80 - 7.4 14 - 41 150 - -104.0 -13.0 - - - 03-24-71 8 z 

0 225 340 - 45 80 2.1 56 520 - -88.5 -11.6 - - - 04-10-85 1 ;;; 

0 

226 405 L - 30 88 - - 510 - -94.0 -12.3 01-14-85 2 -:1 - - - 0 

227 539 L - 50 145 - - 730 - -89.5 -10.9 -- - - 01-14-85 2 "0 

en 228 41 - 3.7 12 .1 24 86 - - - - - - 03-14-73 1 :r 229 210 L - 17 14 2.8 60 280 - -86.5 -11.9 - - - 02-02-84 1 -< 

0 230 100 L -- 7.8 6 1.7 41 140 - -87.0 -12.6 - - - 02-02-84 1 ;;o 

0 

r 231 350 - 44 63 2.3 54 500 - -87.5 -11.7 - - - 02-03-84 1 0 

0 232 360 - 18 136 - - 490 - -88 -9.5 - - - 05-15-85 2 :< 

233 550 I - 52 76 2.3 63 710 - -88.5 -11.4 -- - - 02-01-84 1 0 

234 300 - 42 60 2.3 51 460 - -86.0 -11.6 - - - 01-31-84 1 ;;o 

tn 235 96 - 7.9 7.0 0.7 33 140 - -87.0 -12.0 - - - 06-03-85 1 ~ co 236 261 L - 16 39 - - 300 - -85 -9.4 - - - 05-15-85 2 > 

237 348L - 5.8 35 - - 330 -- -86.0 -10.9 - - - 05-15-85 2 ~ 

238 166L - 11 206 - - 430 - -92.0 -11.9 - - - 05-15-85 2 

239 198L - 8.2 20 - - 200 - -93.0 -12.3 - - - 01-14-85 2 

240 259 - 8.0 33 0.9 30 290 2.3 -108.0 -14.1 -6.7(2) 6.3(3) 0 (2) -- 1,5 

241 270L - 21 34 8.7 29 320 - - - - - - 02-04-74 1 

242 173 L - 9.4 31 - - 200 - -88 -10.4 - - - 05-15-85 2 

243 197 - 9.0 27 - - 210 - -89 -11.2 - - - 05-14-85 2 

244 268L -- 10 26 - - 270 - - - - - - 05-14-85 2 

245 400 L - 11 150 - - 530 - - - - - - 05-17-85 2 

() 

'<:> 

'<:>