Geochemical and Geophysical 

Anomalies in the Western Part 

of the Sheep Creek Range 

Lander County, Nevada 

Geochemical and Geophysical 

Anomalies in the Western Part 

of the Sheep Creek Range 

Lander County, Nevada 

By Garland B. Gott and Charles J. Zablocki 

G E 0 l 0 G I C A l S U R V E Y C I R C U l A R 595 

Washington J 968 
United States Department of the Interior 

STEWART l. UDALL, Secretary 

Geological Survey 

William T. Pecora, Director 

First printing I 968 

Second printing 1968 

Free on application to the U.S. Geological Survey, Washington, D.C. 20242 
CONTENTS 

Abstract ---------------------------------------- -------------------------------------------------------------- ---------------------------------------- ---------------------------------

Introduction ___________________________________________ ---------------------------------------------------------------- -------------------- ---- -- ------------------- -------------

Geologic environment ----------------------------------------------------------------------------------------------------------------------------------------------------------

Geochemical investigations ------------------------------------------------------ ------------------------------------------------------------------------------------------

Materials sampled --------------------------------------------------------------------------------------------------------------------------------------------------------

Analytical procedure -------------------------------------------------------- ------------------------------------------------------------------ ------------------------

Distribution of metals in the Paleozoic rocks ___ ------------------------------------------------------------------------ ----------- -----------------

Geophysical investigations ______________________ ------------------------------ ___________ -------------------- ------ ----------------- --- --------------- ------------

Magnetic data -----------------------------------------------------------------------------------------------------------------------------------------------------------------

Gravity data ------------------------------------------- ___________________________ ___________ -- ------------- --------------------------------------

Resistivity data ---------------------------------------------------------------- ___________________________________ ------------------- -------- --------------------------

Conclusions -------------------------------------------------------------------------------------------------- -------------------------- -------- ----------------------------

References --------------------------------------------------------- ________________________ --------------------------------------

FIGURE 1. 

2. 

3-10. 

11. 

12. 

13. 

14. 

15. 

ILLUSTRATIONS 

Index map of Nevada showing area of this report __ _ ----------------- - ---------------

Photogeologic map of part of the Sheep Creek Range showing sampled localities and area of 

figures 3-10 _ _____________________ ________________ ------------------------- ------------------------- ----------------------

Maps showing highest concentration at each locality sampled for: 

3. Zinc _________________________________________ -----------------,------- ________________ -------------------------- _ -------------------------

4. 

5. 

6. 

7. 

8. 

9. 

Arsenic ____________________________ _ 

Mercury _____________ _ 

Silver _ 

Lead ______ _ 

Copper 

Gold ___________________________ _ 

10. Tungsten _______________ ____ __________________ _____ __________ ---------------------------------------------

Aeromagnetic map of part of the Battle Mountain quadrangle __ __ _ ____ ------------- -----------------------

Aeromagnetic and generalized geologic map of the Rennox area _________ ----------- ----- -- ------- --------------

Diagram showing comparison of magnetic data taken from aeromagnetic map (fig. 12) witl 

model curve for the two-dimensional body shown _ -------------------- --------------------------------

Diagram showing comparison of the simple Bouguer gravity values (fig. 12) with model curve 

for the two-dimensional structure shown ______ _ _______________________________ ---------------- ---------------

Generalized cross section (fig. 12) showing resistivity values of the various zones defined by the 

electrical survey and the diagrammatic shape of the bedrock based on the magnetic and 

gravity models ___ ____________ _ _______________________________ ----------------------------------------------------

III 

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3 

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17 

GEOCHEMICAL AND GEOPHYSICAL ANOMALIES IN THE WESTERN PART OF THE 

SHEEP CREEK RANGE, LANDER COUNTY, NEVADA 

By GARLAND B. GOTT and CHARLES J. ZABLOCKI 

Abstract 

Extensive geochemical anomalies are present along 

the west side of the Sheep Creek Range in Lander 

County, Nev. Anomalous concentrations of zinc, arsenic, 

mercury, silver, copper, lead, and to some extent gold, 

molybdenum, and antimony occur in iron-rich material 

along fracture planes and in quartz veins in Paleozoic 

formations. 

After completion of the fieldwork involving 

both the geochemical and geophysical investigations a photogeologic base map was obtained 

from Knox-Bergman-Shearer, Photogeohgists, 

Denver, Colorado (fig. 2). Neither KnoxBergman-Shearer nor the writers have h:td an 

opportunity to check this map in the field, but 

the map suggests the presence of structures 

related to the geochemical anomalies. 

120° 116° 114° 

A magnetic anomaly occurs over a pediment at the 

southern part of the range, close to one of the geochemical anomalies. Gravity and electrical resistivity 

measurements suggest that the magnetic anomaly is 

caused by an intrusive igneous mass rather than by 

a block of downfaulted basalt. A limited amount of 

shallow drilling would clarify the geochemical and 

geophysical data. 

42°'~----------~~----------+-----~----~ 

INTRODUCTION 

A geochemical reconnaissance of the west 

side of the Sheep Creek Range (fig. 1) was 

made by R. L. Erickson in 1965. Encouraging 

results from this survey prompted a more detailed investigation during the sumn1er of 1967. 

Anomalous concentrations of several metals 

were found throughout an area in which Paleozoic cherts and quartzites are exposed. These 

metals-zinc, arsenic, mercury, silver, lead, 

copper, gold, molybdenum, antimony, tungsten, 

and tellurium-occur in such great concentrations as to suggest that they constitute a dispersion halo around or over a concealed mineral 

deposit. The outcrop belt of the Paleozoic rocks 

is limited to a narrow strip about 10 miles 

long on the west side of the range. The geochemical anomalies occur throughout this belt 

and may extend eastward under basalt and 

westward under alluvial cover. 

Geophysical investigations were made in and 

around an anomalous magnetic feature previously observed on an aeromagnetic map of 

this area. Results of these investigations suggest a shallow exploration target. 

1 

Elko 

40° 

f 

Ren! ~ jOA"'';" Eureka 

Elyo 

,~TY ( 

" 0 Tonopah 38°' 

" 0 50 100 MILES 

FIGURE 1.-Index map of Nevada showing area of 

this report. 

I 

I 

' I 

I 

' I 

I 

' 
FIGURE 2.-Photogeologic map of part of the Sheep Creek Range, Lander County, Nev., showing sanpled localities 

and area of figures 3-10. Photogeology modified from map prepared by Knox-Bergman-She"'Ter, Denver, 

Colo., 1967. 

2 
GEOLOGIC ENVIRONMENT 

One of the major structural features in 

north-central Nevada is the Roberts Mountains 

thrust fault (Roberts, 1964; Gilluly and Gates, 

1965). This fault has thrust a western facies 

of Paleozoic siliceous rocks eastward over a 

carbonate facies of the same age. Ore deposits 

in many mining districts of this region are 

confined to the shattered and crushed rock 

along the thrust plane or to the carbonate rocks 

below the thrust plane. 

The Paleozoic rocks that are exposed on the 

west side of the Sheep Creek Range are part 

of the western siliceous facies of the upper 

plate of the thrust fault. They consist of interbedded cherts and quartzites with some limestones and shales (fig. 2). The center of the 

range is capped by Tertiary basalt flows as 

much as 1,000 feet thick. Trains of basalt 

boulders derived from the basalt cap cover the 

Paleozoic rocks in many areas, and colluvial 

materials cover the lower slopes. A pediment 

thinly mantled by alluvium lies along the southwest base of the range. 

Some of the interbedded chert and quartzite 

sequence was identified by R. J. Roberts 

(oral commun., 1967) as part of the Valmy 

Formation of Ordovician age, but other Paleozoic formations may also be present. In general 

the beds strike about N. 35° W. and dip about 

45° NE. The exposed chert-quartzite sequence 

is probably several thousand feet thick. 

The cherts are mainly gray and grayish 

brown although some are red, green, or grayred mottled. The quartzite beds are predominantly light gray and of high purity. Both 

the cherts and quartzites are highly brecciated 

and fractured. 

Carbonate facies Paleozoic rocks are not 

exposed on the west side of the Sheep Creek 

Range, but on the basis of present knowledge 

of the structure in nearby areas, the Roberts 

Mountains thrust fault can be inferred to be 

present at depth in this area. 

GEOCHEMICAL INVESTIGATIONS 

MATERIALS SAMPLED 

The principal objective of this investigation 

was to evaluate the possibility that metals were 

localized near the thrust plane in either the 

upper or the lower plate. Samples were collected, therefore, that seemed most likely to 

3 

represent introduced material such as vein 

quartz and iron minerals in fractures anc. vugs. 

An effort was made to include such mate.rial in 

all samples collected, but chert with iron oxidestained fractures constitutes the bulk of the 

samples. Where more than one sample was 

collected at the same locality the highest value 

was used to construct the geochemical maps. 

ANALYTICAL PROCEDURE 

Gold, silver, and tellurium were dete~mined 

by a wet chemical method using atomic absorption. Mercury was determined instrumentally 

by an atomic-absorption technique (Vaughn 

and McCarthy, 1964). Arsenic, antimory, and 

zinc were determined by wet chemical methods 

(Ward and others, 1963). The remairder of 

the elements were determined by a semi()uantitative spectrographic method (Wari and 

others, 1963). 

DISTRlBI.:TION OF METALS IN THE PALEOZOIC ROCKS 

Several metals occur in unusually high concentrations along the outcrop belt of Paleozoic 

rocks. The most extensive anomalies are of zinc, 

arsenic, mercury, and silver (figs. 3-6). Lead, 

copper, and gold (figs. 7-9) are pre:;oent in 

highly anomalous concentrations but the 

anomalies are less extensive. Isolated an')malies 

of tungsten (fig. 10), antimony, moly~denum, 

and tellurium are also present. The principal 

concentrations of all the metals are with iron 

oxide on fracture planes and with vein quartz. 

The n1ost consistent anomaly for all the metals 

is, expectably, near the Snowstorm mira. (figs. 

3-10). 

The following comparison of the average 

crustal abundance of 11 metals with their concentration in the Sheep Creek Range illustrates 

the magnitude of these anomalies: 

A l'l'l'n!lc '''"''·eutratitul 

ill the l'fl !'lit's t'/'1181 

(Jijl/11) 

Zn ---------------- 180 

Cu 170 

Ph ---------------- 116 

As ---------------- 15 

Mo ---------------- 12.3 

w ---------------- 11.0 

Sb 11.0 

Hg ---------------- :!.06 

Ag ---------------- 1.02 

Au ---------------- 3 .002 

Te ---------------- 1 .002 

1 From Goldschmidt (1958 ). ~ From (C}reen ( 19:i9). 

3 From Del'}razia anrl Ha~kin ( 1964). 

Rau11e uj t'OIIt't'ufrntiol! 

in lilt' ,.;,'hi'CJI Creek Rauge 

(J'Jiill) 

<25 - 800 

<10 - 15,000 

<10 ->20,000 

<10 - 1,500 

<5 200 

<50 - 1,000 

1 >100 

<.1 - 30 

<.2 - 260 

<.02- 1.3 

<.1 - 17 
T. 

34 

N. 

T. 

33 

N 

T. 

33 

N. 

T. 

32 

N. 

R.45E. R.46E. 

ZINC 

(parts per million) 

23 24 19 <25 

0 

25-99 

0 100-199 

25 30 ~ 

200-399 

400-800 • 

F Float sample 

36 31 

Paleozoic 

~ formations 

6 5 4 

12 7 8 9 

15 13 18 17 16 

22 19 20 21 

27 26 30 29 28 

34 35 32 33 

3 2 

5 4 

0 2 MILES 0 

FIGURE 3.-Zinc distribution, highest concentration at each locality. 

4 
R.45E. R.46E. 

ARSENIC 

(parts per million) 

23 24 19 <io 

0 

10-40 

0 .50-00 

25 30 ~ 

lOO-lOLJ 

200 or • greater 

Value given 

T. 

F Float sample 

34 36 31 

N. 

Paleozoic formations 

T. 

33 6 5 4 N. 

8 9 

17 16 

20 21 

29 28 

32 33 

5 4 

0 2 MILES 0 

FIGURE 4.-Arsenic distribution, highest concentration at each locality. 

5 
R. 45 E. R. 46 E. 

~ MERCURY 

(parts per million) 

23 24 19 ~~:: -~-,~· <O.l 

~- . .2 0 ~. 0.1-0.49 

0 

0,5-0.99 

Q 

25 30 1.0-1. 9Q 

2 or greater • Value given 

Float sample 

34 

T. 34 35 36 31 

Paleozoic 

~ formations 

N. 

T. 

33 

N. 1 6 5 4 

8 9 

17 16 

20 21 

29 28 

T. 34 35 32 33 

33 

N. 

T. 

32 3 2 N. 5 4 

0 2 MILES 0 

FIGURE 5.-Mercury distribution, highest concentration at each locality. 

6 
T. 

34 

N. 

T_ 

33 

N. 

T. 

33 

N. 

T. 

32 

N. 

R. 45 E_ R. 46 E. 

23 24 19 

25 30 

36 31 

6 

12 7 

15 13 18 

22 19 

21 30 

34 35 

3 2 1 

0 2 MILES 0 

SILVER 

(parts per millwnJ 

<<\'2 

0 

IJ.'2-U.LJ 

'ill or greater • Value given if>OO 

F 

Float sample 

PaleuzoiC formations 

5 4 

8 9 

17 16 

20 21 

29 28 

32 33 

5 4 

FIGURE 6.-Silver distribution, highest concentration at each locality. 

7 
R.45E R.46E. 

~l 

~~~ LEAD 

(parts per million) 

s\r~<:9 2-3 24 19 do "2ooo· ·: .:Gl·. a} ... 0 

~' '~ 10-4G 

0 

50-GG 

Q 

25 30 100-4GG 

500 or • greater 

Value given 

F 

Float sample 

T. 

~ 34 36 31 N. 

Paleozmc formations 

T. 

33 6 5 4 N. 

8 9 

17 16 

20 21 

29 28 

32 33 

5 4 

0 2 MILES 

FIGURE 7.-Lead distribution, highest concentration at each locality. 

8 
R 45 E. R.46 E. 

COPPER 

(parts per million) 

23 24 19 <70 

0 

70-149 

0 150-499 

'i) 

25 30 500-999 

27 • 1000 or greater 

Value given 

f 

Float sample 

34 36 

34 

T 31 

Paleozoic 

~ formations 

N. 

T. 

33 

N. 6 5 4 

8 9 

17 16 

20 21 

29 28 

T. 34 35 32 33 

33 

N 

T. 

32 3 2 1 N. 5 4 

0 2 MMS 

FIGURE 8.-Copper distribution, highest concentration at each locality. 

9 
R. 45 E. R. 46 E. 

GOLD 

(parts per million) 

23 24 19" <0.02 

0 

0.02-0.049 

0 

0.05-0.0QQ 

Q 

O.L-0.4Q 

25 30 O.S-1 • Value given if >L 

F 

Float sample 

Paleozoic 

~ formations 

T. 34 36 31 

34 

N. 

T. 

33 

N. 

6 5 4 

8 9 

17 16 

20 21 

29 28 

FIGURE 9.-Gold distribution, highest concentration at each locality. 

10 
R. 45 E. R. 46 E. 

TUNGSTEN 

(parts per million) 

23 24 19 

<SO 

50 or • greater 

Paleozoic ~ formations 

25 30 

T. 34 36 31 32 33 

34 

N. 

T. 

33 

N. 

6 5 4 

8 9 

17 16 

20 21 

29 28 

FIGURE 10.-Tungsten distribution, highest concentration at each locality. 

11 
It is not known whether or not the Paleozoic 

rocks in the Sheep Creek Range originally 

contained a metal content comparable to that 

of the earth's crust, but it appears that most 

of the elements listed have subsequently 

been locally enriched by very large factors. 

The metals were probably introduced into the 

heavily fractured rocks by upward or laterally 

migrating solutions. The anomalies may represent a dispersion halo above or around concealed 

mineral deposits, possibly located along or below 

the thrust plane or associated with a buried 

intrusive mass, or they may constitute the 

whole mineral deposit. Inasmuch as broken and 

crushed rock along the Roberts Mountains 

thrust plane is known to be a favorable host 

for ore deposits elsewhere, the possibility that 

mineral deposits exist along the thrust below 

the anomalies is at least reasonable. The geophysical investigations indicate that the possibility of the existence of an unexposed intrusive mass in the southern part of the area is 

also reasonable. 

A geochemical association of arsenic, mercury, antimony, and tungsten with gold has 

been recognized in many of the ores of northcentral Nevada (Erickson and others, 1966). 

Examples of ore deposits with this kind of 

association are the Getchell, Bootstrap, Carlin, 

and Gold Acres mines and the newly discovered 

gold deposit in the Corte,z area. The, similar 

geochemical association of metals on the west 

side of the Sheep Creek Range may be similarly 

significant. 

GEOPHYSICAL INVESTIGATIONS 

Aeromagnetic surveys of large areas in 

western and north-central Nevada have been 

flown as part of the U.S. Geological Survey's 

program of geologic investigations. Of timely 

interest is an aeromagnetic' map made from a 

1967 survey of the Battle Mountain quadrangle 

(U.S. Geological Survey, 1968) ; part of this 

map is shown in figure 11. A local magnetic 

high near the Rennox railroad siding is superimposed on a northeastward-increasing regional 

magnetic gradient. The prominent, highamplitude magnetic anomaly shown in the 

northeast part of the map is related, in part, 

to basaltic rocks of Tertiary age that form the 

cap rock of the Sheep Creek Range. This 

12 

anomaly is an extension of the linear northweststriking regional magnetic anorr.aly reported 

previously by Mabey (1966). 

The local magnetic anomaly c~ntered near 

Rennox is over alluvium along the western 

front of the Sheep Creek Range. In amplitude 

and shape, the anomaly resembles the magnetic 

anomaly in the Cortez area 40 miles to the 

southeast (Mabey, 1965). 

Subsequent geophysical inve;;-tigations-a 

low-level aeromagnetic survey, a gravity survey, and electrical resistivity soundings-were 

made in and around the Rennox area to provide some insight into the probable source of 

the magnetic anomaly. 

MAGNETIC DATA 

Two prominent magnetic features exist in 

the area of the low-level aeromagnetic survey 

(fig. 12). The feature at the southeast end is 

attributed to exposed basalt; basalt extends 

some distance southward beneath alluvial 

cover. 

The magnetic anomaly near F.ennox, only 

partially surveyed, shows pronounced lineations 

on the north and east sides of the feature; the 

lineation along the east side coinci~es with the 

projection of the inferred fault O"l the photogeologic map. The steepest magnetic gradient 

on the north side of the anomaly indicates a 

source less than a hundred feet below the 

surface. Magnetic material also eY.ists at shallow depths immediately to the south of the 

Snowstorm mine and east of the irferred fault. 

The Rennox anomaly does not fit a simple 

model of a normally magnetized. steep-sided 

body because no low (relative to background) 

is developed on the north and nor~heast sides. 

A model based in part on the gravity and 

electrical data (fig. 13) is a two~dimensional 

tabular body 1,500 feet thick and 3,750 feet 

long, having a minimum depth fron1 the surface 

in the vicinity of the fault of 750 feet and 

inclining to the southwest toward Rennox to 

a maximum depth of 1,500 feet. 

The smaller amplitude anomaly east of the 

fault could not be attributed solely to a thin 

veneer of basalt boulders and fragments on 

the Paleozoic chert-quartzite seouence. The 

magnetic material probably is an intrusive mass 

in the Paleozoic bedrock. 
2 3 4 MILES 

EXPLANATION 

-2000-

Magnetic contours 

Showing total intensity magnetic 

field of the earth in gammas 

relative to arbitrary datum; x, 

location of recorded maximum 

or minimum intensity within a 

closure. Contour interval 10 and 

SO gammas. 

Flight path 

Showing location and spacing of data 

!v--Ja·~ 

:'= 

" APPROXIMATE MEAN 

CiFCLINATION, 1968 

FIGURE H.-Aeromagnetic map of part of the Battle, Mountain quadrangle, Nevada, obtained from a fF~ht elevation of 9,000 feet above sea level. Aeromagnetic survey flown by R. W. Krizman; compilation supervised 

by C. L. Long. 

13 
40° 

44' 

-18"-

APPROXIMATf: MEAN 

DECLINATION, 1968 

EXPLANATION 

--zooMagnetic contours 

Showing total intensity magnetic 

field of the earth in gammas 

relative to arbitrary datum; x, 

location of recorded maximum 

or minimum intenEity within a 

closure. Contour interval 10 and 

50 gammas. 

Flight path 

Showing location and 

spacing of data 

SNOWSTORM MINE rl~ 

0 5000 FEET 

~1 --~~--~~--~f 

FIGURE 12.-Aeromagnetic and generalized geologic map of the Rennox area, Nevada. Aerorr.11gnetics from 

flight elevation of 400 feet above ground. A-A', location and extent of profile discussed in text. Geologic 

symbols explained in figure 2. 

14 
100 

/Observed magnetic field 

• 

-50~------------------------------------------------------------------------~ 

Rennox Inferred fault (fi~. 12) A' 

0 1500 3000 FEET 

FIGURE 13.-Comparison of magnetic data taken from aeromagnetic map along line segment from Rennox to A' 

(fig. 12) with model curve for the two-dimensional body shown. Line of observation is 400 feet abovf~ ground. 

Magnetic susceptibility, 1.5 x 10-3 cgs (centimeter-gram-second system) units; total field, 5.45 X 10-4 gammas; 

inclination, 66°. Strike of model is 37o west of magnetic north. 

GRAVITY DATA 

A two-dimensional model which fits the observed gravity data taken along profile A-A' 

indicates the probable existence of two faults 

that displace the bedrock surface beneath the 

surficial cover (fig. 14). The smaller of the two 

faults is about 750 feet nor~heast of the fault 

inferred on the photogeologic map. Bedrock 

on the northeast side of the smaller fault probably lies less than 100 feet below the surface, 

and bedrock on the downdropped side is about 

750 feet below the surface. The larger fault near 

Rennox is probably a major Basin and Range 

fault with an approximate displacement of 

about 7,000 feet. It may be an extension of the 

fault along the west front of the Shoshone 

Range south of the Argenta Siding reported 

15 

by Mabey (1964) and corroborated by Erwin 

(1967). 

RESISTIVITY DATA 

The interpretation of six Schlumbe1·ger resistivity soundings made between Rennox and 

the Snowstorm mine supports some part:s of the 

gravity and magnetic models presented. Soundings 1 and 2 (fig. 15) indicate that a lowresistivity section (perhaps water-sr..turated 

alluvium) extends to a depth of at least 800 

feet. 

Soundings 3 through 6 indicate that the pediment cover is only 15 to 35 feet thick on the 

northeast side of the fault. A second zone, about 

500 feet thick, has a resistivity of about 50 

ohm-meters at sounding 3, which gradually 

increases to about 140 ohm-meters at sounding 

6. The values in this zone would normally be 
0 

~ -10 Bouguer 

H 

:J 

~ -20 

A Rennox Inferred fault (fig. 12) A' 

Or-------------~--------~-------------L~========------~~--1 

~ 1.5 ~ 

0 

(/) 

~ 3.0 

(/) 

::::> ~(7' = -0.4-5 gm/cm3 0 

R .5 

i:=i 

.. 

~ 6.0 

~ 7.5 

0 1500 3000 4500 FEET 

I I I I 

FIGURE 14.-Comparison of the simple Bouguer gravity values projected along A-A' (fig. 12) with model curve 

for the two-dimensional structure shown. Density contrast between the two bodies is -0.45 gmjcm~ (gram 

per cubic centimenter). 

too low for competent chert and quartzite, 

which have rather low intergranular porosity. 

However, because the chert and quartzite in 

the area are highly brecciated and fractured, 

values such as these are not unlikely. 

Perhaps the most significant result of these 

four soundings is an anomalously lower resistivity zone below 500 feet, extending to at 

least 1,000 feet. Resistivity values of about 

20-30 ohm-meters in the bedrock would likely 

require the presence of some clay minerals with 

high ion-exchange capacity. 

CONCLUSIONS 

The source of the magnetic anomaly in the 

vicinity of Rennox was not resolved by the geophysical studies made in the area. Although 

the simple straight-sided gravity and magnetic 

models presented might be suggestive of a 

block of basalt, the physical counterpart might 

16 

be quite different. The thickness of the magnetic mass could be greater and itE shape more 

irregular than shown. The high-level aeromagnetic data suggest the magnetic n1ass extends 

almost a mile southwest of Rennox at a depth 

in excess of 6,000 feet. This configuration would 

suggest an intrusive mass. Further, the broad 

magnetic anomaly with smaller an1plitude east 

of the fault appears to be causei by an intrusive mass. The anomalously low resistivity 

zone below 500 feet could result from clay 

alteration related to an intrusive b'1dy. 

Because most of the anomalous rocks inferred from the geophysical data are at shallow depths, a drilling program would effectively 

resolve the uncertainties. A drill hole near the 

steepest gradient shown on the n'lrth side of 

the magnetic anomaly should inter·cept the igneous rock within 100 feet from the surface. 
Chert outcrop 

Inferred fault (fi~. 12) (Valmy Formatio1) 

Rennox 

0 

~ 5060 140 OHM-METERS 

~ <20<20 <30 <30 

0 

(/) 

~ 1.5 

~ ~ 

.. ~ 3.0 

~ 

0 1500 3000 FEET 

FIGURE 15.-Generalized cross section along line segment from Rennox toward A' (fig. 12) showing loc.ation of 

the resistivity soundings, (1-6), expanded in a N. 20° W. direction, with the resistivity values of the. various 

zones defined by the electrical survey and the diagrammatic shape of the bedrock based on the magnetic and 

gravity models shown in figures 13 and 14. 

Similarly, a hole placed on the northeast side 

of the inferred fault about one-half mile southwest of the Snowstorm mine would determine 

the composition of the bedrock material. The 

juxtaposition of the geophysical and geochemical anomalies in the vicinity of the Snowstorm 

mine further suggests that consideration should 

be given to an exploration program in that area. 

REFERENCES 

DeGrazia, A. R., and Haskin, Larry, 1964, On the gold 

content of rocks: Geochim. et Cosmochim. Acta, v. 

28, no. 5, p. 559-564. 

Erickson, R. L., Van Sickle, G. H., Nakagawa, H. M., 

McCarthy, J. H., Jr., and Leong, K. W., 1966, Gold 

geochemical anomaly in the 'Cortez district, Nevada: 

U.S. Geol. Survey Circ. 534, 9 p. 

Erwin, J. W., 1967, Gravity map of Battle Mountain 

and adjacent areas, Lander, Pershing, and Humboldt Counties, Nevada: Nevada Bur. Mines Map 

31. 

Gilluly, James, and Gates, Olcott, 1965, Tectonic and 

igneous geology of the northern Shoshone Range, 

Nevada, with sections on Gravity in Crescent Valley, by Donald Plouff, amil Economic geology, by 

K. B. Ketner: U.S. Geol. Survey Prof. Paper 465, 

153 p. 

Goldschmidt, V. M., 1958, Geochemistry (ed. by Alex 

Muir]: London, Oxford Univ. Press, 730 p. [reprint of 1954 edition]. 

17 

Green, Jack, 1959, Geochemical table of the elements 

for 1959: Geol. Soc. America Bull., v. 7"', no. 9, 

p. 1127-1184. 

Mabey, D. R., 1964, Gravity map of Eureka Co•mty and 

adjoining areas, Nevada: U.S. Geol. Surrey Geophys. Inv. Map GP-415. 

---1965, Gravity and aeromagnetic surveys, in 

Gilluly, James, and Masursky, Harold, G~ology of 

the Cortez quadrangle, Nevada: U.S. Geol. Survey 

Bull. 1175, p. 105-111. 

---1966, Regional gravity and magnetic snomalies 

in part of Eureka County, Nevada, in Case histories of mining geophysics, volume 1 : Tulsa, 

Okla., Soc. Explor. Geophysicists, p. 77-83. 

Roberts, R. J ., 1964, Stratigraphy and structut"e of the 

Antler Peak quadrangle, Humboldt and Lander 

Counties, Nevada: U.S. Geol. Survey Prof. Paper 

459-A, p. A1-A93 [1965]. 

U.S. Geological Survey, 1968, Aeromagnetic m"~.p of the 

Battle Mountain and Dunphy quadrangles, Lander 

and Eureka Counties, Nevada: U.S. Geol .. Survey 

open-file report. 

Vaughn, W. W., and McCarthy, J~. H., Jr., 1964, An 

instrumental technique for the determination of 

submicrogram concentrations of mercury in soils, 

rocks, and gas, in Geological Survey reseal'ch 1964: 

U.S. Geol. Survey Prof. Paper 501-D., p. 

D123-D127. 

Ward, F. N., Lakin, H. W., Canney, F. C., ar1 others, 

1963, Analytical methods used in geoche'llical exploration by, the U.S. Geological Surv~y: U.S. 

Geol. Survey Bull. 1152, 100 p. 

* U. S. GOVERNMENT PRINTING OFFICE : 196~ 0 - 326-027