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ADDITIONAL DATA ON THE AGE AND EXTENT OF THE ROBERTS MOUNTAIN THRUST FAULT, NORTH-CENTRAL NEVADA

Ralph J. Roberts and Robert E. Lehner U. S. Geological Survey, Menlo Park, Calif. ~51J The Roberts Mountains thrust fault is probably the most important structural element in central CurJ. Sec.

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I GEOLOGICAL SURVEY CIRCULAR 563

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Favorable Areas for Prospecting Adiacent to the Roberts Mountains Thrust in Southern Lander County, Nevada

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Prepared in cooperation with the Nevada Bureau of Mines r Favorable Areas for Prospecting Adiacent to the Roberts Mountains Thrust in Southern Lander County, Nevada

By John H. Stewart and Edwin H. McKee

G E 0 LOG I CAL SUR V Eye IRe U L A R 563

Prepared in cooperation with the Nevada Bureau of Mines

Washington J 968 United States Department of the Interior STEWART L. UDAll, Secretary

Geological Survey William T. Pecora, Director

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

Abstract ------1 Introduction ------I Ravenswood window ------2 Callaghan window ------3 Toiyabe Range south of Austin ------3 Petes Canyon window ------3 Suggestions for prospecting ------_ . ------__ _ 4 References cited ------__ _ 4

ILLUSTRATIONS

Page

Figure 1. Index maps showing pre-Tertiary rocks, mining districts, and sources of information in southern Lander County ------6 2. Geologic map of Ravenswood window ------8 3. Geologic map of Toiyabe Range south of Austin -- 10 4. Geologic map of Petes Canyon window ------12

TABLE Page

Table 1. Mining districts in southern Lander County and closely adjacent parts of Eureka and Nye Counties ------2

III EX PLAN A TION >-

All uvium ]I o

Volcanic rocks Welded tuJf H LOWE R PLATE OF UPPER PLATE O F RO BE RTS MOUNT)\IN ~ T H RUST ROBER TS MOUNTAINS TH RUST

Roberts Mountains Format ion Platy lirnestone; black cheri at base

Hansen Creek(?) Formation Cherty limestone, siltstone

z « u > Antelope Valley Limestone o Vinini Formation o Massive- to medium-bedded a: Dark shale, black chert, o •l'imesto1lC quartzite FAULT """""""" " """"" ~}}}~}}{: Goodwin Limestone T hin-bedded ch.,"ty limesto-ne

Contact Dashed whe..,'e approximately located

Fault Dashed where approximately located. Bar and ball on downthrown sule

..&....-...... l __ ••• •• Thrust faul t Dashed where approximately located; dotted where concealed. Sawteeth on upper plate

Indined Vert1:cal Strike and dip of beds

Figure 4. - Continued.

J 3

U. s. GOVERNMENT P RINTING OFFICE: 1966 0 - 297-174 Favorable Areas for Prospecting

Adjacent to the Roberts Mountains Thrust

In Southern Lander County, Nevada

By John H. Stewart and Edwin H. McKee

Abstract and others, 1966). In addition, both deposits occur mainly in altered or silicified platy limestone of the Recent geologic mapping by the U.S. Geological Survey of more than 2,500 square miles of a relatively little-studied part of central Silurian Roberts Mountains Formation. The ore bodies Nevada has outlined four areas favorable for the discovery of me­ of the Bootstrap and Number E i g h t mines (Roberts, tallic mineral deposits. In these areas, lower Paleozoic carbonate 1966; Erickson and others, 1966) near the Carlin mine rocks crop out below the Roberts Mountains thrust, a widespread are in breccias along the Roberts Mountains thrust it­ fault in central and north-central Nevada. These areas have a self as are the gold deposits at Gold Acres (Gilluly stratigraphic and structural setting similar to that of the areas where large,open-plt gold depos its have been discovered recently and Gates, 1965, p. 134), about 8 miles northwest of at Carlin and Cortez in north- central Nevada. the Cortez deposits.

The Roberts Mountains thrust and the Roberts Moun­ INTRODUCTION tains Formation in the lower plate of this thrust seem, therefore, to be particularly favorable places for me­ The recent discoveries of large open-pit gold de­ tallic ore deposits in north-central Nevada. We de­ posits at Carlin and Cortez in north-central Nevada scribe here four areas within southern LanderCounty (Hardie, 1966; Roberts, 1966; Roberts and 0 the r s, where the Roberts Mountains Formation crops out be­ 1967; Erickson and others, 1966; Wells and others, low the thrust. Granitic plutons that might have been 1967) have created interest in prospecting for similar a source for mineralizing solutions crop out in two of de p 0 sit s in nearby areas. During the last 2 years, these areas and are within a few miles of the two re­ mapping by the U.S. Geological Survey of more than maining areas. 2,500 square miles of a largely unstudied part of north­ central Nevada directly south and southwest of Cortez Maps of three of these areas are given in this re­ has outlined areas with a stratigraphic and structural port; a map of the fourth has already been published setting similar to that of the areas con t a i n i n g the (Stewart and Palmer, 1967). Detailed geologic maps of Carlin and Cortez deposits. These favorable geologic most of southern Lander County at a scale of 1:62,500 factors indicate that further prospecting is warranted are also available on open file at the U.S. Geological in these areas. Survey at Washington, D. C., Denver, Colo., Salt Lake City, Utah, and San Francisco, Los Angeles, and Menlo Most of the metallic deposits in sou the r n Lander Park, Calif., and material from which copy can be made County (table 1) and in north-central Nevada occur in at private expense is available at the Nevada Bureau pre-Tertiary sedimentary rocks. Many of these de­ of Mines, Reno, Nev. An index to these open-file maps posits are in carbonate strata exposed in windows in is shown in figure 1. the Roberts Mountains thrust, a widespread fault along The work on which this report is based is part of the which siliceous and vol can i c (western) assemblage county mapping program of the U.S. Geological Survey rocks have been thrust eastward, perhaps as much as in cooperation with the Nevada Bureau of Mines. We 100 miles, over carbonate (eastern) or transitional wish to thank R. H. Washburn of Juniata College, Hunt­ assemblage rocks (Roberts and others, 1958; Gilluly ingdon, Pa.; D. B. MacLachlan, Bureau of Topographic and Gates, 1965; Roberts, 1960, 1966). The new gold and Geological Survey, Harrisburg, Pa.; and l-I. F. o 2 MILES discoveries at Carlin and Cortez are both in s uch win­ Bonham, Nevada Bureau of Mines, Reno, Nev., for use dows and lie below the thrust (Hardie, 1966; Erickson of their unpublished information. Figure 4.-Geologic map of Petes Canyon window in northern Toquima Range.

12 Table l.--Mining districts in southern Lander County and closel y adjacent parts of Eureka and Nye Counties EXPLANATION

l Distri ct Metal s Recorded Type of deposit Princi pal references Alluvium production2 (dollars) I>" TV '>J < ., Volcanic rocks Welded tu,[f and lava ./lows; some sedimentary rocks Big Creek Sb Unkn own, Veins in Valmy Formation (Ordovician) Hill (1915, p . 121-123)and but small and Roberts Mountains Formation Lawrence (1963, p . 100-108). (Silurian). Quartz in fault brec­ cia along Roberts thrust . Felsite Birch Creek Au, Ag, Unknown, Veins in quartz monzonite and flank­ Hill (1915, p. 125-127), (Smoky Valley, Pb, (W), but small ing metasedimentary rocks. Placer Lincoln (1923, p . 109- Big Smoky) (Be) , (As) , gold. 110), Vandenburg (1939, (Mo) p . 36), and Hall (1962). Granitic rocks Cortez Ag, Au, 37,799,872 Replacement deposits and fissure Gilluly and Masursky (1965, Cu, Pb, veins in Hamburg Dolomite (Cam­ p . 97-104) , Erickson and MJDDLE PLATE BETWEEN Zn brian). Large l ow -grade deposit others (1966), and Roberts, LOWER PLATE BELOW KINGSTON CANYON AND UPPER PLATE ABOVE in Roberts Mountains Formation Montgomery, and Lehner KINGSTON CANYON THRUST (Silurian ) . ROBERTS MOUNTAINS THRUSTS ROBERTS MOUNTAINS THRUST 4 (1967, p . 69 -74). Gold Basin Au, Ag 419,656 Veins in Tertiary volcanic rocks. Li ncoln (1923, p . Ill). Jackson Au, Ag 47,116 Veins in meta- andesite of Pablo Kral (1951, p . 76-80 ) . (Gold Park) Formation (Permian) . UndifferentiatedR Devonian rocks Kingston Au, Ag 420 ,749 Veins i n l ower Paleozoic rocks. Hill (1915, p. 128-129) and Thin~bedded limestone in lower part; (Sante Fe, massive cliff-forming limestone in Vandenburg (1939, p. 57- 58). upper part. May include some Bunker Hill, Silurian rocks in basal part Victorine, Summit ) New Pass Au, Mn 4247,600 Gold-bearing quartz veins i n upper Lincoln (1923, p . 114), Paleozoic and Triassic rocks. Vandenburg (1939, p . 65 -67 ), Roberts Mo.untailns Formation Roberts Mountains Formation Syngenetic manganese deposits in and Trengove (1959). Platy limestone. Same us Muske! Platy limestone. Twenty-foot chert upper Paleozoic rocks. Formation mapped by Washburn layer at base in some areas. Same Ravenswood Ag, Cu , Unknown, Veins in l ower Paleozoic rocks. Hill (1916, p. 106-113). (I966a, /966b) as Masket Formation mapped by Washburn (1966a, /966b) and (Shoshone) Pb, Au, but small Lowell (1958) Reese River Ag, Au, 418,567,250 Fissure veins in Mesozoic quartz Ross (1953), Lawrence (1963, (Austin, Pb , Cu, monzonite of Austin pluton . Rel­ p. 109-112), and Davidson z Amador, (Sb), (As ) , atively small ore deposits in (1960) . g «: Yankee Blade) (Mo ), (Se) quartzite of Valmy(? ) Formation Antelope Valley Limestone u > (Ordovician) on north f l ank of Massive cliff-formino limestone o o pluton . cr: Skookum Ag, Au Unknown, Veins in Valmy Formation Hill (1915, p . 92-95) . Pogonip Group Valmy(?I) Formation o 4but s~all (Ordovician) . Massive cliff-forming Antelope Black chert and minor amounts of Washington Ag, Pb, 17,558 Veins in lower Paleozoic rocks . Hill (1915 , p. 123-125 ) and Valley Limestone• at top. Under­ dark-oray shale and quartzite (W) lain by shale and limestone pos­ Kral (1951, p. 207- 211). sibly equivalent to Nine mile Wild Horse Hg 5135,458 Silicified Triassic limestone. Dane and Ross (1942) and Formation. Thin-bedded limesUme Bailey and Phoenix (1944, in basal part possibly equivalent to p. 111-113). Goodwin Limestone

lListed in order of importance. Metals in parentheses OcCUr in minor amounts . 2Records of production are incomplete and actual production from some small districts is probably much Broad Canyon sequence of Crane Canyon sequence of z higher than recorded figures . Means (1962) Means (1962) «: cr: 3After Roberts , Montgomery, and Lehner (1967) and Couch and Carpenter (1943). Black phyllite and black argillaceous Laminated to •very thin -bedded lioht­ m 4After Couch and Carpenter (1943), Vandenburg (1939), and "Minerals Yearbooi<:" of U.S . Bureau of Mines limesUme. Unj"ossiliferous gray limestone. Some black shale ::;: and chert. Conlains Upper Cam­ «: u (1933-1955) . brian tribolites 5 miles south of 5After Dane and Ross (1942) . Austin

RA VENSWOOD WINDOW ern part of the window. The strata of the lower plate Gold Hill Formatioll have been intruded by porphyritic quartz monzonite The Ravenswood window (fig. 2) is in'the Shoshone Quur&zi te and minOT amounts 0/ Quartzite and minor amounts of silt­ that crops out over an area of about 2 square miles in siltstone. Cliff-formino limestone stone. Cliff-forming limestone at Range about 15 miles northwest of Austin. In this win­ at top top. Contains Early Cambrian the central part of the window. T e rtiary welded tuffs dow Cambrian, Ordovician, and Silurian qua r t zit e, archeocyathida near top (Wash­ cap much of the higher part of the area, and Tertiary burn, IY66a, /Y66b) limestone, and shale are exposed in the lower plate of and Quaternary sedimentary strata and older alluvium th e Roberts Mountains thrust, and, nearby, Ordovician occur both on the west and northeast parts of the range. --1-____ _ and Silurian chert, shale , sandstone, and quartzite are ---"--"-- .....L. __ _ Contact- Fault Thrust fau lt exposed in the upper plate. The Roberts Mountains The old Ravenswood mining district, which has pro­ Dashed where approximately located Dashed where approximately located; Dashed where approxim.ately located; Formation crops out in two small areas in the north­ duced only a small amount of ore, is in the northern dotted where concealed. Bar and dotted where concealed. Sawteeth ern part of the window and in a fairly large area di­ part of the window. The deposits (Hill, 1916, p. 106- ball on downthrown side on upper plate rectly below the Roberts Mountains thrust in the south- 113) consist of small lenslike quartz veins that are Figure 3. - Continued.

2 11 predominantly in shale, quartzite, and limestone of The Silurian Roberts Mountains Formation is rec­ Early Cambrian age. Many prospect pits in the district ognized in both the lower and mid dIe plates in the show abundant secondary copper minerals. The depos­ Toiyabe Range. The most extensive outcrops are: (1) its, according to Hill (1916, p. 109), contain chalco­ about 8 miles south of Austin on the west side of the pyrite, galena, and tetrahedrite, all of which are said range, (2) in a 5-mile-longnorthwest-trending belt ex­ to carry silver and a little gold. Some prospects are tending from Kingston Canyon on the southeast to the in the southern part of the window, a few of them along west side of the range on the northwest, and (3) about the thrust where the Ordovician Valmy Formation is 1 to 2 miles south of the mouth of Kingston Canyon on thrust over the Silurian Roberts Mountains Formation. the east side of the range.

Five mining districts are 10 cat e d in the Toiyabe CALLAGHAN WINDOW Range from Austin on the north to the vicinity of the The Callaghan window is in the Toiyabe Range about Lander-Nye County line on the south. The largest of 15 miles north of Austin. Its geology has been described these is the Reese River silver district at Austin, which in detail previously (Stewart and Palmer, 1967) and is has a recorded production of over $18 million. In the only briefly considered here. Lower plate strata are Birch Creek district along the east side of the range exposed in an area of about 40 square miles and con­ about 9 miles southeast of Austin, deposits of gold, sist of over 10,000 feet of quartzite, limestone, and silver, and lead occur in granitic rocks along the south­ Cdrs?J shale of Cambrian, Ordovician, and Silurian age. The ern margin of the Austin pluton and in flanking meta­ Upper plate Roberts Mountains Formation crops out in the southern morphosed lower Paleozoic strata. Beryllium, tung­ and northwestern parts of the window. Strata above the sten, arsenic, and molybdenum are also known from this district (table 1). The Big Creek district is in the Middle plate thrust consist of chert and quartzite of Ordovician and Devonian age. The strata in the window are unmeta­ western half of the range from 7 to 12 miles southwest ~ morphosed and no granitic rocks crop out in the win­ of Austin. Here antimony deposits occur in the dark Lower plate dow. The quartz monzonite of the Austin pluton lies 3 shale and chert above the Roberts Mountains thrust, miles south of the southern limit of the window, and in the carbonate strata below the thrust, andin a silic­ granitic rocks also crop out in a small area about 3 ified fault breccia along the thrust. In the Kingston miles north of the northern limit of the window and in district in the eastern part of the range about 20 miles a small area about 7 miles east of the eastern limit of south of Austin, gold and silver have been produced the window. Except for a quicksilver prospect (Bailey from veins in lower Paleozoic rocks. The Washington and Phoenix, 1944, p. 113), no metallic mineral deposits district, which is mostly in Nye County, has produced have been reported. silver and lead ores from veins cutting lower Paleozoic rocks. Some of these deposits occur close to the Aiken Creek and Vindicator plutons (fig. 3). In addition, ura­ TOry ABE RANGE SOUTH OF AUSTIN nium has been mined from deposits in both intrusive rocks and metamorphosed Lower Cambrian sedimen­ Lower plate strata ranging in age from Cambrian to tary rocks along the southern edgeofthe Austin pluton Devonian are extensively exposed in the Toiyabe Range on the west side of the range 3 miles south of Austin south of Austin (fig. 3). These s t rat a have been in­ (DaViS, 1954; Sharp and Hetland, 1954; Thurlow, 1956; 39°15' truded by several plutons, the largest of which contains Nye, 1958). the rich silver veins of the R e e s e River district at / Austin. Three thrust plates are recognized in the Toiyabe PETES CANYON WINDOW Range south of Austin. The lower and middle plates are separated by the Kingston Canyon thrust, a fault at The Petes Canyon window in the Roberts Mountains present recognized only in this part of the Toiyabe thrust is in the Toquima Range about 20 miles south­ Range; the middle and upper plates are separated by the east of Austin (fig. 4). This window covers about 20 1. Modified from Means (1962). Roberts Mountains thrust, which is of regional extent. square miles and exposes Ordovician and Silurian 2. Geologic mapping by J. H. Stewart and E. H. McKee in 1967. The strata in the lower two plates lithologically re­ carbonate strata; the Roberts Mountains Formation is 3. Geologic mapping by D. B. Mac­ semble each other more than they resemble the strata the most widely exposed formation in the lower plate Lachlan (written commun., 1967) of the upper plate, but they are not entirely the same. and occurs directly below the thrust. Upper plate strata and by J. H. Stewart, 1967. The most conspiCUOUS difference is in strata of Middle consist of shale, quartzite, and c her t of the Vinini 4. Modified from Washburn (1966a). 5. Modified from Hansen (1961) . Cambrian to Early Ordovician age, which are mostly Formation. No granitiC intrusive rocks occur in the 6. Modified from Lowell (1958). black phyllite and argillaceous limestone in the lower window, but g ran it i c rocks crop out about 5 miles 7. Modified from Nye (1958). plate and mostly light-gray limestone in the middle southwest of the southern part of the window, and a 8. Modified from Ross (1953). plate. The juxtaposition of these unlike facies suggests small outcrop of granitiC rock is about 4 miles north­ Geology compiled by J . H. Stewart and E. H. McKee, 1967-68. that considerable lateral transport has occurred along west of the northwestern part ofthewindow. No metal­ 2 o 2 4 MILES lic mineral deposits have been reported from the win­ I I I I the Kingston Canyon thrust. Strata above the Roberts Mountains thrust in the Toiyabe Range consist of west - dow, although tungsten has been mined in tactite ad­ Figure 3.-Geologic map of the Toiyabe Range south of Austin. ern assemblage black chert, shale, and quartzite as­ jacent to the previously mentioned small exposure of signed to the Valmy Formation of Ordovician age. granitiC rock northwest of the window.

10 3 SUGGESTIONS FOR PROSPECTING of the granitic pluton in the Ravenswood window north­ EXPLANATION west of Austin (fig. 2), where carbonate rocks could Since the discovery of !he rich silver veins at Austin occur adjacent to granitic rocks under a presumably in 1862, southern Lander County has attracted the at­ thin cover of Tertiary and Quaternary sedimentary Alluvium tention of prospectors. The numerous mines and pros­ rocks. pects in the region attest to the thorough search for surface outcrops of readily recognizable mineral­ fU Qi~.~1 REFERENCES CITED bearing veins and lodes. The possibility of finding a Quaternary and Tertiary sedimentary roeks and Quaternary older alluvium large mineral deposit by using the same methods as Bailey, E. H., and Phoenix, D. A., 1944, QuickSilver previous prospectors seems remote, and the search deposits in Nevada: Nevada Univ. Bull., v. 38, no. 5, for metals in the region should be focused on new pros­ Geology and Mining ser. 41, 206 p. I ~~ ~~ ;(j pecting techniques and deep exploration by drilling. Couch, B. F., and Carpenter, J. A., 1943, Nevada's Volcanic rocks Rhyolitic welded tuff metal and mineraI production (1859-1940, inclu­ and andesite flows Deposi ts of fine-grained gold s i mila r to tho s e sive): Nevada Univ. Bull., v. 37, no. 4, Geology and recently found at Carlin and Cortez, however, mayhave Mining ser. 38, 159 p. gone undetected in southern Lander County, in spite Dane, C. H., and Ross, C. P., 1942, Wild Horse quick­ EI Granitic rocks }~ of extensive earlier prospecting, because exposures silver district, Lander County, Nevada: U.S. Geol. ::> of such deposits show little, if any, metallic minerals Survey Bull. 931-K, p. 259-278. LOWER PLATE OF UPPER PLATE OF detectable to the naked eye and the gold is not easily Davidson, D. F., 1960, Selenium in some epithermal ROBERTS MOUNTAINS THRU ST ROBERTS MOUNTA INS THRUST recognizable using ordinary prospecting methods. Ex­ deposits of antimony, mercury, and silver and gold: ploration for obscure deposits of this type requires U.S. GeoI. Survey Bull. 1112-A, p. 1-16. extensive sampling and abundant chemical data. The Davis, H. C. , 1954, Summary report of reconnaissance Roberts Mountains Formation Elder Sanastone development of rapid and inexpensive methods for de­ and exploration for uranium deposits in northern Platy limestone; as mapped locally includes limestone Sandstone, shale, and termining trace amounts of gold, silver, and mercury Nevada: U.S. Atomic Energy Comm. Rept. RME- and shale qf latest OrdO'Vician age minor chert (Lakin and Nakagawa, 1965; Huffman and others, 1967; 2013 (pt. 1, revised), 23p. FAULT Ward and others, 1963; Vaughn, 1967) has provided the Erickson, R. L., Van Sickle, G. H. Nakagawa, H. M. tools for conducting this type of prospecting econom­ McCarthy, J. H., Jr., and Leong, K. W., 1966, Gold Antelope Valley Limestone ically. g eo c hem i cal anomaly in the Co rt e z district, Massive limestone z Nevada: U.S. Geol. Survey Circ. 534, 9 p. « As outlined here, several areas in southern Lander Ferguson, H. G., Muller, S. W., and Roberts, R. J., ~ > County have a structural and stratigraphic set tin g 1951, Geology of the Mount Moses qua d ran g Ie, o Ninemile Formation o similar to the areas where gold has been f 0 u n d at Nevada: U. S. GeoI. Survey Geo!. Quad. Map GQ- J 2, Valmy Formation Shale, minor lim.estone o Carlin and Cortez; that is, carbonate rocks, including scale 1:125,000. Chert, quartzite, '" the Roberts Mountains Formation, are exposed below Gilluly, James, and Gates, Olcott, 1965, Tectonic and and shale the Roberts Mountains thrust. The areas considered igneous geology of the northern Shoshone Range, favorable for prospecting in southern Lander County Nevada, with sections on Gravity in Crescent Valley, Goodwin(?) Limestone Thin·bedded limestone include the Ravenswood window in the Shoshone Range by Donald Plouff, and Economic geology, ~ K. B. northwest of Austin, the C a II a g han window in the Ketner: U.S. GeoI. Survey Prof. Paper 465, 153 p. Toiyabe Range north of Austin, the Petes Canyon win­ Gilluly, James, and Masursky, Harold, 1965, Geology of ti~~~~~~ dow in the Toquima Range southeast of Austin, and the Cortez quadrangle, Nevada, with a section on Shale and limestone extensive exposures of lower plate rocks in the Toiyabe Gravity and aeromagnetic surveys by D. R. Mabey: Range south of Austin. U.S. GeoI. Survey Bull. 1175, 117 p-:- Hall, Robert, 1962, Sampling of Lynch Creek beryl­ Ledge·forming limestone Prospecting in the region could also be undertaken lium-tungsten prospect, Lander County, Nevada: by drilling. The most likely possibili ty of finding hidden U.S. Bur. Mines Rept. Inv. 6118, 10 p. deposits seems to be by drilling through upper plate Hansen, H. J., 3d, 1960, Geology of the Big Creek area, Quartzite, minor shale, siliceous and volcanic rocks that contain ore deposits Toiyabe Range, Lander County, Nevada: New York, and rare limestone into lower plate carbonate rocks that are more favor­ Columbia Univ., M.A. thesis. able hosts for ore deposits; small deposits in upper Hardie, B. S., J 966, Carlin gold mine, Lynn district, • Contact plate rocks could indicate larger deposits at depth. Nevada: Nevada Bur. Mines Rept. 13, pt. A, p. 73- Dashed where approximately located Within the region, deposits occur in upper plate rocks 83. ~--..... in the Skookum district, 7 miles northwest of Austin, Hill, J. M., 1915, Some mining districts in northeast­ Fault Dashed where approximately located; dotted where concealed. and along the north side of the Austin pluton, 4 miles ern California and northwestern Nevada: U. S. Geol. Bar and ball on downthrown side north of Austin within the Reese River district; in the Survey Bull. 594, 200 p. I , 1 I 1 latter area, however, some supposed upper plate rocks ___-;1916, Notes on some mining districts in east­ Fault scarp may instead by assignable to the Cambrian Gold Hill ern Nevada: U.S. GeoI. Survey Bull. 648, 214 p. Hachures on down thrown side Formation in the lower plate. These areas seem favor­ Huffman, Claude, Jr., MenSik, J. D., and Riley, L. B., able for deposits at depth, but no information is avail­ 1967, Determination of gold in geologic materials Thrust fault Dashed where approximately located able about the depth to the lower plate carbonate rocks. by solvent extraction and atomic-absorption spec­ Sawteeth on upper plate A further possibility for drilling is along the west flank trometry: U.S. Geol. Survey Circ. 544, 6 p. ~O Strike and dip of beds

Figure 2.-Continued.

4 9 Kay, Marshall, and Crawford, J. P., 1964, Paleozoic Sharp, B. J., and Hetland, D. L., 1954, Preliminary facies from the miogeosynclinal to the eugeosyn­ report on uranium occurrence in the Austin area, clinal belts in thrust slices, central Nevada: Geo!. Lander County, Nevada: U.S. Atomic EnergyComm. Soc. America BulL, v. 75, no. 5, p. 425-454. RME-2010, 16 p. Kral, V. E., 1951, Mineral resources of Nye County, Stewart, J. H., and McKee, E. H., 1968, Geologic map Nevada: N e v a d a Bur. Mines Bull., v. 45, no. 3, of the Mount Callaghan quadrangle, Lander County, Geology and Mining ser. 50, 223 p . Nevada: U. S. GeoI. Survey GeoI. Quad. Map GQ-7 30 Lakin, H. W., and Nakagawa, H. M., 1965, A spectro­ (in press). photometric method for the determination of traces _-,,-_1968a, Geologic map of southeastern part of of gold in geologic materials, in Geological Survey Lander County, Nevada: U.S. GeoI. Survey open­ res ear c h 1965: U.S. Geo!. Survey Prof. Paper file map. 525-C, p. C168-C171. _~_1968b, Geologic map of west-central part of Lander County, Nevada: U.S. GeoI. Survey open­ 39·45' ..... Lawrence, E. F., 1963, Antimony deposits of Nevada: Nevada Bur. Mines Bull. 61, 248 p. file map. Lincoln, F. C., 1923, Mining districts and mineral re­ Stewart, J. H., and Palmer, A. R., 1967, Callaghan sources of Nevada: Reno, Nevada Newsletter Pub­ window-a newly discovered part of the Roberts lishing Co., 295 p. thrust, Toiyabe Range, Lander County, Nevada, in Lowell, J. D., 1958, Lower and Middle Ordovician Geological Survey research 1967: U.S. GeoI. Survey stratigraphy in eastern and central Nevada: New Prof. Paper 575-0, p. 056-063. York, Columbia Univ., Ph. D. thesis. Thurlow, E. E., 1956, Uranium deposits at the contact McKee, E. H., 1968a, Geologic map of Ackerman Can­ of metamorphosed sedimentary rocks and granitiC yon quadrangle, Nevada: U.S. GeoI. Survey open­ intrusive rocks in western United States, in Page, file map. L. R_. and others, Contributions to the geology of 1968b, Geologic map of southwestern part of uranium and thorium by the United States Geological --"7--. Lander County, Nevada: U.S. Geol. Survey open- Survey and Atomic Energy Commission for the file map. United Nations International Conference on Peace­ Means, W. D., 1962, Structure and stratigraphy in the ful Uses of Atomic Energy, Geneva, SWitzerland, central Toiyabe Range, Nevada: California Univ. 1955: U.S. GeoI. Survey Prof. Paper 300, p. 85-89. Pubs. GeoI. Sci. , v. 42, no. 2, p. 71-110. Trengove. R. R., 1959, Reconnaissance of Nevada Muller, S. W., Ferguson, H. G., and Roberts, R. J., manganese deposits: U.S. Bur. Mines Rept. Inv. 1951, Geology of the Mount Tobin quadrangle: 5446, 40 p. U. S. GeoI. Survey GeoI. Quad. Map GQ-7, scale Vandenburg, W.O., 1939, Reconnaissance of mining 1:125,000. districts in Lander County, Nevada: U. S. Bur. Mines Nye, T. S., 1958, Geology of the Apex uranium mine, Inf. Circ. 7043, 83 p. Lander County, Nevada: Berkeley, CaliforniaUniv., Vaughn, W. W., 1967,Asimplemercuryvapordetector M.S. thesiS, map scale 1:9,600. for geochem ical pro s p e c tin g: U.S. Geol. Survey

/I Roberts, R. J., 1960, Alinement of mining districts in Circ. 540, 8 p. II" 1/ north-central Nevada, in Short papers in the geolog­ Ward, F. N., Lakin, H. W., Canney, F. C., and others, 1/ 1/ ical sciences: U.S. GeoLSurveyProf. Paper400-B, 1963, Analytical methods used in geochemical ex­ 1/ p. B17-B19. ploration by the U.S. Geological Survey: U.S. Geol. \I II _--,-----,..,1 966, Metallogenic provinces and mineral belts Survey Bull. 1152, 100 p. in N e v a d a: Nevada Bur. Mines Rept. 13, pt. A, Washburn, R. H., 1966a. Paleozoic stratigraphy in ""\I \I p. 47-72. Toiyabe Range, southern Lander County, Nevada II II Ro b erts, R. J., Hotz, P. E., Gilluly, James, and [abs.]: Geol. Soc. America, Rocky Mountain Sec., " Ferguson, H. G., 1958, Paleozoic rocks of north­ 19th Ann. Mtg., Las Vegas, Nev., 1966, Program, "" central Nevada: Am. Assoc. Petroleum Geologists p. 57. MOUNTAINS " ,. Bull., v. 42, no. 12, p. 2813-2857. _--,,--_1966b, Structure and Paleozoic stratigraphy of 111111~ ROBERTS Qa "" THRUST II r the Toiyabe Range, sou the r n Lander County, 1\ Roberts, R. J., Montgomery, K. M., and Lehner, R. E., 1/ 1967, Geology and mineral resources of Eureka Nevada: New York, Columbia Univ., Ph.D. thesis. 1 \I II County, Nevada: Nevada Bur. Mines Bull. 64, 152 p. Wells, J. D., Erickson, Ralph, andStoiser, L. R., 1967, \\ ~ Ross, C. P ., 1953, The geology and ore deposits of the Geology and mineralogy of the Cortez gold depOSit, Reese River district, Lander County, Nevada: U.S. Nevada [absJ: Mining Eng., v. 19, no. 12, p. 40. GeoI. Survey Bull. 997, 132 p.

I , "l... "~'A Geology by J. H. Stewart and E. H. McKee, 1967

o 2 MILES L-_~_-LI ______~~ ______"

Figure 2.-Geologic map of the Ravenswood window, Shoshone Ra nge,

297-1 71 0 - 68 - 2 8 5 EXPLANATION 117' (1:;'1 f: f::f / 1' ::{ K0} Jurassic granitic rocks J

Triassic rocks .I , 111»

SOURCES OF INFORMATION USED IN FIGURES 1-4 AND 1 Pennsylvanian and Permian rocks ) IN U.S. GEOLOGICAL SURVEY OPEN-FILE MAPS OF SOUTHERN LAN DER COUNTY. NEVADA ROCKS ABOV E R OCKS BELOW c-...~ 1. Muller, Ferguson, and 8. Geologic mapping by J . H. 1:1 ~ ROBERTS MOUNTAI NS THRUST ROBERTS MOUNTAINS THRU ST Roberts (1951). Stewart in 1967, based in "" 2. Ferguson, Muller, and part on work by D. B. I Roberts (1951). MacLachlan. " WILD HORSE 3. Gi\luly and Masursky (1965). 9. Modified from Washburn , DISTRICT Cambrian to Devonian siliceous Cambrian to Devonian carbonate 4. Dane and Ross (1942) . (1966b). and volcanic assemblage and transitional assemblage 5. Geologic mapping by J . H. 10. Modified from Hansen '"' • Stewart and E. H. McKee (1960). in 1966 and 1967. 11. Modified from Lowell (1958). \ G 40'" 6. Geologic mapping by E. H. 12. Modified from Nye (1958). Contact McKee in 1967, based in 13. Modified from Ross (1953) . Dashed w here approximat..el.y loclLted part on work by H. F. 14. Mapping by E. H. McKee in LLAGHA~ Bonham. 1967, based in part on work WINDOW .. I ...... 7. Modified from Means (1962) . by Kay and Crawford (1964). ( Roberts Mountains thrust I Saw teeth on upper plate. Elsewhere, contact between siliceous and volcanic I rocks and carbonate and transi tional assemblage rocks is a high anglefault ~ I (not shown on thi s map) PASS t.. I -1:JISTRICT J / )' I 0Jl I ,------; c:/ " : NEVADA J I ( <> I ~ " Area of ~ff(f \ I "" report O-~ I ,,0 Q:"r

I (' 4 5 I I , .., ) _____ J \GOLD BASIN gure 4 C-~ \ DISTRICT I ) I U.S. GEOLOGICAL SURVEY OPEN-FILE MAPS IN SOUTHERN LANDER COUNTY. NEVADA ) I (see references cited for description) ..- 1. Stewart and McKee (1968b). W _-L_ JACKSON 2. Stewart and McKee (1968). ,r DISTRICT __ - --',>jSTRI C1'---1~~~•• IItI: ~ ~ ______3. McKee (1968a). 4. McKee (1968b). 5. Stewart and McKee (1968a). ~ o 10 20 MILES -- I ---- Figure I.-Continued. Figure I.-Pre-Tertiary rocks, mining districts, and sources of Information in southern Lander County.

6 7