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

Home , Toiyabe Range, Window (geology)

GEOLOGICAL SURVEY CIRCULAR 563

Prepared in cooperation with the Nevada Bureau of Mines

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 l 0 G I C A l S U R V E Y C I R C U L A R 563

Prepared in cooperation with the Nevada Bureau of Mines

Washington 1968 United States Department of the Interior STEWART L. UDALL, Secretary

Geological Survey William T. Pecora, Director

First printing 1968

Second printing 1968

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

Abstract------1 Introduction ------1 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

Favorable Areas for Prospecting

Adiacent to the Roberts Mountains Thrust

in Southern Lande.r County, Nevada

By John H. Stewart and Edwin H. McKee

Abstract and others, 1966 ). In addition, both de p o s i t s occur mainly in altered or silicified platy limestone of the Recent geologic mapping by the U.S. Geological Survey of more Silurian Roberts Mountains Formation. The ore bodies than 2,500 square miles of a relatively little-studied part of central Nevada has outlined four areas favorable for the discovery of me of the Bootstrap and Number Eight mines (Roberts, tallic mineral deposits. In these areas, lowerPaleozoiccarbonate 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 Acr~~s (Gilluly stratigraphic and structural setting similar to that of the areas where large,open-pit gold deposits 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 Nevad"' .. We de posits at Carlin and Cortez in nonh-central Nevada scribe here four areas within southern Lanrier County (Hardie, 1966; Roberts, 1966; Roberts and others, where the Roberts Mountains Formation crnps 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 o s i t 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 ofCortez 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 geolorfc maps of Carlin and Cortez deposits. These favorable geologic most of southern Lander County at a scale of I :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 cr'll be made County (table 1) and in north-central Nevada occur in at private expense is available at the Neva<'\a Bureau pre-Tertiary sedimentary rocks. Many of these de of Mines, Reno, Nev. An index totheseopen-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 pan of the which siliceous and v o 1 c ani 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 CoU~ge, Hunt assemblage rocks (Roberts and others, 1958; Gilluly ingdon, Pa.; D. B. MacLachlan, BureauofTooographic and Gates, 1965; Roberts, 1960, 1966 ). The new gold and Geological Survey, Harrisburg, P a.; and H. F. discoveries at Carlin and Cortez are both in such win Bonham, Nevada Bureau of Mines, Reno, N~v., for use dows and lie below the thrust (Hardie, 1966; Erickson of their unpublished information. Table 1.--Mining districts in southern Lander County and closely adjace~t parts of Eureka and Nye Counties

1 District Metals Recorded Type of deposit Principal references production2 (dollars)

Big Creek Sb Unknown, Veins in Valmy Formation (Ordovician) Hill (1915, p. l21-123)and but small and Roberts Mountains Formation Lawrence (1S63, p. 100-108}. (Silurian). Quartz in fault brec cia along Roberts thrust. 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), Vanderburg (1939, (Mo) p. 36), and Hall (1962). Cortez Ag, Au, 37,799,872 Replacement deposits and fissure Gilluly and Mssursky (1965, Cu, Pb, veins in Hamburg Dolomite (cam p. 97-104), Erickson and Zn brian). Large low-grade deposit others (1966}, and Roberts, in Roberts Mountains Formation Montgomery, and Lehner (Silurian). (1967, p. 6)-74). 4 Gold Basin Au, Ag 419,656 Veins in Tertiary volcanic rocks. Lincoln (1923, p. 111). Jackson Au, Ag 47,116 Veins in meta-andesite of Pablo Kral (1951, p. 76-80). (Gold Park) Formation (Permian). 4 Kingston Au, Ag 20,749 Veins in lower Paleozoic rocks. Hill (1915, p. 128-129) and (Sante Fe, Vandenburg (1939, p. 57-58}. Bunker Hill, Victorine, Summit) New Pass Au, Mn 4247,600 Gold-bearing quartz veins in upper Lincoln (1923, p. 114), Paleozoic and Triassic rocks. Vandenburg (1939, p. 65-67), Syngenetic manganese deposits in and Trengove (1959). upper Paleozoic rocks. Ravenswood Ag, Cu, Unknown, Veins in lower Paleozoic rocks. Hill (1916, p. 106-113). (Shoshone) Pb, Au, but small 4 Reese River Ag, Au, 18,567,250 Fissure veins in Mesozoic quartz Ross (1953), Lawrence (1963, (Austin, Pb, Cu, monzonite of Austin pluton. Rel p. 109-112), and Davidson Amsd::>r, (Sb), (As), atively small ore deposits in (1960). Yankee Blade) (Mo), (Se} quartzite of Valmy(?) Formation ~ (Ordovician) on north flank of pluton. Skookum Ag, Au Unknown, Veins in Valmy Formation Hill (1915, p. 92-95). but small 4 (Ordovician). Washington Ag, Pb, 17,558 Veins in lower Paleozoic rocks. Hill (1915, p. 123-125) and (w) Kral (1951, p. 207-211). Wild Horse Hg 5135,458 Silicified Triassic limestone. Dane and Ross (1942) and Bailey and Phoenix (1944, p. 111-113).

1Listed in order of importance. Metals in parentheses occur in minor amounts. 2Records of production are incomplete and actual production from some small districts is prob~bly much higher than recorded figures. 'After Roberts, Montgomery, and Lehner (1967} and Couch and Carpenter (1943). After Couch and Carpenter (1943), Vandenburg (1939), and "Minerals Yearbooil:" of U.S. Bureau of Mines (1933-1955). 5After Dane and Ross (1942).

RAVENSWOOD WINDOW ern part of the window. The strata of tl',~ lower plate have been intruded by porphyritic quartz monzonite The Ravenswood window (fig. 2) is in the Shoshone that crops out over an area of about 2 square miles in Range about 15 miles northwest of Austin. In this win the central part of the window. Tertiar_,, welded tuffs dow Cambrian, Ordovician, and Silurian q u art zit e, cap much of the higher part of the area, and Tertiary limestone, and shale are exposed in the lowerplate of and Quaternary sedimentary strata and older alluvium the Roberts Mountains thrust, and, nearby, Ordovician occur both on the west and northeast partf' of the range. and Silurian chert, shale, sandstone, and quartzite are exposed in the upper plate. The Roberts Mountains The old Ravenswood mining district, ''rhich has pro Formation crops out in two small areas in the north duced only a small amount of ore, is in the northern ern part of the window and in a fairly large area di part of the window. The deposits (Hill, 1916, p. 106- rectly below the Roberts Mountains thrust in the south- 113) consist of small lenslike quartz ,.~ins that are

2 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 d 1 e 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 soutneast to the in the southern part of the window, a few of them along west side of the range on the northwest, arr:l ( 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 1 ocate 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, depos~ts of gold, sist of over 10,000 feet of quartzite, limestone, and silver, and lead occur in granitic rocks along the south shale of Cambrian, Ordovician, and Silurian age. The ern margin of the Austin pluton and in flanking meta 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 tnown from thrust consist of chert and quartzite of Ordovician and this district (table 1 ). The Big Creek distr~.ct is in the 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 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, anclin 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 abo·1t 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 adiition, ura TOIYABE RANGE SOUTH OF AUSTIN nium has been mined from deposits in both intrusive rocks and metamorphosed Lower Cambria'i' sedimen Lower plate strata ranging in age from Cambrian to tary rocks along the southern edge of the 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 strata have been in (Davis, 1954; Sharp and Hetland, 1954; Thurlow, 1956; truded by several plutons, the largest of which contains Nye, 1958). the rich silver veins of the Reese River district at Austin. Three thrust plates are recognized in the Toiyabe FETES 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 Roberts Mountains thrust, which is of regional extent. square miles and exposes Ordovician a'1d Silurian The strata in the lower two plates lithologically re carbonate strata; the Roberts Mountains Formation is semble each other more than they resemble the strata the most widely exposed formation in the lower plate of the upper plate, but they are not entirely the same. and occurs directly below the thrust. Upper plate strata The most conspicuous difference is in strata of Middle consist of shale, quartzite, and chert of the Vinini Cambrian to Early Ordovician age, which are mostly Formation. No granitic intrusive rocks cccur in the black phyllite and argillaceous limestone in the lower window, but granitic rocks crop out ab')ut 5 miles plate and mostly light-gray limestone in the middle southwest of the southern part of the window, and a plate. The juxtaposition of these unlike facies suggests small outcrop of granitic rock is about 4 miles north that considerable lateral transport has occurred along west of the northwestern part of the window. No metal the Kingston Canyon thrust. Strata above the Roberts lic mineral deposits have been reported fr')m the win Mountains thrust in the Toiyabe Range consist of west dow, although tungsten has been mined in tactite ad 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.

3 SUGGESTIONS FOR PROSPECTING of the granitic pluton in the Ravenswood wirdownorth west of Austin (fig. 2), where carbonate rocks could Since the discovery of t11.e rich silver veins at Austin occur adjacent to granitic rocks under a rresumably in 1862, southern Lander County has attracted the at thin cover of Tertiary and Quaternary sedimentary 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 REFERENCES CITED bearing veins and lodes. The possibility of finding a 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. pecting techniques and deep exploration by drilling. Couch, B. F., and Carpenter, J. A., 1943, Nevada's metal and mineral production ( 1859-1940, inclu Deposits of fine-grained gold s i m il a r to tho s e sive): Nevada Univ. Bull., v. 37, no. 4, Geology and recently found at Carlin and Cortez, however, may have Mining ser. 38, 159 p. gone undetected in southern Lander County, in spite Dane, C. H., and Ross, C. P ., 1942, Wild Horse quick 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-Kr p. 259-278. detectable to the naked eye and the gold is not easily Davidson, D. F., 1960, Selenium in some epithermal recognizable using ordinary prospecting methods. Ex deposits of antimony, mercury, and silv~r and gold: ploration for obscure deposits of this type requires U.S. Geol. Survey Bull. 1 112-A, p. 1-16. extensive sampling and abundant chemical data. The Davis, H. C., 1954, Summaryreportofreccnnaissance development of rapid and inexpensive methods for de and exploration for uranium deposits in northern termining trace amounts of gold, silver, and mercury Nevada: U.S. Atomic Energy Comm. Rept. RME- (Lakin and Nakagawa, 1965; Huffman andothers, 1967; 2013 (pt. 1, revised), 23 p. Ward and others, 1963; Vaughn, 1967) has provided the Erickson, R. L., Van Sickle, G. H. Nakafawa, H. M. tools for conducting this type of prospecting econom McCarthy, J. H., Jr., and Leong, K. W., 1966, Gold ically. geochemical anomaly in the Cortez district, Nevada: U.S. Geol. Survey Circ. 534, 9 p. As outlined here, several areas in southern Lander Ferguson, H. G., Muller, S. W., and Rob~rts, R. J., County have a structural and stratigraphic setting 1951, Geology of the Mount Moses qucdrangle, similar to the areas where gold has been f o u n d at Nevada: U.S. Geol. Survey Geol. Quad. Map GQ-12, Carlin and Cortez; that is, carbonate rocks, including scale 1:125,000. the Roberts Mountains Formation, are exposed below Gilluly, James, and Gates, Olcott, 1965, Tectonic and the Roberts Mountains thrust. The areas considered igneous geology of the northern Shostone Range, favorable for prospecting in southern Lander County Nevada, with sections on Gravity in Crescent Valley, include the Ravenswood window in the Shoshone Range ~ Donald Plouff, and Economic geo1og:y, ~ K. B. northwest of Austin, the C a 11 a g h an window in the Ketner: U.S. Geol. Survey Prof. Paper 4~5, 153 p. Toiyabe Range north of Austin, the Petes Canyon win Gilluly, James, andMasursky, Harold, 196~" Geology of dow in the Toquima Range southeast of Austin, and the Cortez quadrangle, Nevada, with B' section on extensive exposures of lower plate rocks in the Toiyabe Gravity and aeromagnetic surveys~ r. R. Mabey: Range south of Austin. U.S. Geol. Survey Bull. 1175, 117 p. Hall, Robert, 1962, Sampling of Lynch Creek beryl Prospecting in the region could also be undertaken lium-tungsten prospect, Lander Count~·. Nevada: by drilling. The most likely possibility 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, Geo1ogyofthe Big Creek area, siliceous and volcanic rocks that contain ore deposits Toiyabe Range, Lander County, Nevada~ New York, 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., 1966, Carlin gold mine, Lrm district, plate rocks could indicate larger deposits at depth. Nevada: Nevada Bur. Mines Rept. 13, p•. A, p. 73- 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 and along the north side of the Austin pluton, 4 miles em California and northwestern Nevadr~ U.S. Geol. north of Austin within the Reese River district; in the Survey Bull. 594, 200 p. latter area, however, some supposed upper plate rocks _____,1916, Notes on some mining districts in east may instead by assignable to the Cambrian Gold Hill ern Nevada: U.S. Geol. Survey Bull. 648, 214 p. Formation in the lower plate. These areas seem favor Huffman, Claude, Jr., Mensik, J. 0., and Riley, L. B., able for deposits at depth, but no information is avail 1967, Determination of gold in geologic materials able about the depth to the lower plate carbonate rocks. by solvent extraction and atomic-absorption spec A further possibility for drilling is along the west flank trometry: U.S. Geol. Survey Circ. 544, 6 p.

4 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: Geol. 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: Nevada Bur. Mines Bull., v. 45, no. 3, of the Mount Callaghan quadrangle, Lander County, Geology and Mining ser. 50, 223 p. Nevada: U.S. Geol. SurveyGeol. Quad. MapGQ-730 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. Geol. Survey open- research 1965: U.S. Geol. Survey Prof. Paper file map. 525-C, p. C168-Cl71. --=---:1968b, Geologic map of west-central part of Lawrence, E. F., 1963, Antimony deposits of Nevada: Lander County, Nevada: U.S. Geol. Survey open 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. Geol. Survey stratigraphy in eastern and central Nevada: New Prof. Paper 575-D, p. D56-D63. 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. Geol. 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 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. Geol. Survey Prof. Paper 300, p. 85-89. Pubs. Geol. 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. Geol. Survey Geol. Quad. Map GQ-7, scale Vandenburg, W. 0., 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, lnf. Circ. 7043, 83 p. Lander County, Nevada: Berkeley, California Univ., Vaughn, W. W., 1967, A simple mercury vapor detector M.S. the~is, map scale 1:9,600. for geochemical prospecting: U.S. Geol. Survey Roberts, R. J., 1960, Alinement of mining districts in Circ. 540, 8 p. north-central Nevada, in Short papers in the geolog Ward, F. N., Lakin, H. W., Canney, F. C., and others, ical sciences: U.S. GeoLSurveyProf. Paper400-B, 1963, Analytical methods used in geochemical ex p. Bl7-B19. . ploration by the U.S. Geological Survey: U.S. Geol. --:--~1966, Metallogenic provinces and mineral belts Survey Bull. 1152, 100 p. in Nevada: Nevada Bur. Mines Rept. 13, pt. A, Washburn, R. H., 1966a, Paleozoic stratigraphy in p. 47-72. Toiyabe Range, southern Lander County, Nevada Roberts, R. J., Hotz, P. E., Gilluly, James, and [ abs. J: 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. 1966b, Structure and Paleozoic stratigraphy of Bull., v. 42, no. 12, p. 2813-2857. ----:--. Roberts, R. J., Montgomery, K. M., and Lehner, R. E., the Toiyabe Range, sou the r n Lander County, 1967, Geology and mineral resources of Eureka Nevada: New York, Columbia Univ., Ph.D. thesis. County, Nevada: Nevada Bur. Mines Bull. 64, 152 p. Wells, J. D., Erickson, Ralph, andStoiser, L. R., 1967, Ross, C. P., 1953, The geology andoredeposits 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. Geol. Survey Bull. 997, 1 32 p.

5 117'

qj, '~ Cl.") ( ,:I ~ I ""

4o·,\ G

ALLAGHA WINDOW .. I ; ( I I \Qj el _.s PASS } I DISTRICT I ) ~ I .'liZ I c; / ) I ( <> I r-/ I l~CF

\GOLD BASIN re 4 DISTRICT I ) I ) I / _ _L_ JACKSON \r DISTRICT _ -- \_ ------0 10 20 MILES Figure 1.-Pre-Tertiary rocks, mining districts, and sources of information in southern Lander County.

6 EXPLANATION

Jurassic granitic rocks

Triassic rocks

SOURCES OF INFORMATION USED IN FIGURES 1-4 AND Pennsylvanian and Permian rocks IN U.S. GEOLOGICAL SURVEY OP.EN-FILE MAPS OF SOUTHERN LANDER COUNTY. NEVADA ROCKS AB CVE R OCKS BELOW 1. Muller, Ferguson, and 8. Geologic mapping by J. H. ROBERTS MOUNTAINS THRUST ROBERTS MOUNTA INS TH RUST Roberts (1951) . Stewart in 1967, based in 2. Ferguson, Muller, and part on work by D. B. Roberts (1951) . MacLachlan. 3. Gilluly and Masursky (1965). 9. Modified from Washburn 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). 6. Geologic mapping by E. H. 12. Modified from Nye (1958). Contact McKee in 1967, based in 13. Modified from Ross (1953). Dashed where approximately locnted part on work by H. F. 14. Mapping by E. H. McKee in Bonham. 1967, based in part on work 7. Modified from Means (1962). by Kay and Crawford (1964). Roberts Mountains thrust Sawteeth on upper plate. Elsewhere, contact between siliceous and volcanic rocks and carbonate and transitional assemblage rocks is a high angle fault (not shown on this map)

~-----: : NEVADA ~ ', Area of ""'report

( 4 5 I I _____ j C-- U.S. GEOLOGICAL SURVEY OPEN-FILE MAPS IN SOUTHERN LANDER COUNTY. NEVADA (see references cited for description) 1. Stewart and McKee (1968b). 2. Stewart and McKee (1968). 3. McKee (1968a). 4. McKee (1968b). 5. Stewart and McKee (1968a).

Figure l. - Continued.

7 39"45'

ROBERTS MOUNTAINS THRUST

0 2 MILES

Figure 2.-Geo!ogic map of the Ravenswood window, Shoshone Range.

8 > EXPLANATION c::

Alluvium }~ :::> 0 >- >- c:: c:: < [!c§£~£1 ce ·oz Quaternary and Tertiary sedimentary roeks } -zc:: and Quaternary older alluvium ~<~ w < I- :::> ~ >- 0 I~ Volcanic rocks Rhyolitic welded tuJJ } and andesite flows ; El Granitic rocks }~ :::> LOWER PLATE OF UPPER PLATE OF ROBERTS MOUNTAINS THRUST ROBERTS MOUNTAINS THRUST

z [ill]] < c:: Roberts Mountains Formation Elder Sandstone l :::> Platy limest.o7u3; as mapped locally i'IUJludes limestone Sandstone, shale, and -' and shale of latest Ordovician age minor chert J (/) g FAULT l~Jt.;~ ]::;j ~~s:: 0 0 Ninemile Formation !- .;! tiC 0 " 0 Shale, minar limestone Valmy Formation c:: ~--~ ~ 0 Chert, quartzite, .s~ m and shale Goodwin(?) Limestone Thin-bedded limest.o7u3~~

~~~d t; · "~ ~ ~.., '<:!~~ { ~~!~~~~ ~ c3 Shale and limestone z < a c:: Ledge-forming limestone "'::E t · "~ < ;l-o u .s ~ c3 Quartzite, minor shale, and rare limestone~~

~~Contact Dashed where approximately located __t______Fault Dashed where approximately located; dotted where CO'IUJealed. Bar and ball on downthrown Bide~~

~~Fault scarp Hachures on downthrown Bide~~

~~Thrust fault Dashed where approximately located Sawteeth on upper plate __,}_0 Strike and dip of beds~~

~~Figure 2.-Continued.~~

~~9 Upper plate~~

~~Middle plate~~

~~Lower~ plate~~

~~39°15'~~

1. Modified from Means (1962). 2. Geologic mapping by J. H. Stewart and E. H. McKee in 1967. 3. Geologic mapping by D. B. Mac Lachlan (written commun., 1967) and by J. H. Stewart, 1967. Modified from Washburn (1966a). Modified from Hansen (1961). Modified from Lowell (1958). 7. Modified from Nye (1958). 8. Modified from Ross (1953).

~~Geology compiled by J. H. Stewart and E. H. McKee, 1967-68. 2 0 2 4 MILES~~

~~Figure 3.-Geologic map of the Toiyabe Range south of Austin.~~

~~10 EXPLANATION~~

~~Alluvium G Volcanic rocks Welded tvj"f and lava flows; some sedimentary rocks~~

~~Felsite~~

~~Granitic rocks~~

~~M.IDDLE PLATE BETWEEN LOWER PLATE BELOW UPPER PLATE ABOVE K I NGSTON CANYON AND KINGSTON CANYON THRUST ROBERTS MOUNTAINS THRUSTS ROBERTS MOUNTAINS THRUST~~

~~Undifferentiated Devonian rocks Thin-bedded limestone in lower part; massive cliff-forming limestone in upper part. May include some Silurian rocks in basal part~~

~~z Roberts Mountains Formation ~ Platy "limestone. Same as Masket Platy limestone. Twenty-foot chert 0: ::::> Formation mapped by Washburn layer at base in some areas. Same ...J~~

~~{1966a, 1966b) as Masket Formation mapped by (f) Washburn {1966a, 1966b) and Lowell (1958)~~

z ~ Antelope Valley Limestone u Massive cliff-forming limestone > 0 I] 0 0: Pogonip Group Valmy(?)I Formation 0 Massive cliff-forming Antelope Black chert and minor amounts of Valley Limestone at top. Under dark-gray shale and quartzite lain by shale and limestone pos sibly equivalent to Ninemile Formation. Thin-bedded limestone in basal part possibly equivalent to Goodwin Limestone

Broad Canyon sequence of Crane Canyon sequence of z Means (1962) Means (1962) ~ 0: Black phyllite and black argillaceous Laminated to very thin-bedded ligh~ co limestone. Uvj"ossiliferous gray limestone. Some black shale ::;; ~ and chert. Contains Upper Cam u brian tribolites 5 miles south of Austin

QuarW:ite and minor amounts of Quartzite and minor amounts of silt siltstone. Cliff-forming limestone stone. Cliff-forming limestone at at top top. Contains Early Cambrian archeocyathids near top (Wash burn, 1966a, 1966b)

__t______Contact- Fault --L...L--Thrust-"- fault- - ·- Dashed where approximately located Dashed where approximately located; Dashed where approximately located; dotted where concealed. Bar and dotted where concealed. Sawteeth ball on downthrown side on upper plate

~~Figure 3.-Continued.~~

~~11 116°45'~~

~~39°1~~

~~Geology by E. H. McKee, 1967 0 2 MILES~~

~~Figure 4.-Geologic map of Petes Canyon window in northern Toquima Range.~~

~~12 EXPLANATION~~

~~Alluvium H0~~

~~Volcanic rocks Welded tuff }I~~

~~LOWER PLATE OF UPPER PLATE OF ROBERTS MOUNTA!Ne TfiRUST ROBERTS MOUNTAINS THRUST~~

~~Roberts Mountains Formation Platy limestlme; black chert at base~~

~~Hansen Creek(?) Formation Cherty limestlme, siltstlme z ..;: u > 0 Antelope Valley Limestone Vinini Formation 0 Massive- to medium-bedded Dark shale, black chert, a:: 0 limestone quartzite FAULT~~

~~Goodwin Limestone Thin-bedded cherty limestlme~~

~~Contact Dashed where approximatel11 located~~

~~Fault Dashed where approximately located. Bar and ball on downthrown side ....___..__ __ , .... Thrust fault Dashed where approximately located; dotted where concealed. Sawteeth on upper plate~~

~~-+- Inclined .Vertical Strike and dip of beds~~

~~Figure 4.-Continued.~~

~~'If U. S, GOVERNMENT PRINTING OFFICE : 1988 0 • 318·335~~