MISCELLANEOUS FIELD STUDIES DEPARTMENT OF THE INTERIOR MAP MF-1244-C U. S. GEOLOGICAL SURVEY CORRELATION OF MAP UNITS topographic ridge extending north from anomaly ·A--does not affect the aeromagnetic pattern; aeromagn,etic Lower plate Upp!!r plate intensities increase over decreasing topographic Tertiary or Cretaceous elevations on the west side of the ridgeline where Gill surface rocks are part of the upper plate. The minus \ Pzus j Pennian through Ordovician} . PALEOZOIC - 400 - gamma magnetic contour interval to the north, !Cam brian anomaly B, is generally over metasedimentary rock and crosses topographic elevations ranging from about 11,000 ft to less than 8,000 ft . Abandoned mine DESCRIPTION OF MAP UNITS workings in the metasedimentary terrane near lat 39°20' N. and long 114°14'U. within the area of TKi INTRUSIVE IGNEOUS ROCKS (TERTIARY .OR magnetic low, anomaly B, are not discerned by the CRETACEOUS)--Composition varying from aeromagnetic survey. monzonite to granodiorite, present only in The north-south-trending contour pattern, anomaly lower plate rocks (below the Snake Range C, showing westward increasing magnetic intensity deco l lement). Exposed as sills and small along the west edge of the map, probably reflects stocks and dikes intrusive rock beneath the upper platie. The upper rzus UNMETAMORPHOSED SEDIMENTARY ROCKS, UNDIVIDED plate is estimated to be about 2,450 ft thick (Hose, (PALEOZOIC)--Upper plate rocks (above the 1981). Low-gradient magnetic-high closures within the Snake Range decollement) consisting of broad north-south-trending anomaly possibly represent limestone, dolomite, shale, siltstone, phases of the buried intrusive rocks with high sandstone, and quartzite of the Arcturus magnetic susceptibility; however, the focal point of Formation, Riepe Spring Limestone, Ely the north-south-trending anomaly is a magnetic high limestone, Chainman Shale ( Joana limestone, located about 1.5 mi west of the roadless area at lat Pilot Shale, Guilmette limestone, Simonson 39°19' N. The magnetic high is located on the west Dolomite, Sevy Dolomite, Laketown Dolomite, ~ediment slope of the•mountain range outside the area Fish Haven Dolomite, Eureka Quartzite, of mapped geology, but its shape and gradient suggest Pogonip Group, Notch Peak Formation, a plug of rock with high magnetic susceptibility near Ounderberg Shale, Lincoln Peak Formation, the surface~ Meta~orphosed rocks of the lower plate and Pole Canyon Limestone are exposed about 1.5 miles to the east. ~ms METAMORPHOSED SEDIMENTARY ROCKS, UNDIVIDED Two east-southeast-trending magnetic higns, (CAMBRJAN)--Lower plate rocks (below the anomalies D and E, appear to be apophyses to the broad Snake Range decollement) consisting of magnetic high along the west side of the map. marble, metaquartzite, garnet schist, and Although the quality of the aeromagnetic data may .be phyllite of the Dunderberg Shale, Lincoln suspect because of single flight line anomalies along Peak Formation, Pole Canyon Limestone, trend E, both E and D appear to extend to the east Pioche Shale, and Prospect Mountain border of the map. Abandoned mine workings are Quartzite located in upper plate rocks along magnetic trends D - - APPROXIMATE BOUNDARY OF MOUNT MORIAH ROADLESS and E. Mineralization occurs in faults and fractures AREA ( 04352) in the upper plate sedimentary rocks, but neither the CONTACT BETWEEN INTRUSIVE IGNEOUS ROCKS AND faults nor the mineralized areas extend into the lower SEDIMENTARY ROCKS ; pl·ate (Robert R. Carlson, geochem:1,,st,. U.S. Geological Survey, oral commun.). t t LOW-ANGLE FAULT (SNAKE RANGE DECOLLEMENT)-­ Sawteeth on upper plate The southernmost apophysis, magnetic-high anomaly HIGH-ANGLE FAULT--Bar and ball on downthrown D, is mostlr over outcropping intrusive rock (TKi), side. Co~lex faulting in upper plate which is believed to be the anomaly source. The rocks not shown steep-gradient magnetic high near the southeast corner of the map and the low magnetic gradient near tfte west end of the outcrop of intrusive rock (TKi) suggest EXPLANATION OF SYMBOLS ON AEROHAGNETIC HAP that different phases of the intrusive (Hose, 1981, Description of Map Units) cause the linear magnetic ridge. ---400 -- MAGNETIC CONTOURS--Represent total intensity magnetic The northern apophysis, magnetic-high anomaly E, field values of earth, in gammas, relative to an is delineated across the metamorphic terrane by the arbitrary datum. Contour interval 20 gammas. minus - 360 - gamma contour interval. The magnetic Hachured to indicate closed areas of lower field is constant over topographic relief that ranges magnetic intensity from about 7,000 ft to about 11,000 ft suggesting that surface metamorphic rocks do not contribute to the MAGNETIC ANOHALY--Discussed in text anomaly. Possibly intrusive rock (TKi) simi.lar to 8 that exposed at the west end of anomaly D occurs at - - FLIGHT-PATH--Flight level 1,000 ft above ground level, depth within the metamorphosed sedimentary rocks flight-line spacing 0,5 mi (€ms). CONCLUSIONS

Aeromagnetic data indicate no significant STUDIES RELATED TO WILDERNESS features that can confidently be interpreted to be directly related to mineral deposits. Low magnetic The Wilderness Act (Public Law 88-577, September relief dominates the aeromagnetic map and reflects 3, )964) and related acts require the U.S. Geological both the sedimentary and metasedimentar~ terrane. Survey and the U.S. Bureau of Mines to survey certain Abandoned mine workings located in rocks of the areas of Federal lands to determine their mineral upper plate along magnetic trends D and E anrl in the resource potential. Results must be made available to northeast corner of the roadless area are not the public and be submitted to the President and the discerned by the aeromagnetic survey. Mineralization Congress. This report presemts the results of an occurs in faults and fractures in the sedimentary aeromagnetic survey of the Mt. Moriah Roadless Area in rocks of the upper plate at the workings, but neither the Humboldt National Fotest, White Pine County, the faults nor the mineralized areas extend into the Nevada. The Mt. Moriah Roadless Area was classified lower plate. One abandoned working near lat 39°20' N. as a further planning area during the second Roadless and long 114°14' W. is in lower plate metasedimentary ,Area Review and evaluation by the U.S. Forest Service in January, 1979. rocks (Robert R. Carlson, geochemist, U.S. Geological Survey, oral commun.), but it shows no identifying INTRODUCTION magnetic pattern. Aeromagnetic anomalies are interpreted to reflect intrusive rocks in the lower The Mt. -Moriah Roadless Area covers 97,205 acres plate. of the Humboldt National Forest in eastern White Pine County, Nevada_ (see index. map). Located in the REFERENCES CITED northern Snake Range and bounded on the west by Spring Valley and on the east by Snake Valley, the area lies Barraclough, D.R., and Fabiano, E. B., 1978, Grid about 1.5 miles north of U.S. Highway 6 and SO. values and charts for the IGRF (International Baker, Nevada, about 10 miles south of the area, is Geomagnetic Reference Field) 1975.0: the only permanent communit y in the immediate area; International Association of Geomagnetism Aeronomy Ely, Nevada, about 35 miles to the west, and Delta, Bulletin No. 38, 131 p.; available from U.S. Utah, about 85 miles to the northeast, are the nearest Department of Commerce, National Technical main population centers. Information Service, Springfield, VA 22151 as PB- The perimeter of the Mt. Moriah Roadless Area 276 630. generally coincides with the boundary of the Hum_boldt National Forest in the northern Snake Range , except in Carlson, R. R., Martin, R. A. 1 Wood, R. H., 1984, the northwest and southwest corners, where the Mineral resource potential of the Mount Moriah roadless area boundary is coincident with Forest Roadless Area, White Pine County, Nevada: Service roads 460, 469, 457 , and 458. These ·and other Miscellaneous Field Studies Map MF-1244-B, scale Forest Service roads, together with several hiking 1:62,500. trails, provide limited access to the interior of the area. Elevations range from 6,000 ft along the Hose, R. K., 1981, Geologic map of the Mount Moriah eastern border and 7,000 ft for much of the western Further Planning (RARE II) Area, eastern Nevada: border to 12,500 ft on Mt. Moriah, which is located in Miscellaneous Field Studies Map MF-1244-A, scale the center of the roadless area. 1 : 62,500. An aeromagnetic survey of the Mt. Moriah Roadless Area was conducted to help i dentify geological features that might be associated with buried mineral deposits. The low-altitude magnetic survey was fl.own at 1 000 ft above the ground to detect shorter lt•E A. 70 E. wave 1ength anomalies. Base f rom U. S. Geol ogical Survey , All rock units across the roadless area are Ely , Ne vada and Utah, 1971, 1:260,000 sedimentary or metasedimenta ry except for the monzonite and granodiorite intrusive igneous rocks ,. (TKi). A low-angle fault (decollement) separates "s. Precambiian and Cambrian metasedimentary rocks and Cretaceous or lower Tertiary intrusive quartz monzonite to diorite rocks (lower plate) from middle I ~ Data flown and compiled in December, 1980 by Geodata International, Inc., under contract Cambrian to Permian rocks that are not metamorphosed MAP LOCATION (upper plate) (Hose, 1981). Lower plate rocks were to the U.S. Geological Survey, regional field metamorphosed by the intrusive igneous rocks (TKi). removed, IGRF 1975 updated to month flown, ' datum base arbitrary "s. INTERPRETATION SCA L E 1 :62 500 Magnetic susceptibilities of the sedimentary and EI::::Ece:a:Yij'a:::Ecio======'C======:i2E======i3======· MI LES metasedirnentary sect_ions appear to be uniformly low across the Mt. Moriah Roadless Area; sedimentary rocks s::B:J·c;I5:H:S:OE==;===3::== ==2E======3C====· Kl LO METERS and unconsolidated deposits usually contain little or no magnetite and show very little magnetic JAN :,; J 1988 expression. Al though the survey was flown ·at a nominal elevation of 1,000 ft above ground, magnetic anomalies associated with t he topography are not evident. Aeromagneti c anomalies are interpreted to reflect intrusive rocks in the lower plate. Low magnetic relief dominates the aeromagnetic map and reflects both the sedimentary and metasedimentary terranes. The minus - 400 - gamma contour, anomaly A, over the southern part of the map CJ AEROMAGNETIC MAP OF THE MT. MORIAH ROADLESS AREA, WHITE PINE COUNTY, NEVADA occurs over sedimentary rocks of the upper plate at topographically high elevations, about 11,000 ft. The INDEX MAP SHOWING LOCATION OF THE MOUNT MOAIA.H AOA.DUSS A.REA. NEVADA. By

R. A. Martin I NTER I OR -G EOLOGICAL SURVE Y, RESTON. Y IRGIN I A- 1987

IIIIIII IIIIIII IHilllliliif~lillllll !illi~l:111111 1111111111111 For sale by Branch of Distribution, U.S. Geological Sur'" e.r , 1987 3 1818 00630221 8 Box 25286, Federal Center, Den ver, CO 80225