Geology topics
Research about Nevada
Source-linked reports with geographic coverage including Nevada.
Geologic and total-intensity aeromagnetic map in the vicinity of Eureka, Nevada
No abstract available.
Uranium-bearing lignite beds at the Gamma property, Churchill County, Nevada
No abstract available.
Uranium in the East Walker River Area, Lyon County, Nevada
Uraniferous quartz veins and deposits of other types occur in an area at least six miles long and three miles wide, along the East Walker River in Lyon County, Nevada. Most of the deposits are on the west side of the river. Six properties of areas were mapped, sampled, and tested radiometrically. These properties are: the Far West Willys group, North-west Willys group, West Willys group, Silver Pick property, Grant View hot springs, and the Boerlin ranch radioactive area. The East Walker River area is underlain by coarse-grained porphyritic granite. Cutting the granite are numerous aplite dikes and a few perthite-quartz pegmatites. Faulting was noted in a few places. Radioactive material has been found in the East Walker River area in deposits of four types: (1) quartz veins carrying small amounts of copper, lead, and silver minerals; (2) partly altered granite adjacent to quartz veins; (3) gouge zones, and (4) hot springs. The quartz vein deposits are the most abundant. The uranium minerals pitchblende and kasolite occur in the quartz veins, in aggregates and streaks associated with copper and silver minerals, galena, and barite. In many quartz veins abnormal radioactivity is absent or only locally present. Samples collected from quartz veins contained from 0.001 to 0.14 percent uranium; only five of 46 samples contained over 0.025 percent uranium. Partially altered granite adjacent to the quartz veins in the West Willys No. 7 property contains scattered torbernite, but the highest uranium content noted in deposits of this type was 0.006 percent. The third type of deposit is represented on the Silver Pick property, where a gouge zone of differing thickness contains scattered flakes of torbernite. Five samples from this deposit contained from 0.00.5 to 0.013 percent uranium. The Grant View hot spring is moderately radioactive near the point where it issues from the hillside. Laboratory analysis of both water and sand from this deposit shows little uranium content (0.02 parts per million), and little radioactivity, indicating that the radioactivity is due to some short-lived daughter product, probably radon . The uraniferous material found to date in the area is of too low a grade and small a size to be of present value.
Ground-water conditions in Whisky Flat, Mineral County, Nevada
As a part of the State-wide cooperative program between the Office of the State Engineer of Nevada and the U.S. Geological Survey, the Ground Water Branch of the Geological Survey made a reconnaissance study of ground-water conditions in Whisky Flat, Mineral County, Nevada.
Tin, copper, and uranium at Majuba Hill, Nevada
Uranium minerals occur with ores of copper, tin, and silver at Majuba Hill, Nevada. During World War I, the Majuba Hill mine produced about 4,000 tons of 12 percent copper ore, and during World War II about 23,000 tons of ore containing 2 to 4 percent copper and enough tin ore to furnish from 10 to 15 tons of metallic tin. No uranium has been produced. The bedrock geology of Majuba Hill consists of a complex; volcanic neck or plug composed of rhyolite porphyry, porphyritic rhyolite, quartz feldspar porphyry, breccia dikes, and irregular breccia masses. This plug intruded Triassic (?) sedimentary rocks, chiefly shale. The principal loci of ore deposition were (l) parts of the breccia bodies, particularly where they were porous and where they were silicified and tourmalinized, and (2) a few small pre-mineral fractures adjacent to the breccia masses, Intense hydrothermal alteration resulted in the formation of sericite, quartz, and tourmaline in the wall rocks. This was accompanied or followed by deposition of arsenopyrite, pyrite, cassiterite, fluorite, and several primary sulfide minerals of copper. All of the ore bodies exposed in the mine are highly oxidized, and a profusion of secondary minerals of copper and iron have been found. The only uranium minerals detected are the phosphates torbernite and matatorbernite and the arsenate zeunerite. These are widely disseminated throughout the mine in small amounts associated with the secondary minerals of copper and iron along minor fault surfaces, bedding planes in the shale, and in porous parts of the breccia. A primary uranium mineral has not been found. The secondary uranium minerals appear to be most abundant where copper ore is highest grade. Although unoxidized uranium ore has not been found, it is inferred from this relation that the deposition of the original uranium minerals favored those areas where primary copper mineralization was most intense. There may have been an intimate association of uranium with silver in the ore, but this has not been established. The U 3 O 8 content of samples of copper ore ranges from .0.002 to 0.30 percent. Because the bottom of the oxidized ore has not been reached in mining or exploration, the downward extensions of the known ore bodies of secondary minerals would appear to be worthy of investigation to determine the grade and extent of the primary ore.
Geology of the Antler Peak quadrangle, Nevada
The Antler Peak quadrangle is bounded by the meridians 117° and 117°15' and the parallels 140°30' and 40°45', in north-central Nevada. It is in the Basin and Range province and includes Battle Mountain, a north-trending range 18 miles long and 114 miles wide. The range is bounded on the east by the Reese River Valley, on the northeast by the Humboldt Valley, on the west by the Buffalo Valley, and on the south by a low divide separating the Buffalo Valley from the Reese River Valley. Altitudes in the quadrangle range from 4,475 to 8,550 feet; the local relief is as much as 3,500 feet, but is generally less than 2,000 feet.
Results and description of test drilling in Argenta Swamp near Battle Mountain, Nevada
In June 1949, the U. S. Geological Survey in cooperation with the State Engineer of Nevada, as part of the State-wide ground-water studies, drilled a test well on the flood plain of the Humboldt River about 4 miles northeast of Battle Mountain. This well was drilled for the purpose of obtaining information concerning the geologic and hydrologic character of the sediments underlying the flood plain, and the quality of the water in those sediments.
Ground-water in the Austin area, Lander County, Nevada
The U.S. Geological Survey, in cooperation with the State Engineer of Nevada, made a preliminary survey of ground-water conditions in the Austin area, Nev., during the period July 25 to 28, 1949. The purpose was to evaluate ground-water conditions with special reference to the quantity of ground water that might be available in the area--an adequate water supply has been a constant problem throughout the history of the Austin area. The investigation was made by the writer under the supervision of Thomas W. Robinson, district engineer, Ground Water Branch, U.S. Geological Survey. Material assistance was given in the field by local residents. Frank Bertrand, water commissioner, Thomas Peacock, county assessor, and George McGinnis, county commissioner, guided the writer to springs new utilized by the town of Austin and rendered other valuable field assistance.
Structural geology of the Hawthorne and Tonopah quadrangles, Nevada
The area lies in west-central Nevada near the western border of the Basin and Range province. Paleozoic and Mesozoic rocks the chief subject of this report occur in isolated mountain ranges separated by stretches of Tertiary and Quaternary volcanic rocks, lacustrine deposits and alluvium. The report is concerned principally with the geology of the pre-Tertiary rocks and attempt is made to unravel the complex diastrophisni that occurred in the area during the Jurassic.
Mineralogy and petrology of the currant creek magnesite deposits and associated rocks of Nevada
Cryptocrystalline magnesite occurs as relatively small dense, white masses in a Tertiary volcanic tuff, here named the Currant tuff, in White Pine and Nye counties, 29 miles southwest of Ely, Nevada. The deposits are small, but some of the magnesite is of very high quality with almost no iron or aluminum. However, much of the magnesite is mixed with dolomite and calcite, and a serpentinelike mineral occurs in one of the deposits in sufficient abundance to be of possible use in ceramics. In scattered areas the tuff has been altered by solutions rich in magnesium and bicarbonic acid to dolomite, magnesite, magnesium silicate, and calcite. Mineral and chemical characteristics are the same throughout the entire rock assemblage of flows and tuffs, suggesting that all the rocks have been derived from the same parent magma. The tuff formation, which ranges in thickness from a few feet to over 400 feet, occurs between two groups of volcanic flows here referred to as the lower volcanics and the upper volcanics. The lower volcanics is composed mainly of flows of hypersthene dacite, but in the southwestern part of the area flows of a hypersthene andesite of balsaltic habit occur between the dacite and the overlying Currant tuff. The upper volcanics which overlie the Currant tuff consist of porphyritic quartz latite and an overlying massive latite crystal tuff. The Currant tuff containing the magnesite has both unmodified and reworked tuff members. The formation of hydrothermal dolomite, magnesite, and deweylite is discussed in detail, and the physical chemistry of solutions containing calcium, magnesium, and carbon dioxide is applied in an explanation of the origin of magnesium-rich solutions.
Magnesite and brucite deposits at Gabbs, Nye County, Nevada
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Mining districts in the Carson Sink region, Nevada
The region lies in an area of primarily sedimentary rocks which are principally Mesozoic and are tilted, folded, and faulted and cut by granular intrusives, and flooded by Tertiary lavas as shown on Figure 4. The Mesozoic sediments were strongly folded and invaded by granular intrusives at or about the time of the intrusion of the great Sierra Nevada batholith. The rocks are exposed chiefly in the mountain ranges and hills. The mountain ranges are mostly fault ranges with much of their structure monoclinical. Faulting in many instances has been prominent since the deposition of the Tertiary lavas and continues down to the present, as shown by fresh scarps and recent earthquake disturbances in the Stillwater and Augusta ranges and in general along the flaks of the various ranges by the tilted attitude of the lava flows and lake beds, and by the older lavas in general being tilted at steeper angles than the overlying lake beds. The faulting may be normal or overthrust. The faulting shown in the various mining districts as Fairview and Wonder may be regarded as indicating that of the region in general. In some parts of the region faulting is so young that it is still shown in the topographic forms as by trunctated gulches in the east base of the Stillwater range in Dixie Valley. As the writer in the present work had but small opportunity to examine the rocks excepting in the various mining districts many of which are located far apart, the accompanying geologic map (Fig. 4) is largely compiled from earlier reports of various authors in order to here present a geologic picture of the region. The portion to the north of Latitude 39°30’ is largely adapted from the 40th Parallel Survey and that to the south of the 39th parallel form the papers and reports by Buwalda, Clark, Merriam, Hill, Spurr, and the unpublished work of H. G. Ferguson of the U. S. Geological Survey on the Hawthorne and Tonopah quadrangles.