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James E. Elliott

Publications and source records attributed to James E. Elliott.

16 recordsLinked to original sources
USGS1986

Mines and prospects of the Butte 1° x 2° Quadrangle, Montana

The Butte quadrangle, in the Northern Rocky Mountains of southwestern Montana, has had a long, productive, and colorful mining history. Butte, the city from which the quadrangle takes its name, is located in the most famous mining district of the quadrangle. This district, the Butte or Summit Valley district, has been described as the "richest hill on earth" and is one of the richest and most productive mining districts of the world. The quantity of metals produced from this district alone are far greater than the combined total of all commodities from all other mining districts of the quadrangle. However, many districts other than Butte have had significant production as compared to other mining districts of the Northern Rocky Mountains. The dollar value of production from the Butte district is more than $6 billion (Miller, 1973) and that of the combined total of production from the other districts in the quadrangle is more than $400 million. These values are based on actual metal prices at the time of production. The totals would be many times larger if converted to present day commodity prices. Mineral occurrence data for a total of 1111 mines, prospects, and mineral occurrences have been compiled for the Butte quadrangle. These mineralized sites are found throughout the quadrangle but most are concentrated in the major mining districts; 78 percent are clustered in 46 established mining districts and the remaining 22 percent are more widely scattered in 24 geographic areas (fig. 1). Only small areas of the quadrangle lack significant mines, prospects, or mineral occurrences. The locations of mines and prospects are shown on maps (pl. 1 and 2) and a brief description of each site is given in a table arranged by mining district or geographic area (table 1) (all tables are at end of report). This table gives a brief description of each district or area and details of each site within the district or area including site number, name and alternate name(s), location by latitude and longitude, commodities present, description of the site, and sources of data. Data for this report come from the U.S. Geological Survey Mineral Resource Data System (MRDS; this was formerly known as the Computerized Resource Information Bank (CRIB)), from many published and unpublished sources, and from geologic field work. The Butte quadrangle is in southwestern Montana and is bounded by latitudes 46° and 47° N. and longitudes 112° and 114° W. The city of Butte is near the southern edge and in the southeastern corner of the quadrangle. Helena, the state capital of Montana, is located on the eastern edge and Missoula is located near the northwestern corner of the quadrangle. Most of the area of the quadrangle is in Granite, Powell, Lewis and Clark, and Jefferson Counties and the remaining area includes parts of Missoula, Ravalli, Deer Lodge, and Silver Bow Counties. The quadrangle includes a number of major and minor mountain ranges separated by intermontane valleys. The continental divide trends nearly north-south through the eastern part of the quadrangle to a point near Butte, then trends generally east-west near the southern boundary of the quadrangle, west of Butte. East of the divide the drainages are tributary to the Missouri River and west of the divide the drainages are tributary to the Clark Fork, which heads in the vicinity of Butte. The geology of the Butte quadrangle is very complex. Sedimentary and igneous rocks range in age from Proterozoic to Tertiary. Most of the pre-Tertiary sedimentary rocks are structurally complex due to widespread faulting and folding. Due to thrust faulting, complete sequences of these sedimentary units are not generally present in the quadrangle and the thicknesses and lithologies are variable from one thrust plate to another. The oldest rocks in the quadrangle are sedimentary rocks of the Belt Supergroup of Middle Proterozoic age. They form very thick sequences, are exposed over a large percentage of the area of the quadrangle, and include formations of the lower, middle, and upper parts of the Belt. Individual formations are as much as 13,000 ft thick (C. A. Wallace, unpub. data) and the maximum thickness of the Belt Supergroup in the quadrangle may be similar to that of the entire sequence near Alberton, Montana, to the northwest of the Butte quadrangle where it exceeds 67,000 ft (Harrison, 1972). In many areas of the quadrangle these Precambrian rocks are overlain by thin to moderately thick sequences of Cambrian to Permian sedimentary rocks. The maximum thickness of the Paleozoic section is about 8,000 ft (C. A. Wallace, unpub. data). A relatively thick sequence of Mesozoic sedimentary rocks, predominantly Cretaceous in age, which is found mostly in the central part of the quadrangle, overlies the Paleozoic rocks. If complete, the Mesozoic sequence would total about 28,000 ft (C. A. Wallace, unpub. data). The Butte quadrangle is located in a structurally complex region. Most of the Butte quadrangle is in the southern part of the Montana Disturbed Belt, a tectonic belt in the Northern Rocky Mountains characterized by northwest-trending faults and intense deformation. An element of the Disturbed Belt, called the Sapphire Thrust System occupies most of the western two-thirds of the quadrangle. Sedimentary rocks of Cretaceous and older ages in the Sapphire Thrust System have been complexly folded and faulted. Plutonic rocks, which intrude the sedimentary units, and volcanic rocks of Cretaceous and Tertiary ages are widespread in the quadrangle. Most of these are post-thrusting but some may be pre- or syn-tectonic and involved in the thrusting and folding. Most of the mineral wealth in the quadrangle, in the form of hydrothermal ore deposits, is genetically related to Cretaceous granitic plutonism. Igneous activity decreased but continued into Tertiary time, at least until the Oligocene. In the Butte quadrangle the Cenozoic Era was important for normal faulting, volcanism, sedimentation, glaciation, and the formation of many important mineral deposits. Many normal faults were especially active during the Miocene and Pliocene and some were active into the Quaternary. Volcanic rocks of Eocene and Oligocene age cover large areas and are genetically related to several important mining districts. During Cenozoic time, thick accumulations of Tertiary basin-fill sediments, Pleistocene glacial till and outwash, and Holocene alluvium and colluvium were deposited. The Cenozoic was important for the formation of placer deposits valuable mainly for gold but some have produced important quantities of sapphires and tungsten. This map is part of a folio of maps of the Butte 1° x 2°quadrangle, Montana, prepared under the Conterminous United States Mineral Assessment Program (CUSMAP). Other maps to be published as part of this folio are a geologic map, geochemical maps, geophysical maps, maps of linear features and limonitic alteration interpreted from satellite and airborne radar data, and mineral resource assessment maps.

Montana↗
USGS1983

Peralkaline and peraluminous granites and related mineral deposits of the Arabian Shield, Kingdom of Saudi Arabia

In the Precambrian Arabian Shield, granitoid plutonic rocks are widespread and range in age from 800 to 550 Ma old; but the mineral-resource potential associated with these plutonic rocks is restricted mainly to the younger, postorogenic granites. Two granite types of current economic interest are zirconium- niobium-enriched per alkaline granites and tin-tungsten-enriched peraluminous granites. Both types are highly evolved, are enriched in lithium, rubidium, and fluorine, and have distinctive mineralogy, textures, and chemistry. The zirconium-niobium-enriched granites are related to medium- to large-sized plutons and complexes of peralkaline granite, and the tin-tungsten-enriched granites are related to medium-sized plutons of biotite or biotite-muscovite granite. Existing geochemical and geologic data for many parts of the Arabian Shield were compiled as a basis for evaluating the resource potential of the granites of the Shield. Commodities associated with granites that have potential for economic mineral deposits include tin, tungsten, molybdenum, beryllium, niobium, tantalum, zirconium, uranium, thorium, rare-earth elements, and fluorite. Prospecting methods useful in discriminating those granites having significant economic potential include reconnaissance geologic mapping, petrographic and mineralogic studies, geochemical sampling of rock and wadi sediment, and radiometric surveying.

Open-File Report↗
USGS1980

Geology and mineral resources of the North Absaroka Wilderness and vicinity, Park County, Wyoming, with sections on mineralization of the Sunlight mining region and geology and mineralization of the Cooke City mining district, and a section on aeromagnetic interpretation

SUMMARY The North Absaroka Wilderness is approximately 560 square miles (1,450 km 2 ) of rugged scenic mountainous terrain that adjoins the eastern boundary of Yellowstone National Park in northwestern Wyoming. The area was studied during 1970, 1971, and 1972 by personnel of the U. S. Geological Survey and the U. S. Bureau of Mines to evaluate its mineral-resource potential as required by the Wilderness Act of 1964. This evaluation is based on a search of the literature courthouse and production records, geologic field mapping, field inspection of claims and prospects, analyses of bedrock and stream-sediment samples, and an aeromagnetic survey. The North Absaroka Wilderness is underlain almost entirely by andesitic and basaltic volcanic rocks of Eocene age. These volcanics rest on deformed sedimentary rocks of Paleozoic and, locally, of Mesozoic age that are exposed at places along the northern and eastern edges of the wilderness. Dikes and other igneous intrusive bodies cut both the volcanic and sedimentary rocks. A nearly flat detachment fault, the Heart Mountain fault, and a related steep break-away fault have displaced middle and upper Paleozoic rocks and some of the older part of the volcanic sequence to the southeast. A much greater thickness of volcanic rocks was found to be involved in Heart Mountain faulting than had previously been recognized; however, most of the volcanic rocks and many of the intrusives were emplaced after Heart Mountain faulting. Local folding and high-angle faulting in mid-Eocene time have deformed all but the youngest part of the volcanic sequence in the southeastern part of the wilderness. This deformation is interpreted as the last pulse of Laramide orogeny. The results of this study indicate that the mineral-resource potential of the wilderness is minimal. Bentonite, petroleum, low-quality coal, and localized deposits of uranium and chromite have been produced in the surrounding region from rocks that underlie the volcanic rocks; but such deposits, if present in the wilderness, would be too deeply buried, too small, or too sporadically distributed to be profitably located and exploited. Copper and gold mines and prospects are present on the fringes of the wilderness, but otherwise the area seems to be devoid of economically valuable concentrations of metallic minerals. No surface evidence of geothermal-energy potential was found. Known mineral deposits in the vicinity of the North Absaroka Wilderness are associated with intrusive rocks. From the Cooke City mining district, just north of the wilderness, replacement deposits in Upper Cambrian carbonate rocks may extend a short distance into the north edge of the wilderness, In the Sunlight mining region, an enclave nearly surrounded by the wilderness, mineralization occurs in veins and is disseminated in volcanic and plutonic rocks. Richer concentrations of metallic minerals may occur in carbonate rocks adjacent to intrusive bodies at depth beneath the volcanic rocks in the Sunlight region. A few small intrusive bodies occur in the wilderness, but no significant associated mineralization was detected. Aeromagnetic data indicate that other intrusives not exposed by erosion may occur in the wilderness; however, no significant metamorphism or alteration is evident at the surface to indicate their presence. Although most of the rocks of the wilderness are of igneous origin, they are all so old (Eocene) that it is unlikely that they retain any original heat. The Pleistocene rhyolitic ash-flow tuffs in the southwestern part of the wilderness were erupted from sources in Yellowstone National Park just to the west; however, in the wilderness these tuffs are too thin to contain any residual heat.

Wyoming↗