USGS Science⌕ Search

SEARCH · USGS Science

Results for “Trace Elements Investigations”

Search indexed USGS publications on groundwater, aquifers, geologic maps, mineral resources and earthquakes. Explore source records by subject and place.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 307 records · Page 17Linked to original sources
USGS1954

Exploration for uranium deposits in the Spring Creek Mesa area, Montrose County, Colorado

The U.S. Geological Survey explored the Spring Creek Mesa area from July 11, 1951, to August 14, 1953. During that period, 280 diamond-drill holes were completed for a total of 180,287 feet. Sedimentary rocks of Mesozoic age are exposed in and adjacent to the Spring Creek Mesa area. These rocks consist of, from oldest to youngest: the Upper Jurassic Morrison formation, the Lower Cretaceous Burro Canyon formation, and the Upper Cretaceous Dakota formation. The Morrison formation consists of two members in the Spring Creek Mesa area: the lower is the Salt Wash member and the upper is the Brusby Basin member. All of the large uranium-bearing deposits discovered by the Geological Survey drilling in the Spring Creek Mesa area are in a series of coalescing sandstone lenses in the uppermost part of the Salt Wash member of the Morrison formation. Most of the ore deposits are believed to be irregular tabular or lens-shaped masses and probably lie parallel to the bedding, although in detail, they may crosscut the bedding. Also, ore deposits that take the form of narrow elongate concretionary-like structures, locally called “rolls”, may be present in the Spring Creek Mesa area. The mineralized material consists mostly of sandstone which has been selectively impregnated and in part replaced by uranium and vanadium minerals. Also, rich concentrations of uranium and vanadium are commonly associated with thin mudstone seams, beds of mudstone pebbles, and carbonaceous material of various types. Two suites of ore minerals are present in the ore deposits - - an oxidized suite of secondary uranium and vanadium minerals and a relatively unoxidized suite of “primary” uranium and vanadium minerals. The following geologic criteria are useful as guides to ore in the Spring Creek Mesa area: 1. Large ore deposits generally occur where the “ore-bearing sandstone” is more than 40 feet thick. 2. The color of the mudstone associated with the “ore-bearing sandstone” in the vicinity of large ore deposits is commonly gray instead of the usual red. 3. The “ore-bearing sandstone” is normally a light red, but in the vicinity of oxidized ore deposits it is light brown and in the vicinity of relatively unoxidized ore deposits it is gray. 4. The “ore-bearing sandstone” in the vicinity of relatively unoxidized ore deposits commonly contains sparse to abundant disseminated pyrite. In the vicinity of oxidized deposits it commonly contains abundant limonite spots and widespread limonite staining.

Colorado↗
USGS1953

Reconnaissance for uranium in the southeastern states, 1953

During the last quarter of 1952 and most of 1953 the U.S. Geological Survey carried on a program of reconnaissance for radioactive material in the southeastern states on behalf to the Atomic Energy Commission. In the course of the study 111 localities were examined and 43 samples were taken for radioactivity measurements at the Survey's Trace Elements laboratory in Denver, Colo. No economic deposits of uranium were found as a result of this work, but weak radioactivity was noted at the Tungsten Mining Coperation property near Townsville, N. C.; the Comolli granite quarry near Elberton, Ga.; in the Beech and Cranberry granite near Roan Mountain, Tenn.; and in several shales in the Valley and Ridge and Appalachian Plateau provinces. Devonian through Pennsylvanian rocks in these two provinces probably constitute the most favorable ground for new discoveries of uranium in the Southeast.

Alabama;Florida;Georgia;Kentucky;Mississippi;North↗
USGS1954

Thorium and rare earth minerals in the Powderhorn district, Gunnison County, Colorado

Thorium has been found since 1949 in at least 33 deposits in an area 6 miles wide and 20 miles long in the Powderhorn district, Gunnison County, Colo. The district is composed largely of pre-Jurassic metamorphic and igneous rocks, which are chiefly if not entirely pre-Cambrian in age. The metamorphic and igneous rocks are overlain by sandstone of the Morrison formation of Jurassic age, and by volcanic rocks of the Alboroto group and Hinsdale formation of Miocene and Pliocene (?) age, respectively. The thorium deposits occur in or near alkalic igneous rocks in which such elements as titanium, rare earths, barium, strontium, and niobium occur in greater-than-average amounts. The greatest mass of the alkalic igneous rocks the Iron Hill composite stoc,- occupies an area of 12 square miles in the southeastern part of the district. The age of the thorium deposits, like that of the alkalic igneous rocks, is not known other than pre-Jurassic. The thorium veins and mineralized shear zones range from a few inches to 18 feet in thickness and from a few feet to 3,500 feet in length. The veins are composed of calcite,.dolomite, siderite, ankerite, quartz, barite, pyrite, sphalerite, galena, goethite,. apatite, alkali feldspar, and many other minerals. The thorium occurs at least partly in thorite or hydrothorite. Sparse xenotime has been tentatively identified in one deposit. Several minerals containing rare earths of the cerium group as major constituents are found in carbonate veins near Iron Hill. Bastnaesite has been identified by X-ray methods, and cerite and synchisite are probably present also.The fluorapatite in some veins and in parts of the carbonate rock mass that occupies 2 square miles in the central part of the Iron Hill complex contains rare earths of the cerium group, generally in amounts of a fraction of a percent of the rock. The radioactivity of the deposits appears to be due almost entirely to thorium and its daughter products The ThO 2 content of selected highgrade samples from the Little Johnnie vein is as much as 4 percent. The ThO 2 content of the veins is generally less than 1 percent, however, and is only 0.05 to 0.1 percent in many of the veins studied. The little Johnnie vein, which was mapped in detail, can be traced discontinuously for a distance of more than 3,500 feet. The thoriumbearing material occurs as irregular veinlets and thin films introduced into the fault zone. The mineralized shear zone ranges from less than 6 inches to 5 feet in thickness. Near its west end the vein is broken by many faults in a zone that marks the edge of a roughly circular fault block, 1 1/2. miles in diameter, that has dropped 1,000 feet or more since the deposition of Miocene volcanic-rocks that now floor the Milkranch basin.

Colorado↗
USGS1954

The copper and uranium deposits of the Coyote district, Mora County, New Mexico

The copper and uranium-vanadium deposits of the Coyote district, Mora County, N. Mec, are confined to the lower 2,000 feet of the Sangre de Gristo formation of Pennsylvanian and Permian age. A narrow belt of deposits in steeply dipping or overturned rocks extends for 7 miles along Coyote Creek south of Guadalupita. Earlier studies showed that the copper deposits contained uranium, but both the reserves and the uranium content of the copper-bearing shale are too low to permit the recovery of uranium. However, small, commercial grade uranium deposits have been discovered in sandstone. Small lenses of copper-bearing carbonaceous shale, siltstone, limestone or sandstone, interbedded with predominantly red rocks, are present at intervals at 12 or more stratigraphic levels. The better deposits, in carbonaceous shale, average about 2 percent copper. The copper content of the other rocks is usually lower, but small concentrations may contain 6 percent copper. The principal copper minerals are chalcocite and malachite. Chalcocite replaces wood and forms nodules that contain small, variable amounts of pyrite, bornite, covellite, and rarely, uraninite. The uranium deposits occur as small closely spaced pockets that are commonly localized by sedimentary structures within one or more fluviatile arkosic sandstone beds near the middle of the formation, particularly" where carbonized wood, clay galls, and rock fragments are abundant. The uraniferous sandstone is commonly stained pink by hematite that probably was introduced with the uranium. The color increases in intensity with the radioactivity. The outcrops of the uranium deposits are typically inconspicuous, but close inspection shows they contain malachite, chalcopyrite, black vanadium minerals of micaceous habit, metatyuyamunite and microscopic grains of an unidentified black uraniferous substance. The proportion of copper, uranium, and vanadium is variable and any metal may be dominant. The metals probably were derived from pre-Cambrian granitic rocks. Copper and minor amounts of uranium were deposited in local stagnant basins by reaction with hydrogen sulfide. and decaying organic material. The uraniferous shales and the copper deposits are believed to be syngenetic, or nearly so, but the uranium deposits in sandstone are epigenetic and probably were deposited from ground waters with a possible hydrothermal admixture. The uranium and vanadium may have been reconcentrated from earlier, low-grade, syngenetic deposits.

New Mexico↗
USGS1955

Relation of uranium to hypogene mineral zoning in the Front Range mineral belt, Colorado

Many of the mining districts of the Colorado Front Range mineral belt contain mesothermal sulfide ores that exhibit a zonal distribution. Present data indicate that in most of the zoned districts pitchblende and/or secondary uranium minerals are most abundant in a transition zone between central areas containing predominantly pyritic gold ores and peripheral areas containing dominantly lead-zinc-silver deposits. Copper in the form of chalcopyrite is also probably more abundant in the transition zone than in adjacent zones. Many mineralized areas in the Front Range mineral belt are roughly co-extensive with and probably related to groups of Tertiary intrusives. The solutions that deposited sulfide and pitchblende in these areas probably were derived from many different types of source magma, but some bostonite magmas were probably particularly important sources of uranium-bearing solutions. At most localities where the relative ages of pitchblende and associated sulfides are known, the pitchblende is early in the paragenetic sequence, and not of intermediate age as suggested by its zonal position. This discrepancy may be the result of overlapping zones of deposition related to adjacent centers of mineralization, to changing environments of deposition within zones during the period of mineralization, or to unknown factors. Uranium is also present in districts in which the dominant mineralization is markedly different from the common pyritic gold-base metal sulfide mineralization. In the Jamestown district uranium appears to be associated'.mainly with fluorspar;, in other districts that exhibit little or no systematic hypogene zoning) it is ubiquitous. If uranium is present in zoned districts, a large proportion of she deposits probably should be in the transition zones. The application of this concept may be a valuable guide in prospecting for uranium.

Arizona;Colorado↗
USGS1959

A Summary interpretation of geologic, hydrologic, and geophysical data for Yucca Valley, Nevada test site, Nye County, Nevada

This report summarizes an interpretation of the geology of Yucca Valley to depths of about 2,300 feet below the surface, the characteristics features of ground water in Yucca and Frenchman Valleys, and the seismic, gravity, and magnetic data for these valleys. Compilation of data, preparation of illustrations, and writing of the report were completed during the period December 26, 1958 to January 10, 1959. Some of the general conclusions must be considered as tentative until more data are available. This work was done by the U.S. Geological Survey on behalf of Albuquerque Operations Office, U.S. Atomic Energy Commission.

Nevada↗