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At least 469 records · Page 26Linked to original sources
USGS1957

Distribution of elements in the Salt Wash member of the Morrison Formation in the Jo Dandy area, Montrose County, Colorado

A study of the distribution of elements in the Salt Wash member of the Morrison formation of Jurassic age from samples taken in the Jo Dandy area, Montrose County, Colo., was made to determine average chemical composition of mudstone and sandstone and to determine the magnitude of variations in concentrations of elements within similar rock types. Analytical data were obtained by semiquantitative spectrographic and radiometric methods. Results of the study show that variations in concentrations of about 20 elements commonly detected by semiquantititive spectrographic analyses of sedimentary rocks are small for a specific rock type; therefore, considerable confidence may be placed upon the average chemical appears to be no significant relation between chemical composition of mudstone or sandstone and distance from known uranium-vanadium ore or mineralization rock. Mudstone generally contains greater concentrations of the elements studied than sandstone. The chemical composition of red mudstone is similar to the chemical composition of green mudstone except that red mudstone was found to contain almost twice as much calcium as green mudstone in the Jo Dandy area. Samples of the unoxidized sandstone from the Jo Dandy area contain about twice as much calcium, three times as much strontium, but only about one-half as much as zirconium as oxidized sandstone; except for these elements the chemical compositions of both categories of sandstone are similar. Samples of sandstone of the Salt Wash member in the Jo Dandy area contain more potassium, magnesium, vanadium, and nickel than “average sandstone” of the Salt Wash member. The distribution of bismuth in rocks of the Jo Dandy area suggests that bismuth and perhaps part of the potassium and magnesium found in rocks of the Salk Wash member were either derived from solutions which ascended from the underlying salt- and gypsum-bearing Paradox member that was incorporated with rocks of the Salt Wash during sedimentation.

Colorado↗
USGS1959

Comparison of thickness, grade, and depth of radioactive layers as determined by gamma-ray logging and by core sampling

Thickness, grade, and depth data were obtained by analyzing gamma-ray logs and core samples from 56 diamond drill holes penetrating uranium deposits in the Colorado Plateau. The data from the two methods were compared to determine variations found in gamma-ray log interpretation and chemical and radiometric analyses of the drill core. Correlations within each parameter varied among the drilling areas analyzed. Gamma-ray interpretations of grade compared to chemical analyses were within the range of -10 to +25 percent. Most depth measurements determined by gamma-ray log interpretation compared to drill core measurement were within 0.5 percent. Results of the study indicate a need for better thickness definition in both gamma-ray logging and core scanning equipment.

Trace Elements Investigations↗
USGS1956

Volumetric determination of uranium using titanous sulfate as reductant before oxidimetric titration

A new method for determining uranium in samples containing 0.05 percent or more U 3 O 8 , using titanous sulfate as reducing agent, is much shorter, faster, and has fewer interferences than conventional methods using reductor columns. The sample is dissolved with sulfuric, nitric, perchloric, and hydrofluoric acids. Elements that would otherwise form insoluble fluorides are kept in solution by complexing the fluoride ion with boric acid. A precipitation is made with cupferron to remove interfering elements. The solution is filtered to remove the precipitated cupferrates instead of extracting them with chloroform as is usually done. Filtration is preferred to extraction because any niobium that may be in solution forms an insoluble cupferrate that may be removed by filtering but is very difficult to extract with chloroform. Excess cupferron is destroyed by oxidizing with nitric and perchloric acids, and evaporating to dense fumes of sulfuric acid. The uranium is reduced to U(IV) by the addition of titanous sulfate, with cupric sulfate used as an indicator of the completeness of the reduction. Metallic copper is formed when all the uranium is reduced. The reduced copper is then reoxidized by the addition of mercuric perchlorate, an excess of ferric sulfate added, and the solution titrated immediately with standard ceric sulfate with ferroin as an indicator. Precision of the method compared favorable with methods in common use, both for uranium ores and for most types of uranium-rich materials.

Trace Elements Investigations↗
USGS1956

Uranium distribution in pseudowollastonite slag from a phosphorus furnace

Silicate slag from the Victor Chemical Company phosphorus furnace at Tarpon Springs, Fla., has been found to consist essentially of pseudowollastonite, α-CaSiO 3 . The first-formed crystals are euhedral laths which form a mesh making up most of the slag. As the slag continues to solidify, its composition changes slightly and more equant, subhedral crystals of pseudowollastonite are deposited within the framework of the earlier material. Finally, anherdral masses of fibrous, poorly crystallized material are deposited in the remaining pore spaces which are not always completely filled. Spherules of iron phosphide, Fe 2 P, occur very sparsely in the slag as inclusions from the immiscible iron phosphide melt. Uranium content increases in the later crystal products of the slag, and by heavy-liquid fractionation it has been possible to segregate partially the phases and to obtain a fourfold concentration of uranium in 5 percent of the material and a twofold concentration in 30 percent of the material. Nuclear-emulsion studies indicate that the last phases of the silicate slag are actually eight times as radioactive as the early phases. In addition, the iron phosphide spherules are comparably enriches in uranium.

Trace Elements Investigations↗
USGS1957

Summary of reconnaissance for uranium in Alaska, 1955

Reconnaissance for uranium in Alaska during 1955 included airborne radiometric traverses, examination of radioactivity anomalies found during the airborne traverses, examination of prospector leads, and examination of areas that seems geologically favorable for the occurrence of uranium. The airborne radiometric traverses in central Alaska revealed 33 anomalies considered worth examining. The ground examinations of a few of these anomalies indicated that they were due to radiation of from accessory minerals in intrusive granitic rocks. The examination of prospector leads revealed several radioactivity anomalies of interest and one, near Bokan Mountain on prince of Wales Island, of possible commercial importance.

Alaska↗
USGS1957

Lead-alpha age determinations of granitic rocks from Alaska

Lead-alpha activity age determinations were made on zircon from seven granitic rocks of central and southeastern Alaska. The results of the age determinations indicate two periods of igneous intrusion, one about 95 million years ago, during the Cretaceous period, and another about 53 million years ago, during the early part of the Tertiary. The individual ages determined on zircon from 2 rocks from southeastern Alaska and 1 from east-central Alaska gave results of 90, 100, and 96 million years; those determined on 4 rocks from central Alaska gave results of 47, 56, 58, and 51 million years.

Alaska↗
USGS1956

The physical behavior and geologic control of radon in mountain streams

Radon measurement were made in several small, turbulent mountain streams in the Wasatch Mountains near Salt Lake City and Ogden, Utah, to determine the relationship between the distribution of radon and its geologic environment. In this area, the distribution of radon in streams can be sued to locate points where relatively large amounts of radon-bearing ground water enter the stream, although other evidence of spring activity may be lacking. These points of influence ground water are marked by abrupt increases (as much as two orders of magnitude within a distance of 50 feet) in the radon content of the stream waters. The excess radon in the stream water is then rapidly lost to the atmosphere through stream turbulence. The rate of radon dissipation is an exponential function, of different slopes, with respect to distance of streamflow, and depend upon the rate and volume of streamflow, and the gradient and nature of the stream channel. The higher radon concentration can be generally related to specific stratigraphic horizons in several different drainage area. Thus, lithologic units which act as the primary aquifers can be identifies. In one area, thrust faults were found to control he influx of ground water into the stream. Estimates, based on radon concentration in stream and related spring waters, can also be made of the major increments of addition of ground water to streamflow where conventional methods such as stream gaging are not practical. The radon in the waters studied was found to be almost completely unsupported by radium in solution.

Utah↗
USGS1956

The determination of calcium in phosphate, carbonate, and silicate rocks by flame photometer

A method has been developed for the determination of calcium in phosphate, carbonate, and silicate rocks using the Beckman flame photometer, with photomultiplier attachement. The sample is dissolved in hydrofluoric, nitric, and perchloric acids, the hydrofluoric and nitric acids are expelled, a radiation buffer consisting of aluminum, magnesium, iron, sodium, potassium, phosphoric acid, and nitric acid is added, and the solution is atomized in an oxy-hydrogen flame with an instrument setting of 554 mµ. Measurements are made by comparison against calcium standards, prepared in the same manner, in the 0 to 50 ppm range. The suppression of calcium emission by aluminum and phosphate was overcome by the addition of a large excess of magnesium. This addition almost completely restores the standard curve obtained from a solution of calcium nitrate. Interference was noted when the iron concentration in the aspirated solution (including the iron from the buffer) exceeded 100 ppm iron. Other common rock-forming elements did not interfere. The results obtained by this procedure are within ± 2 percent of the calcium oxide values obtained by other methods in the range 1 to 95 percent calcium oxide. In the 0 to 1 percent calcium oxide range the method compares favorably with standard methods.

Trace Elements Investigations↗
USGS1956

Uranium content of ground and surface waters in western Kansas, eastern Colorado, and the Oklahoma Panhande

During 1954, 1955, and 1956, 324 water samples were collected in western Kansas, eastern Colorado, the Oklahoma Panhandle, and northeastern New Mexico, to determine the uranium content of water from the various rock units and geologic terranes in the region, and to locate areas in which, large amounts of uranium in the water might reflect the presence of nearby uranium accumulations. Three geologic terranes are present in the report area: the Tertiary-Quaternary tuff ace o us terrane, the Upper Cretaceous shale terrane, and the upper Permian through Lower Cretaceous sandstone terrane. The average uranium content of 179 water samples from the tuffaceous terrane, which is composed primarily of tuffaceous, fluviatile rocks ranging in age from Pliocene to Pleistocene, is 6.7 parts per billion. A total of 48 samples from the Upper Cretaceous shale terrane, which is composed almost entirely of shale and limestone of marine origin, contain an average of 20.4 parts per billion uranium , Sandstone, silt stone, and clay stone of terrestrial and near-shore marine origin are the predominant constituents of the upper Permian through Lower Cretaceous sandstone terrane, and the 83 water samples collected from, or related to, rock units of this terrane contain an average of 10.2 parts per billion uranium. The average uranium content figure derived for the tipper Cretaceous shale terrane may not be representative of the uranium content of waters from this terrane throughout the report area because more than half of the samples assigned to the terrane were collected in an area in which most water samples contain relatively large amounts of uranium. Compared to the shale terrane, the tuffaceous terrane and the sandstone terrane are both represented by a greater number of samples collected over a much larger area and the average uranium content figures derived for them are believed to be representative of the uranium content of waters from, or related to, rock units of the two terranes in the report area. The average uranium content figures derived for different rock units, or groups of rock units, subdivided by the source type from which the samples were collected (well, spring, stream, municipal water system, reservoir, or lake), and in some cases by geographic parts of the report area, are believed to be of more potential use in any future hydrogeochemical exploration in the area than are the average uranium content figures derived for the three geologic terranes. The average uranium content of ground-water samples from 12 individual rock units or groups of rock units ranges from less than 1. 0 to 38 parts per billion. Several rock units were sampled over large enough areas to indicate that waters from the same rock unit in different parts of the report area may range widely in average uranium content. Water samples from some of the rock units in the area, particularly those of Triassic and Permian age, contain large amounts of uranium, and in some parts of the report area, such as the Cimarron River area of westernmost Oklahoma and northeastern New Mexico, and the Rule Creek area in Bent and Las Animas Counties, Colo. , most, or all, of the water samples collected contain relatively large amounts of uranium. Further exploration to determine the source of the uranium in the water from these rock units and areas may be worthwhile.

Colorado;Kansas;New Mexico;Oklahoma↗
USGS1956

Uranium content and leachability of some igneous rocks and their geochemical significance

The uranium content and its leachability in 442 igneous rocks if wide variety were measured. Four-gram samples, crushed below 38 mesh, were leached in in 0.05 M HNO 3 for half an hour at 80 to 85° C; the leachate and undissolved residue were analyzed fluorimetrically. This study explored the relation of uranium content and leachability to petrography. With few exceptions, the relations between uranium content, uranium leachability, rock leachability, rock type, and mineral composition seem to be random. Uranium content and leachability in homogeneous outcrops vary erratically, in heterogeneous outcrops the variation appears nonsystematic. Correlations with geologic environment indicate that uranium content and leachability are largely controlled by geologic processes during and after crystallization.

Trace Elements Investigations↗
USGS1956

A dithizone method for the determination of lead in monazite

In determining lead in monazite [(Ce,La,Th)PO 4 ]--to be used as the basis for geologic age measurements--it was necessary to eliminate interferences due to the presences of phosphates of thorium and the rare-earth metals. The method, in which monazite samples are attacked with hot concentrated sulfuric acid, taken up with dilute nitric acid, lead extracted as the dithizonate and then determined spectrophotometrically at 520 mμ, was successfully applied to a series of monazite samples. Rapid determinations were made with good reproducibility.

Trace Elements Investigations↗