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USGS1952

Stratigraphic sections of the Phosphoria formation in Wyoming, 1947-48

As part of a comprehensive investigation of the phosphate deposits of the western field begun in 1947, the U. S. Geological Survey has measured and sampled the Permian Phosphoria formation at many localities in Wyoming and adjacent states. Because these data will not be fully synthesized for many years, segments of the data, accompanied by little or no interpretation, will be published as preliminary reports as they are assembled. This report, which contains abstracts of some of the sections measured in western Wyoming (pl. 1), is one of this series. The field and laboratory procedures adopted in these investigations are described rather fully in a companion report (McKelvey and others, 1952a). Many people have taken part in this investigation. R. M. Campbell, R. A. Gulbrandsen, R. A. Harris, D. M. Larrabee, F. W. O'Malley, O. A. Payne, R. S. Sears, R. P. Sheldon, and R. A. Smart participated in the description of the strata and the collection of the samples referred to in this report. D. B. Dimick, H. A. Larsen, and T. K. Rigby assisted in the preparation of exposures and the crushing and splitting of samples in the field. The laboratory preparation of samples for chemical analysis was done in Denver, Colo., under the direction of W. P. Huleatt. Most of the P 2 O 5 and acid-insoluble analyses were made for the Survey by the U. S. Bureau of Mines at the Northwest Electrodevelopment Laboratory, Albany, Oreg., under the direction of S. M. Shelton and M. L. Wright. Most of the Al 2 O 3 , Fe 2 O 3 , and loss-on-ignition analyses were made by the Trace Elements Section laboratory of the Survey in Washington, D. C., under the direction of J. C. Rabbitt by chemists I. Barlow, A. Caemmerer, J. Greene, F. S. Grimadli, N. Guttag, H. Levine, H. Mela, Jr., and R. G. Milkey, and most of the spectrographic reports were prepared in this laboratory by C. L. Waring. The samples from one locality (Coal Canyon) were analyzed for P 2 O 5 , Al 2 O 3 , Fe 2 O 3 , V 2 O 5 , F, loss on ignition, and acid insoluble in the Chemical Laboratory of the Tennessee Valley Authority at Wilson Dam, Alabama, and spectrographically by D. M. Mortimer, of the Bureau of Mines at Albany. Compilation of the data has been largely by R. P. Sheldon and F. D. Frieske under the supervision of R. W. Swanson. Organization of the tabular data has been largely by Anita Cozzetto.

Wyoming↗
USGS1953

Stratigraphic sections of the Phosphoria Formation in Idaho, 1949: part II

The U.S. Geological Survey has recently measured and sampled the Phosphoria formation at many localities in Idaho and other western states. These data will not be fully synthesized and analyzed for several years, but segments of the data, accompanied by little or no interpretation, are published as preliminary reports as they are assembled. This is the fifth report of data containing abstracts of sections measured in southeastern Idaho; it includes about half of the data gathered in Idaho in 1949. The field and laboratory procedures adopted in these investigations are described rather fully in a previous report (McKelvey and others, 1953a). Many people have taken part in this investigation, which was organized and supervised by V. E. McKelvey. F. J. Anderson, A. L. Bush, R. S. Jones, K. B. Krauskopf, K. Lutz, M. E. Thompson, R. G. Waring, and M. A. Warner participated in the description of strata and the collection of samples referred to in this report. T. K. Rigby assisted in the preparation of trenches and the collection, crushing, and splitting of samples in the field. The laboratory preparation of samples for chemical analysis was done in Denver, Colo., under the direction of W. P. Huleatt.

Idaho↗
USGS1952

Stratigraphic sections of the Phosphoria formation in Utah, 1947-48

As part of a comprehensive investigation of the phosphate deposits of the western field begun in 1947, the U. S. Geological survey has measured an sampled the full thickness of the Permian Phosphoria formation and its partial correlative, the Park City formation, at many localities in Utah and other western states. Although these data will not be fully analyzed for several years, segments of the data, accompanied by little or no interpretation, will be published as preliminary reports. This report, which contains abstracts of many of the sections measured in northeastern Utah (pl. 1), is one of this series. The field and laboratory procedures adopted in these investigations are described rather fully in a companion report (McKelvey and others, 1952). A large number of people have taken part in this investigation. J. B. Collins, R. A. Gulbrandsen, R. A. Hoppin, J. A. Noel, F. W. O'Malley, O. A. Payne, J. F. Rominger, R. P. Sheldon, J. E. Smedley, and R. G. Waring participated in the description of strata and collection of samples referred to in this report. D. B. Dimick, H. A. Larsen, and T. K. Rigby assisted in the preparation of trenches and the crushing and splitting of samples in the field. The laboratory preparation of samples for chemical analysis was done in Denver, Colo., under the direction of W. P. Huleatt. Most of the chemical analyses reported herein were made for the Survey by the U. S. Bureau of Mines at the Northwest Electrodevelopment Laboratory, Albany, Oreg., under the direction of S. M. Shelton and M. L. Wright. All the samples from one locality (Brazer Canyon) were analyzed in the Chemical Laboratory of the Tennessee Valley Authority at Wilson Dam, Ala. Some of the Al 2 O 3 , Fe 2 O 3 , and loss-on-ignition analyses were made in the Trace Elements Section laboratory of the Survey in Washington, D. C., under the direction of J. C. Rabbitt by chemists I. Barlow, A Caemmerer, J. Greene, N. Guttag, and E. H. Humphrey. The spectrographic analyses were made by D. M. Mortimer, of the Bureau of Mines in Albany. Compilation of the data has been largely by R. P. Sheldon and F. D. Frieske under the supervision of R. W. Swanson. Organization of the tabular data has been largely by Anita Cozzetto.

Utah↗
USGS1952

Geophysical observations in parts of the Grants District, McKinley County, New Mexico

Geophysical observations near Haystack Mesa in the Grants district, McKinley County, New Mexico, had the dual objective of investigating the unusual occurrence of negative aeromagnetic anomalies in close association with airborne radioactivity anomalies, and of investigating other geophysical methods which might assist directly or indirectly in the search for uranium ores in the Grants district. Ground magnetometer tests indicate the apparent correlation shown in the airborne data is fortuitous. Ground magnetometer and self-potential surveys on an experimental basis may be justified to test the applicability of these methods in future exploration. Aeroagnetic surveys would aid field geologic studies in locating concealed Tertiary intrusives, which may have affected ore localization. Continuation of the airborne radiometric survey of the Todilto limestone outcrop is recommended to search for promising areas that might contain additional deposits.

New Mexico↗
USGS1953

Stratigraphic sections of the Phosphoria Formation in Montana, 1949-50: part I

The U.S. Geological Survey has recently measured and sampled the Phosphoria formation at many localities in Montana and other western states. These data will not be fully synthesized for many years, but segments of the data, accompanied by little or no interpretation, are published as preliminary reports as they are assembled. This report, which contains abstracts of the sections measured in southwestern Montana (fig. 1) is one of this series and is the third Montana report; it includes about half of the data gathered in Montana during 1949 and 1950. The field and laboratory procedures adopted in these investigations are described rather fully in a previous report (McKelvey and others, 1953). Many people have taken part in this investigation. The program which this work is a part was organized by V. E. McKelvey and the field program was supervised by R. W. Swanson, T. M. Cheney, J. L. Elliott, F. D. Frieske, R. F. Gosman, R. S. Jones, B. K. Replogle, and R. G. Waring participated in the description of strata and the collection of samples referred to in this report. Crushing and splitting of the samples in the field was done by T. K. Rigby. The laboratory preparation of samples for chemical analysis was done in Denver, Colo., under the direction of W. P. Huleatt.

Montana↗
USGS1953

Stratigraphic sections of the Phosphoria formation in Wyoming, 1949-50

As part of a comprehensive investigation of the phosphate deposits of the western field begun in 1947, the U.S. Geological Survey has measured and sampled the Phosphoria formation of Permian age at many localities in Wyoming and adjacent states. These data will not be fully synthesized for many years, but segments of the data, accompanied by little or no interpretation, are published as preliminary reports as they are assembled. This report, which contains abstracts of the sections measured in western Wyoming (figs 1 and 2) in 1949 and 1950, is the second Wyoming report of this series. The field and laboratory procedures adopted in these investigations are described rather fully in a previous report (McKelvey and others, 1953a). Many people have taken part in this investigation, which was organized and supervised by V. E. McKelvey and most of the field program was supervised by R. W. Swanson. F. J. Anderson, D. F. Davidson, A. M. Gutstadt, J. W. Hill, H. W. Peirce, W. R. Record and M. E. Thompson participated in the description of strata and the collection of samples referred to in this report. T. K. Rigby assisted in the preparation of exposures and the crushing and splitting of samples in the field. The laboratory preparation of samples for chemical analysis was done in Denver, Colo., under the direction of W. P. Huleatt.

Wyoming↗
USGS1953

Stratigraphic sections of the phosphoria formation in Utah, 1949-1951

As part of a comprehensive investigation of the phosphate deposits of the western field begun in 1947, the U.S. Geological Survey has measured and sampled the full thickness of the Permian Phosphoria formation and its partial correlative, the Park City formation, at many localities in Utah and other states. Although these data will not be fully analyzed for several years, segments of the data, accompanied by little or no interpretation, are published as preliminary reports as they are assembled. This report, which contains abstracts of the sections measured in northeastern Utah in 1949, 1950, and 1951, is one of this series and the second report of data gathered in Utah. The field and laboratory procedures adopted in these investigations are described rather fully in a previous report (McKelvey and others, 1953a). Many people have taken part in this investigation. The program which this work is a part was organized by V. E. McKelvey and the field program was supervised by R. W. Swanson. R. P. Sheldon assisted in the location and selection of sample localities and F. J. Anderson, McKelvey, Sheldon, and H. W. Peirce participated in the description of strata and the collection of samples referred to in this report. T. K. Rigby assisted in the preparation of trenches and the crushing and splitting of samples in the field. The laboratory preparation of samples for chemical analysis was done in Denver, Colo., under the direction of W. P. Huleatt.

Utah↗
USGS1951

Stratigraphic sections of the Phosphoria formation in Idaho, 1947-48, Part III

.The U.S. Geological Survey has measured and sampled the Phosphoria formation at many localities in Idaho and other western states. These data will not be fully synthesized and analyzed for several years but segments of the data, accompanied by little or no interpretation, are published as preliminary reports as they are assembled. This report, which contains abstracts of many of the sections in southeastern Idaho (fig. 1), is one of this series and is the third report of data gathered in Idaho during 1947 and 1948. The field and laboratory procedures adopted in these investigations are described rather fully in a companion report (McKelvey and others, 1953). Many people have taken part in this investigation, which was organized and supervised by V. E. McKelvey. D. A. Bostwick, R. M. Campbell, R. A. Gulbrandsen, R. A. Harris, R. L. Parker, R. A. Smart, J. E. Smedley, R. H. Thurston, and R. G. Waring participated in the description of strata and collection of samples referred to in this report. D. B. Dimick, Jack George, W. S. Hunziker, J. E. Jones, H. A. Larsen, and T. K. Rigby assisted in the preparation of trenches and collection, crushing, and splitting of samples in the field. The laboratory preparation of samples for chemical analysis was done in Denver, Colo., under the direction of W. P. Huleatt.

Idaho↗
USGS1954

Stratigraphy of parts of De Soto and Hardee Counties, Florida

The late Cenozoic stratigraphy of part of central Florida immediately south of the land-pebble phosphate district was studies in detail to determine the southern limit of the economically important Bone Valley formation and its relations with marine rocks of late Miocene and Pliocene age in south-central Florida. In addition a reconnaissance type appraisal of the phosphate and uranium resources of this area was desired. The upper Tertiary and Quaternary rocks were mapped, and the economic geology was studied in a general manner. The Hawthorn formation of middle Miocene age, is the oldest rock Exposed. Undifferentiated phosphatic sand and clay may be composed of the Bone Valley formation, of late Miocene to Pliocene age; a combination of Bone Valley formation and residuum of weathered Hawthorn formation; or Hawthorn residuum alone. The Bone Valley formation and residuum of Hawthorn formation appear almost identical in cuttings from auger drilling in this area. It was not feasible nor practical to map these two units separately. The undifferentiated phosphatic sand and clay interfingers with a marine sand of late Miocene age, The Caloosahatchee marl of Pliocene age, is present in the southeast corner of the area investigated. It is apparent that the undifferentiated phosphatic sand and clay was undergoing subaerial erosion and reworking during deposition or the Caloosahatchee marl. Stratified sand and clayey sand containing scattered thin lenses of fresh-water limestone and marl of Pleistocene age are either floodplain deposits or subaerial topset beds of a delta made by the Pleistocene Peace River. Sediments of Recent age are local stream deposits. Bars and shoals in the Peace River south of Brownville, De Soto County, contain appreciable tonnages of low grade "river-pebble" phosphate. The phosphate and uranium content of the undifferentiated phosphatic sand and clay in Hardee County is too low to be of economic significance.

Florida↗
USGS1953

A magnetic investigation of the Round Mountain plug, Castle Valley, Grand County, Utah

A magnetic survey was made in Castle Valley, Grand County, Utah, to determine if the Round Mountain plug was fed laterally from the La Sal Mountains or vertically from a source at depth. Additional measurements were made around the exposure of igneous rock to obtain the shape of the plug at depth. No indication of a buried lateral igneous feeder was detected on the magnetic profileso The magnetic contour map showed that the plug was much larger than indicated by the diorite porphyry outcrop, and that the buried part of the plug southeast of Round Mountain has a higher magnetic susceptibility than the diorite outcrop. Theoretical anomalies, calculated using the susceptibility of the diorite outcrop, indicate that a lateral feeder at a depth of greater than 200 feet could not be detected. The size and shape of the magnetic anomaly as shown on the contour map suggest that the plug was fed from a source at depth.

Utah↗
USGS1956

X-ray powder data for uranium and thorium minerals

The U.S. Geological Survey has in preparation a comprehensive volume on the mineralogy of uranium and thorium. This work has been done as part of a continuing systematic survey of data on uranium and thorium minerals on behalf of the Division of Raw Materials, U.S. Atomic Energy Commission. Pending publication of this volume and in response to a widespread demand among workers in uranium and thorium mineralogy, the X-ray powder diffraction data for the known minerals that contain uranium or thorium as an essential constituent are presented here. The coverage is complete except for a few minerals for which there are no reliable data owing to lack of authentic specimens. With the exception of that for ianthinite, the new data either originated in the Geological Survey or in the Mineralogical Laboratory of Harvard University. Data from the literature or other sources were cross-checked against the files of standard patterns of these laboratories; the sources are indicated in the references. Data not accompanied by a reference were obtained from films in the Harvard Standard File and cross-checked as to the identity of the film with the Geological Survey's file. Minor differences can be expected in the d-spacings reported for the same specimens by different investigators because of the manner of preparation of the mount, the conditions of X-ray irradiation, and the method of photography and measurement of the film or chart. The Harvard and Geological Survey data all were obtained from films taken in 114-mm diameter cameras, using either ethyl cellulose and toluene or collodion spindle mounts and Straumanis-type film mounting. Unless otherwise indicated all patterns were taken with copper radiation (Kα 1.5418 A.) and nickel filter and data are given in Angstrom units. The d-spacings are not corrected for film shrinkage. The correction ordinarily is small and in general is less than either the variation in spacing arising from differences in experimental technique of different investigators, including the varying absorption of samples of different thickness and concentration, or the variation attending slight changes in the chemical composition of the mineral. Some uranium minerals give poor diffraction patterns. The best results are generally obtained by using relatively small diameter spindles and long exposures, with a take-off angle from teh X-ray tube of about 4°. It is sometimes advantageous to shield the film from fluorescence in the visible region excited by X-ray irradiation. Copper radiation is preferable. The patterns of a few uranium minerals are greatly impaired by heavy grinding of the sample. Light crushing of the coarse sample after mixing with about one-third its volume of coarsely powdered low-absorption glass is helpful. Many uranium minerals, such as the members of the torbernite group, readily lose zeolithic water or transform to lower hydrates at or near ordinary conditions of temperature and humidity and care should be taken to control this in the manner of preservation and preparation of the sample.

Trace Elements Investigations↗
USGS1955

Reconnaissance for radioactive deposits in Alaska, 1953

During the summer of 1953 the areas investigated for radioactive deposits in Alaska were on Nikolai Creek near Tyonek and on Likes Creek near Seward in south-central Alaska where carnotite-type minerals had been reported; in the headwaters of the Peace River in the eastern part of the Seward Peninsula and at Gold Bench on the South Fork of the Koyukuk River in east-central Alaska, where uranothorianite occurs in places associated with base metal sulfides and hematite; in the vicinity of Port Malmesbury in southeastern Alaska to check a reported occurrence of pitchblende; and, in the Miller House-Circle Hot Springs area of east-central Alaska where geochemical studies were made. No significant lode deposits of radioactive materials were found. However, the placer uranothorianite in the headwaters of the Peace River yet remains as an important lead to bedrock radioactive source materials in Alaska. Tundra cover prevents satisfactory radiometric reconnaissance of the area, and methods of geochemical prospecting such as soil and vegetation sampling may ultimately prove more fruitful in the search for the uranothorianite-sulfide lode source than geophysical methods.

Alaska↗
USGS1952

Reconnaissance of uranium and copper deposits in parts of New Mexico, Colorado, Utah, Idaho, and Wyoming

Because of the common association of uranium and copper in several of the commercial uranium deposits in the Colorado Plateau Province, a reconnaissance was made of several known deposits of copper disseminated through sandstone to determine whether they might be a source of uranium. In order to obtain more information regarding the relationship between copper, uranium and carbonaceous materials, some of the uraniferious asphaltrite deposits in the Shinarump conglomerate along the west flank of the San Rafael Swell were also investigated briefly. During this reconnaissance 18 deposits were examined in New Mexico, eight in Utah, two in Idaho, and one each in Wyoming and Colorado. No uranium deposits of commercial grade are associated with the copper deposits that were examined. The uraniferous asphaltites in the Shinarump conglomerate of Triassic age on the west flank of the San Rafael Swell, however, are promising from the standpoint of commercial uranium production. Spectrographic analyses of crude oil, asphalt, and bituminous shales show a rather consistent suite of trace metals including vanadium, nickel, copper, cobalt, chromium, lead zinc, and molybdenum. The similarity of the metal assemblage, including uranium of the San Rafael Swell asphaltites, to the metal assemblage in crude oil and other bituminous materials suggests that these metals were concentrated in the asphaltites from petroleum. However, the hypothesis that uranium minerals were already present before the hydrocarbons were introduced and that some sort of replacement or uranium minerals by carbon compounds was effected after the petroleum migrated into the uranium deposit should not be disregarded. The widespread association of uranium with asphaltic material suggests that it also may have been concentrated by some agency connected with the formation of petroleum. The problem of the association of uranium and other trace metals with hydrocarbons should be studied further both in the field and in the laboratory.

Colorado;Idaho;New Mexico;Utah;Wyoming↗
USGS1953

Summary of investigations of uranium deposits in the Pumpkin Buttes area, Johnson and Campbell Counties, Wyoming

Uranium minerals were discovered in the Pumpkin Buttes area Campbell and Johnson Counties by the U.S. Geological Survey in October 1951 From June to November 1952 an area of about 750 square miles was examined for uranium deposits, and 211 localities with abnormally high radioactivity were found uranium minerals are visible at 121 of these localities. All known uranium mineralization is restricted to sandstones of the Wasatch formation exclusive of sparsely disseminated uranium in the White River sandstone which caps the Pumpkin Buttes and several localities on the Great Pine Ridge southwest of the Pumpkin Buttes where ironstone and clinker in the Fort Union formation have above normal radioactivity. The uranium occurrences in the Wasatch formation are in a red sandstone zone 450 to 900 feet above the base of formation and are of two types. (1) small concretionary masses of uranium, iron, and manganese minerals in sandstone and (2) irregular zones in which uranium minerals are disseminated in sandstone The second type is usually larger but lower grade than the first type. Most of the localities at which uranium occurs are in a north -trending belt approximately 60 miles long with a maximum width of 18 miles,

Wyoming↗
USGS1954

Geology and uranium deposits of the Caribou area, Boulder County, Colorado

Pitchblende was discovered in the Caribou mine, Boulder County. Colo., in 1948 by Consolidated Caribou Silver Mines, incorporated during the reopening of the 1040-level. Since 1948, a small quantity of pitchblende has been produced from the Radium vein during exploratory work that was done under contract with the Atomic Energy Commission. The Caribou mine, primarily a silver mine, develops five veins (Caribou. No Name, Poorman, Sherman and Silver Dollar) that were formerly worked as separate mines. Three other veins, the Radium, Elmer, and Nelson, are exposed in the Caribou mine only at and below the 920-level. The general geology of the Caribou area, known since 1869 as a silver district, has been discussed by Bastin and Hill (1917) and more recently by Lovering and Goddard (1950). In 1937 a detailed study of the petrography of the Caribou stock was made by Smith (1938). In 1948 and 1949, R.U. King (1950) of the U. S., Geological Survey examined the Caribou mine to evaluate the uranium deposit. In 1950, D.M. Sheridan and E.N. Hinrichs of the U. S. Geological Survey made a radioactivity reconnaissance of the mine dumps at Caribou and vicinity. This reconnaissance included examination of most of the accessible workings of the Caribou mine. Other reports on the area are listed in the bibliography. As a result of King’s preliminary examination and the later exploration for uranium on the property, the U.S. Geological Survey in 1951 began a detailed investigation of the Caribou area on behalf of the Division of Raw Materials of the Atomic Energy Commission, the principal purpose of which was to evaluate the uranium occurrences in the area. The study was begun by E. P. Kaiser and W. S., Cavender, who established a triangulation net, using a base line in Caribou Park for horizontal control and a U.S. Geological Survey bench mark on the top of Caribou Hill for vertical control. Upon the assignment of Kaiser to another project in August 1951 the investigation was continued until November 1951, by F.B. Moore and W. S. Cavender. During the study of the district the writers prepared a geologic map at a scale of 1 inch to 100 feet of an area of about one square mile. The mapped area includes most of the mines in the Caribou district and embraces the eastern half of Caribou Hill and adjacent areas to the east and north. In addition, all accessible underground workings were mapped at a scale of 1 inch to 40 feet. The writers wish to acknowledge the cooperation of the staff of the Consolidated Caribou Silver Mines incorporated, who made the Caribou mine available for examination at all times and who furnished maps and suggestions that were of great assistance. Mr. A.E. Blakesley, owner of the Comstock mine, was also most cooperative in making possible the examination of his mine. Thanks are due Dr., E.E. Wahlstrom of the University of Colorado and to the Boulder Daily Camera for the use of their files containing information on the Caribou mine. To S. Lovering of the U.S. Geological Survey made many valuable suggestions on the identification of alteration products in thin section.

Colorado↗
USGS1953

Radioactive source materials in Los Estados Unidos de Venezuela

This report summarizes the data available on radioactive source materials in Los Estados Unidos de Venezuela accumulated by geologists of the Direccions Tecnica de Geolgia and antecedent agencies prior to June 1951, and the writers from June to November 1951. The investigation comprised preliminary study, field examination, office studies, and the preparation of this report, in which the areas and localities examined are described in detail, the uranium potentialities of Venezuela are summarized, and recommendations are made. Preliminary study was made to select areas and rock types that were known or reported to be radioactive or that geologic experience suggests would be favorable host for uranium deposits, In the office, a study of gamma-ray well logs was started as one means of amassing general radiometric data and of rapidly scanning many of ye rocks in northern Venezuela; gamma-ray logs from about 140 representative wells were examined and their peaks of gamma intensity evaluated; in addition samples were analyzed radiometrically, and petrographically. Radiometic reconnaissance was made in the field during about 3 months of 1951, or about 12 areas, including over 100 localities in the State of Miranda, Carabobo, Yaracuy, Falcon, Lara, Trujillo, Zulia, Merida, Tachira, Bolivar, and Territory Delta Amacuro. During the course of the investigation, both in the filed and office, information was given about geology of uranium deposits, and in techniques used in prospecting and analysis. All studies and this report are designed to supplement and to strengthen the Direccion Tecnica de Geologias's program of investigation of radioactive source in Venezuela now in progress. The uranium potentialities of Los Estados de Venezuela are excellent for large, low-grade deposits of uraniferous phospahtic shales containing from 0.002 to 0.027 percent uranium; fair, for small or moderate-sized, low-grade placer deposits of thorium, rare-earth, and uranium minerals; poor, for high-grade hydrothermal pitchblende deposits; and highly possible for small, medium- to high-grade despots of carnotite-or copper-uranium bearing sandstone. Recommendations for the Venezuelan uranium program include 1) the systematic collection of a mass general radiometric data by examining sample collections, expanding the gamma-ray program, encouraging the use of Geiger counter by field geologists, and by enlisting the aid of the general public; 2) , the examination of specific areas or localities, chosen on the basis of geologic favorability from the results of the amassing of data, or obtained by hints and rumors; 3), the organization of a unit within the Direccion Tecnica de Geologica to direct, collection, and collate metric data. It is emphasized that to be most fruitful the program requires the application of sounds and imaginative geologic theory.

Trace Elements Investigations↗
USGS1953

Radioactive deposits of Nevada

Thirty-five occurrences of radioactive rocks had been reported from Nevada prior to 1952. Twenty-five of these had been investigated by the U. S. Geological Survey and the U. S. Atomic Energy Commission. Of those investigated, uranium minerals were identified in 13; two contained a thorium mineral (monazite); the source of radioactivity on 7 properties was not ascertained; and one showed no abnormal radioactivity. Of the other reported occurrences, one is said to contain uraniferous hydrocarbons and 9 are placers containing thorian monazite. Pitchblende occurs at two localities; the East Walker River area, and the Stalin's Present prospect, where it is sparsely disseminated in tabular bodies cutting granitic rocks. Other uranium minerals found in the state include: carnotite, tyuyamunite, autunite, torbernite, gummite, uranophane, kasolite, and an unidentified mineral which may be dumontit. Monazite is the only thorium mineral of possible economic importance that has been reported. From an economic standpoint 9 only 4 of the properties examined showed reserves of uranium ore in 1952; these are: the Green Monster mine, which shipped 5 tons of ore to Marysvale, Utah, during 1951, the Majuba Hill mine, the Stalin's Present prospect, and the West Willys claim in the Washington district. Reserves of ore grade are small on all of these properties and probably cannot be developed commercially unless an ore-buying station is set up nearby. No estimate has been made of thorium reserves and no commercial deposits of thorium are known.

Nevada↗
USGS1954

A field method for making a quantitative estimate of altered tuff in sandstone

The use of benzidine to identify altered tuff in sandstone is practical for field or field laboratory studies associated with stratigraphic correlations, mineral deposit investigations, or paleogeographic interpretations. The method is based on the ability of saturated benzidine (C 12 H 12 N 2 ) solution to produce a blue stain on montmorillonite-bearing tuff grains. The method is substantiated by the results of microscopic, X-ray spectrometer, and spectrographic tests which lead to the conclusion that: (1) the benzidine stain test differentiates grains of different composition, (2) the white or gray grains which are stained a uniform blue color are fragments of altered tuff, and (3) white or gray grains which stain in a few small spots are probably silicified tuff. The amount of sand grains taken from a hand specimen or an outcrop which will be held by a penny is spread out on a nonabsorbent white surface and soaked with benzidine for 5 minutes. The approximate number blue grains and the average grain size are used in a chart to determine a reference number which measures relative order of abundance. The chart, based on a volume relationship, corrects for the variation in the number of grains in the sample as the grain size varies. Practical use of the method depends on a knowledge of several precautionary measures as well as an understanding of the limitations of benzidine staining tests.

Trace Elements Investigations↗