English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Tools annual

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Presents the access of premium content as premium feature

Premium Content

Global: Zendy Plus annual

Global: Zendy Free Plan

The Geological Survey has been studying the geology of uranium and thorium continuously since 1939, when it began a comprehensive investigation of the vanadium-uranium deposits of the Colorado Plateau. Greatly increased demand for uranium arising from the advent of controlled fission in 1942 resulted in widening of the study in 1944 to include other possible sources and in further expansion on behalf of the U. S. Atomic Energy Commission since 1947. The wide variety of materials investigated in this study are embraced by five somewhat arbitrary groups of related types of deposits as follows: (1) Igneous rocks, pegmatites, veins, and related deposits; (2) Deposits in sandstone of carnotite, copper-uranium, and other minerals; (3) Other consolidated sedimentary rocks; (4) Placers; and (5) Natural fluids. Much of the Geological Survey's work has been concentrated in geologic study and exploration of the carnotite deposits in sandstone, but many hundreds of etecurrences of uranium, ^or of materials that might possibly be uraniferous, have been examined since 1944. Several bodies of igneous rock among at least 100 tested contain 0.005 to 0.01 percent equivalent uranium. Although none yet found offer a large volume of rock from which uranium might be concentrated by simple means, search is continuing. The small size and low average grade of numerous pegmatites examined suggest that pegmatites constitute only an inconsequent ial source of byproduct uranium or thorium. The study of uraniferous vein deposits has included examination of scores of metalliferous veins and few fluorite veins, mainly in eight western states; detailed studies of some districts; and increasing attention to the association of uranium with other elements, of zonal arrangement of uranium in metalliferous districts, and of wall-rock alteration. These studies have resulted in discovery of new 22087 occurrences in Colorado, in better definition of the position of pitchblende shoots in metalliferous districts in the Colorado Front Range and of the assemblages of minerals that may be guides to new occurrences, and in a more satisfactory basis for appraising resources. Similar investigations have been made of thorium-bearing veins in California, Colorado, Montana, and Idaho. Concentrations of carnotite and other uranium minerals associated with vanadium or copper minerals in sandstones of the Colorado Plateau region are the principal domestic source of uranium. Comprehensive study of ore deposits in the Morrison formation in this region was greatly expanded in 1947 to include extensive exploration by drilling. Areal and detailed geologic mapping and regional and detailed study of the stratigraphy of the Morrison formation has contributed significantly to definition of habits and distribution of ore and to more effective exploration for ore. Similar studies of the Shinarump conglomerate, which is the host for less well-known but increasingly significant deposits of varied mineralogy, are in progress. Preliminary investigations have also been made of recently discovered deposits in the southern Black Hills, S. Dak. and near Pumpkin Buttes, Wyo. Intensive study of uraniferous sedimentary rocks following earlier reconnaissance has served to determine the most uraniferous parts of the Chattanooga shale, of some Florida and western phosphatic rocks, and of some western lignites and to define some of the relevant geologic features of these potentially significant low-grade sources of uranium. Some other black shales as radioactive as the Chattanooga have been noted, but they are thinner or less persistent. Most of the numerous other sedimentary rocks tested are not appreciably radioactive. Some placer deposits contain monazite, the principal source of thorium and rare earths. Monazite-bearing placers in Idaho have been studied in reconnaissance and those of the Carolinas are being studied to determine which are most likely to contain exploitable deposits. Belts of source rocks for monazite in the Carolinas have been partly outlined. Search for natural fresh water that might be a source of uranium or a clue to the presence of uraniferous rocks is in progress; and the significance of radon in some natural gases and of radioactive scale on some oil-well pipes and of the relation between uranium and some oils and aspha kites are being studied. Investigations for uranium and thorium in Alaska have consisted mainly of reconnaissance of areas containing types of rock or an assemblage of metals thought to be possibly favorable for uranium. Some granitic rocks on the Seward Peninsula contain sparse uranothorianite, thorianite, uranothorite, and thorite; and small amounts of radioactive minerals are associated with vein deposits of other metals at five scattered localities. A phosphate bed in the Lisburne limestone on the north flank of the Brooks Range and black shale near the base of the Calico Bluff formation are the only appreciably radioactive sedimentary rocks that have been noted. Small amounts of radioactive minerals found in some placers are useful mainly as a clue to possible bed rock occurrences,, Looking to the future, we believe that the sandstone-type deposits of the Colorado Plateau are an assured source of uranium for a number of years. Increased difficulty and expense of finding additional deposits in new, untested areas may be partly compensated by better definition of geologic controls and improved techniques of exploration,, \ Although most of the known vein-type deposits are small the numerous small deposits in western United States suggest that a few large deposits may yet be discovered,, Finally the low-grade deposits, such as phosphates, shales, and lignites are potential sources of large amounts of uranium.

The Geological Survey's work on the geology of uranium and thorium deposits