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Research about Colorado Plateau

Source-linked reports with geographic coverage including Colorado Plateau.

96 records · Page 6Linked to original sources
USGS1952

Distribution of ore deposits and spectrographic analyses of some rocks and ores on the Colorado Plateau

The geographic pattern of known igneous rocks and ore deposits on the Colorado Plateau suggests a zonal arrangement of several types of ore deposits around centers of igneous activity. Spectrographic analyses of rocks and ores on the Plateau have been obtained in an effort to determine the distribution of elements and to examine the relationships between types of ore deposits and between the ore deposits and igneous rocks. Over 170 analyses of rocks and ores are given in this report. A preliminary study of these analyses suggests that the proportion of uranium, vanadium, copper, and silver in the uranium ores varies geographically, and that the pattern of variation may be in part concentric about some of the major laccolithic intrusions. It is also suggested that the following ratios of metals contained in the uranium ores are possible guides to larger-than-average ore deposits: (1) lead/uranium greater than 1, (2) lead/zinc greater than 10, and (3) zinc/geometric mean of cobalt and nickel less than 10.

Colorado↗
USGS1951

Geologic guides to prospecting for carnotite deposits on the Colorado Plateau

This report describes the geologic features that can be used to appraise the favorability of ground in guiding diamond-drill exploration for carnotite deposits in the Upper Jurassic Morrison formation on the Colorado Plateau. It is based on a statistical study of the geologic logs of about 2,500 holes drilled by the Geological Survey. The most useful features consist of the thickness of the ore-bearing sandstone, the color of the ore-bearing sandstone, the altered mudstone associated with the ore-bearing sandstone, and the abundance of carbonaceous material in the ore-bearing sandstone. Although each feature can be used alone to appraise the favorability of ground, an appraisal based on all of them together is even more useful. A method of expressing this favorability in numerical values is suggested. The results obtained by the Geological Survey using these geologic guides appear to be at least twice as favorable as the drilling results obtained with little or no geologic guidance.

Colorado↗
USGS1950

Uranium-bearing sandstone deposits of the Colorado Plateau

The uranium-bearing sandstone deposits of the Colorado Plateau are commonly referred to as "carnotite deposits." They have been the principal domestic source of uranium, radium, and vanadium. The deposits are largely restricted to a few stratigraphic zones, along which they have a wide but spotty areal distribution. The ore minerals mainly impregnate sandstone, though in places fossil plants are richly mineralized. Most of the ore bodies are small, but have a wide range in size, and within individual deposits the ore has a considerable range in thickness and grade. The deposits are irregularly tabular or lenticular, with their long axes nearly parallel to the bedding, but the ore does not follow the beds in detail.The ore is thought to have been precipitated from ground-water solutions after the enclosing sands had accumulated and before regional deformation. Sedimentary structures that seem to have controlled the movement of these solutions and the features that probably localized the ore deposits are described, and their application as guides to ore finding is explained.

Colorado, Utah, Wyoming↗
USGS1949

Study of radioactive equilibrium in Carnotite ores of the Colorado Plateau

The purpose of this study was to determine the age of Colorado Plateau carnotite. In addition to quantitative analyses of uranium and lead, the radium-uranium equilibrium of each sample was studied. Of the 12 samples studied, 10 are deficient in radium. If a minimum age of 130 million years is chosen for the enclosing sediments, 11 samples are deficient in lead. This deficiency may be explained by (1) leaching of lead or (2) assuming too great an age. Three samples, chosen for lead-isotope analysis, have Pb 207 /Pb 206

Colorado↗