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Research about Colorado Plateau

Source-linked reports with geographic coverage including Colorado Plateau.

At least 91 records · Page 5Linked to original sources
USGS1966

Water from bedrock in the Colorado Plateau of Utah

The bedrock aquifers in the Colorado Plateau of Utah supply water that ranges widely in chemical quality and yield. The range of dissolved solids in 649 samples collected from 534 wells, springs, and water-yielding mine tunnels was from less than 100 to more than 390.000 ppm (parts per million). The yield of wells ranged from less than 1 to 54,000 barrels of water per day (less than 1 to 1,600 gallons per minute); whereas the yield of springs ranged from less than 1 to 4,100,000 barrels of water per day (less than 1 to 121,000 gallons per minute).

Utah↗
USGS1961

Mineralogy and geochemistry of vanadium in the Colorado Plateau

The chief domestic source of vanadium is uraniferous sandstone in the Colorado Plateau. Vanadium is 3-, 4-, or 5-valent in nature and, as oxides or combined with other elements, it forms more than 40 minerals in the Plateau ores. These ores have been studied with regard to the relative amounts of vanadium silicates and oxide-vanadates, uranium-vanadium ratios, the progressive oxidation of black low-valent ores to high-valent carnotite-type ores, and theories of origin.

Arizona, Colorado, New Mexico, Utah↗
USGS1960

Chemical composition as a guide to the size of sandstone-type uranium deposits in the Morrison Formation on the Colorado Plateau

The concentrations of uranium, yttrium, sodium, iron, zirconium, manganese, calcium, and nickel in 75 mill-pulp samples of uranium deposits in the Salt Wash member of the Morrison formation on the Colorado Plateau have been found, by statistical tests, to be significantly related to the size of the deposits represented by the samples. The elements mentioned above are related to the formation of the deposits in a variety of ways. Zirconium is an intrinsic element, contained principally in the detrital syngenetic fraction of the host sandstone. Calcium, manganese, and sodium are intrinsic elements contained principally in epigenetic (diagenetic) carbonate in the host sandstone. Uranium, yttrium, and nickel are principally extrinsic elements, introduced into the host sandstone by uranium mineralization or related processes. Somewhat more than half of the iron is probably intrinsic and the remainder is extrinsic. Three methods can be used to estimate the size of uranium deposits in the Salt Wash, member within broad limits. Method 1 is based on simple linear-regression theory; method 2 is based on multiple-regression theory (long method); and method 3, on multiple-regression theory (short method). For methods 1 and 2 the estimated log size of each deposit can be computed from tables showing the known concentration of uranium, yttrium, sodium, iron, zirconium, manganese, calcium, and nickel in the deposits, as determined by semiquantitative spectrographic analysis. For method 3 the estimated size or log size can be read directly from a table showing known concentration of uranium and yttrium only. About 80 percent of the tonnage-size estimates from method 1 will be within a factor of 13 (12-14) of the true sizes. The precision of the size estimates from method 2, the long multiple-regression method, is highly variable. Some estimates from method 2 will be within a factor of 12 of the true size at the 80-percent confidence level; others, within a factor of 40 at the 80-percent confidence level. About 80 percent of the tonnage-size estimates from method 3, the short multiple-regression method, will be within a factor of 15 (13-16) of the true size. A group of 40 deposits of known size was used to test the theoretical derivation of the confidence intervals given above. It was concluded from the test that the confidence intervals describe the precision of the methods correctly. The methods for estimating the size of uranium deposits are useful where the ore is poorly exposed or where an independent estimate is desired. The error of the estimates may be quite large, as indicated by the confidence limits given above; but the estimates can be used to, at least, distinguish very large from very small deposits. They also may serve to encourage or discourage further expenditures in the development and exploration of ore bodies. The methods of size estimation can be particularly useful in attempts to appraise or compare groups of deposits or mining districts, inasmuch as the average estimate of size of deposits in a group is more precise than any single estimate. The methods for estimating size are established only for deposits in the Salt Wash member of the Morrison formation. Tests indicate that the equations calculated for deposits in the Salt Wash fail completely if applied to deposits in other stratigraphic units, such as the Moss Back and Shinarump members of the Chinle formation. A further restriction, not completely evaluated at present, is that semiquantitative spectrographic analyses of mill-pulp samples are required. No tests have been made to determine the precision and accuracy of the methods when other types of samples, such as drill core, are used.

Arizona, Colorado, New Mexico, Utah↗
USGS1957

Electrical properties of sandstones of the Morrison Formation

The electrical properties of the Morrison formation in the Uravan mineral belt of the Colorado Plateau have been studied to determine if there are anomalous variations in these properties in and near zones of uranium-vanadium minerals which might serve as a target for geophysical prospecting. Measurements of electrical properties of the Morrison formation in place were obtained by the electric logging of 147 drill holes, and measurements were made of the resistivity and porosity of 440 drill cores in the laboratory to aid in the interpretation of the electric logs. The resistivity of the sandstone members of the Morrison formation is highest in areas that are most favorable for the occurrence of ore. This increase in resistivity is probably due to a lower water saturation or a lower salinity of the water in the favorable areas.

Colorado;Utah↗
USGS1956

Summary of the mineralogy of the Colorado Plateau uranium ores

In the Colorado Plateau uranium has been produced chiefly from very shallow mines in carnotite ores (oxidized vanadiferous uranium ores) until recent deeper mining penetrated black unoxidized ores in water-saturated rocks and extensive exploration has discovered many deposits of low to nonvanadiferous ores. The uranium ores include a wide range from highly vanadiferous and from as much as one percent to a trace of copper, and contain a small amount of iron and traces of lead, zinc, molybdenum, cobalt, nickel, silver, manganese, and other metals. Recent investigation indicates that the carnotite ores have been derived by progressive oxidation of primary (unoxidized) black ores that contain low-valent uranium and vanadium oxides and silicates. The uranium minerals, uraninite and coffinite, are associated with coalified wood or other carbonaceous material. The vanadium minerals, chiefly montroseite, roscoelite, and other vanadium silicates, occur in the interstices of the sandstone and in siltstone and clay pellets as well as associated with fossil wood. Calcite, dolomite, barite and minor amounts of sulfides, arsenides, and selenides occur in the unoxidized ore. Partially oxidized vanadiferous ore is blue black, purplish brown, or greenish black in contrast to the black or dark gray unoxidized ore. Vanadium combines with uranium to form rauvite. The excess vanadium is present in corvusite, fernandinite, melanovanadite and many other quadrivalent and quinquevalent vanadium minerals as well as in vanadium silicates. Pyrite and part or all of the calcite are replaced by iron oxides and gypsum. In oxidized vanadiferous uranium ores the uranium is fixed in the relatively insoluble minerals carnotite and tyuyamunite, and the excess vanadium commonly combines with one or more of the following: calcium, sodium, potassium, magnesium, aluminum, iron, copper, manganese, or barium, or rarely it forms the hydrated pentoxide. The relatively stable vanadium silicates are little affected by oxidation. The unoxidized nonvanadiferous ores contain uraninite and coffinite in close association with coalified wood and iron and copper sulfides, and traces of many other sulfides, arsenides and selenides. The oxidized nonvanadiferous ores differ from the vanadiferous ores because, in the absence of vanadium to complex the uranium, a great variety of secondary yellow and greenish-yellow uranyl minerals are formed. The uranyl sulfates and carbonates are more common than the oxides, phosphates, arsenates, and silicates. Because the sulfates and carbonates are much less stable that carnotite, the oxidized nonvanadiferous ores occure only as halos around cores of unoxidized ore and do not form large oxidized deposits close to the surface of the ground as carnotite ores. Oxidation has taken place since the lowering of the water table in the present erosion cycle. Because of local structures and the highly lenticular character of the fluviatile host rocks perched water tables and water-saturated lenses of sandstone are common high above the regional water table. Unoxidized ore has been preserved in these water-saturated rocks and the boundary between oxidized and unoxidized ore is very irregular.

Utah↗
USGS1956

Oxidation potential and state of some vanadium ores and the relation of woody material to their deposition

Oxidation potential studies with a multiple pH-potential recorder designed and constructed for this purpose demonstrated that some uranium-vanadium ores in the Colorado Plateau were in a reduced state when deposited. Any oxidation which took place occurred after deposition. Experimental and theoretical reducing studies on fresh wood, wood degraded by burial for 450 years, and lignite, indicate that such ores may have been deposited by reduction of oxidized vanadium solutions by woody material. A vanadium (III) mineral, V 2 O(OH) 4 , was prepared synthetically by reduction of a vanadium (V) solution with wood. This is the only reported synthesis of any reduced vanadium mineral by any method. It was shown that the origin of almost all vanadium deposits currently of commercial importance involves life processes and products.

Utah↗
USGS1956

Behavior of Colorado Plateau uranium minerals during oxidation

Uranium occurs as U(VI) and U(IV) in minerals of the Colorado Plateau ores. The number of species containing U(VI) is large, but only two U(IV) minerals are known from the Plateau: uraninite, and oxide, and coffinite, a hydroxy-silicate. These oxidize to yield U(VI) before reacting significantly with other mineral constituents. Crystal-structure analysis has shown that U(VI) invariable occurs as uranyl ion, UO 2 +2 . Uranyl ion may form complex carbonate or sulfate ions with resulting soluble compounds, but only in the absence of quinquevalent vanadium, arsenic, or phosphorous. In the presence of these elements in the +5 valence state, the uranyl ion is fixed in insoluble layer compounds formed by union of uranyl ion with orthovanadate, orthophosphate, or orthoarsenate. Under favorable conditions UO 2 +2 may react to form the relatively insoluble rutherfordine, UO 2 CO 3 , or hydrated uranyl hydroxides. These are rarely found on the Colorado Plateau as opposed to their excellent development in other uraniferous areas, a condition which is apparently related to the semiarid climate and low water table of the Plateau. Uranium may also be fixed as uranyl silicate, but little is known about minerals of this kind. In the present study emphasis has been placed on a detailing of the chemical and crystal structural changes which occur in the oxidation paragenetic sequence.

Utah↗
USGS1956

Sources of the elements in the sandstone-type uranium deposits of the Colorado Plateau

Sandstone-type uranium deposits of the Colorado Plateau are epigenetic. Certain elements have been added locally to the sandstone host to form the deposits; the added fraction of each element in the deposits is call extrinsic to distinguish it from the part present in the original unmineralized host. The principal extrinsic components, in their approximate order of abundance, are vanadium, iron magnesium, uranium, sulfur, arsenic, copper, lead, molbedenum, selenium, cobalt, and nickel. At lest six possible sources of the extrinsic components of the uranium deposits may be considered reasonably likely: 1) the sandstone beds enclosing the uranium deposits, 2) the marine Mancos shales of Cretaceous ages, 3) bentonitic shales of Jurassic and Triassic age, 4) petroliferous rocks of Pennsylvanian age, 5) Precambrian crystalline rocks underlying the Colorado Plateau, and 6) magmatic reservoirs of latest Cretaceous or Tertiary age. If the major source of some of the elements of external to the sandstone beds enclosing the deposits, it is likely that several sources have contributed to some if not most of the extrinsic components and that the importance of the various sources differs from one component to the next. Precambrian crystalline rocks are considered the most likely major source of the extrinsic uranium in the deposits.

Arizona;Colorado;New Mexico;Utah↗
USGS1954

Appraisal of the accuracy of U.S. Geological Survey ore reserve estimates for uranium-vanadium deposits on the Colorado Plateau

The U.S. Geological Survey has made estimates of the reserves of uranium and vanadium in the carnotite deposits explored by Geological Survey drilling on the Colorado Plateau. This report presents an appraisal of the accuracy of the reserve estimates for deposits in the Uravan mineral belt, the causes of inaccuracy, and the significance of the estimates in terms of the total known reserves of the region.

Colorado↗