Uranium deposits, types roll-type

Harshman, E.N. 1974. Distribution of elements in some roll-type uranium deposits. In Formation of Uranium Ore Deposits. International Atomic Energy Agency, Athens, 169-183. 

Warren CG (1972) Sulfur isotopes as a clue to the genetic geochemistry of a roll-type uranium deposit. Econ Geol 67 759-767... 

The relationship of the stirring rate in these experiments to the rates of hydrolysis reactions of basalt phases is indicative of surface-reaction controlled dissolution (21). First order kinetics are not inconsistent with certain rate-determining surface processes (22). Approximate first order kinetics with respect to dissolved oxygen concentration have been reported for the oxidation of aqueous ferrous iron (23) and sulfide (24), and in oxygen consumption studies with roll-type uranium deposits(25). 

Figure 13. Simulation of the genesis of a roll-type uranium deposit and of the weathering of a pyrite-rich sandstone. Twenty boxes model at logi = —1 with Vx = 10, In the upper part we present an instant view of the alteration profile with neoformed minerals. Numbers in brackets correspond to the molar percentage of the neoformed minerals vs. total neoformed minerals in each box. In the lower part we present the major physicochemical parameters PE, pH, and [O2] (mol/1) in the percolating water in the above boxes. The scale is the same in the upper part and the lower part. IPW = initial percolating water.

The above results on the simulation of the weathering of a pyritic sandstone are in good agreement with the results of the experimental study of pyrite oxidation at pH 5 - 9 ( 0). They are also in good agreement with the field observations and limitations imposed on the processes of genesis of roll-type uranium deposits (31,32). ... 

The redox processes involved in the chemistry of sulfur and iron can be simulated on a computer. The feasibility of such simulations is supported by the good agreement between computer results and field data on the corresponding system of interest as shown by the example of roll-type uranium deposits. 

Goldhaber N.B., and Reynolds R.L., Experimental study of pyrite oxidation at pH 5 - 9.5 implications for formation of roll -type uranium deposits, p. 59, in Amer. Assoc. Pet. Geol, Rocky Mount. Sect., Abstract," 1977. 

Granger H.C., and Warren C.G., Zoning in the altered tongue associated with roll-type uranium deposits, in "Formation of Uranium Ore Deposits , I.A.E.A., Vienna, 1974. 

Granger H. C. and Warren C. G. (1969) Unstable sulfur compounds and the origin of roll-type uranium deposits. Econ. Geol. and Bull. Soc. Econ. Geol. 64(2), 160-171. 

Fig. 10-3. Contour map of averaged soil-gas (probe) helium concentrations over a roll-type uranium deposit. Weld County, Colorado (from Reimer et al., 1979b).

Reimer, G.M., Bowles, C.G., Murray, D.G. and Been, J.M., 1979a. Helium in soil-gas and hclium/radon in groundwater in the vicinity of a south Texas uranium roll-type deposit. US Geol. Survey, Open File Report, 79-1625, 10pp. 

Some uranium deposits, formed in permeable sandstone units interbedded with less permeable strata, have a characteristic shape from which the name roll-type uranium deposits arises. 

Fig. 4 Schematic diagram of roll-type uranium deposit...

King J. W. and Austin S. R. Some characteristics of roll-type uranium deposits at Gas Hills, Wyoming. Min. Engng, N. K, 18, May-1966, 73-80. 

Reynolds R. L. and Goldhaber M. B. Origin of a South Texas roll-type uranium deposit 1. Alteration of iron—titanium oxide minerals. Econ. Geol., 73, 1978, 1677-89. 

Harshman E. N. and Adams S. S. Geology and recognition criteria for roll-type uranium deposits in continental sandstones. Open File Rep. U.S. Dep. EnergyGJBX-I(81), 1981, 185 p. 

Q ROLL FRONT SUBTYPE Fig. 3 Sandstone-type uranium deposits... 

Mesozoic and Caenozoic strata, especially in the western United States, contain many important sandstone-hosted uranium deposits of blanket, stack and roll-front sub-types, with fewer volcanic-hosted types. As may be expected, the dynamic, migrating roll-front sub-type predominates in the youngest Tertiary rocks of the Wyoming basins, where final fixation of the migrating uranium is yet to be attained. In con-... 

Roll-type uranium deposits occur in intracratonic sedimentary basins in the U.S.A. Best known are those in Tertiary strata of Wyoming (Powder River, Shirley and Wind River basins) and the Texas Gulf Coast. Smaller deposits are present in Jurassic rocks of the Colorado Plateau. 

The term stack deposit was first used to describe uranium ore deposits associated with peneconcordant deposits in the Grants Mineral Belt, New Mexico. Stack deposits are also called tecto-lithologic , redistributed or post-fault ore because they represent uranium that was mobilized from earlier peneconcordant or roll-type occurrences and redeposited in near-vertical bodies. The geometry of stack deposits commonly is controlled by faults or fractures that post-date the formation of the other uranium deposits. Stack deposits generally have greater thicknesses than the associated peneconcordant or roll-type deposits, but their shape is irregular. 

The uranyl molybdate minerals are relatively poorly characterized. The first uranyl molybdate mineral was recognized by Brophy and Kerr, but since then a number of minerals that belong to this group have been described from many different deposits (Table 14). An affinity of uranium and molybdenum, especially in roll-front type deposits, has been known for some time. Initially, only minerals with U were recognized, but the occurrence of such minerals as sedovite shows that U compounds also exist. 

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