Shales, uranium deposits

Furongite was described by the Hunan 230 Laboratory as a yellow, minutely crystalline deposit on carbonaceous shale in the oxidized zone of an illuvial-type uranium deposit. Walenta and Wimmenauer described hallimondite from Lahr, Baden. It is very similar to parsonsite. Pseudo-autunite was characterized by Sergeev from fenitized rocks of the exocontact zone of a massif of ultrabasic-alkaline rocks of northern Karelia, U.S.S.R. Walpurgite-(P), an unnamed phosphate analogue of walpurgite, was described in Soboleva and Pudovkina. ... 

Bell R. T. Uranium in black shales—a review. In Short course in uranium deposits their mineralogy and origin Kimberley M. M. ed. (Toronto The University Press for Mineralogical Association of Canada, 1978), 307-29. 

The Chattanooga shales were deposited at the southern end of a shallow sea, bordered on the southeast, south and west by a stable, nearly peneplained lowland formed on carbonates. Uranium was probably deposited syngenetically with the clay, silt and organic material that constitute the shale. The uranium is more or less evenly distributed throughout the shale, and was probably adsorbed from sea water on plant debris and clay particles. ... 

An example of veins with complex mineralogy is the mined-out uranium deposit at Shinkolobwe, Zaire, at the northwest end of the African Copperbelt. It occurs in a faulted transported fold in metamorphosed dolomitic shales of the middle Proterozoic Mine Series of the Roan Group.Uraninite and uranophane mineralization (about 620m.y. ago) was followed by several later mineralizations in which pyrite, molybdenite, monazite, selenium, Co-Ni sulphides and selenides and copper minerals were formed. It is believed that this orebody was formed by redistribution of metals originally deposited in marine sedimentary rocks." The uranium, originally weathered from granites and deposited in the marine sediments, was in low... 

Uranium deposits in this unit are of numerous geological types, but three are typical of the Hercynian orogen (1) intra-granitic deposits related to leucogranites, (2) deposits bound to the contact-metamorphic haloes of granite intrusives in Lower Palaeozoic shales (the so-called Iberian type ) and (3) deposits bound to Permian cover rocks or Permian acid volcanics. Other types are veins in less differentiated granites, veins in metamorphic environments, sandstone-type deposits in Mesozoic or Caenozoic cover rocks in basin structures of the Hercynian space included in or adjacent to the Moldanubian zone (or its Iberian equivalent). 

Uranium is low in the list of element abundance, comprising only 0.0027% of the earth s crust (Levinson, 1974). Apart from ore deposits, uranium is most abundant in high silica igneous rocks and in shales, especidly black shales. Reported contents for some common rocks and waters are listed in Table 8.1. Uranium ores are referred to on p. 497ff here it need only be mentioned that most known ore bodies occur within sedimentary rock sequences. 

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