Mesothermal to epithermal uranium deposit, hosted mainly by Indosinian medium- to coarse-grained porphyritic biotite granite (whole-rock Rb-Sr isochron age of 215+/-6 Ma) as a batholith (Sanerer pluton) and, to a lesser extent, by Yanshanian fine-grained porphyritic biotite granite (whole-rock Rb-Sr isochron age of 155.7+/-6.4 Ma) as stock. Both granites may have been formed by anatexis of uranium-rich Precambrian and Cambrian metasedimentary rocks. The critical processes for the formation of the deposit were deuteric alteration of primary accessory minerals in the granites, and erosion of the granites under a hot, dry palaeoclimate, resulting in the partial liberation of uranium. In the deposit, it occurs as pitchblende along tectonic fractures, interstitially in granular minerals, and as cements of breccias. The host-rock alteration comprises pre-ore alkali-metasomatism and ore-stage hydrothermal chloritization, pyritization, hematitization, silicification, damouritization, and carbonatization.
Ref.:
- Min, M.-Z., Luo, X.-Z., Du, G.-S., He, B.-A., and Campbell, A.R. (1999): Mineralogical and geochemical constraints on the genesis of the granite-hosted Huangao uranium deposit, SE China. Ore Geology Reviews 14(2), 105-127.
