Genesis of the Witwatersrand gold-uranium deposits

Suggests that the uranium in Precambrian conglomerates of the Witwatersrand, South Africa, is biogenic in origin and was concentrated, together with pyrite, by microorganisms in an anaerobic environment, possibly along a steep coast line in relatively deep waters containing hydrogen sulfide. At some later stage, hydrothermal solutions carrying gold in ionic form percolated through the deposits, and metallic gold was precipitated in the presence of organic material.

This record provided courtesy of AGI/GeoRef.