Evidence of uranium biomineralization in sandstone-hosted roll-front uranium deposits, northwestern China

We show evidence that the primary uranium minerals, uraninite and coffinite, from high-grade ore samples (U3O8N0.3%) in the Wuyiyi, Wuyier, and Wuyisan sandstone-hosted roll-front uranium deposits, Xinjiang, northwestern China were biogenically precipitated and psuedomorphically replace fungi and bacteria. Uranium (VI), which was the sole electron acceptor, was likely to have been enzymically reduced. Post-mortem accumulation of uranium may have also occurred through physio-chemical interaction between uranium and negatively-charged cellular sites, and inorganic adsorption or precipitation reactions. These results suggest that microorganisms may have played a key role in formation of the sandstoneor roll-type uranium deposits, which are among the most economically significant uranium deposits in the world. D 2004 Elsevier B.V. All rights reserved.