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Biogenic non-crystalline U(IV) revealed as major component in uranium ore deposits

June 1, 2017

Historically, it is believed that crystalline uraninite, produced via the abiotic reduction of hexavalent uranium (U(VI)) is the dominant reduced U species formed in low-temperature uranium roll-front ore deposits. Here we show that non-crystalline U(IV) generated through biologically mediated U(VI) reduction is the predominant U(IV) species in an undisturbed U roll-front ore deposit in Wyoming, USA. Characterization of U species revealed that the majority (∼58-89%) of U is bound as U(IV)to C-containing organic functional groups or inorganic carbonate, while uraninite and U(VI) represent only minor components. The uranium deposit exhibited mostly 238U-enriched isotope signatures, consistent with largely biotic reduction of U(VI) to U(IV). This finding implies that biogenic processes are more important to uranium ore genesis than previously understood. The predominance of a relatively labile form of U(IV) also provides an opportunity for a more economical and environmentally benign mining process, as well as the design of more effective post-mining restoration strategies and human health-risk assessment.

Publication Year 2017
Title Biogenic non-crystalline U(IV) revealed as major component in uranium ore deposits
DOI 10.1038/ncomms15538
Authors Amrita Bhattacharyya, Kate M. Campbell, Shelly Kelly, Yvonne Roebbert, Stefan Weyer, Rizlan Bernier-Latmani, Thomas Borch
Publication Type Article
Publication Subtype Journal Article
Series Title Nature Communications
Index ID 70190145
Record Source USGS Publications Warehouse
USGS Organization National Research Program - Central Branch