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

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.
 [1] ;  [2] ;  [3] ;  [4] ;  [4] ;  [5] ; ORCiD logo [6]
  1. Colorado State Univ., Fort Collins, CO (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
  2. U.S. Geological Survey, Boulder, CO (United States)
  3. EXAFS Analysis, Bolingbrook, IL (United States)
  4. Leibniz Univ. Hannover, Hannover (Germany)
  5. Ecole Polytechnique Federale de Lausanne, Lausanne (Switzerland)
  6. Colorado State Univ., Fort Collins, CO (United States)
Publication Date:
Grant/Contract Number:
Accepted Manuscript
Journal Name:
Nature Communications
Additional Journal Information:
Journal Volume: 8; Journal ID: ISSN 2041-1723
Nature Publishing Group
Research Org:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
58 GEOSCIENCES; Element cycles; Geochemistry; Microbial ecology; Nuclear waste
OSTI Identifier: