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

authored by

Amrita Bhattacharyya, Kate M. Campbell, Shelly D. Kelly, Yvonne Roebbert, Stefan Weyer, Rizlan Bernier-Latmani, Thomas Borch

Abstract

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 (-1/458-89%) 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 238 U-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.

Organisation(s)

Institute of Mineralogy
Geochemistry

External Organisation(s)

Colorado State University
Lawrence Berkeley National Laboratory
U.S. Geological Survey
EXAFS Analysis
École polytechnique fédérale de Lausanne (EPFL)

Type

Article

Journal

Nature Communications

Volume

8

ISSN

2041-1723

Publication date

01.06.2017

Publication status

Published

Peer reviewed

Yes

ASJC Scopus subject areas

Chemistry(all), Biochemistry, Genetics and Molecular Biology(all), Physics and Astronomy(all)

Sustainable Development Goals

SDG 3 - Good Health and Well-being

Electronic version(s)

https://doi.org/10.1038/ncomms15538 (Access: Open)