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Uranium Isotope Fractionation During Coprecipitation with Aragonite and Calcite


Abstract Natural variations in 238U/235U of marine carbonates might provide a useful way of constraining redox conditions of ancient environments. In order to evaluate the reliability of this proxy, we conducted aragonite and calcite coprecipitation experiments at pH ~7.5 and ~ 8.5 to study possible U isotope fractionation during incorporation into these minerals.

Small but significant U isotope fractionation was observed in aragonite experiments at pH ~ 8.5, with heavier U in the solid phase. 238U/235U of dissolved U in these experiments can be fit by Rayleigh fractionation curves with fractionation factors of 1.00007+0.00002/-0.00003, 1.00005 ± 0.00001, and 1.00003 ± 0.00001. In contrast, no resolvable U isotope fractionation was observed in an ... (more)
Created Date 2015
Contributor Chen, Xinming (Author) / Anbar, Ariel (Advisor) / Herckes, Pierre (Committee member) / Shock, Everett (Committee member) / Arizona State University (Publisher)
Subject Chemistry / Geochemistry / Aragonite / Calcite / Isotope fractionation / Uranium
Type Masters Thesis
Extent 71 pages
Language English
Copyright
Reuse Permissions All Rights Reserved
Note Masters Thesis Chemistry 2015
Collaborating Institutions Graduate College / ASU Library
Additional Formats MODS / OAI Dublin Core / RIS


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Description Dissertation/Thesis