Element contents
The Uranium Isotope Paleoredox Proxy
Published online by Cambridge University Press: 12 August 2019
Summary
Uranium isotopes (238U/235U) have emerged as a proxy to reconstruct the redox conditions of the Earth's oceans and atmosphere based upon the large isotopic fractionation between reduced U(IV) and oxidized U(VI). Variations in 238U/235U, particularly when recorded in carbonate sediments, can track global trends in marine oxygenation and de-oxygenation. It is unique from other proxies because reduction primarily occurs at the sediment-water interface, and this sensitivity makes U isotopes especially relevant for the habitability of benthic animals. This Element covers the background, methods, and case studies of this promising tool for understanding Earth's environmental transitions, as rapid development continues to refine the accuracy of interpretations of 238U/235U records.
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- Online ISBN: 9781108584142Publisher: Cambridge University PressPrint publication: 29 August 2019
References
Primary Sources
Stirling, C. H., Andersen, M. B., Potter, E.-K. and Halliday, A. N. (2007) Low-temperature isotopic fractionation of uranium. Earth and Planetary Science Letters 264, 208–225.Google Scholar
Weyer, S., Anbar, A. D., Gerdes, A., Gordon, G. W., Algeo, T. J. and Boyle, E. A. (2008) Natural fractionation of 238U/235U. Geochimica et Cosmochimica Acta 72, 345–359.CrossRefGoogle Scholar
Brennecka, G. A., Wasylenki, L. E., Bargar, J. R., Weyer, S. and Anbar, A. D. (2011a) Uranium isotope fractionation during adsorption to Mn-oxyhydroxides. Environmental Science & Technology 45, 1370–1375.Google Scholar
Secondary Sources
Andersen, M. B., Romaniello, S., Vance, D., Little, S. H., Herdman, R. and Lyons, T. W. (2014) A modern framework for the interpretation of 238U/235U in studies of ancient ocean redox. Earth and Planetary Science Letters 400, 184–194.Google Scholar
Chen, X., Romaniello, S. J., Herrmann, A. D., Hardisty, D., Gill, B. C. and Anbar, A. D. (2018a) Diagenetic effects on uranium isotope fractionation in carbonate sediments from the Bahamas. Geochimica et Cosmochimica Acta 237, 294–311.Google Scholar
Tissot, F. L. H., Chen, C., Go, B. M., Naziemiec, M., Healy, G., Bekker, A., Swart, P. K. and Dauphas, N. (2018) Controls of eustasy and diagenesis on the 238U/235U of carbonates and evolution of the seawater 234U/238U during the last 1.4 Myr. Geochimica et Cosmochimica Acta 242, 233–265.CrossRefGoogle Scholar
Andersen, M. B., Vance, D., Morford, J. L., Bura-Nakić, E., Breitenbach, S. F. M. and Och, L. (2016) Closing in on the marine 238U/235U budget. Chemical Geology 420, 11–22.CrossRefGoogle Scholar
Tissot, F. L. H. and Dauphas, N. (2015) Uranium isotopic compositions of the crust and ocean: age corrections, U budget and global extent of modern anoxia. Geochimica et Cosmochimica Acta 167, 113–143.Google Scholar
Kendall, B., Brennecka, G. A., Weyer, S. and Anbar, A. D. (2013) Uranium isotope fractionation suggests oxidative uranium mobilization at 2.50 Ga. Chemical Geology 362, 105–114.CrossRefGoogle Scholar
Lau, K. V., Maher, K., Altiner, D., Kelley, B. M., Kump, L. R., Lehrmann, D. J., Silva-Tamayo, J. C., Weaver, K. L., Yu, M. and Payne, J. L. (2016) Marine anoxia and delayed Earth system recovery after the end-Permian extinction. Proceedings of the National Academy of Sciences 113, 2360–2365.CrossRefGoogle ScholarPubMed
Clarkson, M. O., Stirling, C. H., Jenkyns, H. C., Dickson, A. J., Porcelli, D., Moy, C. M., Pogge von Strandmann, P. A. E., Cooke, I. R. and Lenton, T. M. (2018) Uranium isotope evidence for two episodes of deoxygenation during Oceanic Anoxic Event 2. Proceedings of the National Academy of Sciences 115, 2918–2923.Google Scholar
Zhang, F., Romaniello, S. J., Algeo, T. J., Lau, K. V., Clapham, M. E., Richoz, S., Herrmann, A. D., Smith, H., Horacek, M. and Anbar, A. D. (2018c) Multiple episodes of extensive marine anoxia linked to global warming and continental weathering following the latest Permian mass extinction. Science Advances 4, e1602921.CrossRefGoogle ScholarPubMed
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