@article{cb4bf8c6087347e18d4b75ab29fbe448,
title = "Uranium isotopes in marine carbonates as a global ocean paleoredox proxy: A critical review",
abstract = "The protracted oxygenation of the ocean-atmosphere system is one of the most fundamental changes to the Earth system through its history. The uranium isotopic composition (238U/235U, denoted as δ238U) of marine carbonates has been developed as a proxy to quantitatively track the timing, duration, and extent of global marine redox chemistry changes. This proxy has been applied to many critical evolutionary intervals in the last decade, significantly advancing our understanding of how life on Earth and its environment have co-evolved through geological history. Successful application of the uranium isotope paleoredox proxy requires a thorough understanding of the marine uranium budget, the processes by which seawater U-isotope signatures are recorded in marine carbonates, and the potential for alteration of these primary signatures by syn- and post-depositional diagenetic processes. Here, we provide a critical review of the U isotope proxy in marine carbonates with a focus on the current problems and areas where future work is needed to further develop this proxy. We also use a recently developed global C-P-U cycle model to illustrate that when the carbon cycle is perturbed by volcanic carbon injections, the ensuing transient relationship between seafloor anoxic area and δ238U can be complex and sometimes counter-intuitive.",
author = "Feifei Zhang and Lenton, {Timothy M.} and {del Rey}, {\'A}lvaro and Romaniello, {Stephen J.} and Xinming Chen and Planavsky, {Noah J.} and Clarkson, {Matthew O.} and Dahl, {Tais W.} and Lau, {Kimberly V.} and Wenqian Wang and Ziheng Li and Mingyu Zhao and Terry Isson and Algeo, {Thomas J.} and Anbar, {Ariel D.}",
note = "Funding Information: F.Z. acknowledges financial supports from the Strategic Priority Research Program (B) of the Chinese Academy of Sciences ( XDB18000000 , 26000000 ) and the National Science Foundation of China (grant number 91955201 ). F.Z. and T.W.D. acknowledge support from the Danish Council for Independent Research (No. DFF 7014-00295 ). N.J.P. acknowledges funding from the Packard foundation and the NASA Alternative Earths Astrobiology Institute. T.W.D. acknowledges support from the Carlsberg Foundation (grant number CF16-0876). T.M.L. was supported by NERC ( NE/P013651 and NE/N018508/1 ). MOC acknowledges funding from the European Union {\textquoteright}s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No 795722 . S.J.R. acknowledges support from the NSF ( EAR - 1733598 ). F.Z., S.J.R., and A.D.A. acknowledge funding from NASA Astrobiology Program ( NNX13AJ71G ) and NSF Frontiers in Earth System Dynamics program ( EAR - 1338810 ). Funding Information: F.Z. acknowledges financial supports from the Strategic Priority Research Program (B) of the Chinese Academy of Sciences (XDB18000000, 26000000) and the National Science Foundation of China (grant number 91955201). F.Z. and T.W.D. acknowledge support from the Danish Council for Independent Research (No. DFF 7014-00295). N.J.P. acknowledges funding from the Packard foundation and the NASA Alternative Earths Astrobiology Institute. T.W.D. acknowledges support from the Carlsberg Foundation (grant number CF16-0876). T.M.L. was supported by NERC (NE/P013651 and NE/N018508/1). MOC acknowledges funding from the European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No 795722. S.J.R. acknowledges support from the NSF (EAR-1733598). F.Z. S.J.R. and A.D.A. acknowledge funding from NASA Astrobiology Program (NNX13AJ71G) and NSF Frontiers in Earth System Dynamics program (EAR-1338810). Publisher Copyright: {\textcopyright} 2020 Elsevier Ltd",
year = "2020",
month = oct,
day = "15",
doi = "10.1016/j.gca.2020.05.011",
language = "English (US)",
volume = "287",
pages = "27--49",
journal = "Geochmica et Cosmochimica Acta",
issn = "0016-7037",
publisher = "Elsevier Limited",
}