气候变化领域集成服务门户(CCPortal): Sulfidic anoxia in the oceans during the Late Ordovician mass extinctions – insights from molybdenum and uranium isotopic global redox proxies

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DOI	10.1016/j.earscirev.2021.103748
	Sulfidic anoxia in the oceans during the Late Ordovician mass extinctions – insights from molybdenum and uranium isotopic global redox proxies
	Dahl T.W.; Hammarlund E.U.; Rasmussen C.M.Ø.; Bond D.P.G.; Canfield D.E.
发表日期	2021
ISSN	00128252
卷号	220
英文摘要	The Late Ordovician Mass Extinction wiped out 85% of animal species in two phases (LOME1 and LOME2). The kill mechanisms for the extinction phases are debated, but deteriorating climate and the expansion of marine anoxia appear to have been important factors. Nevertheless, the spatial extent and intensity of marine anoxia and its temporal relationship with the extinctions are not well understood. Here, we review existing global paleoredox proxy data based on molybdenum (Mo) and uranium (U) isotopes from four paleocontinents combined with new Mo isotope data from Dob's Linn, Scotland. Individually, these sedimentary records demonstrate significant redox fluctuations, but our coupled dynamic oceanic mass balance model for the evolution of the marine Mo and U cycles reveals that globally expansive ocean anoxia is best constrained by δ238U in carbonates from Anticosti Island that record expansive anoxia during LOME2. In addition, we consider periodic sulfidic anoxia developing in well-ventilated parts of the shallow oceans (e.g. during warmer periods with greater solar insolation) to have produced temporarily high seawater δ98Mo values during LOME1 in accordance with trends to high values observed in the sedimentary records. In this view, oceanic oxygen loss had a causal role during both extinction phases in the Late Ordovician. © 2021
关键词	Geochemistry Global redox proxies Hirnantian Paleoenvironment Stable isotope fractionation
语种	英语
来源期刊	Earth Science Reviews
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/203998
作者单位	GLOBE Institute, University of Copenhagen, Copenhagen K, DK-1350, Denmark; Translational Cancer Research, Department of Laboratory Medicine, Lund University, Sweden; Nordcee and Institute of Biology, University of Southern Denmark, Odense, Denmark; Natural History Museum of Denmark, University of Copenhagen, Copenhagen K, DK-1350, Denmark; Department of Geography, Geology and Environment, University of Hull, Hull, United Kingdom
推荐引用方式 GB/T 7714	Dahl T.W.,Hammarlund E.U.,Rasmussen C.M.Ø.,等. Sulfidic anoxia in the oceans during the Late Ordovician mass extinctions – insights from molybdenum and uranium isotopic global redox proxies[J],2021,220.
APA	Dahl T.W.,Hammarlund E.U.,Rasmussen C.M.Ø.,Bond D.P.G.,&Canfield D.E..(2021).Sulfidic anoxia in the oceans during the Late Ordovician mass extinctions – insights from molybdenum and uranium isotopic global redox proxies.Earth Science Reviews,220.
MLA	Dahl T.W.,et al."Sulfidic anoxia in the oceans during the Late Ordovician mass extinctions – insights from molybdenum and uranium isotopic global redox proxies".Earth Science Reviews 220(2021).