气候变化领域集成服务门户(CCPortal): Marine sulfur cycle evidence for upwelling and eutrophic stresses during Early Triassic cooling events

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DOI	10.1016/j.earscirev.2018.09.007
	Marine sulfur cycle evidence for upwelling and eutrophic stresses during Early Triassic cooling events
	Stebbins A.; Algeo T.J.; Krystyn L.; Rowe H.; Brookfield M.; Williams J.; Nye Jr S.W.; Hannigan R.
发表日期	2019
ISSN	00128252
起始页码	68
结束页码	82
卷号	195
英文摘要	Perturbations to the global carbon and sulfur cycles recurred episodically throughout the ~5-Myr-long Early Triassic, in the aftermath of the end-Permian mass extinction, the largest biocrisis in Earth's history. In this study, analyses of carbonate-associated sulfate (CAS) sulfur, CAS oxygen, and pyrite sulfur-isotope ratios in a continental shelf section from the southern Neo-Tethys Ocean (Spiti Valley, India) provide new insights into the Early Triassic marine sulfur cycle. Secular variation in CAS sulfur-isotope values at Spiti is similar to that in South China, suggesting that CAS was a robust recorder of a global seawater sulfate signal. The Spiti CAS and pyrite δ34S profiles show that the highest rates of pyrite burial coincided with cooler sea-surface temperatures. We infer that climatic cooling steepened equator-to-pole temperature gradients, invigorating thermohaline overturning circulation, and enhancing upwelling of nutrients that stimulated marine productivity and organic carbon sinking fluxes. Enhanced productivity fueled and sustained microbial respiration, increased oxygen demand, and, within the southern Neo-Tethys, caused the zone of microbial sulfate reduction to migrate upwards and become more connected to the water column. Microbial sulfate reduction, under these conditions, was no longer limited by organic matter or sulfate availability, leading to burial of more 34S-depleted pyrite and 34S- and 18O-enrichment of the oceanic sulfate pool. This environmental scenario suggests possible environmental stresses related to eutrophication during positive carbon-isotope excursions around the Griesbachian-Dienerian, Dienerian-Smithian, and Smithian-Spathian boundaries. Additionally, the difference between CAS and pyrite sulfur-isotope values, Δ34SCAS-pyr, slowly rose through the Early Triassic, reflecting a slow increase in seawater sulfate concentrations following a minimum close to the Permian-Triassic boundary. © 2018 Elsevier B.V.
关键词	Carbonate-associated sulfate Microbial sulfate reduction Neo-Tethys Ocean Pyrite Spiti Valley Sulfur isotopes
英文关键词	carbonate; cooling; eutrophication; marine environment; paleoceanography; pyrite; sulfate; sulfur cycle; sulfur isotope; Triassic; upwelling; Himachal Pradesh; India; Spiti Valley
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/203560
作者单位	School for the Environment, University of Massachusetts Boston, Boston, MA 02125, United States; Department of Geology, University of Cincinnati, Cincinnati, OH 45221, United States; State Key Laboratories of BGEG and GPMR, China University of Geosciences, Wuhan, 430074, China; Institute for Paleontology, Vienna University, Althanstrasse 14, Vienna, 1090, Austria; Bureau of Economic Geology, The University of Texas at Austin, Austin, TX 78758, United States; Department of Geology, Kent State University, Kent, OH 44242, United States
推荐引用方式 GB/T 7714	Stebbins A.,Algeo T.J.,Krystyn L.,et al. Marine sulfur cycle evidence for upwelling and eutrophic stresses during Early Triassic cooling events[J],2019,195.
APA	Stebbins A..,Algeo T.J..,Krystyn L..,Rowe H..,Brookfield M..,...&Hannigan R..(2019).Marine sulfur cycle evidence for upwelling and eutrophic stresses during Early Triassic cooling events.Earth Science Reviews,195.
MLA	Stebbins A.,et al."Marine sulfur cycle evidence for upwelling and eutrophic stresses during Early Triassic cooling events".Earth Science Reviews 195(2019).