气候变化领域集成服务门户(CCPortal): Middle–Upper Ordovician (Darriwilian–Sandbian) paired carbon and sulfur isotope stratigraphy from the Appalachian Basin; USA: Implications for dynamic redox conditions spanning the peak of the Great Ordovician Biodiversification Event

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DOI	10.1016/j.palaeo.2019.01.032
	Middle–Upper Ordovician (Darriwilian–Sandbian) paired carbon and sulfur isotope stratigraphy from the Appalachian Basin; USA: Implications for dynamic redox conditions spanning the peak of the Great Ordovician Biodiversification Event
	Kozik N.P.; Young S.A.; Bowman C.N.; Saltzman M.R.; Them T.R.; II
发表日期	2019
ISSN	0031-0182
起始页码	188
结束页码	202
卷号	520
英文摘要	The Evans Ferry section from the Appalachian Basin of eastern North America has been analyzed for chemostratigraphic trends to elucidate possible causal mechanisms facilitating the Great Ordovician Biodiversification Event (GOBE). Paired stable isotope (δ 13 C and δ 34 S) analyses were used in this carbonate-dominated locality from the Appalachian Basin to reconstruct the marine redox states during this key period of rapid biodiversification. This succession is one of the most expanded Sandbian Stage (Upper Ordovician) deposits known from North America, and it allows new high-resolution reconstructions of long-term, global carbon and sulfur cycle fluctuations. The integrated geochemical and sequence-stratigraphic investigation presented here from the Laurentian epeiric seaway allows for possible identification of the contraction and expansion of reducing water masses during the Middle–Late Ordovician that may have been linked to global-marine paleoredox dynamics. Utilizing new conodont-based 87 Sr/ 86 Sr isotope stratigraphy along with previous conodont biostratigraphy, we can confidently correlate our stable isotope profiles to other carbonate successions globally. Carbonate facies indicate that this area experienced partial restriction from open-marine conditions during certain intervals in the Sandbian. These semi-restricted environments record carbon (δ 13 C carb ) isotope trends that are secular in nature, as they can be correlated to other successions across Laurentia and Baltica. We identify several intervals when δ 13 C carb and δ 34 S CAS (carbonate-associated sulfate) trends are decoupled. These inverse stratigraphic trends are, at times, followed by parallel positive shifts in δ 13 C carb and δ 34 S CAS . Causal mechanisms for the observed decoupled δ 13 C and δ 34 S trends may include a wide variety of factors such as more closed-system, local biogeochemical processes associated in part with diagenesis, or they could instead reflect variations in the global fluxes of organic matter and pyrite burial linked to changing marine paleoredox conditions. The positive covariation in trends presented here likely represents transient increases in organic carbon and pyrite burial in response to expansion of reducing marine environments. © 2019 Elsevier B.V.
英文关键词	Biodiversification; Chemostratigraphy; Oxygenation; Paleoredox; Sea level; Strontium isotopes
语种	英语
scopus关键词	biostratigraphy; carbon isotope; chemostratigraphy; marine environment; Ordovician; organic carbon; organic matter; redox conditions; sea level change; stable isotope; strontium isotope; sulfur isotope; water mass; Appalachian Basin
来源期刊	Palaeogeography, Palaeoclimatology, Palaeoecology
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/151021
作者单位	Department of Earth, Ocean, and Atmospheric Science, National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL 32306, United States; School of Earth Sciences, The Ohio State University, Columbus, OH 43210, United States; College of Charleston, Department of Geology and Environmental GeosciencesSC 29412, United States
推荐引用方式 GB/T 7714	Kozik N.P.,Young S.A.,Bowman C.N.,等. Middle–Upper Ordovician (Darriwilian–Sandbian) paired carbon and sulfur isotope stratigraphy from the Appalachian Basin; USA: Implications for dynamic redox conditions spanning the peak of the Great Ordovician Biodiversification Event[J],2019,520.
APA	Kozik N.P.,Young S.A.,Bowman C.N.,Saltzman M.R.,Them T.R.,&II.(2019).Middle–Upper Ordovician (Darriwilian–Sandbian) paired carbon and sulfur isotope stratigraphy from the Appalachian Basin; USA: Implications for dynamic redox conditions spanning the peak of the Great Ordovician Biodiversification Event.Palaeogeography, Palaeoclimatology, Palaeoecology,520.
MLA	Kozik N.P.,et al."Middle–Upper Ordovician (Darriwilian–Sandbian) paired carbon and sulfur isotope stratigraphy from the Appalachian Basin; USA: Implications for dynamic redox conditions spanning the peak of the Great Ordovician Biodiversification Event".Palaeogeography, Palaeoclimatology, Palaeoecology 520(2019).