DOI: 10.1016/j.earscirev.2019.103072
论文题名: Paleosalinity determination in ancient epicontinental seas: A case study of the T-OAE in the Cleveland Basin (UK)
作者: Remírez M.N. ; Algeo T.J.
刊名: Earth Science Reviews
ISSN: 00128252
出版年: 2020
卷: 201 语种: 英语
中文关键词: Anoxia
; B/Ga
; Brackish
; Early jurassic
; S/TOC
; Sr/Ba
英文关键词: anoxia
; carbon isotope
; depositional environment
; estuarine environment
; inland sea
; Jurassic
; paleoenvironment
; paleosalinity
; redox conditions
; total organic carbon
; Cleveland Basin
; England
; North Yorkshire
; United Kingdom
英文摘要: The Early Jurassic Toarcian oceanic anoxic event (T-OAE) was marked by deposition of organic-rich sediments and a pronounced negative carbon-isotope excursion across the Northwest European Sea (NWES), representing a signal that was stronger regionally than globally. Various models for the T-OAE have been proposed, some focusing on general atmospheric-oceanic controls to reflect its global character and others emphasizing local or regional factors to account for its strong expression in the NWES. In this study, we evaluate watermass dynamics of the Early Jurassic Cleveland Basin (UK) during the T-OAE using a combination of paleosalinity proxies (B/Ga, Sr/Ba, and S/TOC). These proxies suggest that brackish conditions existed prior to onset of the T-OAE, with a shift to nearly freshwater conditions during the T-OAE, reflecting a large increase in terrestrial runoff due to a stronger hydrological cycle, possibly combined with shallowing of the marginal sill of the Cleveland Basin through sea-level fall. Following the T-OAE, basinal salinity conditions first returned to brackish and then gradually shifted to fully marine. This hydrographic history accounts for low Mo concentrations in T-OAE sediments of the Cleveland Basin, demonstrating control by watermass restriction and local (rather than global) aqueous Mo drawdown. These findings demonstrate the importance of local hydrographic controls on the sedimentary expression of the T-OAE. The more general significance of this study is that it highlights the need for application of paired salinity and redox proxies in order to correctly interpret paleoenvironmental variations in marginal-marine basins. © 2019 Elsevier B.V. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/166227
Appears in Collections: 气候变化与战略
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作者单位: Centro de Investigaciones Geológicas (CONICET-UNLP), Diagonal 113 #275, La Plata, B1904DPK, Argentina; Department of Geology, University of Cincinnati, Cincinnati, OH 45221-0013, United States; State Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences, Wuhan, 430074, China; State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan, 430074, China
Recommended Citation:
Remírez M.N.,Algeo T.J.. Paleosalinity determination in ancient epicontinental seas: A case study of the T-OAE in the Cleveland Basin (UK)[J]. Earth Science Reviews,2020-01-01,201