DOI: 10.1016/j.palaeo.2015.10.046
论文题名: Oceanic redox evolution across the end-Permian mass extinction at Shangsi, South China
作者: Xiang L. ; Schoepfer S.D. ; Zhang H. ; Yuan D.-X. ; Cao C.-Q. ; Zheng Q.-F. ; Henderson C.M. ; Shen S.-Z.
刊名: Palaeogeography, Palaeoclimatology, Palaeoecology
ISSN: 0031-0182
出版年: 2016
卷: 448 起始页码: 59
结束页码: 71
语种: 英语
英文关键词: End-Permian mass extinction
; Iron speciation
; Nitrogen isotope of kerogen
; Shangsi
; Trace elements
英文摘要: The end-Permian mass extinction (EPME) was the most severe extinction event of the Phanerozoic. To investigate oceanic redox conditions around the EPME, we conducted a series of geochemical analyses, including iron speciation, trace element geochemistry, total organic carbon (TOC), and nitrogen isotopes of kerogen (δ15Nkero), around the EPME at the Shangsi section, South China. Three intervals with different redox conditions can be distinguished based on iron speciation. During the first interval (early and middle Changhsingian), bottom waters were pervasively euxinic. In the second interval (late Changhsingian and the EPME), bottom water fluctuated between oxic and anoxic, but non-sulfidic conditions, with the oxic mode becoming increasingly predominant over time. During the third interval, following the EPME, bottom waters appeared to have been consistently anoxic, although again not pervasively euxinic. This redox history is supported by enrichments in the authigenic fraction of redox-sensitive elements. These relatively high δ15Nkero values (>1.0‰) corresponding with Changhsingian euxinia suggest reducing bottom waters did not impinge on the photic zone. The shift to values near 0‰ within and above the EPME indicates an ecological expansion of diazotrophs. Stratigraphic trends of Nixs, Cdxs, Pxs, and TOC indicate that primary productivity was highest in the first interval, coinciding with euxinic bottom water, then decreased during the lower part of Interval 2 and remained at low level through the remainder of the studied section. The temporal relationship between redox condition and primary productivity suggests that euxinia was supported by high productivity and carbon export in the early Changhsingian. The expansion of N2 fixation coincides closely with the previously documented warming of the ocean surface at Shangsi and may be related to reduced oceanic circulation and suppressed vertical mixing. The temporal distribution of deepwater anoxia and euxinia suggests that they were not primary causes for the extinction of benthos at Shangsi. © 2015 Elsevier B.V. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/68524
Appears in Collections: 过去全球变化的重建
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作者单位: State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, 39 East Beijing Road, Nanjing, China; Department of Geoscience, University of Calgary, Calgary, AB, Canada; Key Laboratory of Economic Stratigraphy and Palaeogeography, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, 39 East Beijing Road, Nanjing, China
Recommended Citation:
Xiang L.,Schoepfer S.D.,Zhang H.,et al. Oceanic redox evolution across the end-Permian mass extinction at Shangsi, South China[J]. Palaeogeography, Palaeoclimatology, Palaeoecology,2016-01-01,448