DOI: 10.1016/j.palaeo.2014.12.012
论文题名: Changes in marine productivity and redox conditions during the Late Ordovician Hirnantian glaciation
作者: Zhou L. ; Algeo T.J. ; Shen J. ; Hu Z.F. ; Gong H. ; Xie S. ; Huang J.H. ; Gao S.
刊名: Palaeogeography, Palaeoclimatology, Palaeoecology
ISSN: 0031-0182
出版年: 2015
卷: 420 起始页码: 223
结束页码: 234
语种: 英语
英文关键词: Black shale
; Enrichment factor
; Redox-sensitive elements
; South China
; Yangtze platform
英文摘要: Changes in marine productivity and redox conditions during the end-Ordovician (Hirnantian) glaciation and Ordovician-Silurian transition were investigated through Mo-isotope and major- and trace-element analyses of the Wangjiawan (Hubei Province) and Nanbazi (Guizhou Province) sections from the Yangtze Platform of South China. Katian shales of the Wufeng Formation, which yield the graptolites Dicellograptus complanatus, Dicellograptus complexus, and Paraorthograptus pacificus, were deposited under euxinic conditions at both localities, as shown by high MoEF, UEF, and δ98Mo values. A major sea-level regression during the Hirnantian glaciation resulted in shallowing and a shift toward better-oxygenated conditions within the Yangtze Sea, as well as deposition of thin-bedded siliceous sediments, calcirudite debris flows, and limestone turbidites of the Kuanyinchiao Formation, the base of which correlates with the first phase of the end-Ordovician mass extinction. The termination of the Hirnantian glaciation at the top of the Kuanyinchiao Formation was associated with a major sea-level transgression, a rapid expansion of euxinia in the Yangtze Sea (as documented by a return of high MoEF, UEF, and δ98Mo values), and the second phase of the mass extinction, during which the cool-adapted Hirnantian Fauna went extinct.The long-term cooling trend of the Middle and Late Ordovician, which culminated in the Hirnantian glaciation, was driven by enhanced burial of organic carbon, as documented by δ13Ccarb, δ13Corg, and δ34Spy records. Increased organic carbon burial was linked to high rates of marine productivity, as shown by high TOC and biogenic Ba concentrations especially at the deeper, less-restricted Wangjiawan locale, producing the HICE (Hirnantian Isotopic Curve Excursion) δ13Ccarb excursion. The locus of organic carbon burial during the Hirnantian crisis shifted to deeper-water environments that were located outside the study region. The relatively rapid onset and termination of the Hirnantian glaciation were probably due to crossing of tipping points in the Late Ordovician climatic-oceanic system. © 2014 Elsevier B.V. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/69035
Appears in Collections: 过去全球变化的重建
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作者单位: State Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences, Wuhan, China; State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan, China; Department of Geology, University of Cincinnati, Cincinnati, OH, United States
Recommended Citation:
Zhou L.,Algeo T.J.,Shen J.,et al. Changes in marine productivity and redox conditions during the Late Ordovician Hirnantian glaciation[J]. Palaeogeography, Palaeoclimatology, Palaeoecology,2015-01-01,420