期刊
GEOLOGICAL MAGAZINE
卷 154, 期 2, 页码 247-264出版社
CAMBRIDGE UNIV PRESS
DOI: 10.1017/S0016756815001065
关键词
Ireviken Event; redox conditions; inorganic proxies; pyrite framboids; Silurian
资金
- National Science Center of Poland [2012/07/B/ST10/04211, 2014/13/N/ST10/03006]
- Natural Environment Research Council [NE/J01799X/1]
- Wroclaw Research Centre EIT+ within the project 'The Application of Nanotechnology in Advanced Materials' -NanoMat [POIG.01.01.02-02-002/08]
- European Regional Development Fund
- Natural Environment Research Council [NE/J01799X/1] Funding Source: researchfish
- NERC [NE/J01799X/1] Funding Source: UKRI
The stratigraphic variability and geochemistry of Llandovery/Wenlock (L/W) Series boundary sediments in Poland reveals that hemipelagic sedimentation under an anoxic/euxinic water column was interrupted by low-density bottom currents or detached diluted turbid layers that resulted in intermittent seafloor oxygenation. Total organic carbon values and inorganic proxies throughout the Wilkow 1 borehole section suggest variable redox conditions. U/Mo ratios > 1 throughout much of the Aeronian and Telychian stages, together with an absence of pyrite framboids, suggest oxygenated conditions prevailed. However, elevated total organic carbon near the Aeronian/Telychian boundary, together with increased U/Th and V/(V + Ni) ratios and populations of small pyrite framboids are consistent with the development of dysoxic/anoxic conditions at that time. U/Th, V/Cr and V/(V + Ni) ratios, as well as U-authig and Mo concentrations, suggest that during the Ireviken black shale deposition, bottom-water conditions deteriorated from oxic during Telychian time to mostly suboxic/anoxic immediately prior to the L/W boundary, before a brief reoxygenation at the end of the Ireviken black shale sedimentation in the Sheinwoodian Stage. Rapid fluctuations in U/Mo during the Ireviken Event are characteristic of fluctuating redox conditions that culminated in an anoxic/euxinic seafloor in Sheinwoodian time. Following Ireviken black shale deposition, conditions once again became oxygen deficient with the development of a euxinic zone in the water column. The Aeronian to Sheinwoodian deep-water redox history was unstable, and rapid fluctuations of the chemocline across the L/W Series boundary probably contributed to the Ireviken Event extinctions, which affected mainly pelagic and hemipelagic fauna.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据