Warming-driven mass extinction in the Early Toarcian (Early Jurassic) of northern and central Spain. Correlation with other time-equivalent European sections
Warming-driven mass extinction in the Early Toarcian (Early Jurassic) of northern and central Spain. Correlation with other time-equivalent European sections
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DOI：
10.1016/j.palaeo.2011.04.018
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发表时间：
2011-06-15
影响因子：
3
通讯作者：
Goy, Antonio
中科院分区：
文献类型：
--
作者：
Gomez, Juan J.;Goy, Antonio
在早托阿西纪（早侏罗纪）记录的大规模灭绝的原因是有争议的。许多学者认为，大规模灭绝是由假定的早期Toarcian海洋缺氧事件（ETOAE）引起的广泛的海洋缺氧造成的，该事件被认为是所有盆地和全球范围内的同步事件。另一组论文将大灭绝与大灭绝同时发生的重大气候变化联系起来。本文介绍了位于西班牙北方和中部的五个最上层的Pliensbachian和下-中Toarcian沉积层剖面的研究结果。详细的菊石为基础的生物地层学，再加上稳定同位素分析的belemnite方解石和散装碳酸盐，以及总有机碳（TOC）分析已在所有部分。在所研究的四个剖面中，主要记录了底栖动物化石的垂直分布。在西班牙露头获得的结果进行了比较，并与其他欧洲部分。早期Toarcian渐进变暖和随之而来的物种的渐进损失的模式之间的良好的相互关系证明了温度升高和大灭绝之间的因果关系。从最上部的Pliensbachian冷却间隔，变暖开始在下Toarcian Tenuicostatum带。平均海水古温度的增加与游泳生物、浮游生物和底栖生物物种数量的逐步和大幅下降有关，代表了灭绝间隔。一个显着的海水温度升高发生在下托阿尔西Tenuicostatum-Serpentinum带状边界。蛇形地带的平均温度上升了约7摄氏度，标志着灭绝的边界。高温持续在中托阿西亚Bifrons Chronozone期间，代表了人口再增长的间隔。与假定的ETOAE相关的缺氧不可能是大灭绝的原因，因为它在许多欧洲和北方非洲平台的含氧环境中被同步记录下来。层状富含有机物的黑色页岩的沉积物褪色，高于5重量% TOC指示缺氧环境，主要局限于西欧Euxinic盆地的地理位置，主要是在灭绝事件之后，在动物群恢复的间隔期间沉积。(C)2011 Elsevier B. V.保留所有权利。
Causes of the major mass extinction recorded during the Early Toarcian (Early Jurassic) are controversial. Many authors have concluded that the mass extinction is caused by the widespread oceanic anoxia derived from a postulated Early Toarcian Oceanic Anoxic Event (ETOAE), supposedly synchronous in all basins and global in extent. Another group of papers links the mass extinction with a major climate change that occurred synchronously with the mass extinction. The results of the study of five sections of the uppermost Pliensbachian and Lower-Middle Toarcian deposits, located in northern and central Spain are presented. Detailed ammonite-based biostratigraphy, coupled with stable isotope analysis of belemnite calcite and bulk carbonates, as well as total organic carbon (TOC) analyses have been performed in all sections. Records of the vertical distribution of mainly benthic fossils have been compiled in four of the studied sections. Results obtained in the Spanish outcrops have been compared and correlated with other European sections.The excellent mutual relation between the patterns of the Early Toarcian progressive warming and the concomitant progressive losses of species evidences a cause-and-effect relationship between the increase of temperature and the mass extinction. From an uppermost Pliensbachian cooling interval, warming started at the Lower Toarcian Tenuicostatum Zone. Increase of average seawater palaeotemperature is associated with a progressive and substantial drawdown in the number of species of nektonic, planktonic and benthic organisms, representing the extinction interval. A prominent increase in seawater temperature occurred around the Lower Toarcian Tenuicostatum-Serpentinum zonal boundary. Average temperatures at the Serpentinum Zone increased about 7 degrees C, marking the extinction boundary. The high temperatures continued during the Middle Toarcian Bifrons Chronozone, representing the repopulation interval. The anoxia linked to the postulated ETOAE cannot be the responsible for the mass extinction, because it has been synchronously recorded in the oxygenated environments of many European and Northern African platforms. Deposition of laminated organic-rich black shale fades, above 5 wt.% TOC indicating anoxic environments, was mostly confined geographically to the Western Europe Euxinic Basin, and mainly deposited after the extinction event, during the interval of faunal recovery. (C) 2011 Elsevier B.V. All rights reserved.