New range data for marine invertebrate species across the early Toarcian (Early Jurassic) mass extinction
New range data for marine invertebrate species across the early Toarcian (Early Jurassic) mass extinction
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DOI：
10.1144/0016-76492008-0831
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发表时间：
2009-09-01
影响因子：
2.7
通讯作者：
Cohen, Anthony S.
中科院分区：
文献类型：
--
作者：
Caswell, Bryony A.;Coe, Angela L.;Cohen, Anthony S.
我们重新调查了发生在托尔西世早期的海洋大灭绝间隔，这是一个广泛的海洋缺氧时期，利用来自英国克利夫兰盆地的新观测，海洋底栖无脊椎动物的范围发生了显著变化。Goniomya rhombifera在Whitby泥岩建造中首次被报道，加上所有表层动物双壳类多样性的增加，表明该事件接近尾声时有一个短暂的、相对充氧的时期。新的数据和公布的结果表明，在全球范围内有三个明显的灭绝地平线；第一个在普连斯巴契亚-托阿尔西亚边界上方，接下来的两个在半拉登菊石亚带。由于Signor-Lipps效应，真正的灭绝可能只有一次，也可能只有两次。最年轻的消光层与碳同位素的第一次突变相吻合，这是这一区间的特征，并伴随着海洋表面温度、大陆风化速率和海水缺氧的增加。在最恶劣的环境条件下，杜氏拟脊椎动物是唯一数量丰富的大型底栖无脊椎动物，但在每次碳同位素突然负转变后，它和所有其他底栖物种几乎完全消失了数千年。
We have reinvestigated the marine mass extinction interval that Occurred during the early Toarcian, which was a time of widespread marine anoxia, The ranges of marine benthic invertebrates are significantly altered using new observations from the Cleveland Basin, UK. Goniomya rhombifera is reported for the first time from the Whitby Mudstone Formation and together with all increased epifaunal bivalve diversity indicates a brief, relatively oxygenated period towards the end of the event. The new data, together with published results, suggest three apparent extinction horizons on a global scale; the first is just above the Pliensbachian-Toarcian boundary, and the following two are in the semicelatum ammonite Subzone. As a result of the Signor-Lipps effect there may be only one, or possibly two, true extinctions. The youngest extinction horizon coincides with the first of the abrupt carbon isotope shifts that characterize this interval, and with increases in sea surface temperature, continental weathering rates, and seawater anoxia. Pseudomytiloides dubius is the only abundant benthic macroinvertebrate during the most hostile environmental conditions but it and all other benthic species are almost entirely absent for many thousands of years immediately after each abrupt negative carbon isotope shift.