The Late Triassic Extinction at the Norian/Rhaetian boundary: Biotic evidence and geochemical signature
The Late Triassic Extinction at the Norian/Rhaetian boundary: Biotic evidence and geochemical signature
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DOI：
10.1016/j.earscirev.2020.103180
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发表时间：
2020-05
影响因子：
12.1
通讯作者：
M. Rigo;T. Onoue;L. Tanner;S. Lucas;L. Godfrey;M. Katz;M. Zaffani;K. Grice;J. Cesar;D. Yam
中科院分区：
文献类型：
--
作者：
M. Rigo;T. Onoue;L. Tanner;S. Lucas;L. Godfrey;M. Katz;M. Zaffani;K. Grice;J. Cesar;D. Yam
晚三叠世是一个延长的生物灭绝的间隔，最终在三叠纪末灭绝（埃特）。埃特现在与三叠纪末期之前全球碳循环的扰动有关，这归因于环大西洋岩浆区（CAMP）的广泛火山活动。然而，我们认为三叠纪晚期生物多样性下降的原因是全球范围内碳循环（δ 13 Corg）的一个较老的扰动，该扰动位于或非常接近Norian/Rhaetian边界（NRB）。NRB似乎是最晚三叠纪生物逐步更替的高潮，包括全球重要的海洋和陆地化石群的迁移。这些横跨NRB的生物事件在很大程度上被低估了，然而，与碳循环的同时代干扰一起，在晚三叠世的历史中至关重要。在这里，我们提出了新的和发表的δ 13 Corgdata从广泛的部分（意大利，希腊，ODP，澳大利亚，新西兰，美国，加拿大）。这些章节记录了跨越NRB的全球范围的碳循环中以前未知的扰动。扰动延伸穿过泛海到盘古大陆的两侧，并在北方和南半球都有记录。晚三叠世阶段性沉积的开始与NRB的碳扰动（δ 13 Corg）相吻合，表明气候和环境变化的组合在全球范围内影响了生物群。NRB事件可能是由NRB之前的一个大火成岩省喷发的气体排放、大规模的火流星撞击或一些温室气体排放的替代来源触发的。到目前为止，尚不可能明确确定这些触发情景中的哪一个是负责的;证据不足以决定性地确定因果机制，值得进一步研究。
The latest Triassic was an interval of prolonged biotic extinction culminating in the end-Triassic Extinction (ETE). The ETE is now associated with a perturbation of the global carbon cycle just before the end of the Triassic that has been attributed to the extensive volcanism of the Circum-Atlantic Magmatic Province (CAMP). However, we attribute the onset of declining latest Triassic diversity to an older perturbation of the carbon cycle (δ13Corg) of global extent at or very close to the Norian/Rhaetian boundary (NRB). The NRB appears to be the culmination of stepwise biotic turnovers that characterize the latest Triassic and includes global extinctions of significant marine and terrestrial fossil groups. These biotic events across the NRB have been largely under-appreciated, yet together with a coeval disturbance of the carbon cycle were pivotal in the history of the Late Triassic. Here, we present new and published δ13Corgdata from widespread sections (Italy, Greece, ODP, Australia, New Zealand, USA, Canada). These sections document a previously unknown perturbation in the carbon cycle of global extent that spanned the NRB. The disturbance extended across the Panthalassa Ocean to both sides of the Pangaean supercontinent and is recorded in both the Northern and Southern Hemispheres. The onset of stepwise Late Triassic extinctions coincides with carbon perturbation (δ13Corg) at the NRB, indicating that a combination of climatic and environmental changes impacted the biota at a global scale. The NRB event may have been triggered either by gas emissions from the eruption of a large igneous province pre-dating the NRB, by a bolide impact of significant size or by some alternative source of greenhouse gas emissions. As yet, it has not been possible to clearly determine which of these trigger scenarios was responsible; the evidence is insufficient to decisively identify the causal mechanism and merits further study.