Collaborative Research: Investigating Early Triassic Ocean Chemistry, Stratigraphy, and Paleobiology During the Protracted Biotic Recovery from the Permo-Triassic Mass Extinction

自动物起源以来最具破坏性的大规模灭绝发生在二叠纪末期(约2.51亿年前)，当时超过80%的海洋物种灭绝。在大灭绝事件发生后，海洋领域在随后的三叠纪时期仍有数百万年的扰动，但细节鲜为人知，可能有助于我们更全面地了解大灭绝。不同寻常的地质特征让人想起地球历史上更早的时代，例如海底沉淀的文石扇体、潮下叠层石，以及海水d13C和d34S的显著漂移，表明非典型的海洋化学和环境一直持续到早三叠世，但鉴于以前研究的边界中心性质，他们的确切性质还没有得到很好的理解。我们将研究异常生物群、不合时宜的岩相、强同位素位移(d13C、d34S)与早三叠世(大灭绝后的地质期)动物长期恢复之间的关系。我们建议的研究区域美国西部，在这一地质时期位于巨大的泛海边缘，因此提供了与其他地方正在进行的研究(中国，欧洲等)的全球比较。我们在美国西部的初步工作表明，样品保存完好，并提供了亚阶段的时间对比潜力。反映海水条件的富硫沉积物在岩石记录中很少见。我们将通过使用一种新的技术来解决这个问题，从世界上常见的正常海相石灰岩(即所谓的碳酸盐伴生硫酸盐或CAS)中提取硫同位素信息。组装的数据集很可能是此类数据集中的第一个，并揭示了一些特征，这些特征可能会让我们深入了解之前没有发现的大灭绝。

ABSTRACTThe most devastating mass extinction since the origin of animals occurred at the end of the Permian Period (c. 251 million years ago) when over 80% of all marine species went extinct. The marine realm remained perturbed into the subsequent Triassic Period for several million years after the extinction events, but the details are poorly known and may help us more completely understand the extinction. Unusual geologic features reminiscent of earlier times in Earth's history, such as seafloor precipitated aragonite fans, subtidal stromatolites, and remarkable excursions in seawater d13C and d34S, indicate that atypical ocean chemistries and environments persisted into the Early Triassic, but their exact nature is not well-understood, given the boundary-centric nature of previous studies. We will investigate connections between unusual biotas, anachronistic lithofacies, strong isotopic shifts (d13C, d34S) and the protracted animal recovery in the Early Triassic (the geologic period following the mass extinctions). The western U.S., our proposed study area, resided on the eastern margin of the giant Panthalassic Ocean during this geologic time and thus provides a global comparison with ongoing research elsewhere (China, Europe, etc.). Our preliminary 87Sr/86Sr work in the western US demonstrates that samples are well preserved and that 87Sr/86Sr provides sub-stage time correlation potential. Sulfur-rich deposits that reflect seawater conditions are rare in the rock record. We will surmount this problem by using a new technique to extract sulfur isotopic information from normal marine limestones (the so-called "carbonate associated sulfate" or CAS), which are common around the world. The assembled dataset will likely be the first of its kind and reveal features that may give insight into the mass extinction not previously recognized.