Patterns in post-extinction recovery in the aftermath of the Permian-Triassic biotic crisis

三叠系是北美西部的一个关键层段，蕴藏着2 x 108 m3的石油和1.15 x 1012 m3的天然气，代表着阿尔伯塔和不列颠哥伦比亚省经济的重要组成部分，但也记录了地球历史上最严重的大规模灭绝事件后的恢复期。这项研究计划的目的是建立生物复苏的性质后，这一灭绝事件，同时提供了一个岩石地层和生物地层框架的能源工业在加拿大西部。这次大灭绝后的恢复期持续了数百万年。地球海洋的生物多样性直到侏罗纪晚期才达到灭绝前的水平，间隔约9000万年。生物地球化学分析和古生物代用指标表明，溶解氧水平和海洋化学在下三叠世波动很大。一般认为，环境稳定，并伴随着生物恢复，发生在中三叠世。中生代浅海动物群在分类组成上与古生代动物群有很大的不同，但这种转变既不突然也不简单。 古动物型动物群（以海百合、腕足动物等为主）在中生代早期经历了几次复活，最终被“现代”动物群（双壳类、腹足类、十足类等）所取代。以往关于恢复模式的研究主要集中在下三叠世的演替、在有限的地理环境中的狭窄时间间隔以及通常集中在动物群的选定部分。这限制了演替和动物群之间的比较，妨碍了对灭绝后海洋动物群落化和再多样化的分析。** 为了确定灭绝后动物群和环境恢复的性质，需要进行详细的区域分析，纳入生态系统的所有要素（包括遗迹化石、无脊椎动物化石和脊椎动物化石），并与环境健康评估（海水氧化和化学）相联系。该项目通过整合古生物学、遗迹学、沉积学和地球化学数据集来解决这些缺点，以提供泛大陆西北缘三叠纪浅海生态系统的全面图片。这项研究从最低的三叠纪延续到卡尼期结束，这段时间以前被证明记录了一段时间的长期环境危机（Indian-Olenekian），海洋条件逐渐恢复到灭绝前的规范（Anisian-Ladinian），以及一段时间的快速再多样化和环境稳定（Ladinian-Carnian）。该项目旨在确定加拿大西部三叠纪环境稳定的时间，并澄清浅海动物群定居和稳定的模式。

The Triassic is a key interval in western North America, hosting 2 x 108 m3 oil and 1.15 x 1012 m3 gas representing a critical component of Alberta's and British Columbia's economies, but also recording the recovery interval after the most severe mass extinction event in earth's history. The purpose of this research program is to establish the nature of biotic recovery after this extinction event while concurrently providing a lithostratigraphic and biostratigraphic framework for the energy industry in western Canada.***The recovery period after this extinction lasted for millions of years. The biological diversity of Earth's oceans did not reach pre-extinction levels until the late Jurassic, an interval of ~90 million years. Biogeochemical analyses and palaeontological proxies have shown that dissolved oxygen levels and ocean chemistry fluctuated wildly during the Lower Triassic. It is commonly presumed that environmental stability, and concomitantly biotic recovery, occurred by the Middle Triassic. Mesozoic shallow marine faunas differ significantly in taxonomic composition from Paleozoic faunas, however the transition was neither abrupt nor simple. Palaeozoic-type faunas (dominated by crinoids, brachiopods, etc.) experienced several resurgences in the early Mesozoic before eventually being replaced by `modern' faunas (bivalves, gastropods, decapods, etc.).******Previous studies on recovery patterns have focused primarily on Lower Triassic successions, on narrow temporal intervals in restricted geographical settings and commonly on selected portions of the faunas. This limits comparison between successions and faunas, hampering analyses on marine faunal recolonization and rediversification in the extinction's aftermath. ******Detailed regional analyses that incorporate all elements of an ecosystem (including trace fossils, invertebrate fossils and vertebrate fossils), linked to assessments of environmental health (seawater oxygenation and chemistry) are required to establish the nature of post-extinction faunal and environmental recovery. This project addresses these shortcomings by integrating paleontological, ichnological, sedimentological and geochemical datasets to provide a comprehensive picture of Triassic shallow marine ecosystems on the northwestern margin of the Pangaea. The study extends from the lowermost Triassic to the end of the Carnian, an interval previously demonstrated to record an interval of prolonged environmental crisis (the Induan-Olenekian) with marine conditions gradually recovering to pre-extinction norms (the Anisian-Ladinian) and an interval of rapid re-diversification and environmental stabilization (the Ladinian-Carnian). This project seeks to establish the timing of environmental stabilization in the Triassic of western Canada and clarify the patterns of shallow marine faunal colonization and stabilization.**