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

二叠纪-三叠纪生物危机后的灭绝后恢复模式

• 批准号: RGPIN-2015-05635
• 负责人: Zonneveld, JohnPaul
• 金额: $ 1.97万
• 依托单位: University of Alberta
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2018
• 资助国家: 加拿大
• 起止时间: 2018-01-01 至 2019-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=669972
• 关键词: Patterns; post; extinction; recovery; aftermath

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.**

三叠系是北美西部的一个关键时期，蕴藏着2×108立方米的石油和1.15×1012立方米的天然气，是艾伯塔省和不列颠哥伦比亚省经济的关键组成部分，但也记录了地球历史上最严重的大灭绝事件后的恢复时期。这项研究计划的目的是确定这次灭绝事件后生物恢复的性质，同时为加拿大西部的能源行业提供岩石地层和生物地层框架。*这次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，时间间隔约9000万年。生物地球化学分析和古生物替代物表明，下三叠世水溶氧水平和海洋化学变化剧烈。通常认为，环境的稳定以及伴随而来的生物恢复发生在中三叠世。中生代浅海动物群与古生代动物群在分类组成上有很大差异，但这种转变既不突然也不简单。古生代动物群(以海百合、腕足类等为主)在中生代早期经历了几次复苏，最终被“现代”动物群(双壳类、腹足类、十足类等)所取代。*以前对恢复模式的研究主要集中在下三叠统序列，在有限的地理环境下的狭窄时间间隔，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，阻碍了对灭绝后海洋动物群再殖民和再多样化的分析。*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(海水氧合和化学)相联系，以确定灭绝后动物和环境恢复的性质。该项目综合了古生物、生物、沉积学和地球化学数据，全面描绘了盘古大陆西北缘的三叠纪浅海生态系统，解决了这些不足之处。这项研究从最低的三叠纪延伸到卡尼期的末期，这一间隔期以前被证明记录了一个长期环境危机的间隔期(印度河-奥伦基期)，海洋状况逐渐恢复到灭绝前的常态(阿尼西亚-拉迪尼期)，以及一个迅速再多样化和环境稳定的间隔期(拉迪尼亚-卡尼期)。该项目旨在确定加拿大西部三叠纪环境稳定的时间，并澄清浅海动物群系定居和稳定的模式。