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: 2016
• 资助国家: 加拿大
• 起止时间: 2016-01-01 至 2017-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=613659
• 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.

三叠纪是西部西部的关键间隔，拥有2 x 108 M3石油和1.15 x 1012 m3气体，代表了艾伯塔省和不列颠哥伦比亚省经济的关键组成部分，但在地球历史上最严重的质量扩展事件之后，还记录了恢复间隔。该研究计划的目的是在此扩展事件之后建立生物恢复的性质，同时为加拿大西部的能源行业提供岩石地层学和生物地层学框架。 此扩展后的恢复期持续了数百万年。直到侏罗纪晚期，地球海洋的生物多样性才达到预估计水平，间隔约为9000万年。生物地球化学分析和古生物学的代理表明，在较低的三叠纪下，溶解的氧气水平和海洋化学发生了巨大波动。通常认为环境稳定性及其伴随的生物恢复是由中部三叠纪发生的。中生代浅海动物群在与古生代动物的分类学组成中的显着不同，但是过渡既不突然也不简单。古生代型动物群（以甲状腺素，腕足动物等为主导）在中生代早期经历了几种复活，然后最终被“现代”动物群（双壳类，胃足，dec脚架，dec脚架等）取代。 先前关于恢复模式的研究主要集中在较低的三叠纪继任，狭窄的临时间隔限制的地理环境，通常是在动物区系的选定部分上。这限制了继任与动物群之间的比较，阻碍了对扩展后期的海洋动物群认识和反转的分析。 详细的区域分析结合了生态系统的所有元素（包括痕量化石，无脊椎动物化石和脊椎动物化石），与对环境健康的评估（海水氧合和化学的评估）有关，以建立后炎后炎后炎后炎和环境恢复的性质。该项目通过整合了古生物学，流行病学，沉积和地球化学数据集来解决这些缺点，以便在Pangea西北边缘提供三叠纪浅海生态系统的全面图景。这项研究从最低的三叠纪延伸到卡尼亚人的末端，此前的间隔旨在记录长时间的环境危机（Induan-Olenekian）的时间间隔，海洋条件逐渐恢复到预估计规范（Anisian-Ladinian）和快速的重复稳定和环境稳定性（LADIANIAN-LADINIAN-LADINIAN）。该项目旨在在加拿大西部的三叠纪建立环境稳定的时机，并阐明浅海动物动物殖民和稳定的模式。