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

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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.**