Can the end-Permian mass extinction be attributed to a single, catastrophic event?

Robert Broughton (UK) The end Permian mass extinction occurred 251mya and marked the end of the Palaeozoic era. The loss of life is currently estimated to consist of 95% of the marine fauna and around 70 to 77% of the known terrestrial fauna (where the fossil record is inevitably less complete). This article will provide an overview of the many events and processes that played a part and a discussion whether they can all be attributed to a single, root cause. Reef evidence At this time, the landmass was united into the single, super-continent of Pangea, surrounded by warm shallow seas with abundant reef systems. This extensive reef fauna supported a variety of suspension feeders (for example, crinoids, rugose and tabulate corals, and so on), which were the most heavily hit by the extinction event, with all the known corals dying out. Modern scleractinian corals only appeared in the Triassic and there is a considerable gap in the coral fossil record at this time. Other reef inhabitants, such as the last phillipsid trilobites also became extinct. All these creatures were sessile or relatively immobile inhabitants of the reefs that occupied a relatively narrow zone on the continental shelf. This habitat must have been destroyed almost globally by a number of factors, but importantly, the single shelf margin around Pangea meant there was no other shallow reef environment for the fauna to migrate to. Fig. 1. Reef evidence. Tectonic activity The single continent of Pangea was always doomed to split apart. … Read More

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