Permo-Triassic mass extinction

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  • Permo-Triassic mass extinction
    • What we know
      • Around 251 million years ago
      • Marks the end of the Palaeozoic Era
      • Around 95% of all marine invertebrates extinct
        • Extinct - Trilobites, tabulate corals, rugos corals and many brachiopods
        • Depleted - Foraminifera and cephaalopods
      • 77% of tetrapods, large amphibians and insects extinct on land
    • Super-continent formation
      • End of Permian = Pangaea formed
      • Fewer continental shelves
        • Lack of shallow marine habitat
        • Evidence in decline of shallow marine species
      • Presence of single continent caused rapid climate fluctuations
        • Unstable weather
      • Single continent= reduced input into oceans from rivers / estuaries
        • Less amount of nutrients available for shallow marine life
        • Possibly altered salinity of oceans
      • Widespread glaciation in southern hemisphere (Australia, South Africa, South America, Antarctica)
        • Sea level fall (regression)
        • Reduced shallow shelf environments
    • Major volcanic activity (Siberian Traps)
      • Believed to be the largest volcanic eruption in Earth History
      • Emission of poisonous gasses
        • Kill any plants or animals close by
      • Gas+Ash emitted during eruption
        • Could've initially lowered global temps by blocking heat from the sun
        • As it was global it could have caused global glaciation and sea level falls
        • May have lasted from hundreds to thousands of years
      • Emission of Greenhouse Gasses like CO2 and SO2
        • Increase in Global temperatures after cooling period
        • Could have lasted for thousands to millions of years
    • Methane hydrates (methane ice)
      • Solid form of methane believed to have formed within sediments
        • Solid and stable up to around 18°C
      • The global temperature increase could have triggered the release of these hydrates
        • Mobile and gaseous on the seabed
        • Could have disrupted life in the seas + increased greenhouse gasses

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