permo-triassic mass extinction

• 250 million years ago, 95% of all marine invertebrates became extinct. Extinction on land effected plant and insect species. 
• Siberian traps hide a flood basalt which occurred a the same time as the extinction. 
• The laki eruption in Iceland is a smaller but similar style eruption, it changed the northern hemispheres climate in 1783/4 there was no summer and snow in august. Its used to model impacts of Siberian traps. 
• 10s years is short term and causes volcanic winters leading to cooling. 
• 1000s years is long term and include co2 leading to global warming. 
• To estimate volume of lava, calculations of CO2 released and then global temp increase are needed. 5ºc cause mild extinctions, 10ºc rise is needed for large mass extinctions. 
• Greenland has a thick rock sequence spanning Permian-Triassic extinction.

  There were 3 phases spanning 80,000 years:

  • Land extinctions 
  • Abrupt ocean extinctions 
  • Land extinction 

   
• There was an increase in carbon-12 on boundary, methane hydrates are rich in carbon-12, if ocean temperatures increase by 5ºc, methane hydrates melt. During the Pe-T extinction enough methane was released to increase temps by 4-5ºC. 
• There are a number of pyrite sediments due to a lack of oxygen - perhaps due to an increase in temperature. An increase in demand for oxygen due to increased temperatures.
• Supercontinent formation may have also contributed to mass extinctions.