EVIDENCE

Despite being the most catastrophic extinction event in geological history there has been little research done into the end-Permian, especially compared to events such as the Cretaceous-Tertiary (KT) mass extinction, with the associated extinction of the dinosaurs.

This has been in part due to a dearth of sedimentary sections dating from this time, as the result of a widespread marine regression which reduced sediment deposition rates, thus reducing the diagenesis of new rocks entering the geological record.

The recent discovery of sections from the Permo-Triassic boundary in localities in places such as Italy, Pakistan and South China has allowed more detailed analysis to take place. This has permitted new hypotheses of possible extinction mechanisms to be drawn up, and older hypotheses of what caused the mass extinction to be either discredited or backed up.

Where localities were in Permian.
 Where localities are now.
Localities(1)Greenland. (2)Southern Alps. (3)Iran-Armenia border. (4)Central Iran. (5)Pakistan. (6)Kashmir. (7)Southern China.

The majority of the extinction occurred in the low latitude equatorial regions, with marine species being particularily affected. These marine species were mostly benthonic, living in the warm, shallow tropical seas of the continental shelf surrounding the continents.
These were mostly filter feeders, often utilising a calcium carbonate shell for a means of protection and to support the soft bodied parts allowing feeding and respiration. It is these hard parts which are usually found in the fossil record, soft parts only ever being seen in circumstances of exceptional preservation.

Orders of organisms present.

The discovery of the more complete sections of strata from this time has allowed the extent and rate of the extinction to be better assessed, through study of the contained fossil remains and isotope ratio studies.
It is seen that many species were in decline throughout the Permian, before the final apocalyptic extinction event. This suggests that there may have been a prolonged climatic extinction mechanism, or a combination of many factors, rather than one catastrophic event.

Analysis of extinction rate.

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