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.
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.