The end-Permian mass extinction and its aftermath on an equatorial carbonate platform: insights from ichnology

P>A semi-quantitative analysis of the endobenthic activity across the Permo-Triassic boundary (PTB) was carried out on a similar to 445-m-thick well core interval from the Persian Gulf by logging the degree of bioturbation, trace fossil distribution and ichnodiversity (ID). This analysis enables for the first time the evaluation of recovery of endobenthic organisms after the end-Permian mass extinction by direct comparison of post-extinction (Lower Triassic) with pre-extinction (Upper Permian) units. The results indicate that the studied shallow-marine carbonate platform within an equatorial setting acted as oxygenated refugee for the biotic recovery. Traces of suspension and deposit feeders reappear simultaneously shortly after the extinction event, but are reduced in size. Macroborings - so far unknown from the Lower Triassic - occur where suitable firm or hard substrate was available. Recovery took place in two phases: Early Induan (50% pre-extinction ID and 20-30% bioturbation) and Late Induan (> 75% ID and almost 90% bioturbation re-established).