Sedimentary records of sea level fall during the end-Permian in the upper Yangtze region (southern China): Implications for the mass extinction.

Sea level fall is considered one of the significant factors leading to the end-Permian mass extinction (EPME). We studied the relative sea level changes in the Beifengjing and Shangsi sections, and the results indicate that a sea level fall occurred in the Upper Yangtze region during the Permian-Triassic transition. Considering that there is no significant change in fossil abundance in the strata following the two sea level falls observed in the Beifengjing section, we conclude that the reduction in shallow marine habitat for sea level fall solely was insufficient to cause the mass extinction. However, sea level fall did exacerbate the input of terrestrial debris into the ocean, leading to the deterioration of the marine environment. We propose that the combined adverse effects of volcanic eruptions, sea level falls, and other events exceeded the threshold for biological survival, ultimately resulting in the catastrophic EPME.