第六届青年地学论坛

1432 / 2019-08-10 14:52:11

Protracted recovery of lake ecosystem after the end-Permian mass extinction

14、古生物、古地理与古环境 > 专题3：中生代陆地生态系统演化

The end-Permian mass extinction, the most severe extinction event in Earth history, led to profound changes in marine and terrestrial ecosystems. The post-extinction recovery of marine ecosystem has been widely investigated; however, the pattern of recovery of lake ecosystem is still unclear. We reported the earliest known Triassic lacustrine oil shales with abundant tuff interlayers and fossils from Ordos Basin of China, dated to approximately 242−240 million years ago. These oil shales were deposited under oxic-suboxic bottom-water conditions, supported by pyrite framboid diameters, δ13Corg, and δ34Spyr data, suggesting an oxic, highly productive lake. The fossil assemblage includes notostracans, spinicaudatans, insects, freshwater fishes and fish coprolites, and thus documents a remarkably complex lake ecosystem. Our findings suggest that Triassic lake ecosystem took 10 million years to recover, which is consistent with the recovery pattern of peat-forming forest. Our results suggest that lake ecosystem may take longer time to recover than marine ecosystem.