科研之友
微信
新浪微博
Facebook
分享链接
摘要
Analysis of 16 marine Permian-Triassic boundary sections with a near-global distribution demonstrates systematic changes in sediment fluxes and lithologies in the aftermath of the end-Permian crisis. Sections from continent-margin and platform settings exhibit higher bulk accumulation rates (BARs) and more clay-rich compositions in the Griesbachian (earliest Triassic) relative to the Changhsingian (latest Permian). These patterns, which largely transcend regional variations in tectonic setting, sequence stratigraphic factors, and facies, are hypothesized to have resulted from a substantial (average similar to 7x) increase in the flux of eroded material from adjacent land areas owing to accelerated rates of chemical and physical weathering as a function of higher surface temperatures, increased acidity of precipitation, and changes in landscape stability tied to destruction of terrestrial ecosystems. This sediment surge may have been a contributory factor to the latest Permian marine biotic crisis as well as to the delayed recovery of Early Triassic marine ecosystems owing to the harmful effects of siltation and eutrophication. Contemporaneous deep-sea sections show no increases in sediment flux across the Permian-Triassic boundary owing to their remoteness from continental siliciclastic sources and location below the paleo-carbonate compensation depth.
- 出版日期2010-11
