第六届青年地学论坛

1770 / 2019-08-29 10:43:56

Mercury anomalies across the Cretaceous-Paleogene mass extinction innorthern China: Links to Deccan volcanism and paleoecosystem impacts

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 Cretaceous-Paleogene boundary (KPB) mass extinction is commonly attributed to both the Deccan Traps
volcanism and Chicxulub impact, although the exact mechanism is still controversial, the mercury (Hg) as a new
proxy could help us to better interpret the relationship between large igneous provinces and mass extinctions.
Here we present new Hg geochemical data from the terrestrial Songliao Basin, northern China. Our results show
one significant Hg concentration anomaly which occurred ~120 ky before the Chicxulub impact, is temporally
corresponding to the second (main) phase of Deccan eruptions with maximum eruption rates and high losses of
charophytes and ostracods in the Songliao Basin. There is no correlation between the Hg concentration and total
organic carbon (TOC) & clay content, which suggests that the Hg anomaly was potentially caused by volcanic
activities. We, therefore, suggest that the Deccan Traps volcanism triggered the latest Cretaceous warming ~300 ky
prior to the Chicxulub impact and then the initial KPB mass extinction ~120 ky prior to the Chicxulub impact.We
also speculate that the brief eruptions with extreme eruption rates (e.g. ~66.1 Ma) would tend to heavily disturb
the ecosystem than those long-term eruptions with limited intensities (e.g. ~66.3 Ma).