中国科学院南京地质古生物研究所机构知识库

The timing and ecological impacts of the Deccan Traps large igneous province eruption are vigorously debated. Pre-Cretaceous-Paleogene (KPg) boundary impacts of Deccan volcanism have been widely identified in marine sediments, but direct evidence of terrestrial impacts remains rare. We used mercury concentrations and isotopic compositions, a proxy for volcanic activity, to assess impacts on terrestrial environments. We studied two drill cores across the KPg boundary in eastern China that represent two different depositional environments: elastic deposits in the Jiaolai Basin and carbonate deposits in the Pingyi Basin. Both drill cores exhibit strong Hg enrichment prior to the KPg boundary. Near consistent mass-independent fractionation (MIF) of odd-Hg isotopes (odd-MIF) in the Jiaolai Basin likely indicates a volcanogenic source of Hg spikes below the KPg boundary. Odd-MIF isotopes in the Pingyi Basin likewise suggest a volcanogenic Hg source but with a terrestrial Hg signature of lower Delta Hg-199 values before and after the Hg spike interval. The Hg enrichment level can be stratigraphically correlated to the beginning of the Latest Maastrichtian warming event (LMWE) and is consistent with a strong, negative carbon-isotope excursion (CIE) in both delta C-13(org) (organic matter) and delta C-13(carb) (carbonate), suggesting a disturbance of the global carbon cycle induced by a major pulse of Deccan Traps volcanism. Our discovery of a terrestrial record of pre-KPg boundary Deccan volcanism provides robust evidence of global influence of the Deccan Traps large igneous province during the LMWE.