Increasing evidence suggests that the four most recent mass extinction events: end-Guadalupian; end-Permian; Triassic-Jurassic boundary; Cretaceous-Paleogene boundary (KPB)- are closely associated in time with continental flood basalt (CFB) volcanism. Paradoxically, the KPB is associated with both the Deccan Traps CFB and the Chicxulub impact in Yucatan, Mexico, engendering an intense three-decades-old debate over causal relationships. Deccan volcanism began well before and continued well after KPB/Chicxulub time, but the largest Deccan eruptions (Wai Sub-group) appear to have been initiated within ~50,000 years of both the KPB and the Chicxulub impact, suggesting that this subset of eruptions may have been triggered by the impact. It remains unclear whether large Deccan flood basalt eruptions or the Chicxulub impact (or both) were the cause of the KPB extinction, because both may have injected massive amounts of volatiles, aerosols, and particulates into the atmosphere. This project's research will improve our understanding of the genesis, timing, and environmental effects of Deccan Traps volcanism by considering Earth systems interactions from mantle plume convection to crustal magmatism to eruption and to atmosphere/biosphere effects.
The research will include studies of: (1) The genesis and geodynamic context of Deccan magmatism based on physical volcanology and geochemical signatures, coupled with analysis of volatile contents; (2) Radioisotopic geochronology of the Deccan Traps to tightly constrain their eruptive tempo and relation to other KPB events; (3) Geophysical modeling of mantle and crustal magmatic processes, launching of volatiles and aerosols by the Deccan eruptions, and mechanisms of volcanic triggering by dynamic (seismic) stresses due to earthquakes and impacts; (4) Analysis of geophysical exploration data from offshore western India that has not previously been integrated into the main on-land Deccan stratigraphy. Results of these studies will be compared with other Phanerozoic CFB events, some of which are and, importantly, some of which are not associated with mass extinction.
