EAPS

Assessing the role of flood basalt volcanism in the end-Cretaceous mass extinction.

Abstract:
Temporal correlation between some continental flood basalt eruptions and mass extinctions has been proposed to indicate causality, with eruptive volatile release driving environmental degradation and extinction. My lab group has been testing this model for the Deccan Traps flood basalt province, which, along with the Chicxulub bolide impact, is implicated in the Cretaceous-Paleogene (K-Pg) extinction ca. 66 million years ago. We estimate Deccan eruption rates with U-Pb zircon geochronology, and resolve four high-volume eruptive periods. Maximum eruption rates are observed before and after the K-Pg extinction, with one such pulse initiating tens of thousands of years prior to both the bolide impact and extinction. Our dataset and other recently published data do not support models suggesting a mechanistic relationship between the impact and the volcanic eruptions. These findings combined with geochemical and paleontological datasets support extinction models that incorporate both catastrophic events as drivers of environmental deterioration associated with the K-Pg extinction and its aftermath. Future work needs to focus on a better understanding of volatile release associated with the Deccan Traps and additional geochronology covering the entirety of the volcanic province.