SGER: Deccan Volcanism Implicated in K-T Mass Extinction

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The biotic effects of Deccan volcanism and its potential impact on the K-T mass extinction are perhaps the major unsolved problems in K-T studies today. Recent studies indicate that the bulk (80%) of the Deccan trap eruptions occurred over less than 0.8 m.y. in magnetic polarity C29r spanning the Cretaceous-Tertiary (K-T) boundary and that the last Deccan eruption occurred in the early Danian C29n. These two Deccan Traps form the longest lava flows extending 1000 km across India and out to the Sea of Bengal. However, determining just where within the C29r major eruptive phase the K-T mass extinction occurred has remained problematic because intertrappean sediments were generally deposited in fluvial or estuarine environments, which provide poor age control. As a result, models estimating the biotic and environmental consequences of Deccan volcanism have generally underestimated the rate and quantity of Deccan gas emissions by orders of magnitude leading to conclusions that volcanism could not have caused the K-T mass extinction. PIs preliminary investigations of the intertrappean sediments in shallow marine sequences of the Krishna-Godavari Basin in SE India revealed that the major Deccan C29r volcanic eruptions ended at the K-T mass extinction, which suggests that volcanism and impact(s) may have caused this catastrophe.In this project PIs propose to investigate the onset, duration and end of the main phase of C29r Deccan volcanism and its biotic consequences in the marine realm as well as the dinosaur extinction and C29n volcanism and its relationship to the long delayed early Danian biotic recovery. Specifically, they will test two hypotheses: (1) Deccan volcanism played a crucial role in the K-T mass extinction, and (2) Deccan volcanism is responsible for the long-delayed biotic recovery after the mass extinction. PIs plan to accomplish this by building on their initial discovery that the main Deccan volcanic phase ended at the K-T mass extinction (Rajahmundry and Meghalaya) and by analyzing new drill cores that recover intertrappean and infratrappean sediments of the two longest Deccan Trap lava flows. The results of this project may open the contentious mass extinction debate to potentially transformative research ideas by directly linking mass extinctions to large igneous provinces.This research is jointly funded with NSF's Office of International Science and Engineering.