Deccan volcanism induced changes in global climate during the late Cretaceous and early Paleogene

Abstract

The temporal link between large igneous provinces (LIPs) magmatism and global environmental changes including mass extinctions have led to extensive studies on cause-and-effects relationship between them. The volatile released from LIPs magmatism (SO2, CO2, HCl etc.) have been hypothesized to have both short term effects (e.g., cooling associated with sulphate aerosols, acid rain, ozone depletion) on time scale of several years to long term environmental changes (e.g., warming associated with CO2) up to several 100 ka. One such well-studied LIP is Deccan flood volcanism (DFV) or simply "Deccan volcanism", which erupted between ~66.3 and 65.4 Ma and is temporally linked with the Cretaceous-Paleogene (K-Pg) boundary mass extinctions at ~66 Ma. The K-Pg boundary mass extinction has also been linked to Chicxulub asteroid impact, which often argued for a primary driver of mass extinction. The latest Maastrichtian warming event (LMWE) and Dan-C2 hyperthermal event in the early Danian fall in the timeline of the DFV and are generally linked with early (/main) and late phase of Deccan eruptions. However, these hyperthermal events are also often debated to be a regional expressions rather than global events. In this project, we propose to study the effect of Deccan LIP on global climate change during the latest Maastrichtian and early Danian using the marine K-Pg sections of the South Atlantic (DSDP 356 and 516) and NE Himalaya. These sections are currently being studied for the ongoing FAPESP postdoctoral project (Bolsa no Pais) entitled "Investigating ocean acidification during the late Maastrichtian and early Danian from marine sections of Brazil and India: Implications for impact vs. volcanism roles in the Cretaceous-Paleogene boundary mass extinction". The stable oxygen isotope (d18O) results on bulk carbonate samples of the DSDP 356 showed significantly decreased values in the early Danian coinciding with eruptions of the DFV. The Hg and Pb anomalies (marker for volcanism) were also found in the early Danian samples of the DSDP 356. The warming events may lead to ocean acidifications, therefore, it is important to have an understanding on these hyperthermal events. In the proposed BEPE work, we will compile the multi-proxy results on the sections being investigated under Bolsa no Pais along with generation of new data (rock magnetism, stable isotopes, and foraminifera) on the samples from NE Himalayan K-Pg section as well as on selected samples of DSDP 356 and 516 cores to understand role of Deccan volcanism in the hyperthermal events at both shallow marine (proximal site) and deep-ocean (distal sites). (AU)