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.
Presently, the Earth biodiversity is going into a phase of extinction due to the anthropogenic activity, and this modern day extinction is now being commonly termed as "sixth mass extinction". The abrupt increase in atmospheric CO2 due to fossil fuel burning leads to global warming and ocean acidification. In the projected future estimate for year 2100, pH of ocean surface water will be reduced by 0.5 units (0.1 unit = ~30% increase in the concentration of hydrogen ions), which might have severe impact on marine organisms. Investigating past climatic changes and ocean acidification will provide a detailed understanding on the future changes.The Cretaceous-Paleogene (K-Pg) boundary mass extinction at ~66 Ma witnessed extinction of ~75% species of all genera and demise of the non-avian dinosaurs. The two catastrophes namely Chicxulub asteroid impact and Deccan volcanism have been consistently argued upon for the trigger of mass extinction. Ocean acidification has been suggested as one of the kill mechanisms during the K-Pg boundary mass extinction. However, detailed global investigation has not been carried out on this kill mechanism for the K-Pg boundary mass extinction. In the proposed project we will investigate events of ocean acidification during late Maastrichtian to early Danian from the marine sediments of Brazil and India. Two proxies of ocean acidification i.e., dissolution of magnetites (bacterial and detrital) and carbonate will be studied using advanced methods of rock magnetism, geochemistry and stable isotopes. The results will be correlated with records from other locations. In this project, we aim to (1) reconstruct high resolution paleoclimate during the late Maastrichtian to early Danian from Brazil and India; (2) identify whether single or multiple events of ocean acidifications occurred during late Maastrichtian to early Danian; and (3) understand whether both asteroid impact and volcanism were responsible for the K-Pg mass extinction or only one catastrophe was responsible for the extinction.
News published in Agência FAPESP Newsletter about the scholarship: