Van Tuyl Lecture, April 1, 2024, Berthoud 204, 12-1pm

Kaustubh Thirumalai, University of Arizona

“Individual Foraminifera as Tracers of Paleomonsoon Intensity and Methane Seepage History from Indian Margin Sediments”

Abstract: Sediments accumulating offshore the Indian subcontinent hold a rich record of southern Asian paleoclimate change, where freshwater outflow is primarily driven by Indian Summer Monsoon (ISM) precipitation. Additionally, gas hydrate exploration and the discovery of methane seeps have generated interest in understanding the history of carbon cycling in Indian margin sediments. In this talk, I will provide a brief overview of the development of the ‘individual foraminiferal analyses’ (IFA) geochemical approach and how it can be applied to infer past ISM variability, its impact on marine biogeochemistry, and the history of methane seepage in the Indian margin at International Ocean Discovery Program (IODP) Site U1446, northwest Bay of Bengal. The IFA approach leverages the short, weekly-to-monthly lifespan of calcareous foraminifera and generates geochemical histograms from within sediment samples that span centuries. I will show how statistical comparisons of downcore IFA histograms allow for detailed insights into past water column variability at IODP Site U1446. Whereas planktic foraminiferal stable isotopes are used to unravel upper-ocean changes linked to monsoonal ocean-atmospheric processes, IFA applied to benthic foraminiferal shells document episodic methane seepage events in the Indian margin sediments across the Pleistocene.

This lecture is scheduled in a hybrid format. If you would like to join the meeting please:

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Food/ Refreshments will be served.