213-2 Benthic Foraminiferal Ecology from a New IODP Cretaceous-Paleogene Boundary Record Near Deccan Volcanism Activity

Session: Cushman Symposium: Microfossils of Extremophiles: Living in the Danger Zone

Presenting Author:

Debarpita Paul

Authors:

Paul, Debarpita¹, Burkett, Ashley M², Nana Yobo, Lucien³, Fendley, Isabel M⁴, Sprain, Courtney J⁵, Westerhold, Thomas⁶, Bohaty, Steve M.⁷

(1) Boone Pickens School of Geology, Oklahoma State University, Stillwater, Oklahoma, USA, (2) Boone Pickens School of Geology, Oklahoma State University, Stillwater, Oklahoma, USA, (3) Department of Geology & Geophysics, Texas A&M University, College Station, Texas, USA, (4) Department of Geosciences, Pennsylvania State University, University Park, Pennsylvania, USA, (5) Geological Sciences, University of Florida, Gainesville, Florida, USA, (6) MARUM - Center for Marine Environmental Sciences, University of Bremen, Bremen, Germany, (7) Institute of Earth Sciences, Heidelberg University, Heidelberg, Germany,

Abstract:

The Cretaceous–Paleogene (K/Pg) mass extinction had a profound impact on marine ecosystems, including benthic foraminifera. While extinction and recovery patterns have been widely studied across the Atlantic, Pacific, and Southern Oceans, the Indian Ocean remains underrepresented, despite its proximity to the Deccan Traps, which is one of the major potential drivers of environmental stress. During IODP Expedition 392, a new core was recovered from Site U1579 on the Agulhas Plateau (SW Indian Ocean), providing the first high-resolution benthic foraminiferal data across the K/Pg boundary from this volcanically proximal region (~4000 km from the paleolocation of the Deccan Traps). More than 50 samples from the Upper Maastrichtian to Lower Danian (4.89 m of core) were analyzed for changes in the benthic foraminiferal assemblage. This research is the only other study from the Indian Ocean, after Nomura (1991) at Broken Ridge, that confirms this study’s finding of the persistence of Gavelinella beccariiformis across the boundary. At Broken Ridge, the benthic foraminiferal numbers per million years remained unchanged for 2 m above the extinction boundary and then drastically decreased for 2 m before increasing again. However, benthic foraminifera assemblages at Site U1579 (3.16 m of post-extinction Paleogene core) reflect rapid proliferation of taxa, potentially driven by surface productivity despite regional volcanism. Specifically, the post-extinction surge in abundance of opportunistic taxa, as well as foraminiferal taxa diversity and heterogeneity, contrasts with the relatively sharp declines reported in widely studied sites like Blake Nose (western North Atlantic). However, it correlates with buliminid abundance patterns seen in Walvis Ridge (eastern South Atlantic), as the post-extinction samples of this research contain a higher abundance of Buliminids than the Maastrichtian, presumably caused by an abundant food supply to the sea floor, suggesting a relatively rapid recovery in the benthic foraminifera ecosystem. As only the second K/Pg benthic foraminiferal record from the Indian Ocean, this work fills a critical gap in the global K/Pg extinction and recovery picture and provides valuable ecological context for future multiproxy studies.

Geological Society of America Abstracts with Program. Vol. 57, No. 6, 2025

doi: 10.1130/abs/2025AM-11050

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