Date of Award

8-2025

Degree Type

Report

Degree Name

Master of Science (MS)

Department

Geosciences

Committee Chair(s)

Donald E. Penman (Committee Chair)

Committee

Donald E. Penman

Committee

Tammy M. Rittenour

Committee

Dennis L. Newell

Abstract

The Paleocene-Eocene Thermal Maximum (PETM, ~56 million years ago) represents an ancient episode of rapid global warming, offering critical insights into climate dynamics and the Earth's response to increased greenhouse gases. This project aims to quantify the magnitude of warming across the PETM at newly recovered IODP Site U1580 (Agulhas Plateau, Southern Ocean) through the analysis of Mg/Ca and δ18O ratios of planktic foraminifera. Understanding the extent of warming at Site U1580 is crucial for comprehending past climate variability and improving future climate predictions. Site U1580 is particularly well-suited to foraminiferal geochemistry because of high carbonate content throughout the event: well-preserved foraminifers are present even in the PETM onset phase, which is typically missing from deep-sea records because of dissolution. Because of vertical sediment mixing across the Paleocene-Eocene boundary, individual foraminifera were analyzed for carbon and oxygen isotopic composition using a modified small-sample isotope-ratio mass spectrometry technique. Individual foraminifer results show two distinct populations representing pre-CIE individuals and CIE individuals. The proportion of pre-CIE vs. CIE individuals can then be used to "unmix" multi-shell Mg/Ca data. Combined oxygen isotope and Mg/Ca data indicate an SST warming of 5-8°C at Site U1580. A secondary result was to establish the magnitude of the carbon isotope excursion in planktic foraminifera, thereby contributing to our understanding of past climate dynamics and improving predictive models for future climate scenarios.

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