Geological Society of America

10 D5. Paleoclimate, Paleontology, and Sedimentology (Posters)

Monday, 18 May 2020
8:30 AM - 5:30 PM
Lake Superior Ballroom KJ

TEMPERATURE AND OXYGEN ISOTOPE SEASONALITY OF THE LAST INTERGLACIAL (MIS-5E) FROM ANALYSIS OF STABLE AND CLUMPED ISOTOPES OF BERMUDA BIVALVES

Paper number: 10-1
Program: Technical Sessions
Time: 8:30 AM – 5:30 PM

Authors

Steven Wedel Presenting Author
University of Michigan, Ann Arbor, MI
Sierra Petersen
University of Michigan, Ann Arbor, MI
Jade Zhang
University of Michigan, Ann Arbor, MI
Ian Z. Winkelstern
University of Michigan, Ann Arbor, MI
Ian Z. Winkelstern
Grand Valley State University, Allendale, MI
Kyger C. Lohmann
University of Michigan, Ann Arbor, MI

Abstract

Reconstructing climate during periods of past global warmth can improve predictions of future climate change. During the Last Interglacial (MIS-5e, ~125ka), the Earth experienced a climate ~1-2°C warmer and global sea level 6-9 m higher than present. This led to extensive shallow marine carbonate deposits currently exposed above the water-line on Bermuda that contain abundant molluscan fossils. In our study, we have undertaken high-resolution δ¹⁸O and clumped carbonate isotope analysis to reconstruct seasonal variations in surface water temperature and seawater δ¹⁸O values. Shell δ¹⁸O analysis reveals a sinusoidal pattern indicating a seasonality in temperature of ~7°C, similar to today. Prior clumped isotope studies of Bermuda mollusca, based on bulk sample analysis, suggest an overall cooling at this location despite an overall warmer global climate. Our high-resolution clumped isotope analysis targeting the seasonal maximum and minimum values of carbonate δ¹⁸O in each shell allows for the separation of the seasonal influences of temperature and potential variation in seawater salinity and δ¹⁸O values. Reconstruction of Bermuda’s climatic conditions during MIS-5e will help constrain predictions and numerical model simulations of future climate as modern global warming continues.

Geological Society of America Abstracts with Programs. Vol. 52, No. 5

doi: 10.1130/abs/2020NC-347790

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