Geological Society of America

T18 Sea Level and Ice-Sheet Changes, Glacial Isostatic Adjustment, and Landscape Evolution I

Monday, 26 October 2020
1:30 PM - 5:30 PM
Meeting Rooms

RECONSTRUCTION OF GLOBAL SEA LEVEL CHANGE OVER THE LAST 5 MYR

Paper number: T18-2
Program: Technical Sessions
Time: 1:35 PM – 1:50 PM

Authors

Peter Clark Presenting Author
Oregon State University, Corvallis, OR
Jeremy D. Shakun
Boston College, Chestnut Hill, MA
Yair Rosenthal
Rutgers, The State University of New Jersey, New Brunswick, NJ
David Pollard
Pennsylvania State University, University Park, NJ
Daniel P. Schrag
Harvard University, Cambridge, MA
Hari Mix
Santa Clara University, Santa Clara, CA

Abstract

We use a global array of ~120 sea-surface temperature (SST) records based on Mg/Ca, alkenone, and faunal proxies to reconstruct global and regional temperature change over the last 5 Myr. All records are on the LR04 age model. Average global temperature has cooled by ~6.5oC since ~3.5 Ma, with a significant increase in the rate of cooling between ~1.2 and 0.8 Ma. We also use our global SST reconstruction to remove the temperature signal from the LR04 d¹⁸O_benthic stack to derive the d¹⁸O_seawater. Accounting for the influence of changing temperature on the isotopic composition of ice sheets, we use the d¹⁸O_seawater record to reconstruct global sea level for the last 5 Myr. These results suggest inception of Northern Hemisphere glaciation ~3 Ma, with sea-level minima equivalent to or greater than the LGM sea-level low stand starting at ~2.5 Ma. Since inception, sea level has varied at a dominant ~41-kyr period, with first appearance of a low-frequency (~100-kyr) signal at ~0.65 Ma.

Geological Society of America Abstracts with Programs. Vol. 52, No. 6

doi: 10.1130/abs/2020AM-352621

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