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Paper No. 18-1
Presentation Time: 1:35 PM

RECONSTRUCTION OF GLOBAL SEA LEVEL CHANGE OVER THE LAST 5 MYR (Invited Presentation)


CLARK, Peter U., College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, OR 97331-5506, SHAKUN, Jeremy D., Department of Earth and Environmental Sciences, Boston College, Chestnut Hill, MA 02467, ROSENTHAL, Yair, Marine and Coastal Sciences, Rutgers, The State University of New Jersey, 71 Dudley Rd, New Brunswick, NJ 08901, POLLARD, David, Earth and Environmental Systems Institute, Pennsylvania State University, 2217 Earth-Engineering Science Building, Pennsylvania State University, University Park, NJ 16802, SCHRAG, Daniel P., Department of Earth and Planetary Sciences, Harvard University, 20 Oxford St., Cambridge, MA 02138 and MIX, Hari, Environmental Studies and Sciences, Santa Clara University, 500 El Camino Real, Santa Clara, CA 95053

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 d18Obenthic stack to derive the d18Oseawater. Accounting for the influence of changing temperature on the isotopic composition of ice sheets, we use the d18Oseawater 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.

Session No. 18

T138. Sea Level and Ice-Sheet Changes, Glacial Isostatic Adjustment, and Landscape Evolution I
Monday, 26 October 2020: 1:30 PM-5:30 PM
Geological Society of America Abstracts with Programs. Vol 52, No. 6
doi: 10.1130/abs/2020AM-352621
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