T139 Advances and New Voices in Marine and Coastal Geoscience I

Tuesday, 12 October 2021
8:00 AM - 12:00 PM
D136 (Hybrid Room)

MULTI-PROXY CONSTRAINTS ON MARINE ISOTOPE STAGE 5E SEA-LEVEL POSITION IN THE U.S. ATLANTIC COASTAL PLAIN: IMPLICATIONS FOR GLACIO-ISOSTATIC ADJUSTMENT AND SEA-LEVEL MODELING

Paper number: T139-9
Program: Technical Sessions
Time: 9:50 AM – 10:05 AM

Authors

Abstract

The U.S. Atlantic Coastal Plain (ACP) preserves a number of marine terraces associated with paleo-shoreline escarpments that record various Quaternary sea-level highstands. One of the most widely studied periods of the late Quaternary is Marine Isotope Stage (MIS) 5e (~125-115 ka), which is the most recent period where significant ice-mass loss likely occurred from the Greenland and Antarctic Ice Sheets. As such, MIS 5e provides insights relevant to future sea-level rise. Constraining local, relative sea level (RSL) for different regions compared to globally averaged eustatic sea level is extremely important for predicting the complex patterns of sea-level rise we can expect in the future. Recent work has yielded closed-system U-Th coral ages corresponding with MIS 5e from the southern ACP in South Carolina and Florida (RSL 7-8m above present), providing the first confirmed RSL estimates from north of the Florida Keys for that time period. In contrast, RSL during MIS 5e farther north in the mid-ACP is largely unconstrained, with no surficial deposits dated to MIS 5e. Instead, MIS 5a (~80-75 ka) deposits are prevalent, reaching similar elevations as the MIS 5e deposits to the south. The lack of MIS 5e-dated deposits and the prevalence of MIS 5a-dated deposits at 7-8 m elevations has been attributed to the post-glacial subsidence of the pro-glacial forebulge (glacio-isostatic adjustment – GIA), centered in the region between New Jersey and the Delmarva Peninsula. However, GIA models cannot yet constrain RSL during the Holocene (~11.7-0 ka) or MIS 5e in the peripheral region of the pro-glacial forebulge of the mid-ACP. We present multi-proxy datasets (stratigraphy, lithology, micro-paleontology, stable isotope geochemistry) providing new RSL constraints for MIS 5e from multiple sites in the mid-ACP near the mouth of the Chesapeake Bay, which can ultimately be used to improve estimates of GIA and ice-mass loss contributions in future studies.

Geological Society of America Abstracts with Programs. Vol. 53, No. 6

doi: 10.1130/abs/2021AM-368190

© Copyright 2021 The Geological Society of America (GSA), all rights reserved. Permission is hereby granted to the author(s) of this abstract to reproduce and distribute it freely, for noncommercial purposes. Permission is hereby granted to any individual scientist to download a single copy of this electronic file and reproduce up to 20 paper copies for noncommercial purposes advancing science and education, including classroom use, providing all reproductions include the complete content shown here, including the author information. All other forms of reproduction and/or transmittal are prohibited without written permission from GSA Copyright Permissions.