URANIUM SERIES DATING OF QUATERNARY CORALS FROM THE SOUTHEASTERN U.S. ATLANTIC COASTAL PLAIN YIELDS INSIGHT FOR RECONSTRUCTING RELATIVE SEA LEVEL OVER THE LAST FULL GLACIAL CYCLE

We discuss an extensive Uranium-series (U-Th) dataset (Poirier et al., in review) that provides comprehensive insights into local, relative sea-level (RSL) history of the southeastern U.S. Atlantic Coastal Plain (ACP) during Quaternary high-stand events. The dataset includes 71 new U-Th analyses, in addition to 98 published coral dates that have been re-evaluated. The dated fossil corals were collected from marine deposits in outcrop, as well as from boreholes and excavations from sites between Virginia and Florida. Closed-system U-Th coral dates align with sea-level highstand events during early Marine Isotope Stage (MIS) 3, MIS 5a, MIS 5c, and MIS 5e. Importantly, the new closed-system results corresponding with the early MIS 3, MIS 5c, and MIS 5e represent the first robust U-Th coral ages from units north of the Florida Keys for those time periods. Additionally, we document an apparent ~10 kyr offset in the closed-system ages of deposits dated to MIS 5a in the northern study region of the Norfolk Arch to Albemarle Embayment region of Virginia and North Carolina (average = 74.0 ± 4.9 ka [2σ], n=13) relative to those from the southeast Georgia Embayment of South Carolina and Georgia (average = 84.0 ± 4.6 ka [2σ], n=9) and the corresponding paleo-reef tract in the Florida Keys (average = 84.7 ± 4.7 ka [2σ], n=9). Various new insights derived from refining the ages of these marine deposits and their associated paleoshorelines provide the opportunity to compare the regional RSL signals to global estimates for sea-level over the last glacial cycle with implications for long-term impacts of subsidence related to glacio-isostatic adjustment.