Defining and Modeling the Response of a Low Gradient Coastal System to Rapid Sea-Level Rise during the Late Pleistocene Grant uri icon

abstract

  • This proposal will address the overarching objective of understanding the geological, morphological, and hydrodynamic (morphodynamic) response of a low-gradient coastal system to sea-level rise, based on observations and models of past conditions. In eastern North Carolina and Virginia there is a record of late Pleistocene rapid relative sea-level changes that occurred between ca. 130 ka and 40 ka. The late Pleistocene (ca. 130 ka to 11.7 ka) paleoshoreline (the Suffolk Shoreline) is a highstand prism stranded up to 120 km inland from the modern ocean shoreline. It is quite possible that if the West Antarctic Ice Sheet collapses, this is where the future shoreline will be. Late Pleistocene transgressive to highstand deposits occur seaward of the paleoshoreline, on the coastal plain and beneath the estuaries, and occur above the MIS6/5 (Termination 2) transgressive ravinement surface. These deposits contain a record of past morphodynamic conditions occurring during rapid rise and highstand that provide an analog for future conditions. We propose to collect and analyze geophysical data (seismic and GPR) and cores to develop the chronostratigraphic and sequence stratigraphic framework of this region to understand the response of the coastal system to rapid sea-level rise. We will use these empirical observations to validate hydrodynamic models during that period. Additionally, the identification of Pleistocene sea-level limiting and index points from this work will contribute to a greater understanding of the glacio-isostatic response of this system, and mantle rheology.

date/time interval

  • May 2019 - April 2023