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

Rates of sea-level rise have accelerated over the last 120 years, from global rates of approximately zero in the 19th century, to an average rate in the 20th century of approximately 1.7 mm/y, to the present rate of 3.4 +/- 0.4 mm/y. Geologic observations of sea-level high-stand markers from 130,000 to 80,000 years ago suggest that global sea level attained a height of approximately +2 m (relative to modern sea level) for several millennia, possibly followed by a rapid rise to approximately +6 m. The goal of this proposal is to determine how the coasts of North Carolina and Virginia responded to sea level changes during these times. This project will collect geophysical data and sediment cores in the North Carolina and Virginia region. The deposits contain a record of past changes due to erosion and sedimentation that occurred during rapid sea level rise that could provide an analog for future conditions in this region. The project provides training for graduate and undergraduate students.

This proposal will address the objective of understanding the geological and morphodynamic response of a low-gradient coastal system to sea-level rise. In eastern North Carolina and Virginia, late Pleistocene transgressive to high-stand deposits occur seaward of the Marine Isotope Stage 5 paleoshoreline on the coastal plain and beneath the modern estuaries. Geophysical data and sediment cores will be collected in two study areas in the region. These data will be used in the future to develop a 3D model of facies relationships and the sequence stratigraphic framework of the region, to develop numerical hydrodynamic models to understand the response of the coastal system to rapid sea level rise, and to place vertical constraints on Pleistocene sea levels.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.