183-9 Detailed Mapping of the Post-Cretaceous Depositional Evolution Along the Northeastern South Carolina Coast with Implications for Future Studies of Modern Local Subsidence

Session: Recent Advances and New Voices in Marine and Coastal Geoscience (Posters)

Presenting Author:

Authors:

Abstract:

The buried paleo-topography of pre-Quaternary landscapes, along with changes in sea level and sediment supply, control the thickness, distribution and depositional ages of sedimentary facies of overlying Quaternary deposits. These antecedent topographies, along with local sedimentary composition, thickness and lateral extent of Quaternary paleo-environments, are assumed to have a strong influence on the development of modern coastal environments. Prior studies demonstrated that shallow and young deposits (uppermost 5 to 10 m) are more susceptible to compaction than underlying older successions, while deeper sediment type and unit thickness can be important factors leading to increased rates of local-scale land subsidence. Characterizing the sedimentary evolution in this region will provide insight for the future investigation of local variability in vertical land motion along the modern coast of South Carolina, which is growing increasingly vulnerable to the impacts of coastal and estuarine flooding.

          This project utilizes a database of 1,145 sediment boreholes collected by the South Carolina Geologic Survey and others in the Northern Lower Coastal Plain of South Carolina (Georgetown and Horry Counties). Sediment descriptions from borehole logs and unit thickness are compared with published data from the region to identify known stratigraphic formations and to map the extent of these post-Cretaceous deposits (Paleocene, Eocene, Pliocene, and Quaternary). Additionally, detailed facies separation and mapping of the Quaternary deposits will be completed to provide context for modern sediment distribution and the controlling processes related to the evolution of coastal environments.

Geological Society of America Abstracts with Program. Vol. 57, No. 6, 2025

doi: 10.1130/abs/2025AM-9053

© Copyright 2025 The Geological Society of America (GSA), all rights reserved.