8 D4. Mapping in the Southeast using Interstate Collaboration, Correlation, and Cores (Posters)

Thursday, 20 March 2025
8:00 AM - 5:00 PM
Shenandoah ABC

GEOTECHNICAL, PALEONTOLOGICAL, AND STRATIGRAPHIC ANALYSIS OF SHALLOW OFFSHORE SEDIMENTS FOR DECISION-MAKERS IN NORTH AND SOUTH CAROLINA'S LONG BAY REGION: A PROGRESS REPORT ON STATE, FEDERAL, AND ACADEMIC COOPERATION

Paper number: 8-4
Program: Technical Sessions
Time: 8:00 AM – 5:00 PM

Authors

Abstract

Potential beach quality sediment resources offshore in Long Bay (southeast North Carolina and northeast South Carolina) are scarce because of geology and geography factors. Scarcity factors include the characteristics of shallow offshore stratigraphy, long-term low-sediment supply, lack of accommodation space, and modern oceanographic processes. The scarcity of sediment resources is reflected in the history of borrowing sand for nearby beaches.

The Long Bay South Carolina Department of Natural Resources Cooperative Agreement (SC COOP) aims to refine the geologic framework across Long Bay to identify zones of potential sand and gravel resources using spatial and temporal relationships and develop sand-search strategies built on these relationships.

A collaborative group of state, federal, and academic geoscientists met in 2024 to collect samples for paleontological, sedimentological, geochronological, and geotechnical analyses on a set of 30 shallow-depth (<5 m) vibracores collected under contract to the Bureau of Ocean Energy Management (BOEM). Results will assist in understanding the following: 1) onshore-offshore stratigraphic relationships between Long Bay sediments and those of the nearby shoreline; 2) distribution and character of shallow-water deposits across the bay, focusing on the distribution of sands versus clay-silt; and 3) mineralogical and physical properties of materials.

Future work will determine: the percentage of glauconite in shallow stratigraphic units; the ages of the sediments; if there are mappable distributions of resource sand in Long Bay; and the geotechnical soil classification and cement content of the sediments. Integrating these data with existing onshore borehole data will provide insight into composition, erodibility, and preservation potential of offshore sediments.

Geological Society of America Abstracts with Programs. Vol. 57, No. 2

doi: 10.1130/abs/2025SE-408865

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