DEFINING THE QUATERNARY GEOLOGIC FRAMEWORK OF THE BUXTON INLET AREA, NORTH CAROLINA

The Buxton Inlet study area is approximately 4 miles in length and is located along the Outer Banks of North Carolina just north of Cape Hatteras between the towns of Avon and Buxton. The North Carolina Department of Transportation has identified the area as one of seven erosional “hot spots” along Highway 12. The Buxton Inlet area is one of five specific sites being studied in detail by the North Carolina Coastal Geology Cooperative (NCCGC) with the objective of understanding the role of antecedent geology in controlling coastal geomorphology and erosion. The Buxton Inlet site is highly susceptible to coastal erosion and has a previous inlet history (Buxton Inlet: opened from 1962 to 1964). This study is utilizing split-spoon samples at 5 ft. intervals collected from six boreholes by the NCDOT down to approximately 160 ft. and two vibracores from the North Carolina Geologic Survey (NCGS). AAR and radiocarbon dating methods, and foraminiferal investigations are being used to define the chronostratigraphy and depositional environments. The biostratigraphy, lithostratigraphy, and chronostratigraphy of these samples are being used for correlations to define the geologic history of Pleistocene and Holocene sediments underlying the Buxton Inlet area. Current sedimentary analysis has revealed seven distinct lithofacies within the study area. From bottom to top, the lithofacies consist of a moderately sorted fine to medium grained sand overlain by muddy sand with abundant foraminifera and shell fragments, followed by fine grained sand, overlain by a slightly muddy fossiliferous sand, followed by a fine to coarse grained sand with reworked shell fragments, overlain by an organic rich sand, and finally a fine to coarse grained sand with shell fragments. Borehole data are being correlated to high resolution single-channel seismic data to define the sequence stratigraphic framework.