GEOLOGIC EVOLUTION OF PLEISTOCENE AND HOLOCENE COASTAL FEATURES, CARTERET COUNTY, NORTH CAROLINA

LiDAR elevation data in Carteret County, North Carolina reveal apparent paleoshoreline geomorphic features. We hypothesize that these features represent at least three shoreline units of late Pleistocene to Holocene age: Unit 1 – a strandplain or possible cuspate foreland beach ridge feature; Unit 2 – a younger paleoshoreline ridge occurring on the mainland, and; Unit 3 – the present Holocene barrier islands. The objectives of this study are to discern the evolutionary history of the area, determine how the ridges are related to the nearby Suffolk Shoreline and Holocene barrier islands, and to place constraints on Pleistocene sea level. This study combines seismic and ground-penetrating radar geophysical data, sedimentological and foraminiferal analysis of core materials, and optically stimulated luminescence (OSL) data to characterize the evolution of these coastal deposits. The Suffolk Shoreline, a 300+ km feature formed by late Pleistocene sea-level highstands, has been dated to approximately 80 to 100 ka. Initial results from OSL dating indicate that the age of the mainland beach ridge (Unit 2) is approximately 50 ka, roughly the same age as the paleoshoreline ridges and tidal flat deposits in northeastern North Carolina and southeastern Virginia and 30 ka younger than the Suffolk Shoreline. Sedimentological and foraminiferal data from core samples correlated to geophysical and chronostratigraphic data are being used to provide sea-level index points and define paleoenvironments. This study will contribute to a more complete knowledge of how siliciclastic coastal systems respond to sea-level change and the record of late Pleistocene relative sea level on the southeast Atlantic margin.