| Summary |
The main objective of this project is to define the stratigraphy and geochronology of the two sand ridge deposits, the Land of Promise Ridge and the Powells Point Ridge, that comprise southern Currituck County. Optically stimulated luminescence dating, ground-penetrating radar, lithology, radiochronology, and diatoms were used to determine the depositional age and mechanisms for deposition of this region. This study also examined the sea-level implications associated with the deposits of Currituck County. Geochronological data show the Land of Promise Ridge was deposited between 65.3 +/- 10.2 ka and 59.7 +/- 10.2 ka, and the Powells Point Ridge was deposited between 54.9 +/- 6.3 ka and 43.2 +/- 7.9 ka. Three optically stimulated luminescence dates indicate dune reactivation before and after the onset of the last glacial maximum (~18 ka). Radiochronological data for four samples collected from a peat layer, on which the dune ridges sit, were inconclusive. Six radar facies and three lithofacies with six sub-lithofacies were defined to determine the depositional environments of southern Currituck County during the formation of the sand ridges. The sand ridges were interpreted as paleoshorelines that formed from sea-level highstands during marine isotope stage 3 (between 65 ka and 35 ka). These shorelines have been subaerialy exposed due to the uplift caused by glacioisostatic rebound since the last glacial maximum. |
