Surficial deposits of the submerged and emerged parts of the Coastal Plain province in the Cape Lookout area, North Carolina, consist mainly of terrigenous sand, silt, and clay of Quaternary age which almost completely mantle more consolidated Pliocene strata of the Yorktown Formation. Calcareous deposits composed largely of skeletal calcirudites and calcarenites and oolitic calcarenites, probably late Pleistocene to Holocene in age, are present on the shelf southwest of Cape Lookout. A narrow band of algal limestone and calcareous quartz sandstone is exposed along the shelf break. Abundant ooliths and a displaced fossil faunal assemblage, which includes intertidal, inlet, and inner-shelf species, indicate that the Quaternary Continental Shelf sediments are of shallow-water origin. Sediments underlying the emerged Coastal Plain were deposited mainly in barrier, backbarrier, and very nearshore marine environments.
The geologic map (pl. 1) resulting from this study combines and synthesizes geologic information across the shoreline separating the submerged Atlantic Continental Shelf and the emerged Coastal Plain to the west. To accomplish this, a morpho-stratigraphic mapping technique similar to that described by Frye and Willman (1962) was used where possible. Different aspects of this technique are emphasized in the submerged and emerged parts of the map area, but nonetheless some degree of continuity across the shoreline has been achieved. Although the emerged areas clearly have a somewhat more complex pattern of map units, this difference appears to be real rather than a reflection of different mapping techniques. That is, present-day estuarine and oceanic conditions, including wave, tide, and storm-induced currents, tend to homogenize topographic forms and disperse sediments, resulting in broader and simpler patterns of sediment distribution on the submerged shelf. By Robert B. Mixon and Orrin H. Pilkey, 1976. 45 pages. Includes 2 color plates.
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