| Summary |
The nearshore ocean floor (water depths of fifteen meters or less) in West Onslow Bay, North Carolina reflects a complex relationship between the carbonate rock exposures and the surrounding modern sediments, A limestone containing pelecypod molds and casts, probably the Pollocksville Member or the Belgrade Formation, with extensive interbeds of fossil oyster bioherms (Crassostrea gigantissima ) is exposed on approximately 50% of the sea floor around New River Inlet. Two major kinds of processes are presently acting upon this ancient rock surface to produce the modern topography, sediments and carbonate rock exposures. The dominant destructive processes are controlled by biologic agents which include vermitid gastropod reefs, encrusting algae, corals and sediment trapping bryzoans. The dominant destructive processes are controlled by the mechanical agents of waves and currents and by the biologic agents of boring pelecypods and polychates and burrowing crustaceans. The results of the processes are: 1) highly irregular rock surfaces with steep landward scarps (up to 5 meters in relief) subparallel to the beach with large boulders at their base; 2) a series of vermitid gastropod the crest reefs growing along of New River Inlet; and 3) the production of a thin blanket of loose sediment that varies in texture from boulders to mud and is composed dominantly of limestone rock fragments, quartz sand, carbonate mud and a mixed assemblage of modern and fossil shell material. Thus, the modern processes operating on the rock surface result in distinct morphologic features and the production of sediments which have a strong internal heritage. |
