Influence of geologic framework on Barrier Islands in North Carolina
- East Carolina Univ., Greenville, NC (United States). Dept. of Geology
The geologic framework of the NC coastal zone forms the basal platform upon which the modern barriers are perched; two distinct provinces exist north and south of the Cape Lookout High. The northern province is characterized by a thick Quaternary sequence that fills the Albemarle Embayment. The southern province is dominated by older and more lithified, offlapping stratigraphic sequences of Tertiary and cretaceous units that wrap around the Carolina Platform High and crop out across much of the continental shelf in Onslow and Long Bays. Thus, the modern barrier island system is stacked on top of highly dissected, lithostratigraphic units with irregular, erosional geometries and composed of sediments ranging from tight peat and mud to indurated limestones, sandstones and gravels. Consequently, many of the NC barrier islands are perched on top of pre-existing sediments of variable morphology and composition. These variabilities result in different responses to erosional forces of waves and currents and thus determine the detailed morphology of the ravinement surface on the shoreface and inner shelf. The present shape, erosion rates, and beach profiles on many Carolina barriers are determined by this geologic framework. The result is a series of eroding headlands on the NC coast, only a few of which are sub-aerial, most are submarine and generally occur either in the shallow sub-surface below the barrier or on the shallow, inner shelf. Underlying geological units composed of sands and soft muds have little obvious effect upon the 3-D barrier island geometry, but do effect the sediment regime; however, those composed of tight muds or indurated sediments have dramatic effects upon aerial shape of the barriers, morphology of the shoreface and inner-shelf, and sediment regimes.
- OSTI ID:
- 6118869
- Report Number(s):
- CONF-9304188-; CODEN: GAAPBC
- Journal Information:
- Geological Society of America, Abstracts with Programs; (United States), Vol. 25:4; Conference: 42. annual Geological Society of America (GSA) Southeastern Section meeting, Tallahassee, FL (United States), 1-2 Apr 1993; ISSN 0016-7592
- Country of Publication:
- United States
- Language:
- English
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