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Correlation of high-resolution seismic profiles from the Georgia continental shelf with available core data reveals a stratigraphic interval of Miocene to recent age. The sedimentary components consist of relatively thin, aerially extensive units which grade from primarily shallow-water carbonates and clastics nearshore, to predominantly open-marine, fine-grained clastics offshore.
A prominent erosional scarp, developed in the middle Miocene adjacent to and beneath the present coastal area, extends from Ossabaw Sound, Georgia, to Daytona Beach, Florida. Prograding seaward over this scarp are large-scale clinoforms of Pliocene age.
Although the regional tectonic framework of the Georgia coast and continental shelf is considered to be that of a stable, passive margin, several large-scale, low-relief, north-south trending undulations within Miocene and Oligocene sediments are present: a high beneath the coastline and inner shelf of Georgia which follows the trend of the Beaufort arch; the Inner-Shelf low, into which Pliocene clinoforms have prograded; and the Outer-Shelf high, which broadens and rises to the north. These features probably resulted from gentle folding and subsequent erosion. The latter two features significantly influenced sedimentation on the shelf during late Miocene and Pliocene time.
The Neogene stratigraphic section consists of a sequence of deposits, separated by unconformities that appear to be related to glacio-eustatic fluctuations in sea level. With the notable exception of the Pliocene section, the sequences are comparable with the third-order global cycles of sea level changes proposed by Vail et al.
Irregular bottom topography, shallow, large subbottom channels, and smaller cut-and-fill structures similar to sedimentary structures in present-day barrier island inlet and back-barrier complexes are evidence of a midshelf Quaternary stillstand event at or about the 30-m isobath.
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