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Virginia Institute of Marine Science
Christopher M. Bailey, W. Cullen Sherwood, L. Scott Eaton, David S. Powars
The Geology of Virginia
Virginia Museum of Natural History
Special Publication Number 18
The continental margin of Virginia, and of North America more broadly, is the physical transition from the high elevation of the continent to the low of the ocean basin. This transition was created as rifting pulled apart the ancient supercontinent Pangaea to create the Atlantic Ocean basin. Tectonic forces fractured and stretched the bedrock to create a stair-step ramp that subsequently would be mantled with sediment built up by erosion and transport off the continent.
The Coastal Plain and Continental Shelf of Virginia are contiguous and discrete physiographic provinces of the continental margin delimited by the present elevation of sea level. On geologic time scales of thousands to millions of years, the coastal zone—the boundary between the coastal plain and shelf—is dynamic and migrates hundreds of kilometers landward and seaward. Today, the Atlantic shore of Virginia lies just past halfway across the margin: about 150 km (93 mi) from the edge of the Piedmont at the Fall Zone, and about 100 km (62 mi) from the seaward edge of the shelf (Figure 1). The modern coastal zone occupies nearly the same position as during several previous interglacial highstands of sea level that have recurred at approximately 100,000-year (abbreviated 100 ky, for “kilo year”) intervals since the middle Pleistocene (about the last 750 ky). more ...
Krantz, David E.; Hobbs, C.; and Wikel, Geoffrey L., "Atlantic Coast and Inner Shelf" (2016). VIMS Books and Book Chapters. 117.