Sediments and Shallow Stratigraphy of a Portion of the Continental Shelf of Southeastern Virginia

A network of high-resolution, seismic-reflection profiles and grab samples of the surficial sediments of the inner continental shelf of southeastern Virginia demonstrate that the Quaternary geology of the region is more complex than indicated by earlier studies. The spatial variability of the surficial sediments depicts active processes, such as outflow from Chesapeake Bay, as well as the underlying geology in outcrops of finer grained sediments near False Cape. The complexity of the Quaternary geology results from large and small scale fluctuations in sea level. Individual, relatively large-scale, seismostratigraphic units are separated by erosional surfaces formed during the major changes in sea level that created the Cape Charles, iii iv Eastville, Belle Haven, and Exmore paleochannels in Chesapeake Bay. The low amplitude, high frequency variations in sea level that occurred during the midPleistocene impacted the inner shelf forming several thi~ depositional strata separated by local erosional surfaces. Substantial resources of sand exist on the inner shelf and are suitable for use in beach nourishment and construction aggregate. The deposits occur in three distinct stratigraphic settings: discrete shoals on the surface, filled channels, and laterally variable stratigraphic facies. The three types of filled paleochannels within the inner shelf have different origins: 1) riverine flow, 2) back-barrier or lagoonal channels, and 3) migration of (Holocene?) tidal inlets