Abstract DNAG Transect E-3. Part of GSA’s DNAG Continent-Ocean Transect Series, this transect contains all or most of the following: free-air gravity and magnetic anomaly profiles, heat flow measurements, geologic cross section with no vertical exaggeration, multi-channel seismic reflection profiles, tectonic kindred cross section with vertical exaggeration, geologic map, stratigraphic diagram, and an index map. All transects are on a scale of 1:500,000.

Abstract The middle Atlantic Coastal Plain records the late Pliocene transition from typical marine deposition and coastlines of the Tertiary to that of fluvial-estuarine-marine of the Quaternary. The Early Pliocene Yorktown Formation (4.5-3.0 Ma) and Late Pliocene Chowan River Formation (approx. 2.8 Ma) record dominantly marine deposition in temperate to warm temperate climates with moderate- to low-sedimentation rates in a tectonically controlled basin. The Late Pliocene Bacons Castle Formation in Virginia (2.3-2.0 Ma) and the upper Beaverdam Formation of Delaware (2.3-2.0 Ma?) contain deposits with indicators of high rates of sedimentation, abundant sediment supply, an Appalachian source, and a cool terrestrial climate. Deposition was in response to a colder climate in the source area associated with Northern Hemisphere glaciation at approximately 2.4 Ma. Mechanical weathering and colluviation during a colder period moved sediment into the transport system that was later moved and deposited by high-discharge streams flowing into the coastal plain during subsequent warming. Deposition during the ensuing transgression kept pace with sea-level rise with some progradation of coastline. Later, Quaternary erosion and deposition in the region incised and partially reworked these late Pliocene deposits.