PLIOCENE AND QUATERNARY STRATIGRAPHY OF DELAWARE: IMPLICATIONS FOR CORRELATION OF ATLANTIC COASTAL PLAIN DEPOSITS WITH THE MARINE MIS RECORD

Late Pliocene to early Pleistocene deposits in Delaware consist of the fluvial to estuarine Beaverdam Fm. and the fluvial Columbia Fm. The Beaverdam Fm. represents regional response to climate change as coarse clastic deposition. The Columbia Formation represents glacial outwash in the Delaware River drainage basin. Middle to late Pleistocene estuarine to nearshore marine deposits are subdivided into three lithostratigraphic groups: the Delaware Bay Group (Lynch Heights and Scotts Corners Fms.), the Assawoman Bay Group (Omar, Ironshire, and Sinepuxent Fms.) and the Nanticoke River Group (Turtle Branch and Kent Island Fms.). These units represent deposition related to interglacial sea levels along the ancestral Delaware Bay, Atlantic Ocean, and Susquehanna River, respectively. Land surface elevations of these units become progressively lower with decreasing age of the units.

Regional correlation of the late Pliocene and early Pleistocene deposits with similar, age-constrained deposits, northern hemisphere glacial history, and the MIS record is used for broad-scale dating of these deposits. Aminostratigraphy from mollusk shells is used for the dating and relative ages of the middle to late Pleistocene units. These data indicate periods of deposition related to MIS stages 11, 9, and 5. Lithostratigraphic relationships indicate that there are several periods of deposition related to these stages which suggest that substages within interglacials such as 5e and 5a may be preserved. The timing of deposition, stratigraphic relationships, and relative land surface elevations are in general agreement with the MIS record in terms of estimated heights of sea levels, duration of sea level highs, and climate conditions. This indicates that Atlantic Coastal Plain deposits do preserve a record of Plio-Pleistocene sea levels that can be used as a tool linking the marine MIS record with the terrestrial glacial record.