Ground Penetrating Radar Analysis of an Emergent Mid-Pleistocene Estuarine Shoreline Complex, Chesapeake Bay, Maryland, USA.

In northeastern Dorchester County, Maryland, 100 and 250 MHz ground penetrating radar surveys were used to define the east-west trending, linear Parsonsburg Sand deposit as a stranded estuarine shoreline complex, composed of three distinct highstand successions emplaced during climate-driven sea level cycles during the mid Pleistocene. These deposits form a broad ridge with 5 meters of relief, rising from their contact with the Kent Island Formation at + 10 m MSLto ~ + 14 m MSLalong the crest. The thin (<5 m) highstand deposits are cut into the underlying Pliocene Beaverdam and/or Miocene Pensauken Formations and overtop one another, attaining modern elevations of + 12 m, + 11 m, and + 14 m MSL, in succession. Radar facies and lithologic data were used to identify transgressive and highstand components of these deposits, as well as backbarrier, shoreface, and nearshore facies and structures which can be traced into their equivalent bay bottom facies in the adjacent Kent Island Formation. These data correlate well with similar regional and global coastal deposits of marine oxygen isotope stage 11 age.