Mainland influence on coastal transgression: Delmarva Peninsula Article

Demarest, JM, Leatherman, SP. (1985). Mainland influence on coastal transgression: Delmarva Peninsula . MARINE GEOLOGY, 63(1-4), 19-33. 10.1016/0025-3227(85)90078-7

cited authors

  • Demarest, JM; Leatherman, SP

authors

abstract

  • The morphology of present-day barrier beaches and lagoons along Delmarva Peninsula is controlled by wave climate, tidal energy, sediment texture, and sand supply. However, morphology is also affected by coastal plain physiography, largely the product of Pleistocene sea-level change over the last million years. Five distinct transgressive coastal systems have been identified on Delmarva Peninsula using geomorphic and subsurface data. Each was produced during interglacial high sea levels and range in age from over one million years to 60,000 yrs B.P. Eroding pre-Holocene sediments represent major sand sources for present-day beaches. Baymouth barriers that formed adjacent to eroding headlands, such as Bethany Beach, Delaware, are characterized by infrequent inlets and robust dune systems. The mainland lagoonal shoreline follows the contours of the incised paleodrainage system. To the south, a long continuous barrier with infrequent inlets is present where littoral drift maintains a high sediment supply. Further south and away from this primary source of sand, short drumstick islands exist. This barrier chain is the result of the present transgression of a pre-existing 60,000 yr old shoreface. The mainland lagoonal shoreline follows the trend of Pleistocene beaches, which have experienced only minor stream dissection due to their young age. Along the southern part of the Peninsula, sea-level rise will eventually cause Holocene barriers to be welded onto the ancient barrier shore (the mainland). Whereas to the north, baymouth barriers will persist as the well-developed paleo-drainage system is flooded farther inland. © 1985.

publication date

  • January 1, 1985

published in

Digital Object Identifier (DOI)

start page

  • 19

end page

  • 33

volume

  • 63

issue

  • 1-4