SEDIMENTARY RECORD OF TIDAL WETLAND DEVELOPMENT IN THE DELAWARE ESTUARY DURING THE LATE HOLOCENE

Here we present the preliminary results of a student research project conducted along the Delaware Bay coastline in Sea Breeze, New Jersey. The goals of the project were: to develop stratigraphic framework of tidal wetland development along the Delaware Bay estuary, interpret stratigraphy in terms of paleoenvironmental changes related to late-Holocene transgression, and identify and explain the mechanism of marsh erosion.

Stratigraphy reconstructed from 52 cores taken along the Delaware Bay shoreline and across the marsh platform documents a continuous development of tidal wetlands during at least the last 2,500 years BP. The timing of marine influence in the study area was correlated with well documented sea-level history of Delaware and supported by radiocarbon dating. Lithostratigraphic data suggests that accumulation of salt marsh peats were interrupted by deposition of tidal mud units. Five mud units were documented and correlated along a 2 km long transect. Deposition of these units could result from migrating tidal creeks, salt pan development, increase in tidal range, and acceleration of sea level rise and erosion during storm-surge conditions. Contacts separating mud units from underlying salt marsh peat and their more or less uniform stratigraphic position suggest their erosional nature and possible association with severe storms.