HIGH RESOLUTION CORES AND REFINEMENT TO UNCONSOLIDATED SEDIMENT STRATIGRAPHY FROM NEW JERSEY’S EASTERN SHORE OF THE DELAWARE RIVER

Stratigraphic studies in New Jersey, Delaware and Pennsylvania tend to ignore the narrow band of Coastal Plain sediments directly adjacent to the Delaware River, even though detailed stratigraphic data are available due to environmentally focused drilling at industrial sites located proximal to the river. The challenge of properly placing these near surface units within the regionally established stratigraphic framework stems from the similar lithological composition of the eroding source areas within the upper drainage basin and subsequent reworking of the various alluvial and fluvial deposits. Thus the identification and correlation of distinctly contemporaneous lithostratigraphic units can be both challenging and debatable. It is against these uncertainties that high resolution geologic investigations were undertaken for the purposes of creating hydrostratigraphic conceptual models that can be used to identify contaminate source areas and their fate and transport at a site located along the Delaware River. These efforts include the sub-regional correlation of widely and closely spaced geotechnical and high resolution stratigraphic cores (e.g. sonic technology). Thus far, these investigations have yielded macroscopic generalizations of lithologic characteristics. Findings at small scale test cells have not been projected to the larger site generalizations, although they are useful for understanding scale of features, aquifer characteristics and flow potential. Additional small scale test cells are being planned to determine the amount and location of new data needed to bridge the micro to macro scale models.

To better understand the stratigraphy and structure of the units underlying the site over 2500 feet of continuous core has been recovered, logged and sampled from 2003 through 2015 from more than 100 boring locations. The oldest strata cored belong to the Cretaceous age Potomac Formation and the youngest belong to the recent marsh deposits of the Delaware River. The goal of this presentation is to share updated nearshore Delaware River geologic cross sections that are based on rotosonic drilling techniques that can capture high resolution continuous stratigraphic cores.