Ground-Penetrating Radar Stratigraphy and Sedimentology of Fluvial Deposits in the Delaware Water Gap National Recreation Area: Landscape Formation Processes and Paleoclimatic History of the Northern Delaware River Basin Since the Last Glacial Maximum
Kelsey S. Bitting
Rutgers University, Department of Earth and Planetary Science Piscataway, NJ, USA; [email protected]
Ancient fluvial deposits can be valuable reservoirs for hydrocarbons or groundwater. Fluvial deposits are complex, ranging from nearly 100% organics to gravel. Locating types of sediment within fluvial deposits is integral to evaluating the potential for resource retention and extraction.
The Delaware River provides a unique opportunity for examination of latest-Pleistocene to modern fluvial landforms as analogues to ancient systems, since the river remains un-dammed. This study seeks to address the following questions: First, what was the morphology and migration rate of the Delaware during the immediate postglacial period, and how have they changed since then? How have competence, sediment supply, and water budget changed? What processes are responsible for these changes, and at what rates do they operate? Have facies distributions changed through time in response to these shifts?
Ground-penetrating radar profiles image the subsurface and permit interpretation of the sedimentary architecture, bounding surfaces, and lateral and vertical relationships between facies assemblages. These details allude to past morphology and migration.
Description and analysis of cores permit detailed sedimentological characterizations. Grain size translates to competence; unconformities suggest water budget; percent carbonate, percent organic material, and magnetic susceptibility allow further interpretations about depositional environment.
The integration of GPR-stratigraphic and sedimentologic observations allow me to construct a detailed profile of small-scale depositional features and facies relationships. Improved understanding of the floodplain record aids the understanding of past fluvial processes, which helps predict the behavior of similar systems. Finally, this study demonstrates the value of incorporating subsurface imaging into river studies.
AAPG Search and Discovery Article #90083 © 2008 AAPG Foundation Grants in Aid