49 Coastal and Nearshore Environments of the Northeast II

Tuesday, 24 March 2015
1:30 PM - 3:00 PM
Grand Ballroom North

PALEOCHANNELS IN LOWER DELAWARE BAY AND THE DELAWARE INNER CONTINENTAL SHELF

Paper number: 49-1
Program: Theme Sessions
Time: 1:30 PM – 1:50 PM

Authors

Abstract

Located under the lower Delaware Bay are three buried drainage systems for the Delaware River: the Northern, Central and Southern were suggested by Knebel and Circé (1988). Four major subsurface paleochannels of the Delaware River were identified in several in seismic data collected by Belknap and Kraft (1985), and McGeary et al., 1991; Krantz et al., 1993, 1994). This study will improve the understanding of the stratigraphy underlying Delaware Bay and the inner shelf and examine the correlation to the paleochannels within bay. The Central paleochannel is the youngest and continues on the shelf as the Blue paleochannel, heading southeast 50 km, where it turns to the east and extends toward Baltimore Canyon. The Southern paleochannel extends as the Orange and appears also to extends toward Baltimore Canyon, is the next oldest. The oldest paleochannel is the Northern and is suggested to be connected to the Green on the inner shelf. A deeper high-amplitude reflection was observed in the seismic profiles and this study shows that it correlates with the unconformable contact between the Omar and Beaverdam Formations onshore

A method was developed for taking older analog seismic profiles and building a database of depths to significant reflection events that can be entered into GIS software to create models of subsurface features. Subsequent maps and three-dimensional (3-D) images of the subsurface can then be visualized allowing for more accurate analysis and interpretation. This methodology has been applied to the networks of paleochannels that are present in the subsurface beneath the lower portion of Delaware Bay and the bordering Mid-Atlantic inner continental shelf. The project uses older analog seismic profiles to model these paleochannels in ArcGIS™ and as a 3-D model in ArcScene™.