Date of Award

Winter 2008

Project Type


Program or Major

Earth Sciences: Ocean Mapping

Degree Name

Master of Science

First Advisor

James V Gardner


A low-backscatter acoustic anomaly was recently mapped on the New Jersey continental margin between Hudson and Wilmington channels using a 12-kHz multibeam echo-sounder (MBES). The presence of the low-backscatter anomaly indicates a change in the physical properties of the seafloor or near sub-surface. Analyses of seafloor and sub-surface acoustic data with previously collected sediment cores suggest three hypotheses as possible geological causes for the anomalously low-backscatter strength: (1) a sediment deposit, (2) an outcrop of sediment strata due to sediment removal and non-deposition, or (3) the presence of gas in the sub-surface sediments. Multibeam bathymetry and backscatter data, high-resolution 3.5-kHz chirp sonar profiles, airgun single-channel seismic-reflection profiles, and sediment cores collected nearby the low-backscatter anomaly most strongly support the hypothesis that the low-backscatter anomaly is an outcrop of older sediments that have been exposed by Western Boundary Undercurrent (WBUC) erosion and non-deposition induced by local seafloor morphology.