Geological Interpretations of a Low-backscatter Anomaly Found in 12-kHz Multibeam Data on the New Jersey Continental Margin
Title | Geological Interpretations of a Low-backscatter Anomaly Found in 12-kHz Multibeam Data on the New Jersey Continental Margin |
Publication Type | Thesis |
Year | 2008 |
Authors | Sweeney, E |
Degree and Program | Master of Science |
Degree | Earth Sciences/Ocean Mapping |
Number of Pages | 167 |
Date Published | 12/2008 |
University | University of New Hampshire |
Location | Durham, NH |
Keywords | 12-kHz multibeam data, continental margin, low-backscatter, new jersey |
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. |