Origins of Stratal Surfaces in Channel Fills on the New Jersey Continental Shelf

摘要

The goal of this project was to advance an understanding of acoustic anomalies created by sub-seafloor paleochannels by investigating the geologic properties of channel-rich strata on the New Jersey continental shelf. Specific objectives were as follows: (I) perform a synthesis of chirp seismic stratigraphy and physical properties measurements of AHC-800 drill cores recovered for ONR's Geoclutter program in 2002; and (2) interpret channel sedimentary units with regard to mechanisms of formation and depositional environments. Three types of seismic reflectors consistent with the following stratal features were observed: (1) depositional surfaces; (2) erosional surfaces; and (3) diagenetic surfaces. Results indicate that the origin and physical properties of these surfaces are characteristic of siliciclastic shelves in general, but that the particular depositional history of the New Jersey shelf is such that all three types occur within a single, relatively short sediment column. Depositional and erosional surfaces were apparent in high-resolution seismic reflection profiles, whereas diagenetic surfaces displayed an indistinct acoustic signature.