Sedimentology of the New Hampshire inner continental shelf based on subbottom seismics, side-scan sonar, bathymetry, and bottom samples

Typical of glaciated environments, the inner continental shelf of New Hamps hire is composed of bedrock outcrops, remnants of glacial deposits (for exa mple, drumlins), sand and gravel deposits, as well as muddier sediments far ther offshore. A number of previous studies have defined the general trends of the New Hampshire inner shelf from the coarser deposits nearer the shor e to the muddier outer basins. Most recently, a seismic survey (similar to 150 km of side-scan sonar and subbottom seismic profiles), as well as botto m sediment sampling (similar to 74 stations), has provided a detailed botto m map of the southern New Hampshire shelf area (landward of the 30-m contou r). The surficial sediments within this area range from very fine sand to g ravel. Bedrock outcrops are common. The seismic survey indicated several la rge sand deposits exceeding 6-8 m in thickness that occur relatively close to the coast. These sedimentary units, which are within 3 km of the shoreli ne, are composed of fine to medium sands. Examination of the general morpho logy and depositional setting indicates at least some of these features are probably relic ebb tidal delta shoals. However a large eroding drumlin occ urs between two of the sand bodies and may represent the source of these de posits. Additional work is needed to verify the origin of these sediment bo dies.