Sand Resources and Geological Character of Long Island Sound.

Long Island Sound, covering almost 3,400 square kilometers of the region between Long Island, New York, and the Connecticut mainland, was studied using 700 kilometers of high-resolution seismic profiles and 75 vibratory cores to determine the geologic character and Quaternary history and evolution of the Sound, as well as to assess the resource potential of sand and gravel in seafloor deposits. The subbottom consists of igneous and metamorphic bedrock that crops out close to the Connecticut shore and slopes south to depths of -250 meters at the Long Island north shore. The bedrock surface under the Sound is highly irregular and exhibits relief on the order of or - 30 meters. There are numerous buried river channels that generally trend north-south in the western Sound, and apparently project south under Long Island a large east-west channel along the Long Island north shore that underlies eastern Long Island and Gardiners Bay, projects south to possibly join the Block Island Shelf channel. Many channels, deeply scoured by Pleistocene glaciers, project south from present-day rivers along the Connecticut shore. The deepest channel at 244 meters MSL underlies New Haven Harbor and trends southwest past a bedrock high at Stratford Shoal and then projects south under the Long Island mainland.