02913nas a2200205   4500008004100000245012300041210006900164300001200233490000700245520224600252653002202498653001302520653003102533653002302564653001602587100001802603700002102621700001902642856004602661       1999                        eng d00aSeismic Reflection and Vibracoring Studies of the Continental Shelf Offshore Central and Western Long Island, New York0 aSeismic Reflection and Vibracoring Studies of the Continental Sh  a141-1530 v173 a<p>The ridge-and-swale topography on the continental shelf south of Fire Island, New York, is characterized by northeast-trending linear shoals that are shore attached and shore oblique on the inner shelf and isolated and shore parallel on the middle shelf. High-resolution seismic reflection profiles show that the ridges and swales occur independent of, and are not controlled by, the presence of internal structures (for example, filled tidal inlet channels, paleobarrier strata) or underlying structure (for example, high-relief Cretaceous unconformity). Grab samples of surficial sediments on the shelf south of Fire Island average 98 % sand. Locally, benthic fauna increase silt and clay content through fecal pellet production or increase the content of gravel-size material by contribution of their fragmented shell remains. Surficial sand on the ridges is unimodal at 0.33 mm (medium sand, about 50 mesh), and surficial sand in troughs is bimodal at 0.33 mm and 0.15 mm (fine sand, about 100 mesh). In addition to seismic studies, 26 vibracores were recovered from the continental shelf in state and federal waters from south of Rockaway and Long Beaches, Long Island, New York. Stratigraphic and sedimentological data gleaned from these cores were used to outline the geologic framework in the study area. A variety of sedimentary features were noted in the cores, including burrow-mottled sections of sand in a finer silty-sand, rhythmic lamination of sand and silty-sand that reflect cyclic changes in sediment transport, layers of shell hash and shells that probably represent tempestites, and changes from dark color to light color in the sediments that probably represent changes in the oxidation reduction conditions in the area with time. The stratigraphic units identified are an upper, generally oxidized,nearshore facies, an underlying fine-to medium-sand and silty-clay unit considered to be an estuarine facies, and a lower, coarse-grained, deeply oxidized, cross-laminated preHolocene unit. Grain-size analysis shows that medium-to fine-grained sand makes up most (68-99 %) of the surficial sediments. Gravel exists in trace amounts up to 19 %. Silt ranges between 3 % and 42 %, and clay ranges from 1 % to 10 %.</p>
10acontinental shelf10aNew York10aridge-and-swale topography10aseismic reflection10avibracoring1 aKelly, W., M.1 aAlbanese, J., R.1 aHarsch, A., A.  uhttp://dx.doi.org/10.1080/106411999273819