DEPOSITIONAL HISTORY OF THE PAST 20,000 YEARS IN WESTERN LONG ISLAND SOUND, NEW YORK
One of the major scientific objectives was to study the deglaciation of the Laurentide Ice Sheet and Holocene transgression of sea level in western Long Island Sound to document age, sedimentation processes, and climate from high-resolution geophysics and sediment cores. Our initial results show fou...
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| Format: | Text |
| Language: | English |
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| Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.564.9784 http://www.geo.sunysb.edu/lig/Conferences/abstracts07/abstracts/Acosta_etal_LIGC.pdf |
| Summary: | One of the major scientific objectives was to study the deglaciation of the Laurentide Ice Sheet and Holocene transgression of sea level in western Long Island Sound to document age, sedimentation processes, and climate from high-resolution geophysics and sediment cores. Our initial results show four seismic units that we interpret as glacial moraines or bedrock, glacial lake sediments, trasngressive marine and initiation of estuarine conditions, and recent sedimentation. The data was collected during a one-week survey of western Long Island Sound in June 2006 from the R/V HUGH SHARP. Multibeam bathymetry, chirp subbottom profiling, side-scan sonar imagery, and sediment samples (25 gravity cores, 11 multicores, and 10 grabs) were collected. Subbottom penetration reached in some instances 40 m, but is limited to less than 5 m where sediments are gas-charged. Four seismic sequences are imaged on the chirp records that we interpret to span the Last Glacial Maximum to Present: strong irregular erosional surfaces beneath parallel seismic reflectors are interpreted as glacial erosional surface and/or moraines, and as glacial lake sediments ~25 m thick, respectively. A thin veneer (<1 m) of acoustically transparent sediment is interpreted as recent deposits by dating the sediments with short-lived |
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