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Morphology and processes associated with the accumulation of the fine-grained sediment deposit on the southern New England shelf

Journal of Sedimentary Petrology

By:
, , and
DOI: 10.1306/212F7C6B-2B24-11D7-8648000102C1865D

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Abstract

A 13,000 km2 area of the southern New England Continental Shelf which is covered by anomalously fine-grained sediment has been surveyed by means of high-resolution, seismic-reflection and side-scan sonar techniques to map its morphology and structure, and a near-bottom instrument system contributed to understanding present activity of the deposit. Seismic-reflection profiles show that the fine-grained deposit, which is as much as 13 m thick, has accumulated during the last transgression because it rests on a reflector that is geomorphically similar to and continuous with the Holocene transgressive sand sheet still exposed on the shelf to the west. The ridge and swale topography comprising the sand sheet on the shelf off New Jersey and Long Island are relict in origin as these same features are found buried under the fine sediment deposit. Southwestward migrating megaripples observed on the sonographs in the eastern part of the deposit are evidence that sediment is still actively accumulating in this area. In the western part of the deposit, where surface sediment is composed of silt plus clay, evidence of present sediment mobility consists of changes in the near-bottom, suspended-matter concentrations primarily associated with storms. Nantucket Shoals and Georges Bank are thought to be the sources for the fine-textured sediment. Storms and strong tidal currents in these shoal areas may still erode available fine-grained material, which then is transported westward by the mean drift to the southern New England Shelf, where a comparatively tranquil environment permits deposition of the fine material.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Morphology and processes associated with the accumulation of the fine-grained sediment deposit on the southern New England shelf
Series title:
Journal of Sedimentary Petrology
DOI:
10.1306/212F7C6B-2B24-11D7-8648000102C1865D
Volume
51
Issue:
1
Year Published:
1981
Language:
English
Contributing office(s):
Coastal and Marine Geology Program
Description:
12 p.
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Journal of Sedimentary Petrology
First page:
269
Last page:
280