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The AAPG/Datapages Combined Publications Database

AAPG Bulletin


Volume: 65 (1981)

Issue: 9. (September)

First Page: 1662

Last Page: 1662

Title: Variability of Sedimentary Textures and Processes on Continental Margin North of Wilmington Canyon: ABSTRACT

Author(s): Evan B. Forde, Terry A. Nelsen

Article Type: Meeting abstract


Sedimentary properties and processes of a 7,500-km2 corridor seaward of the Baltimore Canyon Trough off New Jersey were studied in detail using over 100 bottom samples consisting of grab samples and box, hydroplastic, and piston cores.

The sediments in both canyon and intercanyon areas are primarily bioturbated, olive-gray, sandy silts with local features indicative of gravity-induced mass sediment movements (i.e., graded sequences and load structures). C14-based sediment accumulation rates vary by a factor of three in cores separated by as little as 6 km. These variations seem to be a function of shelf-edge spillover rates.

Detailed analyses of the sand grain-size distribution throughout the corridor reveal that the sand component of the slope and rise sediments contains a high percentage of material currently present on the adjacent shelf. The relatively large percentage of sandy sediment in the upper parts of cores from Spencer Canyon suggests its recent role in transporting shelf sediments seaward. Sandy intervals in other slope cores are commonly obscured by intense bioturbation. Cores from the continental rise show an upward decrease in the number of sand layers and lenses.

Active transport of sediment to the slope and rise occurred during the late Pleistocene and, although the intensity has declined, the slope is presently the site of deposition for both fine and coarse sediment.

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