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The AAPG/Datapages Combined Publications Database

AAPG Bulletin


Volume: 65 (1981)

Issue: 5. (May)

First Page: 904

Last Page: 905

Title: Past and Potential Mass Movement on Continental Slope Off Northeastern United States: ABSTRACT

Author(s): James S. Booth, James M. Robb, John M. Aaron

Article Type: Meeting abstract


Although evidence of mass movement is common on continental slopes, the importance of mass movement as a geologic process in most slope areas remains unknown, and questions concerning the likelihood of future events are still largely unanswered. Accordingly, the U.S. Geological Survey

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and Bureau of Land Management are investigating mass movement on segments of the slope off Georges Bank and in the Baltimore Canyon area off New Jersey.

Preliminary results show that considerable variation in extent and magnitude of previous mass movements exists between the study areas. Off Georges Bank, the slope is typified by many scars, allochthonous blocks, and other mass-movement deposits. Geotechnical analyses of cores taken on two scars indicated that approximately 10 m and 35 m of overburden may have been removed from two sites. Slumps or slides a few tens of meters thick are apparently common. Core data also suggest that most surficial sediments on the Georges Bank continental slope are normally consolidated or slightly overconsolidated and, thus, relatively stable at present.

In contrast, the slope area off New Jersey between Lindenkohl and South Toms Canyons shows little evidence of previous mass movement. Identified features are predominantly on canyon heads and walls. Most events in this region were small, rarely exceeding 10 m in thickness. Despite the general absence of past mass movement, geotechnical data indicate that the surficial sediments is underconsolidated at many sites. This underconsolidation, which implies relative weakness, coupled with the presence of steep gradients and gas in some areas, suggests that these surficial sediments may be marginally stable.

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