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The AAPG/Datapages Combined Publications Database

AAPG Bulletin


Volume: 63 (1979)

Issue: 3. (March)

First Page: 480

Last Page: 480

Title: Slumping in Intercanyon Areas, Middle Atlantic Continental Slope: ABSTRACT

Author(s): Harley J. Knebel, David C. Twichell, James M. Robb

Article Type: Meeting abstract


Analyses of high-resolution seismic reflection profiles show that slump deposits are ubiquitous within the intercanyon areas of the continental slope of the Middle Atlantic Bight. Of 15 widely spaced 3.5-kHz profiles obtained between Hudson Canyon and Chesapeake Bay, 12 define slump deposits that vary from thin, homogeneous or parallel-bedded lenses of sediments, to masses of intermediate thickness containing contorted bedding, to relatively thick slump blocks with discontinuous bedding. These deposits constitute the upper 10 to 90 m of sediments, extend downslope for 2 to 7 km, and are present at water depths ranging from 545 to 1,500 m. Minisparker profiles obtained during a detailed survey of a 9 by 28 km area of the slope between Hudson and Wilmington Canyons define 1 slump deposits in water depths of 398 to 2,190 m that comprise 12% of the survey area. Individual masses are as much as 50 m thick, cover as much as 5.3 sq km, and contain a maximum of 0.11 cu km of sediments. Although some of the slump deposits on the Middle Atlantic slope undoubtedly are relict, stemming from sediment instability produced by rapid deposition during Pleistocene sea-level regressions, the acoustic characteristics of others suggest recent formation. Data from this study indicate that slumping in the intercanyon areas may be quantitatively important in transporting sediments to the deep sea and suggest that recent mass movements may constitute a geologic hazard to future economic development of this part of the continental slope.

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