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The AAPG/Datapages Combined Publications Database

AAPG Bulletin


Volume: 65 (1981)

Issue: 5. (May)

First Page: 921

Last Page: 921

Title: Morphology of Continental Shelf-Slope Break: ABSTRACT

Author(s): Larry J. Doyle

Article Type: Meeting abstract


The continental shelf-slope break has been defined as the point of first change in gradient at the outermost edge of the continental shelf, fundamental boundary of the earth's crust. Through the projection of its strike must pass all materials carried from the continents to the ocean basins. Although morphology of the shelf-slope break commonly depends on the crustal change between continents and ocean basins, it is a reflection of tectonics and structure, lithology, age of the margin, sea level, deposition, erosion, reworking, and diagenesis. Many details of specific physical factors and processes influencing morphology of the break remain to be discovered. Therefore, analysis of the resultant of all these factors, the morphology of the break itself, will be useful in un erstanding the components which formed it. As many of the factors which affect the transition from shelf to slope are dynamic, continental shelf-slope break morphology must commonly interact in a feedback loop to alter the processes contributing to that morphology. If the elements of formation were to remain constant, the shelf-slope break would go through a regular morphologic evolution as it ages. Variation in the processes involved, such as sea-level state, most commonly interrupt the cycle.

Because the shelf-slope break represents the upper boundary of the continental slope, it is convenient to discuss the interplay of the various factors involved as extensions of the 6 types of continental slopes. The resulting framework for shelf-slope breaks is: folded or faulted, stepped breaks; progradational transitions; pull-apart transitions; sharp, steep shelf-slope breaks resulting from crustal convergence; breaks associated with reefal dams; and breaks associated with diapir dams. A shelf-break classification emphasizing shelf-to-slope morphology, based on comparison of different world margins, is proposed.

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