Date of Award

Fall 1972

Document Type


Degree Name

Master of Science (MS)


Ocean & Earth Sciences



Committee Director

Donald J. P. Swift

Committee Member

John C. Ludwick

Committee Member

Carl S. Andrews

Committee Member

Richard H. Bigelow

Call Number for Print

Special Collections LD4331.O35M46


Submarine sand ridges several km long locally merge southward into the U. S. Atlantic coastline. Shallow (< 8m) observations of -such a ridge at False Cape, Virginia, favor a modern hydraulic origin. Time series maps show the ridge to be paralleled by a landward trough of approximately equal volume. Ridge flanks are usually steeper on the trough side.

Northeasterly winds and waves generate a coast-parallel current which funnels southward into the trough scouring it out and providing sediments for ridge aggradation. The current may be organized as a helical flow cell or cells. Bottom currents converge southward along the ridge crest causing landward transport of traction load along the crest. The trough current eventually breaches the confining ridge at the head of the trough, cutting saddles with steeper seaward slopes and producing outlying sediment fans.

The ridge and trough rest obliquely on an exponentially curved surface or marine profile of equilibrium. Auxiliary profiles at 1/3 water depth shoaler and deeper than this surface approximate the limits of ridge building and trough excavation, the same limits which appear to control the geometry of submarine sand bars formed by steep breaking waves.

Knowledge of these process and response relationships of shoreface-connected ridge systems can be applied to coastal engineering, search and rescue operations and to commercial fisheries.


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