Shelf-edge deltas and drowned barrier–island complexes on the northwest Florida outer continental shelf

Abstract

A high-resolution multibeam survey of the northwest Florida shelf mapped six relict shelf-edge deltas, each with a drowned barrier–island system developed on its south and southwestern rims. The deltas appear to have formed during periods of sealevel stasis that occurred between 58,000 and 28,000 years ago. The barrier islands formed on the deltas during periods of slow regression during this same time interval. Large fields of asymmetric dunes are found on the delta surfaces as well as on the south and southwestern flanks of the deltas. The asymmetry and orientation of the dunes suggest that a northward-flowing current was sheared by the presence of the delta topography, and as a result, the upper layer of the flow continued to the north, whereas the lower layer was steered by the topography. The topographic steering accelerated the northward flow around the south and southwestern flanks with speeds adequate to form large dunes. The flow slowed after rounding southwestern flank but accelerated again as it encountered the next delta flank to the north. The age of the dune formation is unknown, and no northward-flowing geostrophic flow has been reported in the literature from this area.

Department

Center for Coastal and Ocean Mapping

Publication Date

1-2005

Volume

64

Journal Title

Geomorphology

Pages

133-166

Publisher Place

New York, NY

Rights

D 2004 Elsevier B.V. All rights reserved.

Publisher

Elsevier

Digital Object Identifier (DOI)

10.1016/j.geomorph.2004.06.005

Document Type

Journal Article

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