Side-scan sonar data

Location | Sonar | Sediments Profile | Cross Section

Projection: UTM, GRS 1980, NAD83, Zone 17. Coordinates: Geographic. Bathymetry (areas > 4 m) after Gelfenbaum and Guy (1999). Coastal areas (< 4 m) represented by Digital Orthophoto Quarter Quadrangle (1995).

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›	Location Map
›	Surface Sediments
›	Seismic-Profile Data
›	Transect Cross Section

Side-scan sonar imagery overlain on bathymetry reveals widespread high backscatter (dark) in the inner half of the transect and lower backscatter (light grey) in the outer half of the area. Low-relief sand ridges in the inner area are oriented NE-SW and encompass both high and low backscatter bottom types due to changes in grain size across the ridges (Twichell and Paskevich, 1999; Twichell and others, 2000). Offshore of this mosaic area, thicker sand waves or ridges are more common and appear more uniformly as low backscatter (sandy) bottom types. The sand ridges in the inner portion of this transect area are dominated by a NE-SW trend with apparently no second-order smaller bedforms (sand waves). This contrasts with the northwest-trending sand ridges off Indian Rocks Beach north of Tampa Bay that contain numerous secondary sandwave fields (Harrison and others, 2000). The bathymetric-surface model to the right (Gelfenbaum and Guy, 1999), however, suggests sand-ridge trends may shift to the NW-SE trend in the outer portion of the transect area.