INNER CONTINENTAL SHELF OFF SOUTHWEST FLORIDA
Published:December 01, 1989
RICHARD A. DAVIS, JR., PLINY JEWELL, IV, ROGER J. SUSSKO, 1989. "INNER CONTINENTAL SHELF OFF SOUTHWEST FLORIDA", Shelf Sedimentation, Shelf Sequences and Related Hydrocarbon Accumulation, Robert A. Morton, Dag Nummedal
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The inner continental shelf off southwest Florida is a shallow, low-energy environment that displays many of the characteristics of ancient epicontinental and pericontinental seas. The gradient is about 1:3,000, mean annual wave height is less than 0.5 m, and tides are in the lower microtidal range.
This inner shelf area contains two distinct provinces. The northern one near Cape Romano is characterized by tide-dominated quartz sand ridges, whereas the southern province contains a transition from siliciclastic to carbonate sand.
The area of WNW-trending linear sand ridges extends for about 30 km south of Cape Romano. These ridges range from a few to 10 km in length and have a relief of up to 4 m with an asymmetric profile. Sediments on the ridges are well-sorted, fine quartz sand and are covered with various types of bedforms including ripples, megaripples, and sand waves. Swales are less well-sorted with a relatively high shell content. Tidal currents in this area typically peak at 50-60 cm/sec during spring tidal cycles and about half that during neap tides. They show bidirectional patterns with little time-velocity asymmetry.
South of the linear ridge complex and north of Florida Bay is a broad, gently sloping shelf that is subjected to very low wave and tidal energies. The 10 m isobath is approximately 35 km from the coast. The transition zone from siliciclastic sediment in the north to carbonate sediment in the south is several kilometers wide and trends generally WNW.