West Florida/Alabama
Lowstand Systems Tract

Offshore Florida/Alabama, lowstand depositional features include broad lowstand channels incised into the top of early and late highstand deltas on the shelf. Canyons do not occur on the upper slope. Thin lowstand wedges are confined to the shelf margin and upper slope but the position of the sequence boundary within the clinoforms is uncertain. Lowstand deposits offshore Florida/Alabama have the form of an onlapping wedge, but may also contain a narrow shelf-attached prograding wedge. These strata are very thin compared to highstand deposits, but the lowstand wedge offshore Florida is more extensive than highstand delta lobes. The down slope limits of the lowstand wedge extend beyond our data set and is perhaps contiguous between offshore Florida and offshore East Louisiana.

Offshore Florida, a narrow (approximately 1 kilometer), base of foreset slope erosional channel is oriented oblique to the margin. The channel does not extend to the shelf edge. Channel incision is believed to have been caused by marine currents impinging and locally scouring the slope. Along the slope, the channel cuts into aggrading bottom sets and the foreset slope of previously deposited deltas along the upper slope. We speculate that this mechanism supplies and/or distributes the bulk of the sediments contained with the lowstand wedge in this area. This could potentially be an important mechanism of down slope transport if the impinging currents scour into sandy prograding foreset strata.

Gulf Bottom Imagemap

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