SPATIAL AND TEMPORAL VARIABILITY OF A COARSE-SAND ANOMALY ON A SANDY INNER SHELF, NORTHEASTERN GULF-OF-MEXICO

A 10-km(2) area of anomalously uniform coarse sand and low relief, in 30 m water depth off Panama City, Florida, USA, exists as a palimpsest hardbottom within the prevailing sand-wave system. Side-scan sonar ob servations over a ten-year period document the morphologic response of the anomaly to the bottom-wave-current interaction regime. The anomal y and surrounding sand waves remained fixed during this period. Ripple s form within the anomaly in response to seasonal storms and decay dur ing quiescent periods. Hurricane response includes minor realignment o f sand waves, formation of megaripples, and deposition of a thin mud l ayer.