Integrated stratigraphic cross section combining line-drawing interpretation of seismic data, ground-truthed by coring, with a coastal cross section based on vibracores. The modern sediment cover can be over 4 m thick offshore, corresponding with the higher-relief portions of the sand waves or ridges seen here. Over 8 m of Holocene sediment are indicated beneath Anna Maria Island. The subsurface is highly deformed due to karstic processes forming structures ranging from sinkholes to shelf valleys. The base of the Holocene is a major unconformity that truncates these structures, indicating that most, if not all of the deformation occurred after deposition of the Miocene limestone. Subsequently, the major hiatal surface, reworked during Quaternary transgressions and regressions of sea level, has not been significantly deformed.
