A succession of elevated ridge deposits on the south Florida margin was mapped using
high-resolution seismic and side-scan sonar imaging in water depths ranging from 50 to
124 m. The ridges are interpreted to be subtidal shoal complexes and paleoshorelines
(eolian dune or beach) formed during the last sea-level transgression. Oolitic and skeletal
grainstones and mixed skeletal-peloidal-ooid packstones were recovered using a research
submersible. All of the grains are of shallow-water or intertidal origin, and both marine and
nonmarine cements were identified.
Formation and preservation of these features are attributed to episodic and rapid
changes in the rate of the deglacial sea-level rise at the onset of the termination 1A d18O
excursion. This high-resolution record of sea-level change appears to be related to deglacial
processes operating on submillennial time scales and supports increasing evidence of rapid
episodic fluctuations in ice volume, climate, and ocean-circulation patterns during glacialinterglacial transitions.