Geomorphology of the Southeast Florida continental reef tract (Miami-Dade, Broward, and Palm Beach Counties, USA)
- First Online:
- 419 Downloads
This paper describes the geomorphology of the northern, relict, portion of the Florida reef tract that extends along the southeast Florida (USA) continental coast northward to latitude N26° 43.1′. The descriptions are based on high-resolution Laser Airborne Depth Sounding bathymetric data along Miami-Dade, Broward, and Palm Beach Counties as well as chirp subbottom-profiles and reef cores. The SE Florida continental reef tract consists of relict Holocene reefs and lithified sand ridges that apparently formed during backstepping of the reefs in response to sea-level rise. The outer reef is a linear structure that is more or less continuous from Miami-Dade to Palm Beach County and as such is one of the longest continuous reef structures in the western Atlantic. Its relation with the modern Florida Keys reef tract cannot be clearly resolved without further study. The outer reef may be equivalent to the shelf-edge reefs of the Florida Keys. It is broken by reef gaps that likely represent paleo-river channels cross-cutting the underlying Pleistocene substrate. The upward growth of the outer reef ceased approximately 8,000 cal BP (calibrated 14C age before present). A middle reef may represent a remnant shoreface with continuous reef framework. Its growth ceased approximately 3,700 cal BP. An inner reef of Acropora palmata framework is perched on shoreline deposits. It ceased growth approximately 6,000 cal BP. Several nearshore ridges consist of coquina and carbonate/quartz sandstone.