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Miami Geological Society Publications The Rebecca Shoal Dolomite Barrier Reef of Paleocene and Upper Cretaceous Age - Peninsular Florida and EnvironsBy George O. Winston ABSTRACT The Upper Cretaceous-Paleocene Rebecca Shoal is a completely dolomitized reef complex. It is usually 15 to 20 miles wide and is 1,000 miles long. In its late stages (Tavernier), it is in the form of an atoll which completely encloses the Florida Peninsula. The deposition of the lagoonal anhydrite-dolomite Cedar Keys facies occurred in the restricted back-reef lagoon of the Rebecca Shoal barrier reef complex. The Rebecca Shoal Dolomite consists of three varieties: anhedral, cryptocrystalline, and fine to coarse crystalline euhedral. Porosity is common, but not universally present. Caverns up to 60 feet high have been reported at or near the base of the reef or its various Tongues. Locally, three tongues of the main reef extend into the lagoonal facies. The basal Card Sound Tongue has been penetrated only in two locales: the upper Keys and offshore on the West Florida Shelf. There are no intervening data to indicate whether these two occurrences are connected. The absence of dolomite in the lagoonal Pine Key facies consisting of white chalky limestone, suggests that they do not connect. The younger dolomite of the Plantation Tongue has, in one well, coalesced with the older Card Sound Tongue. In several other wells dolomites of the youngest tongue (Tavernier) of the Rebecca Shoal coalesce with the older Plantation Tongue. Elsewhere the Plantation is an independent tongue of the reef protruding into the lagoonal facies. The youngest (Tavernier) tongue extends farther into the lagoon than do the other two. In certain offshore
areas where well control is lacking, seismic data confirm the presence of
the reef. (The entire report is available below)
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Last updated:
30 September, 2003 @ 09:39 AM
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