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The AAPG/Datapages Combined Publications Database

AAPG Bulletin


Volume: 65 (1981)

Issue: 5. (May)

First Page: 908

Last Page: 909

Title: Recent, Supracrustal, Carbonate Cementation, Florida Keys: ABSTRACT

Author(s): William A. Butcher, Don C. Steinker, Jack C. Floyd

Article Type: Meeting abstract


Algal stromatolites, the crust of which ranges in age from 5,680 years B.P. at the bottom to 400 years B.P. at the top, overlie Pleistocene bedrock in the Florida Keys. Recent beachrock has been reported at Dry Tortugas, and recent cay rock was discovered at Bahia Honda.

Two examples of supracrustal carbonate cementation were found in the intertidal zone of the Florida Keys. On the Florida Bay side of Grassy Key, small gastropod shells of the genera Cerithium and Batillaria are cemented to the top surface of the laminated crust that overlies the Pleistocene Key Largo Limestone. On the Atlantic side of Missouri Key, isolated blocks of rubble are cemented to the top of the crust. Preliminary observations of thin sections suggest that the low-magnesium calcite cement includes alteration products of the underlying crust as well as supracrustal clasts at both Grassy

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Key and Missouri Key. The top of the crust has been dated at approximately 400 years B.P., indicating very recent cementation in the littoral zone of these areas.

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Copyright 1997 American Association of Petroleum Geologists