Cedar Keys/Lawson, Central Florida Region (08)

Comments on Geologic Parameters

08 Continuity of Top Seal:

As mentioned earlier, the middle Cedar Keys Formation, which makes up the top seal for the lower Cedar Keys and Lawson Dolomites, is a laterally continuous unit composed of massively bedded anhydrite (Miller, 1986; J. Haberfeld, Florida Department of Environmental Protection, personal communication, 2000). Miller (1986) provided numerous cross sections across southern Florida, demonstrating that this unit is laterally continuous. Although basement faults have been reported by numerous authors (Randazzo, 1997) across southern Florida, they should not regionally affect the hydraulic integrity of this anhydrite unit. To characterize the continuity of the top seal, we chose the map of Chen (1965), which shows the percent evaporites in the Paleocene Cedar Keys Dolomite. Winston (1994) also discussed evaporite distribution in the middle Cedar Keys interval (c8cedarkey). This map shows that the evaporites compose at least 20 percent of the Cedar Keys Dolomite throughout south central Florida.

08 Reference:

Chen, S. C., 1965, The regional stratigraphic analysis of Paleocene and Eocene rocks of Florida: Florida Geological Survey Bulletin No. 45, 105 p.

Miller, J. A., 1986, Hydrogeologic framework of the Floridan Aquifer system in Florida and in parts of Georgia, Alabama, and South Carolina: U.S. Geological Survey, Professional Paper 1403-B, 91 p., 33 plates.

Randazzo, A. F., 1997, The sedimentary platform of Florida: Mesozoic to Cenozoic, in Randazzo, A. F., and Jones, D. S., eds., The geology of Florida: Tallahassee, University of Florida Press, p. 39-56.

Winston, G. O., 1994, The Paleogene of Florida, v. 3. Lithostratigraphy of the Cedar Keys Formation of the Paleocene and Upper Cretaceous age-Peninsular Florida and environs: Miami Geological Survey, 52 p.