Cedar Keys/Lawson, Central Florida Region (16)

Comments on Geologic Parameters

16 Rock Mineralogy:

Published lithologic descriptions of the lower Cedar Keys and Lawson Dolomites vary (Applin and Applin, 1944, 1967; Vernon, 1951; Chen, 1965), indicating that (1) the boundaries of these units remain poorly defined and/or (2) these units vary laterally. Difference in lithology is primarily degree of dolomitization, crystal size, and relative proportion of anhydrite. Winston (1977) gave perhaps the best summary of lower Cedar Keys and upper Lawson Dolomite composition. He stated that the lower Cedar Keys was tan, microolitic or micropeletal dolomite of varying thickness and cemented by clear calcium sulfate, whose mineralogy has not been determined. He described the upper Lawson Dolomite as very fine to fine crystalline anhedral or euhedral dolomite with occasional streaks of very fine to fine-grained skeletal dolomite. Applin and Applin (1944) and Vernon (1951) reported gypsum in the upper Lawson Dolomite.

16 Reference:

Applin, P. L., and Applin, E. R., 1944, Regional subsurface stratigraphy and structure of Florida and southern Georgia: American Association of Petroleum Geologists, v. 28, p. 1673-1753.

___________ 1967, The Gulf Series in the subsurface in northern Florida and southern Georgia: U.S. Geological Survey, Professional Paper 524-G, 35 p., 8 plates.

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

Vernon, R. O., 1951, The geology of Citrus and Levy counties, Florida: Florida Geological Survey Bulletin 33, 256 p.

Winston, G. O., 1977, Cotype wells for the five classic formations in peninsular Florida: Gulf Coast Association of Geological Societies Transactions, v. 27, p. 421-427.