Radiocarbon measurements on two peat profiles near Belle Glade, Fla., indicate that peat formation in the Upper Everglades began during late Hypsithermal time, about 4,400 years B.P. (before present). Initially, peat development was very slow. About 500 to 1,000 years were required to build up the 7.6 cm of basal mucky peat, composed of a mixture of marl and organic matter. Then about 3,500 to 4,000 years ago, as a result of environmental changes, plant growths increased rapidly and were preserved as fibrous peats with very little mineral admixture. This rapid development of peat is contemporaneous with a rapid eustatic rise in sea level.
Peat development proceeded rapidly (about 7.3 cm/century) from about 3,500 years to 1,200 years B.P. During this interim the existing peat, measuring about 1.37 m in thickness, was developed. By A. D. 1914 the peat had developed to a depth of about 3.65 m. This represents an average peat development of about 8.4 cm/century (4,400 B.P. to A.D. 1914).
The Everglades Basin, prior to the initiation of drainage programs in the early 1900's, was inundated for a large part of the year. Since drainage, over a period of 50 years, about 1.8 m, or one-half, of the original profile has been destroyed by the prevailing aerobic conditions.