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SepteMler 2015 3-15 14-14979 The Florida Platform basement rocks separated from the African plate and became a part of the North American craton as the super-continent Pangea rifted apart in the Triassic age (Smith, 1982). These basement rocks then served as a platform on which a thick sequence of primarily carbonate rocks (limestone, dolomitic limestone, dolomite, calcareous sands, anhydrite) with minor amounts of siliciclastic sediments (quartz sands, silts, marls, and clays) were deposited. Strata overlying the basement rocks range in age from mid-Mesozoic to Recent (Scott, 1992). A generalized description of the geology and hydrogeology in the vicinity of the Site is provided in Figure 3.3.1-1. Post- Mesozoic geologic units underlying the Site include, from youngest to oldest, undifferentiated Pleistocene to Pliocene age sediments, the Hawthorn Group of Miocene to Late Oligocene age, the Ocala Limestone of late Eocene age, the Avon Park Formation of middle Eocene age, the Oldsmar Formation of early Eocene age, and the Cedar Keys Formation of the Paleocene Age. Each of the geologic units is described in the paragraphs that follow. Undifferentiated Deposits The undifferentiated Holocene to Pliocene age sedimentary deposits consist of clayey sand, coarse to fine-grained sand, silt, clay, marl, and shell deposits. These deposits are commonly interbedded and can be variable laterally and vertically and are typically 100 to 200 feet (ft) in thickness in Okeechobee County (USDA, 2003). The undifferentiated Holocene and Pliocene sediments are anticipated to be present at the project Site from land surface to a depth of approximately 150 feet below land surface (ft bls). The base of the undifferentiated deposits typically consists of low- permeability clayey sand and silt. The undifferentiated Holocene to Pliocene sediments comprises the Surficial Aquifer. The Surficial Aquifer is the primary fresh water source in the vicinity of the Site. The water table in the Surficial Aquifer in Okeechobee County ranges from land surface to approximately 10 ft bls and fluctuates in response to seasonal changes(Bradner, 1994). Hawthorn Group The Hawthorn Group of the Miocene Age to late Oligocene Age includes the Peace River and Arcadia Formations in Okeechobee County. The Peace River Formation consists of greenish-gray phosphatic clay and silt interbedded with quartz sand and sandstone and overlies the Arcadia Formation. The Arcadia Formation consists primarily of poorly consolidated phosphatic limestone and dolomite. The Hawthorn Group constitutes the confining interval between the Surficial Aquifer and the Floridan Aquifer System (FAS); often called the Intermediate Confining Unit (ICU). It is anticipated to be present at the Site from a depth of approximately 150 to 400 fl bis (Scott T. M., 1988). The Hawthorn Group is anticipated to have very limited productivity at this location due to the generally low permeability of the sediments. Attachment 1 b Fes= 198