Abstract Introduction Material & Methods Lithostratigraphy Petrography, Biostratigraphy & Sr-isotope Analysis Collier-Seminole Old Pump Road F.S.-Ranger Station F.S.-Gate 12 F.S.-Jones Grade Picayune Strand >Southern States Conclusions References Figures Tables Appendix 1 Appendix 2 PDF version

Southern States Utilities core

The Southern States Utilities corehole site (fig. 1, table 1) is on the property of Southern States Utilities at the northeast quadrant of the intersection of Rtes. 951 and 41. In September 1996, the corehole was drilled to a depth of 210 ft (fig. 9). The core has been sampled for thin sections, X-ray diffraction, strontium analysis of shells, and for dinocyst, pollen, mollusk, foraminifer, and ostracode content.

The unnamed formation occurs from the bottom of the core at 210 ft to 86 ft. It consists of unconsolidated dolomitic clay, silt, and quartz sand from the bottom of the core up to 165 ft; a sandy dolostone to dolomite-cemented sandstone up to 121.5 ft; and an unconsolidated, calcareous quartz sand up to 86 ft. Quartz pebbles were observed from about 120 to 97 ft. The Ochopee Limestone Member of the Tamiami Formation extends from 86 to 7 ft in this core. From 86 to 38 ft, the Ochopee is a well lithified, moldic limestone that forms the main part of the aquifer, locally referred to as the lower Tamiami aquifer (Gary Susdorf, personal communication, 1996). From 38 to 21 ft, it is poorly consolidated moldic limestone; from 21 to 10 ft, it is poorly recovered clay with carbonate concretions; and from 9.5 to 7 ft it is a tightly cemented limestone. The upper 7 ft in this core appears to be a natural soil. X-ray diffraction and petrographic analyses of samples from this core will be presented in a later report.

Biostratigraphy. Six samples were examined for dinocysts; three were barren (appendix 2, table 3). The samples at 205 and 98 ft are late middle or late Miocene, and contain Erymnodinium delectabile; the lower sample also contains Hystrichosphaeropsis obscura, whereas the upper sample contains Achomosphaera andalousiensis. The highest sample (9 ft) is not diagnostic.

Ten samples were examined for molluscan faunal content. Eight samples from 146.5 to 8.3 ft contained mollusks identified for this report (table 4). A single recognizable species is present at 146 ft (Turritella pontoni). This species has been reported only from the Pinecrest Beds of the Tamiami (late Pliocene). However, based on the occurrence of this species in the Fakahatchee Strand-Ranger Station and Fakahatchee Strand-Gate 12 cores, it is possible the first appearance of this species occurred in the Miocene and the range should be revised. The full ranges of Turritella apicalis and T. perattenuata also appear to be longer than has been recorded previously. The questionable occurrence of Trochita floridana at 35.8 ft indicates that the sample may be late Pliocene. Trochita floridana has been reported from the Pinecrest beds of the Tamiami (Olsson and Petit, 1964). Samples at 35 and 8 ft did not yield diagnostic mollusks.

Strontium-isotope stratigraphy. No samples from this core are included in the present study. Strontium-isotope data from this core will be presented in a later report.

Age summary. The unnamed formation (210-86 ft) in the Southern States Utility core is late middle or late Miocene based on the presence of the dinocyst species E. delectabile.

The Ochopee Limestone Member of the Tamiami Formation (86-7 ft) contains Pliocene mollusks and nondiagnostic dinocysts.