Planktonic Foraminifera and Biostratigraphy of Some Neogene Formations, Northern Florida and Atlantic Coastal Plain
AbstractPlanktonic foraminifera are identified and illustrated (by scanning electron photomicrographs) from the Chipola, Yellow River, Red Bay, and Jackson Bluff formations of northwestern Florida. Similar studies of material from Yorktown and Waccamaw localities on the coastal plains of the eastern United States, the Moin Formation of Costa Rica, and the Encanto and Agueguexquite formations of Mexico indicate stratigraphic relationships, which are different from the ages and correlations previously proposed for some of these strata based on other criteria. The calcareous nannofossil genera Discoaster, Catinaster, and Sphenolithus, were also included in the present studies. Comparative ranges of these microfossils indicate a Burdigalian age for the Chipola Formation, a late Langhian age for the Encanto and Yellow River formations, a Tortonian to Messinian age for the Red Bay Formation, and an early to middle Pliocene age for the Jackson Bluff, Yorktown, and Agueguexquite formations. Material from several localities assigned to the Waccamaw Formation are correlated with the Main Formation of Costa Rica for which an early Pleistocene age is indicated. A total of 52 species and subspecies of planktonic foraminifera were identified from these Neogene formations. One of these species, Globorotalia (Globorotalia) praeoscitans is new. This report is intended primarily as documentation of planktonic foraminifera from some American formations which long have been neglected by specialists on this group of fossils.