Ocala Limestone

Ocala Limestone
Name	Ocala Limestone
Type	Formation
Age	Late Eocene
Period	Eocene
Primary lithology	Limestone
Other lithology	Dolomite, chalk, marl
Region	Florida, United States
Named for	Ocala
Named by	Robert W. Lightbourne
Year named	1897

Ocala Limestone The Ocala Limestone is a Late Eocene shallow-marine carbonate formation widely exposed in Florida and influential in regional geology, paleontology, and hydrogeology. It forms prominent outcrops and retains abundant fossil assemblages that have been cited in studies associated with Floridan Aquifer System, United States Geological Survey, and paleontological research at institutions such as the Smithsonian Institution, Florida Museum of Natural History, and Harvard University. Its mapping and stratigraphic interpretation have involved agencies and projects including the Florida Geological Survey and the National Park Service.

Description and Lithology

The formation consists predominantly of highly fossiliferous, fine- to coarse-grained limestone with intervals of chalky marl and dolomitized facies documented by fieldwork associated with United States Geological Survey campaigns and academic studies at University of Florida, Florida State University, and University of South Florida. Petrographic analysis published by researchers affiliated with American Association of Petroleum Geologists and the Society for Sedimentary Geology describes primary components such as skeletal fragments from foramina and bivalves, micrite matrices, sparite cements, and secondary dolomite consistent with processes investigated by geologists from Massachusetts Institute of Technology and Columbia University. Diagenetic features, including stylolites, solution vugs, and secondary calcite spar, have been characterized in reports by the Florida Geological Survey and the United States Geological Survey.

Stratigraphy and Age

The Ocala Limestone is assigned to the Late Eocene and correlates stratigraphically with units referenced in regional frameworks developed by the United States Geological Survey and the Florida Geological Survey. Biostratigraphic control using foraminifera and mollusks has been applied in studies connected to researchers from University of Miami and Yale University, while isotopic and nannofossil work from teams at Woods Hole Oceanographic Institution and Scripps Institution of Oceanography helped refine its age. The Ocala overlies older Paleogene units and interfingers with or is succeeded by younger Neogene sediments in cores logged by the National Oceanic and Atmospheric Administration and state borehole programs. Regional cross-sections published by the American Association of Petroleum Geologists illustrate its relationship to the Peninsular Florida Platform and adjacent stratigraphic units.

Geographic Distribution and Formation

Exposures and subsurface occurrences are widespread across central and northern Florida, including notable outcrops near Ocala National Forest, Silver Springs (Florida), and the Withlacoochee River valley, with additional subsurface extent beneath parts of Gulf of Mexico coastal plains documented by the United States Geological Survey and the Bureau of Ocean Energy Management. Depositional models developed by researchers at University of South Florida and Florida State University interpret the Ocala as a product of shallow, warm epeiric sea conditions tied to global Eocene transgressions recorded in work from Paleogene stratigraphy researchers and institutions like University of California, Berkeley. Sea-level and paleoclimate reconstructions involving collaborators at Lamont–Doherty Earth Observatory and National Aeronautics and Space Administration contextualize its carbonate accumulation and subsequent diagenesis.

Paleontology and Fossil Content

The unit is renowned for abundant marine fossils including mollusks, large- and small-foraminifera, echinoids, bryozoans, and benthic biota studied by paleontologists at Florida Museum of Natural History, Smithsonian Institution, and Natural History Museum, London. Notable fossil taxa have been compared with collections from American Museum of Natural History, Royal Ontario Museum, and university museums at University of Florida and Harvard University. Microfossil studies using nannofossils and benthic foraminifera involve researchers from Scripps Institution of Oceanography and Woods Hole Oceanographic Institution and have informed biostratigraphic zonations used by the United States Geological Survey. Taphonomic and paleoecologic analyses published in journals associated with the Paleontological Society and the Geological Society of America document reefal and carbonate shelf assemblages analogous to Eocene faunas reported from Europe and Caribbean localities.

Economic Importance and Uses

Ocala Limestone is a significant resource for construction aggregate, roadstone, and lime production with commercial activity overseen by companies and regulatory frameworks connected to Florida Department of Environmental Protection and local county governments. Quarrying operations have been conducted by private firms that liaise with agencies such as the United States Environmental Protection Agency and the Florida Department of Transportation. The formation’s physical properties make it suitable for dimension stone and agricultural lime, supply chains involving logistics partners and industrial facilities often interact with economic development offices in municipalities like Ocala, Florida and Gainesville, Florida.

Hydrogeology and Environmental Significance

Hydrogeologic studies recognize the Ocala Limestone as an important component of the upper Floridan Aquifer System with high secondary porosity and permeability caused by solutioning and karstification documented by the United States Geological Survey, National Park Service, and university hydrogeology groups at University of Florida and Florida State University. Karst features such as springs, sinkholes, and conduits occur in areas like Silver Springs (Florida) and influence water supply issues addressed by regional water management districts including the Southwest Florida Water Management District. Environmental monitoring and groundwater modeling involving the Environmental Protection Agency and research teams at Florida International University evaluate contaminant transport, aquifer recharge, and ecosystem services linked to springs and wetland communities managed by entities such as the Florida Fish and Wildlife Conservation Commission.

Category:Geologic formations of Florida