View source for Earth:Ocala Limestone

{{short description|Late Eocene geologic formation}}
{{Infobox Rockunit
| name           = Ocala Limestone
| image          =Ocala_Limestone.jpg
| caption        =
| type           = [[Earth:Geological formation|Geological formation]]
| age            = [[Earth:Eocene|Eocene]]
| period         = Eocene
| prilithology   = [[Earth:Limestone|limestone]] and [[Earth:Dolomite (rock)|dolomite]]
| otherlithology =
| namedfor       = Ocala, Florida (city)
| namedby        =
| region         = North Florida
| country        = {{flag|United States}}
| coordinates    =
| unitof         =
| subunits       =
| underlies      = [[Earth:Suwannee Limestone|Suwannee Limestone]] ([[Earth:Oligocene|Oligocene]])
| overlies       = Avon Park Formation
| thickness      = Lafayette-Sumter counties
| extent         =
| area           =
| map            =
| map_caption    =
}}
[[File:Ocala Limestone map.png|thumb|right|190px|Extent and location of Ocala Limestone.]]
The '''Ocala Limestone''' is a late [[Earth:Eocene|Eocene]] geologic formation of exposed [[Earth:Limestone|limestone]]s near Ocala, Marion County, Florida.

==Age==
'''Period''': [[Earth:Paleogene|Paleogene]]<br />
'''[[Earth:Epoch (geology)|Epoch]]''': Late [[Earth:Eocene|Eocene]]<br />
'''Faunal stage''': Late [[Earth:Clarkforkian|Clarkforkian]] through early [[Biology:Orellan|Orellan]]<br />
'''[[Physics:Geochronology|Absolute Age]]''': ~55.8 to ~33.9 [[Physics:Mya (unit)|mya]], calculates to a period of approximately {{Mya|55.8-33.9|million years}}

==Location==
The Ocala Limestone is at or near the surface within the Ocala Karst District located in west-central to the northwestern part of the peninsula. It is also within the Dougherty Plain District in the north-central panhandle where it easily forms [[Earth:Karst|karst]]s. These karsts often have several feet (meters) of relief which dramatically influence the topography of the Ocala Karst District and the Dougherty Plain District. The area is abundant with disappearing streams and springs.

==Composition==
Formerly a geologic group, Ocala Limestone was downgraded to formation status by T.M. Scott in 1991.<ref>Scott, T.M, Lloyd, J.M, and Maddox, G., A Geological overview of Florida: Florida's Ground Water Quality Monitoring Program- Hydrogeological Framework: Florida Geological Survey Special Publication 32, p. 5-14.</ref> The Ocala Limestone consists of almost pure limestones with occasional [[Earth:Dolomite (rock)|dolomite]]s. It can be subdivided into both lower and upper [[Earth:Facies|facies]] with the lower facies composed of a whitish to cream-colored, fine to medium grained, poorly to moderately hard, fossil rich grainstone and packstone. The upper Ocala is white and somewhat weak and poorly sorted. Its extremely fossil rich grainstone, packstone and wackestone and some [[Earth:Chert|chert]] is common in the upper facies. Its [[Earth:Permeability (earth sciences)|permeable]] and transmissive properties allow it to form a vital portion of the Floridan Aquifer.

==Overlay==
The Ocala Limestone overlies the Avon Park Formation and forms part of the Floridan Aquifer System. (USGS)

==Fossils==
* Foraminifers, ''Lepidocyclina''
* Echinoids
* [[Biology:Bryozoa|Bryozoa]]ns
* Mollusks
* Rare vertebrates

==References==
{{reflist}}

== External links ==
* [http://sofia.usgs.gov/publications/maps/florida_geology/units.html SOFIA, United States Geological Survey: Florida geology maps]


[[Category:Geologic formations of Florida]]

{{Sourceattribution|Ocala Limestone}}