# Suwannee Limestone

Canonical page: https://lithomap.app/resources/geologic-formations/united-states/suwannee-limestone
Last reviewed: September 17, 2026
Page purpose: Comprehensive United States geologic formation reference for human readers, search systems, and language models.
Major region: Gulf / Atlantic
Regional setting: Florida Platform and south Georgia Coastal Plain
Age: Oligocene
Age detail: Mostly early Oligocene in current southeastern usage
Depositional setting: Shallow marine carbonate platform
Rock types: Limestone, Dolomitic limestone, Dolostone, Minor sand
States in recognized usage: Florida, Georgia

## Summary

The Suwannee Limestone is an Oligocene marine carbonate beneath much of Florida and south Georgia, recognizable by fossil-rich limestone and important to regional groundwater and karst.

## Distribution

The unit is exposed along portions of the Suwannee River and in west-central Florida and lies beneath younger sediment across a much larger area. It is absent or difficult to distinguish in parts of northern and eastern Florida.

Thickness varies from thin erosional remnants to hundreds of feet in the subsurface. Ocala Limestone generally lies below, while younger Miocene units rest above across unconformities.

## Geological history

Carbonate mud and skeletal grains accumulated in warm shallow water on the Florida Platform. Changes in water depth, circulation, and exposure produced micritic, crystalline, fossiliferous, and locally dolomitic rock.

Later freshwater circulation dissolved limestone and enlarged fractures, while magnesium-rich fluids converted some calcite to dolomite. Erosion created irregular upper and lower contacts.

## Fossil record

Mollusks, benthic foraminifera, echinoids, and other shallow-marine organisms occur commonly. Fossil assemblages help separate the unit from older Ocala and younger carbonate formations.

Recrystallization or dolomitization can obscure shells, and a fossil-rich hand sample does not establish a precise member or contact without mapped context.

## Minerals and geological resources

Calcite is dominant, with dolomite common in altered zones and minor quartz sand, clay, and iron oxides. Cavities may contain secondary calcite crystals.

The formation contributes to the Floridan aquifer system and supplies carbonate aggregate in some areas. Water movement through solution openings can be rapid and uneven.

## Field context

- River exposures may be submerged or dangerously swift depending on water level.
- Karst openings and thin roofs can be hidden by soil or vegetation.
- Check land ownership and spring-protection rules before approaching an exposure.

## Connected field guides

- Dolostone (rock; Named rock type) — https://lithomap.app/resources/rock-identification/dolostone
- Limestone (rock; Named rock type) — https://lithomap.app/resources/rock-identification/limestone
- Calcite (mineral; Mineral discussed in this formation) — https://lithomap.app/resources/mineral-identification/calcite
- Dolomite (mineral; Mineral discussed in this formation) — https://lithomap.app/resources/mineral-identification/dolomite
- Quartz (mineral; Mineral discussed in this formation) — https://lithomap.app/resources/mineral-identification/quartz

Mapped location and formation context support an identification but cannot establish one. Compare several physical properties and use laboratory analysis when the material remains ambiguous.

## Connected state geology guides

- Florida geology — https://lithomap.app/resources/geology/united-states/florida

## Authoritative sources

- Geolex Suwannee unit record — U.S. Geological Survey: https://ngmdb.usgs.gov/Geolex/Units/Suwannee_4029.html
- Geolex Suwannee references — U.S. Geological Survey: https://ngmdb.usgs.gov/Geolex/UnitRefs/SuwanneeRefs_4029.html

## Formation photograph

- Image: https://lithomap.app/_delivery/formations/suwannee-limestone.webp
- Description: Pale Suwannee Limestone exposed at the surface in Florida
- Creator: RealGatba
- License: CC BY-SA 4.0 — https://creativecommons.org/licenses/by-sa/4.0/
- Source record: https://commons.wikimedia.org/wiki/File:Suwannee_limestone_exposure.jpg

Formation-level information does not prove that a fossil or mineral occurs at a specific coordinate. It also does not establish ownership, access, collecting permission, present conditions, or specimen identity.