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Suwannee Limestone

The Suwannee Limestone is an Early Oligocene geologic formation of exposed limestones in North Florida, United States.

Suwannee Limestone
Stratigraphic range: Early Oligocene Late Oligocene-aged fissure fill deposits
TypeGeological formation
UnderliesHawthorn Group-Arcadia Formation
OverliesOcala Limestone
Thickness160 ft (49 m)
Lithology
PrimaryLimestone
OtherSandstone, claystone (fissure-fill deposits)
Location
RegionNorth Florida
Country United States
ExtentLeon to Hamilton to Taylor counties
Type section
Named forSuwannee River
Named byC.W. Cooke and W.C. Mansfield
Location of Suwannee Formation in red.

Description

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Suwannee Limestone is found in the peninsula carbonate outcroppings on the northwestern, northeastern and southwestern flanks of the Ocala Platform. However, Suwannee Limestone is not present on an area known as Orange Island on the eastern side of the Ocala Platform due to erosion, nondeposition or both.[1] This limestone is present in southeastern Leon, Jefferson, Madison, Taylor, Lafayette counties as well as Hamilton along the upper Suwannee River basin, and southward into Suwannee County, Florida.

Early Oligocene Suwannee Limestone was recognized in the northwestern peninsula by P. F. Huddleston in 1993 as a triple subdivision of Suwannee Limestone, Ellaville Limestone, and Suwannacoochee Dolostone.[2] The Suwannacoochee Dolostone was later officially renamed as the Suwannacoochee Dolomite.[3]

Sedimentology

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Suwannee Limestone consists of a white to cream, poorly to well hardened, fossil rich, vuggy to moldic grainstone and packstone. The dolomitized parts of the Suwannee Limestone are gray, tan, light brown to moderate brown, moderately to well indurated (hard), finely to coarsely crystalline, dolomite with limited occurrences of fossil-bearing beds. Limestone in silicate form is common in Suwannee Limestone.[4][5]

Stratigraphy

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The Suwannee Limestone overlies the Ocala Limestone and forms part of the intermediate confining unit/aquifer system. (USGS)

Paleobiota

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The Suwannee Limestone preserves numerous calcifying marine invertebrates, including foraminifers, echinoids, bryozoans and mollusks. Shark teeth belonging to Ginglymostoma and Carcharhinus are known from the Brooksville 2 site, which likely originate from the limestone formation rather than the fissure-fill fauna from the same locality.[6]

Fissure-fill fauna

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Not long after the formation of the Suwannee Limestone, falling sea levels during the latter part of the Oligocene led to its exposure on land. Terrestrial vertebrates that inhabited this newly-exposed karstic landscape at the time sometimes became trapped within sinkholes that opened in the limestone, which filled up with sand and clay as fissure-fill deposits, fossilizing their remains. These deposits date to the latest Oligocene (late Chattian or Arikareean stage), and preserve numerous animals whose remains are otherwise rare in the region due to a lack of terrestrial deposits. Two major localities that preserve such fossils are Brooksville 2 in Hernando County and SB-lA/Live Oak in Suwanee County.[6][7]

The following fauna is known:[6][8]

Amphibia

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Anura
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Genus Species Locality Material Notes Images
Eleutherodactylus E. sp. Brooksville 2, Live Oak 174 fossils An eleutherodactylid frog. The dominant frog taxon at the Brooksville site.[7]  
Hylidae indet. A tree frog of uncertain affinities.[7]
Ranidae indet. A true frog of uncertain affinities.[7]
Rhinophryne R. sp. Brooksville 2 A rhinophrynid frog, related to the modern Mexican burrowing toad.  
Scaphiopodidae indet. A spadefoot toad of uncertain affinities.[7]
Caudata
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Genus Species Locality Material Notes Images
Notophthalmus N. sp. Brooksville 2 A newt.  
Sirenidae indet. Brooksville 2 A sirenid.

Mammalia

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Metatheria
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Genus Species Locality Material Notes Images
Herpetotherium H. sp. Brooksville 2, Live Oak A herpetotheriid.  
Eulipotyphla
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Genus Species Locality Material Notes Images
Centetodon C. magnus Brooksville 2 A geolabidid.
Parvericius P. montanus Brooksville 2 An erinaceid related to modern hedgehogs.
Perissodactyla
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Genus Species Locality Material Notes Images
Miohippus M. sp. Brooksville 2 A three-toed horse.  
Artiodactyla
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Genus Species Locality Material Notes Images
Nanotragulus N. loomisi Brooksville 2 A hypertragulid.
Nothokemas N. waldropi Brooksville 2, Live Oak A camelid.
Phenacocoelinae indet. An merycoidodontid of uncertain affinities.
Carnivora
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Genus Species Locality Material Notes Images
Acheronictis A. webbi Brooksville 2 A mustelid.
Arikarictis A. chapini Brooksville 2, Live Oak A mustelid.
Daphoenodon D. sp. Live Oak An amphicyonid.  
Enhydrocyon E. cf. pahinsintewakpa Brooksville 2 A hesperocyonine canid.  
Mammacyon M. sp. Live Oak An amphicyonid.  
?Leptocyon ?L. sp. Live Oak A canine.  
Megalictis M. sp. Live Oak An oligobunine mustelid.  
Osbornodon O. wangi Brooksville 2 A hesperocyonine canid.
Palaeogale P. minuta Brooksville 2, Live Oak A palaeogalid.  
Phlaocyon P. taylori Brooksville 2, Live Oak A borophagine canid.  
Chiroptera
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Genus Species Locality Material Notes Images
Emballonuridae indet. Brooksville 2 A sac-winged bat of uncertain affinities.
Mormoopidae indet. Brooksville 2 A ghost-faced bat of uncertain affinities.
Phyllostomidae indet. Brooksville 2 A leaf-nosed bat of uncertain affinities.
Koopmanycteris K. palaeomormoops Brooksville 2 A ghost-faced bat.
Vespertilionidae indet. Brooksville 2 A vesper bat of uncertain affinities.
Lagomorpha
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Genus Species Locality Material Notes Images
Megalagus M. abaconis Brooksville 2 A leporid related to modern hares and rabbits.
Rodentia
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Genus Species Locality Material Notes Images
Agnotocastor A. sp. Brooksville 2 A castorid related to modern beavers.  
Entoptychinae indet. Brooksville 2, Live Oak An entoptychid geomyoid of uncertain affinities.
Eomyidae indet. Brooksville 2 An eomyid of uncertain affinities.
Florentiamyidae indet. Brooksville 2 A florentiamyid of uncertain affinities.
Heliscomyidae indet. Brooksville 2 A heliscomyid of uncertain affinities.
Proheteromys P. sp. Brooksville 2, Live Oak
Sciuridae indet. Brooksville 2 A squirrel of uncertain affinities.

Aves

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Genus Species Locality Material Notes Images
Galliformes indet. Brooksville 2 A landfowl of uncertain affinities.

Reptilia

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Crocodylia
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Genus Species Locality Material Notes Images
Alligator A. sp. Brooksville 2 A small-sized alligator.  
Testudines
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Genus Species Locality Material Notes Images
Testudinidae indet. Brooksville 2 A small-sized tortoise of uncertain affinities.
Xenochelys X. floridensis Brooksville 2 A kinosternoid turtle.
Squamata
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Genus Species Locality Material Notes Images
Anolis A. "informal morphotype A" Brooksville 2 An anole, two morphotypes known.  
cf. A. "informal morphotype B"
Calamagras C. sp. Brooksville 2 A boid.
Eublepharidae indet. Brooksville 2 An eyelid gecko of uncertain affinities.
Geringophis G. sp. Brooksville 2 A boid.
Helodermatidae indet. Brooksville 2 A beaded lizard of uncertain affinities.
Iguanidae indet. Brooksville 2 An iguanid of uncertain affinities.
Ogmophis O. sp. Brooksville 2 A boid.
Rhineuridae indet. Brooksville 2 A rhineurid amphisbaenian, related to the modern Florida worm lizard.
Scincidae indet. Brooksville 2 A skink of uncertain affinities.
Scolecophidia indet. Brooksville 2 A blindsnake of uncertain affinities.

References

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  1. ^ Bryan, J.R., 1991, Stratigraphic and paleontologic studies of Paleocene and Oligocene carbonate facies of the eastern Gulf Coastal Plain: unpublished Ph.D. dissertation, University of Tennessee, Knoxville, TN, 324 p.
  2. ^ Huddleston, P.F., A revision of the lithostratigraphic units of the Coastal Plain of Georgia - The Oligocene: Georgia Geological Survey Bulletin 105, 152 p.
  3. ^ Stamm, N., 2018, Geologic Unit: Suwannacoochee. National Geologic Map Database Geolex — Unit Summary, U.S. Department of the Interior, U.S. Geological Survey, Reston Virginia.
  4. ^ Cooke, C. W., and Mansfield, W. C., 1936, Suwanne Limestone of Florida (abstract): Geological Society of America Proceedings, 1935, p. 71–72.
  5. ^ USGS: Geology of Florida
  6. ^ a b c Hayes, F. Glynn (2000). "The Brooksville 2 Local Fauna (Arikareean, latest Oligocene): Hernando County, Florida" (PDF). Bulletin of the Florida Museum of Natural History. 43 (1): 1–47. doi:10.58782/flmnh.isca2513.
  7. ^ a b c d e Vallejo-Pareja, Maria Camila; Stanley, Edward L.; Bloch, Jonathan I.; Blackburn, David C. (2024). "Fossil frogs (Eleutherodactylidae: Eleutherodactylus) from Florida suggest overwater dispersal from the Caribbean by the Late Oligocene". Zoological Journal of the Linnean Society. 201 (2): 431–446. doi:10.1093/zoolinnean/zlad130. Retrieved 2024-11-16.
  8. ^ "PBDB Collection". paleobiodb.org. Retrieved 2024-11-22.
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