Pitkin Formation

Pitkin Formation
Stratigraphic range: Upper Visean-Serpukhovian[1]
Type Formation
Sub-units Imo Shale
Underlies Hale Formation
Overlies Fayetteville Formation
Thickness up to and over 400 feet[2]
Lithology
Primary Limestone[1]
Other Shale
Location
Region Arkansas
Country United States
Type section
Named for Pitkin post office, Washington County, Arkansas[3]
Named by George Irving Adams and Edward Oscar Ulrich

The Pitkin Formation, or Pitkin Limestone, is a fossiliferous geologic formation in northern Arkansas that dates to the Chesterian Series of the late Mississippian.[4] This formation was first named the "Archimedes Limestone" by David Dale Owen in 1858, but was replaced in 1904.[3] The Pitkin conformably overlies the Fayetteville Shale and unconformably underlies the Pennsylvanian-age Hale Formation. Some workers have considered the top of the Pitkin Formation to be a separate formation called the Imo Formation. However more recently, others have considered it as an informal member of the Pitkin Formation.

Paleofauna

Early work aimed at creating a comprehensive list for all fossils found in the Pitkin Formation was done by Easton in 1943.[1] Unless otherwise stated, all species below can be found in his 'Fauna of the Pitkin Formation.'

Formanifera

Porifera, Sponges

A modern Cliona from the coastal waters of northern France.

Scyphozoa

  • Conularia Originally considered to be a gstropod.

Anthozoa, Corals

Blastoidea

Pentremites godoni from the Lower Carboniferous of Illinois.
P. elongatus[9]
P. godoni[9]
P. laminatus[9]
P. obesus[9]
P. platybasis[1]

Crinoidea, Sea Lilies

Ophiuroidea, Brittle Stars

This group was originally place under Stelleroidia in early studies.[1]

  • Aganaster
A. singulatus
  • Schoenaster

Echinoidea, Sea Urchins

An upper Carboniferous species of Archaeocidaris.

Worms

Previous studies have grouped these diverse animals into a single, obsolete taxon: Vermes.[1]

Bryozoa, "Moss-animals"

Stereo image
Right frame 
Fossilized skeleton of Archimedes Bryozoan.
A Devonian Fenestella from Belgium.

Brachiopoda

Bivalvia, Bivalves

This group was also referred to by another name in earlier studies: Pelecypoda.[1]

Scaphopoda, Tusk Shells

  • Laevidentalium

Gastropoda, Snails

Cephalopoda

Trilobita

  • Grifithides
G. pustulosus
  • Kaskia
K. chesterensis
K. pitkinensis[14]
P. mucronatus

Ostracoda

  • Glyptopleurain
G. optina
  • Paraparchites
  • Primitia
P. fayettevillensis

Vertebrata

Plantae, Plants

"Encrusting Algae" has been reported but not assigned to any genus.[1]

A. cordillerensis[5]

Unidentified

Following is a list of fossils also found in the Pitkin by Easton in 1943 that have gone unidentified.[1]

  • A "Cup Coral"
  • A member of the genus Pentremites
  • Three species within Agassizocrinus
  • Two species within Scytalocrinus
  • A totally unidentifiable Crinoid
  • Two species of Bellerophon
  • Two species of Gosseletina
  • Two species of Leptoptygma
  • Two Species of Strobeus
  • One species each of Composita and Echinoconchus
  • Two species of Cypricardella
  • Two species of Coloceras, one of which may actually be Leuroceras
  • One species of Dolorthoceras
  • An unnamed shark spine

See also

References

  1. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 Easton, William H., The Fauna of the Pitkin Formation of Arkansas., Journal of Paleontology: vol. 17:2. March, 1943.
  2. ↑ McFarland, John David (2004) [1998]. "Stratigraphic summary of Arkansas" (PDF). Arkansas Geological Commission Information Circular. 36: 12–13.
  3. 1 2 Adams, G.; Ulrich, E. (1904). "Zinc and lead deposits of northern Arkansas". U.S. Geological Survey Professional Paper. 24: 27, 109.
  4. ↑ Various Contributors to the Paleobiology Database. "Fossilworks: Gateway to thefix Paleobiology Database". Archived from the original on 31 July 2014. Retrieved 8 July 2014.
  5. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 Brenckle, Paul (1977). "Foraminifers and other calcareous microfossils from Late Chesterian (Mississippian) strata of northern Arkansas" (PDF). Oklahoma Geological Survey Guidebook. 18: 73–87. Retrieved 3 February 2018.
  6. 1 2 3 4 5 6 Nodine-Zeller, Doris E. (1977). "Microfauna from Chesterian (Mississippian) and Morrowan (Pennsylvanian) rocks in Washington County, Arkansas, and Adair and Muskogee Counties, Oklahoma" (PDF). Oklahoma Geological Survey Guidebook. 18: 89–99. Retrieved 3 February 2018.
  7. 1 2 3 4 Webb, Gregory., 1987., The Coral Fauna of the Pitkin Formation (Chesterian), Northeastern Oklahoma and Northwestern Arkansas. Journal of Paleontology vol. 61:3
  8. 1 2 Webb., Gregory., 1990., A New Tabulate Coral Species from the Pitkin Formation (Chesterian) of north-central Arkansas. Journal of Paleontology vol. 64:4.
  9. 1 2 3 4 Horowitz, Alan S.; Macurda Jr, D. B. (1977). "Late Mississippian and Early Pennsylvanian blastoids from northeastern Oklahoma and northwestern Arkansas" (PDF). Oklahoma Geological Survey Guidebook. 18: 169–170. Retrieved 31 January 2018.
  10. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Strimple, Harrell L. (1977). "Chesterian (Upper Mississippian) and Morrowan (Lower Pennsylvanian) crinoids of northeastern Oklahoma and northwestern Arkansas" (PDF). Oklahoma Geological Survey Guidebook. 18: 171–176. Retrieved 30 January 2018.
  11. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 Horowitz, Alan S. (1977). "Late Mississippian and Early Pennsylvanian bryozoan faunas of Arkansas and Oklahoma: a review" (PDF). Oklahoma Geological Survey Guidebook. 18: 101–105. Retrieved 3 February 2018.
  12. ↑ Henry, Thomas W.; Gordon Jr., Mackenzie (January 1985). "Chesterian davidsoniacean and orthotetacean brachiopods, Ozark region of Arkansas and Oklahoma". Journal of Paleontology. 59 (1): 32–59. JSTOR 1304826.
  13. 1 2 3 4 5 6 Saunders, W. Bruce; Manger, Walter L.; Gordon Jr., Mackenzie (1977). "Upper Mississippian and Lower and Middle Pennsylvanian ammonoid biostratigraphy of northern Arkansas" (PDF). Oklahoma Geological Survey Guidebook. 18: 117–137. Retrieved 1 February 2018.
  14. ↑ Brezinski, David K. (31 March 2017). "Some New Late Mississippian Trilobites from Oklahoma and Arkansas". Annals of Carnegie Museum. 84 (2): 173–178. doi:10.2992/007.084.0203.
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