Earth:Bigfork Chert
From HandWiki
| Bigfork Chert Stratigraphic range: Ordovician | |
|---|---|
| Type | Formation |
| Unit of | none |
| Sub-units | none |
| Underlies | Polk Creek Shale[1] |
| Overlies | Womble Shale |
| Thickness | 450 to 750 feet[2] |
| Lithology | |
| Primary | Chert |
| Location | |
| Region | Arkansas, Oklahoma |
| Country | United States |
| Type section | |
| Named for | Big Fork, Montgomery County, Arkansas |
| Named by | Albert Homer Purdue[3] |
The Bigfork Chert is a Middle to Late Ordovician geologic formation in the Ouachita Mountains of Arkansas and Oklahoma. First described in 1892,[4] this unit was not named until 1909 by Albert Homer Purdue in his study of the Ouachita Mountains of Arkansas.[3] Purdue assigned the town of Big Fork in Montgomery County, Arkansas as the type locality, but did not designate a stratotype. As of 2017, a reference section for this unit has yet to be designated. The Bigfork Chert is known to produce planerite, turquoise, variscite, and wavellite minerals.[5]
Paleofauna
- C. antiquus[6]
- Dicellograptus
- D. divaricatus[6]
- Glyptograptus[6]
- Lasiograptus
- L. flaccidus[6]
- Mesograptus
- M. perexcavatus[6]
- Orthograptus
- O. quadrimucronatus[6]
See also
- List of fossiliferous stratigraphic units in Arkansas
- Paleontology in Arkansas
References
- ↑ Harlton, B.H., Wikidata Q63311479
- ↑ McFarland, John David (2004). "Stratigraphic summary of Arkansas". Arkansas Geological Commission Information Circular 36: 19. http://geology.ar.gov/pdf/IC-36_v.pdf. Retrieved 2018-01-09.
- ↑ 3.0 3.1 Purdue, A.H. (1909). Slates of Arkansas. Geological Survey of Arkansas. pp. 30, 35.
- ↑ Griswold, L.S. (1892). "Whetstones and the novaculites". Annual Report of the Geological Survey of Arkansas for 1890 3.
- ↑ Barwood, Henry (1997). "Occurrence of turquoise group minerals in the eastern United States". The Mineralogical Record 28 (1): 53. https://www.proquest.com/openview/bf4edf58388002c2b065bc6d45c21cb6/1?pq-origsite=gscholar&cbl=15490.
- ↑ 6.0 6.1 6.2 6.3 6.4 6.5 6.6 6.7 6.8 Miser, H.D.; Purdue, A.H., Wikidata Q60894700
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