Bigfork Chert

Last updated
Bigfork Chert
Stratigraphic range: Ordovician
Type Formation
Unit ofnone
Sub-unitsnone
Underlies Polk Creek Shale [1]
Overlies Womble Shale
Thickness450 to 750 feet [2]
Lithology
Primary Chert
Location
Region Arkansas, Oklahoma
Country United States
Type section
Named for Big Fork, Montgomery County, Arkansas
Named byAlbert 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]

Contents

Paleofauna

Graptolites

C. antiquus [6]
D. divaricatus [6]
D. trifidus [6]
D. vulgatus [6]
L. flaccidus [6]
M. perexcavatus [6]
O. quadrimucronatus [6]

See also

References

  1. ↑ Harlton, B.H. (1953). "Ouachita chert facies, southeastern Oklahoma". AAPG Bulletin . 37 (4): 778–796. ISSN   0149-1423. Wikidata   Q63311479.
  2. ↑ McFarland, John David (2004) [1998]. "Stratigraphic summary of Arkansas" (PDF). Arkansas Geological Commission Information Circular. 36: 19. Archived from the original (PDF) on 2016-12-21. Retrieved 2018-01-09.
  3. 1 2 Purdue, A.H. (1909). Slates of Arkansas. Geological Survey of Arkansas. pp. 30, 35.
  4. ↑ Griswold, L.S. (1892). "Whetstones and the novaculites". Annual Report of the Geological Survey of Arkansas for 1890. 3.
  5. ↑ Barwood, Henry (1997). "Occurrence of turquoise group minerals in the eastern United States". The Mineralogical Record. 28 (1): 53.
  6. 1 2 3 4 5 6 7 8 9 Miser, H.D.; Purdue, A.H. (1929). "Geology of the De Queen and Caddo Gap quadrangles, Arkansas" (PDF). U.S. Geological Survey Bulletin. 808. doi:10.3133/B808. ISSN   8755-531X. Wikidata   Q60894700.


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