Английская Википедия:Bigfork Chert

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Шаблон:Infobox rockunit

The Bigfork Chert is a Middle to Late Ordovician geologic formation in the Ouachita Mountains of Arkansas and Oklahoma. First described in 1892,[1] this unit was not named until 1909 by Albert Homer Purdue in his study of the Ouachita Mountains of Arkansas.[2] 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.[3]

Paleofauna

Graptolites

C. antiquus[4]
D. divaricatus[4]
D. trifidus[4]
D. vulgatus[4]
L. flaccidus[4]
M. perexcavatus[4]
O. quadrimucronatus[4]

See also

Шаблон:Portal

References

Шаблон:Reflist


Шаблон:US-geologic-formation-stub

  1. Шаблон:Cite journal
  2. Ошибка цитирования Неверный тег <ref>; для сносок Purdue не указан текст
  3. Шаблон:Cite journal
  4. 4,0 4,1 4,2 4,3 4,4 4,5 4,6 4,7 4,8 Шаблон:Cite Q