Stanley Shale (original) (raw)

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The Stanley Shale, or Stanley Group, is a Mississippian stratigraphic unit in the Ouachita Mountains of Arkansas and Oklahoma. First described in Arkansas in 1892,[4] this unit was not named until 1902 by J.A. Taff in his study of the Ouachita Mountains of Oklahoma.[3] Taff assigned the town of Stanley in Pushmataha County, Oklahoma as the type locality, but did not designate a stratotype. After introduction into Arkansas in 1909 by Albert Homer Purdue,[5] the unit was redefined in 1918, when the formation known as the Fork Mountain Slate was abandoned and partially combined into the Stanley Shale.[6] As of 2017, a reference section for the Stanley Shale has yet to be designated.

The Stanley Shale is recognized as a geologic formation with two sub-units in Arkansas, the Hatton Tuff Lentil and the Hot Springs Sandstone Member,[1] however, several others have been proposed. These include the Chickasaw Creek Member,[7] Chickasaw Creek Tuff,[8] Gap Ridge Sandstone Member,[9] Moyers Member,[7] Parker Hill Sandstone Member,[9] Polk County Ash Bed,[10] and Tenmile Creek Member.[7] In 1963, it was first proposed to raise the rank of the Stanley Shale Formation to Group status in Arkansas,[11] with proposed sub-units consisting of the Chickasaw Creek Formation, Moyers Formation (with the Gap Ridge Sandstone and Parker Hill Sandstone Members), and Ten Mile Creek Formation.[12] However, the proposal was not accepted and the unit remained as a formation.

In Oklahoma, this unit is recognized as a group called the Stanley Group composed of three formations: the Chickasaw Creek Shale Formation, the Moyers Formation, and the Tenmile Creek Formation. The Hatton Tuff Lentil, recognized in Arkansas, is also in Oklahoma as a unit of the Tenmile Creek Formation. Several informal members have been noted including the Smithville chert lentil, the Faith chert member, and the Chickasaw Creek tuff among others[2]

Mining in the Stanley Shale is limited to cinnabar, barite, and quartz. Cinnabar is primarily used for mercury, however, production in Arkansas essentially ended by the mid-20th century. Barite mining, mostly useful for oil and gas drilling fluid, is ongoing.[13]

• List of fossiliferous stratigraphic units in Arkansas
• Paleontology in Arkansas

1. ^ a b c McFarland, John David (2004) [1998]. "Stratigraphic summary of Arkansas" (PDF). Arkansas Geological Commission Information Circular. 36: 22.
2. ^ a b Suneson, Neil (2016). "Stratigraphic nomenclature of the Ouachita Mountains in Oklahoma: formal, informal, obsolete, and incorrect or the good, the bad, and the ugly" (PDF). Oklahoma Geology Notes. 75: 5–35. Retrieved 6 June 2018.
3. ^ a b Taff, Joseph A. (1902). "Description of the Atoka Quadrangle" (PDF). Folios of the Geologic Atlas. 79: 4. doi:10.3133/GF79. Wikidata Q63225784.
4. ^ Griswold, L.S. (1892). "Whetstones and the novaculites" (PDF). Annual Report of the Geological Survey of Arkansas for 1890. 3.
5. ^ Purdue, A.H. (1909). Slates of Arkansas (PDF). Geological Survey of Arkansas.
6. ^ Miser, Hugh D. (1918). "Manganese deposits of the Caddo Gap and De Queen quadrangles, Arkansas" (PDF). U.S. Geological Survey Bulletin. 660C: 59–122. doi:10.3133/B660C. ISSN 8755-531X. Wikidata Q61463723.
7. ^ a b c Cohee, G.V.; Wright, W.B. (1976). "Changes in stratigraphic nomenclature by the U.S. Geological Survey, 1975" (PDF). U.S. Geological Survey Bulletin. 1422-A.
8. ^ Mose, Douglas G. (1969). "The age of the Hatton Tuff of the Ouachita Mountains, southeastern Oklahoma". Geological Society of America Bulletin. 80 (11): 2373–2378. Bibcode:1969GSAB...80.2373M. doi:10.1130/0016-7606(1969)80[2373:TAOTHT]2.0.CO;2. ISSN 0016-7606. Wikidata Q66258936.
9. ^ a b Stearn, N.H. (1935). "Quicksilver deposits near Little Missouri River, discussion". Transactions of the American Institute of Mining and Metallurgical Engineers. 115: 244–246.
10. ^ Williams, J.F. (1891). "The igneous rocks of Arkansas". Annual Report of the Geological Survey of Arkansas for 1890. 2.
11. ^ Seely, D.R. (1963). "Structure and stratigraphy of the Rich Mountain area, Oklahoma and Arkansas" (PDF). Oklahoma Geological Survey Bulletin. 101.
12. ^ Walthall, B.H. (1967). "Stratigraphy and structure, part of Athens Plateau, southern Ouachitas, Arkansas". American Association of Petroleum Geologists Bulletin. 51 (4): 504–528. doi:10.1306/5d25c0a1-16c1-11d7-8645000102c1865d.
13. ^ Rains, Daniel S.; Hanson, William D. (2017). "Geologic report of Pike County" (PDF). Arkansas Geological Survey County Geologic Report. 62: 28. Retrieved 26 May 2018.
14. ^ a b c d e f g h i j k l m n o p q r s t u White, David (1937). "Fossil plants from the Stanley shale and Jackfork sandstone in southeastern Oklahoma and western Arkansas" (PDF). Geological Survey Professional Paper. 186C: 43–67. doi:10.3133/PP186C. ISSN 0096-0446. Wikidata Q61049457.