Blakely Sandstone

The Blakely Sandstone is a Middle Ordovician geologic formation in the Ouachita Mountains of Arkansas and Oklahoma. First described in 1892,[3] this unit was not named until 1909 by Albert Homer Purdue in his study of the Ouachita Mountains of Arkansas. Purdue had initially named this unit the Caddo Shale at a 1907 Geological Society of America meeting,[4] but later redefined and renamed the unit as the Ouachita Shale.[5] He again renamed the unit to the Blakely Sandstone in a letter to Edward Oscar Ulrich, to which Ulrich used in a 1911 publication, becoming the first reference using this name.[2] Ulrich assigned the Blakely Mountain in Garland 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.

Blakely Sandstone
Stratigraphic range: Ordovician
Blakely Sandstone (Coleman Quartz Mine, Arkansas)
TypeFormation
Unit ofnone
Sub-unitsnone
UnderliesWomble Shale
OverliesMazarn Shale
Thicknessup to 700 feet[1]
Lithology
PrimarySandstone
Location
RegionArkansas, Oklahoma
CountryUnited States
Type section
Named forBlakely Mountain, Garland County, Arkansas
Named byAlbert Homer Purdue[2]

Paleofauna

Conodonts

C. horridus[6]
  • Hisiodella
H. holodentata[6]
  • Leptochirognathus
L. quadratus[6]
  • Paraprioniodus
P. costatus[6]
P. aculeatus[6]

Graptolites

D. euodes[7]
D. manus[7]
D. spinosus[7]
  • Glossograptus
G. echinatus[7]
G. horridus[7]

See also

References

  1. 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 2018-01-08.
  2. Ulrich, E.O. (1911). "Revision of the Paleozoic systems". Bulletin of the Geological Society of America. 22 (1): 677. Bibcode:1911GSAB...22..281U. doi:10.1130/GSAB-22-281.
  3. Griswold, L.S. (1892). "Whetstones and the novaculites". Annual Report of the Geological Survey of Arkansas for 1890. 3.
  4. Purdue, A.H. (1909). "Structure and stratigraphy of the Ouachita Ordovician area, Arkansas (abstract)". Geological Society of America Bulletin. 19: 557. doi:10.1130/GSAB-19-513.
  5. Purdue, A.H. (1909). Slates of Arkansas. Geological Survey of Arkansas.
  6. Ethington, R.L.; Finney, S.C.; Repetski, J.E. (1989). Biostratigraphy of the Paleozoic rocks of the Ouachita orogen, Arkansas, Oklahoma, west Texas.
  7. Miser, Hugh D.; Purdue, A.H. (1929). "Geology of the De Queen and Caddo Gap quadrangles, Arkansas" (PDF). U.S. Geological Survey Bulletin. 808: 30–31.


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