|Name||Jackfork Group or Jackfork Sandstone|
|Geologic age||Early Pennsylvanian|
Sedimentary > Clastic > Sandstone (Bed)
Sedimentary > Clastic > Mudstone > Shale (Bed)
Sedimentary > Clastic > Conglomerate (Bed)
|Comments||Raised in rank to group--upper of two groups of the Pushmataha series (new) of the Bendian period. Is found in the Ouachita Mountains of OK in the Ouachita tectonic belt province. Best exposure in undisturbed sequence is in Prairie Mountain, T1S, R12E, Atoka Co, OK. This typically clastic deposit is divided into four newly named formations (ascending order); Wildhorse Mountain formation, Prairie Mountain formation, Markham Mill formation, and Wesley shale. (Harlton, 1938) Named for Jackfork Mountain, Pittsburg and Pushmataha Cos, OK. No type locality designated. Occurs in northeastern part of Atoka quad and to the east is the mountain-making formation of the Ouachita Range. Consists of a series of even-textured, fine-grained, brown and gray sandstone strata ranging from thin layers to massive beds 50 ft thick. Occasionally interstratified are thin beds of clay shale and shaly sandstone. Total thickness is 3,800 ft in Atoka quad. (Taff, 1902) Typical greywacke.|
Heran, W.D., Green, G. and Stoeser, D.B., 2003, A Digital Geologic Map Database of Oklahoma: USGS Open File Report 03-247, scale 1:250,000.
Hart, D.L., 1974, Reconnaissance of the water resources of the Ardmore and Sherman quadrangles, southern Oklahoma: Oklahoma Geological Survey, Hydrologic Atlas 3, scale 1:250,000, 4 sheets. (Geology on sheet 1 compiled by D.L. Hart, and R.O. Fay, in 1970.)
Cederstrand, J.R., 1996a, Digital geologic map of Ardmore-Sherman quadrangles, south-central Oklahoma: U.S. Geological Survey Open-File Report 96-370, (3 diskettes), URL address is: http://ok.water.usgs.gov/gis/geology
Marcher, M.V. and Bergman, D.L., 1983, Reconnaissance of the water resources of the McAlester and Texarkana quadrangles, southeastern Oklahoma: Oklahoma Geological Survey, Hydrologic Atlas 9, scale 1:250,000, 4 sheets. (Geology on sheet 1 compiled by M.V. Marcher and D.L. Bergman, in 1971 and revised by R.O. Fay, in 1978.)
Cederstrand, J.R., 1996h, Digital geologic map of McAlester-Texarkana quadrangles, southeastern Oklahoma: U.S. Geological Survey Open-File Report 96-377, (3 diskettes), URL address is: http://ok.water.usgs.gov/gis/geology
Harlton, B.H., 1938, Stratigraphy of the Bendian of the Oklahoma salient of the Ouachita Mountains: Bulletin of the American Association of Petroleum Geologists, vol.22, no.7, pp.852-914.
Taff, J.A., 1902, Description of the Atoka quadrangle [Indian Territory]: U.S. Geological Survey Geologic Atlas of the United States, Folio 79.
|Counties||Atoka - Choctaw - Latimer - Le Flore - McCurtain - Pittsburg - Pushmataha|