{{Short description|Geologic group in the United States}} {{Infobox rockunit | name = Council Grove Group | image = | caption = | type = Group | age = <br/>Carboniferous-Permian boundary<ref name=boundary/> | period = Early Permian | prilithology = | otherlithology = | namedfor = Council Grove, Kansas | namedby = | region = Midcontinent (Kansas, Nebraska, Oklahoma, Colorado (subsurface) ) | country = United States | coordinates = | unitof = | subunits = Speiser Shale<br/> Funston Limestone<br/> Blue Rapids Shale<br/> Crouse Limestone<br/> Easly Creek Shale<br/> Bader Formation<br/> Stearns Shale<br/> Beattie Limestone<br/> Eskridge Shale<br/> Grenola Limestone<br/> Roca Shale<br/> Red Eagle Limestone<br/> Johnson Shale<br/> Foraker Limestone | underlies = Chase Group | overlies = Admire Group | thickness = | extent = | area = | map = | map_caption = }}
The '''Council Grove Group''' is a geologic group in Kansas, Oklahoma, and Nebraska as well as subsurface Colorado. It preserves fossils dating to the Carboniferous-Permian boundary.<ref name=boundary>{{cite journal |journal= Current Research in Earth Sciences |issue= 1 |date= January 2006 |author= Robert S. Sawin, Ronald R. West, Evan K. Franseen, W. Lynn Watney |url= https://www.researchgate.net/publication/251528028 |title= Carboniferous-Permian Boundary in Kansas, Midcontinent, U.S.A |volume= 252 |quote= ... the Carboniferous-Permian boundary in Kansas can now be confidently defined. Based [on fossil changes, the] boundary in Kansas can be placed at the base of the Bennett Shale Member of the Red Eagle Limestone.}}</ref><ref name= GeolexUnit>{{cite web | title = Geologic Unit: Council Grove | series = Geolex — Unit Summary | work = National Geologic Database | publisher = United States Geological Survey | url = https://ngmdb.usgs.gov/Geolex/Units/CouncilGrove_7740.html |access-date = 2019-06-02 }}</ref> This group forms the foundations and lower ranges of the Flint Hills of Kansas, underlying the Chase Group that forms the highest ridges of the Flint Hills.
The Group particularly consists of megacyclothems alternating between massive mudstone paleosols and massive shallow marine limestone. The sequences of these alternations correlate with the ~400,000 year component of Milankovitch cycles. A number of the limestones have minor flint-filled marine animal burrows, anticipating the massive flint beds of the Chase Group.
With the exposure of the group's lower formations in the 1993 flooding,<ref name=repair>{{cite journal |author= David Mathews, Vlad G. Perlea, Francke C. Walberg, Douglas R. Anderson (U.S. Army Corps of Engineers, Kansas City, Missouri) |title= Erosion and Repair of Unlined Spillway Chute Excavated in Rock |journal= International Conference on Case Histories in Geotechnical Engineering |date= 1998 |publisher= Missouri University of Science and Technology |access-date = 2019-06-01 |url= https://scholarsmine.mst.edu/cgi/viewcontent.cgi?referer=https://www.google.com/&httpsredir=1&article=1726&context=icchge }}</ref> the entirety of the Council Grove Group, from hillcrest Speiser Shale down to pond-level Americus limestone, is exposed for study from top to bottom in the Tuttle Creek Lake Spillway.<ref>{{cite web |url= http://www.kgs.ku.edu/General/Geology/County/nop/pt/pt_11_5.html |title= Pottawatomie County T. 9 S., R. 8 E. |publisher= Kansas Geological Survey |access-date= 2019-06-02 }}</ref>
==See also== {{Portal|Earth sciences|Kansas|Paleontology}} * List of fossiliferous stratigraphic units in Kansas * List of fossiliferous stratigraphic units in Nebraska * List of fossiliferous stratigraphic units in Oklahoma * Paleontology in Kansas * Paleontology in Nebraska * Paleontology in Oklahoma
==References== {{reflist|30em}}
==Further reading== * {{cite journal |title= Stratigraphy and Paleontology of the Uppermost Pennsylvanian and Lowermost Permian Rocks in Kansas |author= Melville R. Mudge and Ellis L. Yochelson |year= 1962 |url= https://pubs.usgs.gov/pp/0323/report.pdf |publisher= USGS Professional Paper |issue= 323 |access-date= 2021-11-27 }} :: This report encyclopedically covers the units exposed in the Tuttle Creek Lake Project area, predominantly the lower Permian.
Category:Permian Colorado Category:Permian Kansas Category:Permian geology of Nebraska Category:Permian Oklahoma Category:Carboniferous southern paleotropical deposits Category:Geologic groups of Colorado Category:Geologic groups of Oklahoma Category:Geologic groups of Kansas Category:Geologic groups of Nebraska Category:Permian System of North America
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