Kiowa Shale

Kiowa Shale
Stratigraphic range: Albian
around 101–97 Ma
↓
TypeKansas: Formation
Sub-unitsLongford
UnderliesDakota Formation
Overlies
Lithology
Primaryshale
Othermudstone, lignite (with amber)
Location
CountryUnited States
Type section
Named forKiowa County, Kansas[1]
Named byCragin, F.W., 1894[1]

The Kiowa Formation or Kiowa Shale is a Cretaceous geologic formation in Kansas, diminishing to member status in Colorado and Oklahoma. In Colorado, the Kiowa Shale was classified as a member of the now abandoned[2] Purgatoire Formation.[1] In the vicinity of Longford, Kansas, the local Longford member comprises thinly bedded siltstone, clay, polished gravel, lignite, and sandstone suggests a river and estuary environment.[3]

In other regions, the same strata is called Skull Creek Shale, named after its exposure in Skull Creek, in Wyoming.[4]

  1. ^ a b c "Geologic Unit: Kiowa". National Geologic Database. Geolex — Significant Publications. United States Geological Survey. Retrieved 2020-09-23.
  2. ^ "Geologic Unit: Purgatoire". National Geologic Database. Geolex — Significant Publications. United States Geological Survey. Retrieved 2021-03-24. Use of Purgatoire formation in Tucumcari-Sabinoso area, Guadalupe, Harding, San Miguel, and Quay Cos, northeast NM in the Palo Duro basin and on the Sierra Grande uplift abandoned [should read "areally restricted"].
    Term Purgatoire abandoned. Both Lytle and Glencairn are mappable at 1:24,000, and they are separated by a disconformity--the most significant break in the Lower Cretaceous. Authors believe there is no reason to retain them as member rank or to raise the Purgatoire to group rank.
  3. ^ "Geologic Unit: Longford". National Geologic Database. USGS Geologic Names Committee Archives. United States Geological Survey. Retrieved 2020-09-23.
  4. ^ Cite error: The named reference Weimer84 was invoked but never defined (see the help page).