Benton Shale
| Benton Shale Stratigraphic range: Cretaceous | |
|---|---|
 Gray shale (Benton Shale; Colorado Springs, Colorado) | |
| Type | Formation |
| Underlies | Niobrara Formation |
| Overlies | Dakota Sandstone |
| Lithology | |
| Primary | Shale |
| Other | Limestone, sandstone, bentonite |
| Location | |
| Region | Montana, Wyoming, North Dakota, South Dakota, Colorado, Nebraska |
| Country | United States |
| Type section | |
| Named for | Fort Benton, Montana |
The Benton Shale (also Benton Formation or Benton Group) is a geologic formation in Montana, Wyoming, North Dakota, South Dakota, Colorado, Kansas, and Nebraska.[1] It preserves fossils dating to the Cretaceous Period. The term Benton Limestone has also been used to refer to the chalky portions of the strata, especially the upper beds of the strata presently classified as Greenhorn Limestone. The Benton classification is obsolete in some regions, having been replaced by the ascending sequence Graneros Shale, Greenhorn Limestone, and Carlile Shale.[2][3]
The classification derives its name from Fort Benton, a small city in Montana on the Upper Missouri River.
Concretionary cone-in-cone structures in Benton Shale
Gray shale (Benton Shale)
Gray shale and bentonites (Benton Shale)
See also[]
References[]
- ^ National Geologic Map Database - Geolex, USGS
- ^ Donald E. Hattin (1962). "Stratigraphy of the Carlile Shale (Upper Cretaceous) in Kansas". State Geological Survey of Kansas. Kansas Geological Survey, University of Kansas, Lawrence, Kansas (Bulletin 156). Retrieved 2018-08-04.
- ^ Donald E. Hattin (1962). "Stratigraphy and Depositional Environment of Greenhorn Limestone (Upper Cretaceous) of Kansas". State Geological Survey of Kansas. Kansas Geological Survey, University of Kansas, Lawrence, Kansas (Bulletin 209). Retrieved 2018-08-04.
- Various Contributors to the Paleobiology Database. "Fossilworks: Gateway to the Paleobiology Database". Retrieved 17 December 2021.
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- Shale formations of the United States
- Cretaceous Colorado
- Cretaceous Montana
- Cretaceous geology of Wyoming
- Cretaceous geology of North Dakota
- Cretaceous geology of South Dakota
- Cretaceous geology of Nebraska
- Western United States geologic formation stubs
- Montana geography stubs
- Cretaceous stubs