Benton Shale facts for kids
Quick facts for kids Benton ShaleStratigraphic range: Cretaceous |
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Gray shale (Benton Shale; Colorado Springs, Colorado)
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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. 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 The Benton classification is obsolete in some regions, having been replaced by the ascending sequence Graneros Shale, Greenhorn Limestone, and Carlile Shale.
The classification derives its name from Fort Benton, a small city in Montana on the Upper Missouri River.
Images for kids
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Benton Group outcrop identified in Kansas by F.V. Hayden in 1871
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Chalk rhythmites in "old Benton" Greenhorn member in Kansas
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Chalk rhythmites in "old Benton" Lower Carlile member in Kansas