The Pierre Shale is a Late Cretaceous geologic formation lying east of the Rocky Mountains across the Great Plains, extending from the Pembina Valley in Canada to New Mexico, and dating to the Campanian and Maastrichtian stages. It consists mainly of dark gray, fossiliferous shale with veins and seams of gypsum and concretions of iron oxide, reaching about 3,138 feet thick at its type locality, and was named for an exposure near Fort Pierre on the Missouri River in South Dakota, formally described by Meek and Hayden in 1862. It overlies the Niobrara formation and underlies the Fox Hills beds, formed from marine sediment deposited in the Western Interior Seaway, and correlates with other marine shales including the Bearpaw, Mancos and Lewis Shales and Alberta's Lea Park Formation; it hosts commercial petroleum in Colorado and has yielded abundant ammonites, marine reptiles and other invertebrate fossils documenting the ancient seaway.
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Source Pierre Shale (Wikipedia)
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Source Pierre Shale (Wikipedia)
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Also in Geography Atlas: where this subject is found.
Also in Geography Atlas: where this subject is found.
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Pierre Shale (Wikipedia)
In Discipline: Stratigraphy, Lead paragraph
The Pierre Shale is a geologic formation or series in the Upper Cretaceous which occurs east of the Rocky Mountains in the Great Plains, from Pembina Valley in Canada to New Mexico
Caused By: Sedimentation, Lead paragraph
The Pierre Shale is of marine origin and was deposited in the Western Interior Seaway
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