Pierre Shale
From Wikipedia, the free encyclopedia
The Pierre Shale is a geologic formation or series of Upper Cretaceous age which occurs east of the Rocky Mountains from North Dakota to New Mexico.
The Pierre Shale was described by Meek and Hayden in 1862 in the Proceedings of the Academy of Sciences (Philadelphia). They described it as a dark-gray shale, fossiliferous, with veins and seams of gypsum, and masses of iron. The Pierre Shale was about 700 feet thick at the type locality. It overlies the Niobrara division and underlies the Fox Hills beds. It was named for an occurrence near Fort Pierre on the Missouri River in South Dakota. [1]
The Pierre Shale is of marine origin, and was deposited in the Western Interior Seaway.
[edit] References
- ^ M.E. Maclachlan, New Mexico Geological Society Guidebook, 27th Field Conference, Vermejo Park, 1976
