Coteau des Prairies
Encyclopedia : C : CO : COT : Coteau des Prairies
The Coteau des Prairies is a plateau, approximately 200 miles in length and 100 miles in width (320 by 160 km), rising from the prairie flatlands in eastern South Dakota and southwestern Minnesota in the United States.
The flatiron-shaped plateau was named by early French explorers from New France (Quebec). Coteau means "slope" in French.
The plateau is composed of thick glacial deposits, the remnants of many repeated glaciations, reaching a composite thickness of approximately 900 feet (275 m). They are underlain by small ridge of resistant Cretaceous shale. During the last (Pleistocene) Ice Age, two lobes of the glacier appear to have parted around the preexisting plateau and further deepened the lowlands flanking the plateau.
The plateau has numerous small glacial lakes and is drained by the Big Sioux River in South Dakota and the Cottonwood River in Minnesota. A quarry in the plateau was once the site for obtaining the traditional stone used in Native American peace pipes. Red pipe stone (catlinite), a fine-grained, easily-worked mineral was quarried near present day Pipestone, Minnesota and in adjacent Minnehaha County, South Dakota.
References
External links
- [USGS Site] on the Coteau des Prairies
- [Glacial History] of Coteau des Prairies (University of South Dakota).
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