Monday, April 25, 2016

The Missouri Plateau

The Missouri Plateau is an unglaciated region of the Great Plains of North America, extending from central Montana and northeast Wyoming across western portions of North and South Dakota.  Bounded by glaciated plains to its north and east, by the Rocky Mountains Province to its west and by the High Plains to its south, the Plateau is drained by the the Missouri River and tributaries arriving from the south and west: the Yellowstone, Little Missouri, Grande, Moreau, Cheyenne and White Rivers.

Since the Missouri Plateau is coated with relatively soft Tertiary sediments, eroded from the Rockies, many of these tributaries have produced "badlands" along their valleys; the most famous of these, protected within Badlands National Park, was eroded by the White River of southwestern South Dakota.  The most prominent geographic feature within this province, however, is the Precambrian dome of the Black Hills, that rose through the younger sediments.  Another region of topographic relief is along the Pine Ridge Escarpment of northwest Nebraska, northeast Wyoming and southwest South Dakota, where the north edge of the High Plains drops into the dissected terrain of the Missouri Plateau.

To the disinterested traveler, the Great Plains of our Continent may seem to be a single, vast province of prairie and crop fields, extending from the Mississippi Valley to the Rocky Mountain corridor.  In reality, the Plains are a mosaic of geographic regions, the products of underlying geology, glaciation, stream erosion, elevation and climate.  For those who care to look, each region offers unique natural features, including its own mix of fauna and flora.