South Dakota’s Badlands

December 12, 2019


Photographer: Saundra Simmons 
Summary Authors: Saundra Simmons; Jim Foster

As shown above, a foreground of prairie grasses gives way to a treeless, sharp-toothed backdrop of eroded sandstone. This is the badlands of South Dakota. A weathered wonderland took shape here when the Black Hills, some 70 miles (112 km) to the west, shed sediment during uplift processes into a basin region to its east. Approximately 500,000 years ago, what’s now the Cheyenne River flowed through this basin, triggering wide-scale erosion. Since then, wind and rain have exposed sedimentary strata (primarily sandstone, siltstone and shale) into a variety of shapes that can be easily viewed from the many overlooks in Badlands National Park.