Geology of the Badlands of South Dakota
The geology of the Badlands isn’t a story of dramatic uplift like its neighbor to the west – the Black Hills. Instead, the Badlands is a story of what millions of years of erosion stripped away.
Over a period of 75 million years, ancient rivers, inland seas, and volcanic eruptions laid down ribbons of sediment. The sediment was compressed into very soft and fragile rock formations such as: mudstone, siltstone, shale, and ash.
The Black Hills uplift shifted water flow to the east into soft sedimentary layers. The erosion carved buttes, towers, ridges, and canyons into what is now known as the Badlands.
The Process Continues
When we visit the Badlands today, we see a unique landscape still in the making. Erosion is Nature’s sculptor. Working through rain, wind, and the freeze-thaw cycle, it continues to pare back the cliffs at a rate that is one of the fastest in North America.
