One of the most intriguing features of Theodore Roosevelt National Park is the texture of the geologic formations in the Badlands. The various layers seen in these formations are a visible record of the Earth’s transformation in this area going back 65 million years. According to information from the National Park Service website, lightning strikes and prairie fires ignited coal beds that burned for years baking the overlying soft sedimentary layers into a hard, natural brick called “scoria.” The orange red color is the result of oxidation of iron released from the burning coal. The hardened rocks are more resistant to erosion than the unbaked rocks and over time, erosion has worn down the less resistant rocks, creating slumped hillsides, jumbles of knobs, ridges, cannonballs, and buttes, many topped with durable red scoria caps.
