Mesa

geology · landforms · desert

Flat-topped giants. Mesas are isolated hills with completely flat tops and super steep sides that drop straight down. They stand out by themselves, rising high above the surrounding land like giant stone platforms.

Protected by caprock. The secret to a mesa's flat top is a hard, resistant layer called caprock, usually made of sandstone or limestone. This tough caprock sits on top of softer rocks below and protects them from wearing away, which is why the top stays flat while everything around it erodes.

How mesas form. Mesas start out as thick layers of sedimentary rock, like shale, laid flat on top of each other. Over millions of years, water and wind wear away the surrounding land, leaving behind the plateau with its hard caprock on top, which resists erosion better than the softer rocks around it.

Common in dry places. You'll find spectacular mesas in deserts and dry regions, especially in the American Southwest like Arizona, Utah, and New Mexico. The dry climate means less rainfall to erode the rocks, so these amazing landforms can stand tall for a very long time.