Mesa Facts for Kids

Mesas in the Glass Mountains of western Oklahoma.

Cerro Negro one of a few mesas near Zapala, Argentina.

Mesa (Spanish and Portuguese for "table") is a steep-sided, flat-topped hill or mountain. They are sometimes called "table mountains" because of their shape. These mountains are mainly found in Spain, Africa and in some parts of the United States.

The largest mesa in the world is the Grand Mesa in western Colorado in the United States.

The term mesa is used in the southwestern United States, in both English and Spanish, to describe a flat-topped mountain or hill. Elsewhere, in Spanish such a landform is more usually known as a meseta.

Formation

Mesas are formed by weathering and erosion of horizontally layered rocks. Variations in the ability of different types of rock to resist weathering and erosion cause the weaker types of rocks to be eroded away, leaving the more resistant types of rocks standing higher relative to their surroundings. This process is called differential erosion.

The most resistant rock types include sandstone, conglomerate, quartzite, chert, limestone, lava flows and sills. Lava flows and sills, in particular, are very resistant to weathering and erosion, and often form the flat top, or caprock, of a mesa. The less resistant rock layers are mainly made up of shale, a softer rock that weathers and erodes more easily.

Differences in rock type also shape up the sides of a mesa. Instead of smooth slopes, the sides may be broken into a staircase pattern called "cliff-and-bench topography." The more resistant layers form the cliffs, or stair steps, while the less resistant layers form gentle slopes, or benches, between the cliffs.

Some other planets also have mesas. Mars is famous for its mesas.