How the Interior Plateaus Formed: Tectonics, Mountains, and Erosion

The Interior Plateaus (Ozark, Colorado, etc.) rose from ancient tectonic collisions:

• Ouachita uplift: North American–African plate collision (late Paleozoic) built the Ouachita Mountains.
• Rocky Mountain uplift: North American–Pacific plate collision (Laramide orogeny) raised the Rockies.
• Basin fill: Erosion from these ranges washed sediments into intervening basins, leveling them into plateaus.

Time, water, and wind then sculpted the plateaus’ current topography—canyons, mesas, and layered cliffs.