The terms mesa and plateau are often used interchangeably to describe large, elevated landforms with flat tops, known broadly as tablelands. These features are common in arid and semi-arid regions, such as the southwestern United States. While both share the characteristic of a high, relatively flat surface rising sharply above the surrounding terrain, they are distinct based on their size, shape, and the degree of erosion they have undergone.
Characteristics of a Plateau
A plateau is characterized as a broad, extensive area of elevated land with a surface that is largely flat or gently rolling. Plateaus are defined by their sheer size, often spanning hundreds or thousands of square miles, which is their primary distinguishing feature. The edges of a plateau typically descend abruptly, forming steep slopes or cliffs known as escarpments. Plateaus are formed through large-scale geological processes, including tectonic uplift or the widespread extrusion of volcanic lava.
Characteristics of a Mesa
A mesa is a specific, isolated type of elevated landform that is significantly smaller in area than a plateau. The term “mesa” is Spanish for “table,” reflecting its appearance: a flat top and very steep sides. Mesas are typically found in dry climates where horizontal rock layers have been exposed to weathering.
The top surface is protected by a layer of hard, erosion-resistant rock called a caprock. This durable caprock shields the softer rock layers beneath it from being quickly worn away. The steep sides completely surround the formation, defining it as a distinct, standalone feature.
The Defining Influence of Erosion
The most significant difference between a plateau and a mesa is their placement along an erosional timeline. A mesa is essentially a residual landform, created through the extensive dissection and erosion of a much larger plateau. This transformation is driven by differential erosion, where water and wind wear away softer rock layers at different rates than the harder layers.
The sequence begins when a vast, elevated plateau is cut into by rivers and weathering, which creates deep valleys and canyons. As the surrounding softer material is stripped away, isolated sections of the plateau are left standing. These remnants, protected by their resistant caprock, are the mesas. The caprock prevents the vertical degradation of the top surface, forcing erosion to attack the softer, unprotected sides, which maintains the steep cliff face.
As erosion continues over geological time, the mesa shrinks in area and retreats. If the flat top continues to decrease until the feature becomes taller than it is wide, it is then classified as a butte. Therefore, the landforms—plateau, mesa, and butte—represent three distinct stages of degradation, with the mesa being the intermediate form between the massive parent plateau and the smaller, needle-like butte.