A MESA is a flat-topped mountain bordered on all sides by steep cliffs. There are many different types of rock. Some erode quickly and some slowly. This is what gives mesas their distinctive shape. Softer rocks are eroded away on the surface into valleys, where they collect water drainage from the surrounding area, while the stronger rock layers are left standing out. A large area of strong rock may shield the layers below it from erosion while the softer rock surrounding it is eroded into valleys, thus forming a cap rock.” A MESA can be formed quickly or slowly.
Mesas get smaller as their cliffs erode and become small, flat-topped hills called BUTTES. Buttes are formed by erosion when hard rock covers a layer of softer rock that is easily worn away. The hard rock avoids erosion while the soft rock around it wears down.
A CANYON is a deep valley between cliffs often carved from the landscape by a river. This erosion takes a very long time. The canyon is formed by the water flowing through the river valley eroding the earth beneath it and carrying away loose rock and soil. The rock and soil being carried away weathers the ground beneath it by one object rubbing against another. Canyon walls are often formed of strong sandstones or granite. The Colorado River and the Snake River run through canyons. Over time, a canyon valley can get deeper and deeper.
VALLEYS are formed by a rivers or glaciers. A valley formed by flowing water is V-shaped. If the water is moving fast, there will be a narrow valley at the bottom. Slower moving waters create wider valleys. Valleys created by glaciers are U-shaped and they are created when the glacier warms up and disappears.
Mesas get smaller as their cliffs erode and become small, flat-topped hills called BUTTES. Buttes are formed by erosion when hard rock covers a layer of softer rock that is easily worn away. The hard rock avoids erosion while the soft rock around it wears down.
A CANYON is a deep valley between cliffs often carved from the landscape by a river. This erosion takes a very long time. The canyon is formed by the water flowing through the river valley eroding the earth beneath it and carrying away loose rock and soil. The rock and soil being carried away weathers the ground beneath it by one object rubbing against another. Canyon walls are often formed of strong sandstones or granite. The Colorado River and the Snake River run through canyons. Over time, a canyon valley can get deeper and deeper.
VALLEYS are formed by a rivers or glaciers. A valley formed by flowing water is V-shaped. If the water is moving fast, there will be a narrow valley at the bottom. Slower moving waters create wider valleys. Valleys created by glaciers are U-shaped and they are created when the glacier warms up and disappears.