Sediments that are carried by streams to the Missouri River may be carried on past New Orleans and deposited as part of the Mississippi River delta. As sediments are deposited, the land rises. The Great Plains were probably much lower before the Rocky Mountains rose. T he Great Plains slope downward as you travel east away from the Rockies. The opposite of deposition is erosion, which can be caused be wind, water, glaciers, temperature changes and plants and animals.
Erosion is typically most intense in arid areas that have little or no plant cover.
Areas of heavy erosion in the Great Plains are called badlands. Some of the most spectacular examples of erosion in the world can be seen in the Southwest, notably Arizona s Grand Canyon. When deposition is greater than erosion, sediments grow thicker and the land rises. When erosion is greater, sediments are carried away, and the land is lowered. A balance is reached when deposition and erosion are equal, whether they re both minimal or extreme.