My flight home to Atlanta last week afforded me a spectacular view of the Grand Canyon.
No one knows for sure how the canyon was formed but there are some pretty good guesses. The chances are that a number of processes combined to create the views that you see in todays Grand Canyon. The most powerful force to have an impact on the Grand Canyon is erosion, primarily by water (and ice) and second by wind. Other forces that contributed to the Canyon's formation are the course of the Colorado River itself, vulcanism, continental drift and slight variations in the earths orbit which in turn causes variations in seasons and climate.
For more visit: http://www.bobspixels.com/kaibab.org/geology/canform.htm