Over the past 6 million years, the Colorado River has carved through almost 2 billion years of the earth’s geologic history at the Grand Canyon. Layers of limestone, sandstone, shale, granite, and schist make up the Grand Canyon’s rock sequences. These layers continue to be worn away through water and wind erosion, creating the cliffs and slopes that make up this fantastic play of shape and color through time and space.
Because of the carving forces of the Colorado River through the Grand Canyon, the river’s course tells the story of the earth’s formation and structure like few places on earth. The canyon's varies from 5280 feet to 6000 feet in depth. It also ranges from 16 km to 28.8 km in width rim to rim.