<P> The geology of the Grand Canyon area includes one of the most complete and studied sequences of rock on Earth . The nearly 40 major sedimentary rock layers exposed in the Grand Canyon and in the Grand Canyon National Park area range in age from about 200 million to nearly 2 billion years old . Most were deposited in warm , shallow seas and near ancient , long - gone sea shores in western North America . Both marine and terrestrial sediments are represented , including fossilized sand dunes from an extinct desert . There are at least 14 known unconformities in the geologic record found in the Grand Canyon . </P>
<P> The geology of the Grand Canyon area includes one of the most complete and studied sequences of rock on Earth . The nearly 40 major sedimentary rock layers exposed in the Grand Canyon and in the Grand Canyon National Park area range in age from about 200 million to nearly 2 billion years old . Most were deposited in warm , shallow seas and near ancient , long - gone sea shores in western North America . Both marine and terrestrial sediments are represented , including fossilized sand dunes from an extinct desert . There are at least 14 known unconformities in the geologic record found in the Grand Canyon . </P>
what does each layer of the grand canyon represent
what does each layer of the grand canyon represent
age
age