Scientists have studied rock deposits along course of the present day Colorado River. By looking at the type of sediments the deposits contain, scientists determine whether or not the rocks were deposited by the river. Rocks deposited by the river are younger than the river, as the river needed to be around to deposit them. Rocks not deposited by the river are older than the river because the river was not yet there to drop them.
[{"rock_types": "n/a", "era_formed": "n/a"}]
[{"rock_types": "sediments", "era_formed": "n/a"}] [{"rock_types": "n/a", "era_formed": "n/a"}]