Introduction to sedimentary rocks: The rock formations of the Grand Canyon are mainly sedimentary rocks. After being fractured by the Tianshan Mountains and crustal movement, the rock formations underwent a series of wavy bends. Obvious folds and fracture lines can be seen on the side walls of the canyon. Its landforms can be divided into upright folds, oblique folds, inverted folds, etc. Among them, oblique folds are the most common.