Du Chengfeng, a member of the Chinese Rock Art Institution and the founder of the Qilian Mountain Rock Painting Studio, said, "The chiseling technique of these deer rock paintings is to use the point-like chisel point to carry out the contour composition, and then the whole body is carved. It could be determined on the spot that the chiseling tool belongs to metal tools, which may be bronze tools or early iron tools. Using the attributes of chiseling tools combined with the prehistoric climate research of the Hexi Corridor and the living habits of deer, it was inferred that the deer paintings, with a history of 3,500 years, belongs to the Bronze Age or the early Iron Age."
Most of rock paintings of Yumu Mountain, located in the Qilian Mountains, are engraved on the lacquer slate and shale of the black Cambrian desert with relatively hard texture. Because of its high altitude, the vegetation is mainly xerophytic semi-shrub herbs, and there are a certain number of spruce, eucalyptus, sand jujube and shrub forests in the north of the valley.
