The geology of the sand dunes is an intriguing subject. The sand comes from Navajo sandstone from the geologic period call Middle Jurassic. The same iron oxides and minerals that give us spectacular red rock country are responsible for this landscape of coral pink sand.
Sand dunes are created by three factors: Sand, high winds, and a unique influence upon the wind. The notch between the Moquith and Moccasin mountains causes this unique influence. The wind is funneled through the notch, thereby increasing wind velocity to a point where it can carry sand grains from the eroding Navajo sandstone.
This phenomenon is known as the Venturi Affect. Once the wind passes through the notch and into the open valley, the wind velocity decreases, causing the sand to be deposited. These dunes are estimated at 10,000 to 15,000 years old.