Arizona’s petrified dune sand of the dinosaur age

The Wave is a beautiful undulating rock formation in the Coyote Buttes of the Paria Canyon and Vermilion Cliffs Wilderness in Arizona that originated from 150 million year old Jurassic sand dunes that have lithified into Navajo sandstone.
This Jurassic dune field resembled today’s Sahara, a vast desert stretching along the American west coast. With increasing sand accumulation, the buried dunes slowly reached the groundwater table and were saturated with water. Soluble minerals in the groundwater such as calcium cemented the sand grains together and slowly turned the buried sand dunes into rock. This Navajo sandstone is the most widespread rock formation on the Colorado Plateau. In today’s region of The Wave, the dune forming processes of the wind have been preserved in great detail. Each slanting line in the rock represents the cross-bedding of the former dunes, where the sand was sliding down the steep dunes in downwind direction. In addition, the geology of The Wave magically outgrew itself when it transformed the usually white to salmon-colored wave symmetry of the sloping strata into a color explosion of deep red and yellow. For this to happen, the groundwater contained traces of manganese and iron oxide minerals that penetrated the buried dunes. Subtle differences in the chemical composition of the minerals stained the sand grains and the binding cement into the amazing color palette exposed in The Wave.
The Paria River, a tributary of the Colorado River, has carved this intricate network of canyons, cliffs and buttes into the Coyote Buttes. Summer flash floods caused by thunderstorms further eroded the landscape into gently rounded U-shaped troughs. The sandstone is most effectively weathered along preexisting joints in the dune cross-bedding. The abrasive forces of blowing sand have additionally sculptured The Wave into its present form.
Today the Coyote Buttes with the famous Wave are located at an altitude of 1590 m (5220 ft). Uplifted together with the entire Colorado Plateau this landscape is again situated in an arid environment that is cut off from the Pacific moisture supply by the Sierra Nevada mountains for most of the year. Only winter low-pressure systems and summer monsoon thunderstorms bring significant rainfall, which in turn can lead to irregular flash floods that continue to shape the Wave.
This fanciful landscape of fabulously shaped sandstones creates an atmosphere in which one would not be surprised if a herd of dinosaurs were to wander through the scenery. In fact, the Navajo sandstone contains traces of dinosaur activity. Their traces, churnings and droppings are omnipresent. These dinosaurs roamed a world of sand.