The Coconino Sandstone

In Northern Arizona

(Uploaded 12/27/08)

This Permian Terrestrial sequence was formed as a dune eolian deposit 270 to 265 million years ago, and exhibits the typical high angle cross bedding and sandy texture of such deposits. The formation is widespread over much of the Mogollon Rim, and forms a thick unit over the Schnebly Hill Formation's Sycamore Pass member, and lies under the Kaibab Limestone. As you might expect, the Coconino represents a Sahara type desert, left behind by the regressing Pedregosa Sea. The beds contains "locally abundant" trace fossils of mammal like reptiles, spiders, scorpions, lizards, and raindrop impressions, and extremely rare plant impressions.


On the tunnel trail on Forest Road 300 - the Rim Road, the Coconino outcrops all along the trail. Here we can see the dune pattern cross bedding planes weathering to a dull gray color. The less weathered material is yellowish, and can be seen to the lower left.

From the top of the Mogollon Rim, just off the Rim Road, the yellow colored Coconino sandstone forms spectacular outcrops along the Rims face, often with a cap of the marine Kaibab Limestone.

On highway 89a out of Sedona, numerous isolated outcrops occur along the roadway. In this image, the yellow Coconino Sandstone thrusts out of a ridge to form a spectacular cliff. The ridge just behind is completely volcanic, with basalt capping the top. I took this one in the parking lot of the Dairy Queen recently.

Capitol Butte seen in the distance from the village of Oak Creek. This dome shaped hill, nicknamed because of its resemblance to the Capitol Building in Washington DC, is composed entirely of Coconino Sandstone.

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