Oak Creek Canyon - Geology

Geology

Geologic evidence suggests the formation of an ancestral Oak Creek Canyon along the Oak Creek Fault about eight to ten million years ago. The ancestral Oak Creek Canyon was then filled in by gravel deposits and a series of lava flows between six and eight mya during the Miocene Epoch. About this time, the Oak Creek Fault became active again and the modern Oak Creek Canyon began to develop along the fault zone as a result of the erosional action of Oak Creek. The normal, down-to-the-east motion of the Oak Creek Fault during the most recent faulting period resulted in the west rim of the canyon being about 700 feet (210 meters) higher than the east rim.

The spectacularly eroded walls of the canyon are formed mostly of Paleozoic sedimentary rocks. Exposures of the Kaibab Limestone, (the geologic formation found at the top of the Grand Canyon), and the Toroweap Formation are found only at the northern end of the canyon. The more predominant rock units exposed in the cliffs of southern Oak Creek Canyon are the buff to white colored, frequently cross-bedded Permian Coconino Sandstone and the red sandstones of the Permian Schnebly Hill Formation. Unlike all the other formations exposed in Oak Creek Canyon, the Schnebly Hill Formation is not present at the Grand Canyon. The youngest rocks exposed in the canyon are a series of basalt lava flows that form the east rim, the youngest of which is an estimated 6 million years old.