Natural Setting and Geological History
Geologically, the history of Sedona began about 500 millions years ago. Over a
period of 300 million years, the land was alternately ocean bottom and coastal
plain. Sedimentary layers of sandstone formed. Between 200 and 65 million years
ago, dinosaurs roamed the land. From 65 to 20 million years ago, there were
uplifts in southern Arizona and down faulting and wind erosion in northern
Arizona. From 20 to 12 million years ago, volcanic activity caused the Verde
Valley to down fault into a deep basin with lakebeds, creating the Mogollon
Rim.
About 3 million years ago, the Colorado Plateau uplifted. Since then, erosion by
wind, rain and snowmelt has created Oak Creek Canyon and exposed the layers of
sediment (Schnebly Hill Formation sandstone) to form the spectacular red rock
formations we now see in Sedona. Vegetation and wildlife evolved and migrated.
The process continues today, however slowly.
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