The Verde Valley: A geological history

In this issue of Plateau Magazine, Wayne Ranney delves deep into the geological history of the Verde Valley. "The Precambrian" The geological record of the Verde Valley begins with rocks formed in the Precambrian Era, a time period so vast and far removed from the present that even geologists experience difficulty comprehending the length of time that it represents. "The Early Paleozoic" Whereas the Precambrian rocks exposed at Jerome give evidence for a submarine volcanic setting, most of the Paleozoic rocks in the Verde Valley record a time of hot, desert environments. "The Late Paleozoic" Without a doubt, the most spectacular rocks within the Verde Valley are the red rocks exposed near Sedona that were deposited during the Pennsylvanian and Permian periods. "The Mesozoic" When the Kaibab seas finally retreated about 260 million years ago, there were other environments that may have left sediment on top of the Kaibab formation. But the following 35 million years of earth history have no record on the Colorado Plateau. "The Cenozoic" Although it seems that the most recent history should be the easiest to document, the Cenozoic throughout much of Arizona was a time of erosion, and rocks either were never deposited or were stripped away.