Sedona Westerners in the Red Rock News

April 9, 2010

Westerners Find Sedona to be Highly Evolved

 


by Curt Kommer

Sedona is a highly evolved place to live …. Geologically. That is what attracted Ron Blakey to the Sedona area more than 35 years ago. A Professor of Geology at Northern Arizona University for 34 years, his specialty has been the study of the Colorado Plateau, and Sedona’s unique position on its flank. Professor Blakey recently led a group of interested Sedona Westerners on an informational Wednesday “Tracker Hike” to point out some of our areas unique features. Using the easily accessed Huckaby Trail as his classroom, Professor Blakey pointed north toward the Colorado Plateau and its southern edge, the Mogollon Rim.


Hermit Formation in foreground (reddish with river cobblestones from major rivers) in the Bear Wallow Fault. On top and in background is Wilson Mountain. Photo by Curt Kommer.

The Plateau, formed by hundreds of millions of years of deposition of sedimentary rock, is defined by a complex system of rivers eroding and dissecting downward, i.e.: the Grand Canyon. In Sedona, we live at the edge of this erosion, between plateau and basin. This unique location says Blakey, makes Sedona “the best place in the world” to view exposed rocks formed hundreds of millions of years ago. As an example, he pointed south to Airport Mesa; “The power of this erosion is such that just a short 120,000 years ago the top of Airport Mesa was the rocky bottom of Oak Creek.” As this erosion progressed it exposed older layers such as the Coconino Sandstone (white, petrified sand dunes topping our highest elevations), the Schnebly Hill Formation (vertical red walls of ancient windblown sand), and the Hermit Formation (the sloping red sand and mud rocks that Sedona rests upon). Of note, it was Professor Blakey who originally identified and named the Schnebly Hill layer, thereby immortalizing a local icon.

Erosion was not the only force working our landscape. Earthquakes and fault lines also have defined the Sedona we see today. From the Huckaby Trail, the Professor pointed northwest to Wilson Mountain. “Look at the flat top of Wilson, and then look northeast to the flat bench about 400 feet lower. They were once continuous until the Oak Creek fault shifted eons ago, creating the Wilson skyline we see today.”

Climbing to the top of Wilson Mountain via either the North or South Trails will take a hiker directly across this fault. Next, from our location near the north end of town, Blakey focused the group’s attention on our east-west axis and pointed out an easily recognizable rock layer. To our north, this layer was at least 100 feet higher than it was to the south of where we were standing, marking another major local fault line, the Bear Wallow fault. The Professor did reassure the group, all local residents, that there is no evidence that these faults continue to be active.

As the day concluded, many Westerners were struck by the thought that a simple three mile hike along an easy, downtown trail could yield such an extraordinary glimpse into our Geologic history. At the trailhead, a smiling Professor Blakey told the group that he loved Geology because he felt it was “the most artistic and uncertain of all the sciences”.

On this day, the Westerners were fortunate to share his experience and passion for the geology of Sedona.

The Westerners always welcome new members! If you are interested in joining the club, log onto our website www.sedonawesterners.org.