Wooster Geologist in Arizona

ARIZONA – This Wooster Geologist has exchanged Ohio’s cool fall weather for blue skies and sunshine in Arizona. I’m here for a conference on Volcanism in the American Southwest, but I thought I’d come out early to explore some of Arizona’s geological wonders. My first stop was near the airport at Papago Park.

Papago Park hosts the Phoenix Zoo, the Desert Botanical Garden, and several striking erosional landforms. The panoramic image below, from Pewe et al. (1986), shows the famous Hole in the Rock, Barnes Butte, and Contact Hill.

According to Pewe et al. (1986), Papago Park is a pediment, or a gently sloping erosional surface that typically consists of bedrock with a thin sedimentary cover.

Barnes Butte and Hole in the Rock are remnants of mid-Tertiary alluvial fan deposits that unconformably overlie Precambrian granite (Pewe et al., 1986).

They consist of arkosic breccias with large clasts of granite and quartz in a red, sandy matrix (Pewe et al, 1986).

My second stop was on the way to Flagstaff at Montezuma Castle National Monument.

Although the name suggests this archaeological site was built by the Aztecs, this pueblo ruin was actually built by the Sinagua people in the early 1100s.

This impressive 5-story building was constructed in a recess of the limestone cliffs overlooking Beaver Creek.

On a day like today, with fantastic weather and a scenic view, I can understand why the Sinagua people decided to stay for a while. I lingered as long as I could, but I had to make it to Flagstaff today. I’ll be taking day trips out of Flagstaff until the conference starts, so stay tuned for more stories about Arizona’s geological playground.

References:
Pewe, T.L., C.S. Wellendorf, and J.T. Bales, (1986) Geologic cross sections of Papago Park pediment, Tempe quadrangle, Maricopa County, Arizona, AZ Bureau of Geology and Mineral Technology, Geological Investigation Series Map GI-2-C.