Posted by: paulgarner | July 18, 2010

Studying the Coconino Sandstone at Holbrook and Sedona

On Thursday night we stayed in Page, Arizona. On Friday morning we took the opportunity to sample the Navajo Sandstone again, near the Marble Canyon overlook along Highway 89. We also sampled the sand accumulating at the foot of the outcrop in the form of a large eolian dune. It’ll be interesting to see what, if any, differences there are between the two.

However, most of Friday was spent studying the Coconino Sandstone itself, the main focus of our project, around Holbrook in Arizona. We went to several sites that we’d visited previously in order to collect additional samples and take further measurements. We took several more strikes and dips in a section at Five Mile Wash. At another location, John Whitmore even swam across the very muddy Little Colorado River to sample a flat-bedded portion of the Coconino that we hadn’t been able to collect from previously. If John looks a little low in the water in the photo, remember that he’s swimming with a geological hammer in one hand and a chunk of rock in the other!

On Friday evening we moved on to Sedona, where we’re spending the weekend in the home of Guy and Cindy Forsythe of Crying Rocks Ministries. We’re very grateful for their hospitality during this part of our field work. In fact, Guy led us on today’s hike to a new Coconino site accessed via Boynton Canyon. We started off at 7.00 am, soon leaving the ‘official’ trail to hike right up through the Schnebly Hill Formation and into the overlying Coconino Sandstone. It was a long, steep and demanding hike in temperatures of around 102 degrees. On the way back down my heart raced a little when I began to slide down a steep face with a big drop at the bottom, but fortunately John was able to help me regain a foothold. We all feel pretty exhausted this evening. However, we found some extremely interesting things, which appear to have been overlooked in the mainstream literature, and which we think provide strong evidence for the rapid subaqueous deposition of the Coconino, instead of the conventional eolian explanation. We can’t wait to see the thin sections of the samples we collected today. The photo shows Ray Strom collecting a sample from a cross-bedded unit of the Coconino with John Whitmore taking notes on the outcrop (left click on the image for a larger version).

Advertisements

Categories

%d bloggers like this: