Article on geology on the Williams Ranger District.
Check out photos at: http://www.flickr.com/photos/kaibabnationalforest/sets/72157626793688861/
Thanks,
Jackie
Jacqueline C. Banks
Public Affairs Officer
Kaibab National Forest
928-635-8314
cell 928-606-7490
jcbanks@xxxxxxxxx
Well-Known Author Takes Geology Tour of Kaibab National Forest
WILLIAMS, Ariz. – Well-known author and geologist Wayne Ranney recently participated in a geology tour of the Williams Ranger District of Kaibab National Forest. In fact, Ranney helped lead the earth science discovery tour by teaming with Kaibab National Forest geologist Jessica Lopez Pearce to explain geologic features at six locations across the district.
The goal of the field trip was to provide Forest Service resource specialists with a more in-depth understanding of the geology of the local area – information that might prove valuable when planning projects or doing field work.
The group started their tour at Summit Mountain, which is located about 8 miles southeast of Williams. From this high point, Ranney and Lopez Pearce explained the evolution of the Colorado Plateau, Basin and Range, and the San Francisco Volcanic Field. Ranney provided a description of the ancient Mogollon Highlands, which once stood like an Andean-type mountain range across the southwestern border of the Colorado Plateau approximately 100 million years ago. These long-gone mountains have been replaced by the Arizona Transition Zone and the Basin and Range Province, which are now visible in the area.
Kaibab National Forest resource specialists expressed particular interest in the presence of local faults, like the nearby Mesa Butte fault. Local faults like Mesa Butte are reminders that there is always the possibility of an earthquake on the Williams Ranger District.
Next, the group stopped along the southern boundary of the Williams district in Grindstone Wash. Participants observed the various sedimentary rock layers of the Coconino Plateau including the Toroweap Formation, Coconino Sandstone, Hermit Formation, and Schnebly Hill Formation. Ranney provided insight into the unique depositional environments of each rock layer and showed beautiful illustrations of paleogeographic reconstructions from a book he coauthored with Ron Blakey, titled Ancient Landscapes of the Colorado Plateau.
The next stop was a sandstone quarry near Ash Fork, at which tour participants discovered many fossilized reptile tracks within the Coconino Sandstone. Ranney described how the Coconino Sandstone was deposited in a 275-million-year-old desert environment containing a large sand dune sea, or erg. A short drive through the sandstone quarries provided participants an opportunity to see more three-dimensional examples of the ancient sand dunes.
“It was fascinating to discover that our beautiful pine forest was once a harsh desert complete with sand dunes,” said Roger Joos, a Kaibab National Forest wildlife biologist. “And, it was really awesome to understand the processes that created what are now our flagstone quarries. The coolest part for me was to learn exactly how the fossilized tracks that we often find in flagstone were formed and preserved.”
As the tour headed south on Forest Road 6, participants were able to see volcanic features in the San Francisco Volcanic Field including a dike, or vertical lava intrusion, and several lava flows. The trip concluded with a stop at Johnson Crater, a geological oddity, where Ranney and Lopez Pearce discussed the possible ways this collapse structure was formed.
“I had no idea that we had so many geological treasures out there,” said Mark Thibodeau, visitor information specialist on the Williams Ranger District. “Now that I am more educated, I can pass that information along to our visitors so that they can enjoy the district even more and have a better experience during their time here.”
To view photos of the Williams Ranger District geology field tour, please visit http://www.flickr.com/photos/kaibabnationalforest/sets/72157626793688861/. To learn more about Wayne Ranney, please visit his website at www.wayneranney.com. For geology information about the Kaibab National Forest, please contact Jessica Lopez Pearce at jlopezpearce@xxxxxxxxxx
Attachment:
1650-1_so_geology_field_tour_jcb_2011_0614.pdf
Description: Binary data
