GEO 372 - Geological Field Studies
-Field Studies in The Grand Canyon Region (Spring 2005)

View of eastern Grand Canyon from Desert View.  The Desert Watchtower was designed by Mary Colter
in 1930 for the Fred Harvey Co.  Most of these gorgeous photos were taken by Dr. David J. Hoffman.

-Topics For Student Reports

-Final Road Log

-Suggested Equipment For Grand Canyon Field Trip


John Hogan (left) and Dave Rogers (right) taught the Spring 2005 Geological Field Studies
course, which explored the Grand Canyon region.  This photo was taken along the Colorado River at
the mouth of Diamond Creek, at River Mile 225.


Pictures From The Field Trip:
(Click Thumbnails For Larger Images)

John Hogan and Oleg Kovin looking at andesitic tuff breccia exposed in right abutment of Hoover Dam

Empty Nevada Outlet Works, or valve house.  The six 84-inch needle valves were removed from both outlet works in the early 1960s and used on other projects

Geo 372 students and instructors posing by transformers on the Arizona Powerhouse

Looking at downstream face of Hoover Dam, built between 1931-35.  It is 726 feet high.

Looking at Nevada Outlet Works, where rockbolts were used for the first time in a non-mining application in 1954 to secure rock slabs bounded by sheet joints.

Dr. Rogers standing next to a seep in the right abutment, leaving calcareous effervesence salts. Excessive seepage necessitated re-grouting of the entire foundation between 1938-49.

Students and instructors gathering to hear a mini-lecture on landslide dams by Dr. Rogers in upper Peach Springs Canyon

Profile of paleolandslide dam in Upper Peach Springs Canyon.  This feature developed sometime during the Tertiary Epoch

Diamictite sequence exposed in the paleolandslide dam testifies to a catastrophic outbreak flood down Peach Springs Canyon

Incipient Toreva block landslide along western wall of Peach Springs Canyon

Telephoto view of the detachment headscarp, which has dropped about 200 feet, leaving an isolated pinnacle

Peach Springs Canyon is structurally controlled by the Hurricane fault.  Strata are down-thrown on the west side

The Hurricane fault has dropped the western side of Peach Springs Canyon by as much as 3000 feet, making for different geology on either side of the valley

Back rotated Toreva blocks are a common sight in Peach Springs Canyon.  As elsewhere in the region, these landslides floor in the fissile Bright Angel Shale

Diamond Peak is a distinctive feature that is bounded by the Hurricane and Three Spring faults.  It was named by LT Joseph Ives in 1858 when he traveled this same path to the Colorado River.

Professors John Hogan (left) and Dave Rogers on the banks of the Colorado River at Diamond Creek on Easter Sunday 2005.

Diabase dike in the preCambrian granite basement adjacent to Diamond Creek rapids

Examining slickensides on an exposed fault in the preCambrian granite, about 1.5 miles north of Diamond Creek

Cross bedding in Cambrian age Tapeats Sandstone, the basal member of the Paleozoic sequence in the Grand Canyon region

Pegmatite dikes intruding preCambrian granitic basement along eastern side of lower Peach Springs Canyon

The west side of middle Peach Springs Canyon is comprised of the classic Paleozoic sequence seen across the Grand Canyon.  Here the lower slopes are mantled by bedrock landslides.

Students feeling texture of lineations along shear surfaces developed in the diamictite in upper Peach Springs Canyon.

Exploring one of the larger rooms in Grand Canyon Caverns, off Old Highway 66, about 12 miles east of Peach Springs.

Petroglyphs exposed on the Puerco Pueblo at Petrified Forest National Park

Petrified wood exposed along the Blue Mesa Loop Trail at Petrified Forest

Agate Bridge is an intact petrified tree trunk lying across a small ravine at Petrified Forest. Oleg Kovin provides sense of scale.

Petrified tree trunk exposed along the Crystal Forest Loop Trail at Petrified Forest

San Francisco Peaks stratovolcano complex, as seen from the Grand falls of the Little Colorado River.  This peak was about 16,000 feet high before it blew its summit off about 400 ka

Merriam Crater is one of about 600 volcanic cones/vents in the San Francisco Volcanic Field.  Lava erupting from this source flowed 7 miles to a 200 feet deep gorge containing the Little Colorado River, blocking it.

The latest work estimates that the Little Colorado River was blocked by lava flows between 20 and 40 ka.  The river flows around the distal rim of the flows and spills over the rim of its former canyon

Looking upstream at the Grand Falls of the Little ColoradoRiver spilling 200 feet back into its incised gorge

Dr. Rogers standing next to columnar joints in the pour-over flows that filled the Canyon of the Little Colorado River, exposed opposite the foot of the falls

Jeff Foster studied the Grand Falls for his research topic, providing everyone with their own set of handouts

Looking upstream at the falls from the narrows, where the USGS has a gaging station

Jeff Foster gives us an oral presentation on the evolution of the Grand Falls over a small rise so we could hear him

The lava filled up the 200 feet deep gorge, then flowed 15 miles downstream, due to its low silica content.  The River has only removed a fraction of the blockage.

View of the Grand Falls flowing full width on March 29, 2005, looking downstream at the Narrows

The rough Aa surface of the Bonito Lava Flow at Sunset Crater National Monument.

Devon Rumbaugh gives us some background on the Humphreys Peak stratovolcano from the summit of Lenox Crater.

Amy Boulch tells us about the eruption of Sunset Crater in 1064-65 AD, spewing 3 cubic kilometers of material over an area of 2100 square kilometers

We enjoyed learning about fumaroles and spatter cones on the Lava Flow Trail beneath Sunset Crater.

Our intrepid band of hikers poses on the South Rim before heading down the Bright Angel Trail to see the Canyon up close and personal.

Dr. Rogers waves good-bye at the Bright Angel trail head.  The upper 500 feet of the trail was covered with snow and ice.

Telephoto view of our group heading down the Bright Angel Trail.

Overview of the upper Bright Angel Trail, which is structurally controlled by the Bright Angel fault.

The upper part of the trail was icey and slippery and more than a few people were slipping, sliding and falling down.

Short tunnel hacked out of the Kaibab Limestone along the Bright Angel Trail.

Overview of Three Mile House on the trail, perched atop the Redwall Limestone.

Jeff Foster and Stacey Greer at Three Mile House on the Bright Angel Trail, 2000 feet beneath the trail head

California Condor who joined our group for picnic lunch at Plateau Point (elevation 3860 ft).

Condors were introduced into the Grand Canyon about three years ago.  They look like something out of Jurassic Park.

Telephoto view of Granite Rapids, the only rapid that can be easily seen from the Rim.

Looking down the Bright Angel fault trace across the Canyon, from South Rim to North Rim.

Looking down at the trail to Plateau Point from Mather Point, up on the South Rim.  Our lunch spot was 3000 vertical feet below.

The class assembles for a mini lecture at Mather Point.

A nice view of Horseshoe Mesa from Grandview Point on the South Rim.  Dave Hoffman told tales of past backpacking trips...

Telephoto view of a portion of Hance Rapid, at the mouth of Red Canyon.  Hance is one of the most difficult rapids in the Canyon.

Telephoto view of Unkar Delta and Unkar Rapids in the preCambrian Dox Sandstone, taken from Lipan Point.

Looking towards the Carbon Butte Landslide that Tom Jerris lectured us on.  Tanner Creek in foreground, where Dave Hoffman crossed the river in a raft he packed down the trail.

View of eastern Grand Canyon from Desert View.  Desert Watchtower was designed by Mary Colter
in 1930 for the Fred Harvey Co.

We stop to peer into the incised gorge of the Little Colorado River a few miles inside the Navajo Reservation.  At this spot the chasm is 1,600 feet deep.

Hiking along the rim of Meteor Crater looking at samples of shocked quartz

Sean O'Donnell lecturing the class on the historical significance of Meteor Crater, where the salient features of impact structures were unraveled by Gene Shoemaker.

Questions or comments on this page?
E-mail Dr. J David Rogers at