Field trip: Northern Arizona
This outcrop of an ancient river channel was the first stop for SNC Geology after leaving the Phoenix airport. We pulled off the road in Black Canyon City and took notes.
Students sit on the side of Montezuma Well taking notes. Montezuma Well is a sinkhole that formed when rock collapsed into a cavern beneath the surface. The water has a constant temperature of 76 degrees Fahrenheit and contains 5 species that are found nowhere else in the world.
The Grand Canyon
The Grand Canyon is made up of a sequence of rock layers. The rocks at the bottom of the canyon are around two billion years old. The rocks in the canyon represent land masses colliding and drifting apart, mountains forming and eroding away, sea level rising and falling, and relentless forces of moving water. The Grand Canyon was carved during the uplifting of the Colorado Plateau, starting about 6 million years ago. While we were at the Grand Canyon, we hiked roughly 1,000 vertical feet down (only 1/5 of the mile-deep canyon!), studying the stratigraphy along the way.
These are brachiopod fossils we found in the walls of the Grand Canyon. Brachiopods were filter feeders that lived in warm, shallow oceans.This helps us determine the environment at the time they were alive, which was about 270million years ago!
A couple of students taking notes in their field books. A field book is an important tool to a geologist. It is key to record everything you osbserve in the field so as not to forget any details later.
Students take a break from hiking to learn how to use a Brunton compass. The seniors demonstrate how to use the compasses to measure the angle of a plane, useful for determining ancient wind directions in one of the formations along the side of the canyon.
Glen Canyon Dam
After we left the Grand Canyon, we made our way north to Page, Arizona to study the geology of the Glen Canyon Dam and Lake Powell, the large reservoir behind the dam. We took a tour inside the dam learning its history. We also learned about some of the environmental effects of the dam.
Near the Glen Canyon Dam is a spectacular set of sedimentary rocks from the Mesozoic Era. These sediments were deposited in the Western Interior Seaway, a large ocean that covered parts of the central United States during the Cretaceous.
Oak Creek Canyon
Oak Creek Canyon formed during the second phase of the uplift of the Colorado Plateau and follows the path of a large fault. The fault of the canyon had three different types of movement: right-lateral (during the Precambrian), reverse (70 million years ago), and normal (6 million years ago).
Students listen as one of the seniors gives a lecture on the Sedona redrocks and the vortexes. The Schnebly Hill Formation makes up the famous red rocks of Sedona and are only found here because the area was once an estuary, which is a partially enclosed area along the coast. Vortexes are an interesting bit of pseudoscience in Sedona. They are said to be circular fields of energy that give people good health, but the students did not feel any different while at a vortex.
San Francisco Volcanic Field
SNC Geology hiked the Lava Flow Trail at Sunset Crater Volcano National Monument. HIking up the crater is no longer allowed due to erosion caused by early hikers. Sunset Crater is the youngest volcano in the San Francisco Volcanic Field and erupted only 950 years ago. In the background is San Francisco Mountain, which is a stratovolcano that formed 3 million years ago and is the tallest peak in Arizona.
A student stands in to show size of the spatter cone. A spatter cone forms when lava squirts out of the ground like a paste.
This view of the San Francisco Volcanic Field from the top of Mount Elden shows various volcanic features.
A student uses his hand lens to identify a rock on Mount Elden. We drove to the top of Mount Elden and practiced rock descriptions.
The Geology group sits outside the entrance to a lava tube getting ready to hike underground.
Inside the lava tube there is a constant temperature of 40 degrees and headlamps are needed to see. Lava tubes are formed when the top of a lava flow cools quicker and crusts over while lava below keeps flowing through an insulated tube. If all of the lava empties out, the tube is left behind. We were able to see lava stalactites, stalagmites, and ridges along the edge that represented different heights of the lava.
At the end of a long day students and the professors sat on the porch of Kendrick Cabin and watched the sunset next to a cinder cone.
SNC professors and students pose in front of Meteor Crater. Meteor Crater formed 50,000 years ago when an asteroid crashed into Arizona. The asteroid was about 150 ft across and weighed several hundred thousand tons. It struck Earth with a force greater than 20 million tons of TNT. The crater is 550 ft deep (60 story building) and 2.4 miles in circumference. To better imagine the size, picture twenty football games being played simultaneously on its floor, while more than 2 million spectators watch from its sloping sides.
This picture is a close-up of the inverted stratigraphy at Meteor Crater. When the meteorite hit Earth, the blast caused the rock layers to "flip" over and become inverted.
Petrified Forest National Park
Students and their guide, paleontologist Bill Parker, look for fossils in Petrified Forest National Park. Students were able to find pieces of bones, teeth, and plenty of petrified wood. Outside of the park, it is not as easy to find
fossils, so we were lucky.
The various colors of the sedimentary layers in the park can be seen.
This petrified wood formed 50 to 200 million years ago. Petrified wood forms when a tree falls into water and does not decompose right away, because it is covered in ash. Silica from the ash carried by groundwater then replaces the wood, preserving it. Different minerals in the water give petrified wood its color.
U.S. Geological Survey - Flagstaff
The USGS campus in Flagstaff was the last stop of the trip. Students got a tour of the facility and were able to talk to some of the people who work there. This picture is of George Billingsley and his maps of the Grand Canyon. He has spent most of his career mapping the Grand Canyon, which took him about 40 years!