ECSTASY SPELLED IN NEEDLES AND ARCHES
By Marc Mayes, ScB '09
An epic extravaganza of exploration, the 2009 Undergraduate spring break field trip, brought nearly twenty students and faculty to sites around the Colorado Plateau in western Colorado and eastern Utah, including the Colorado National Monument, and Canyonlands and Arches National Parks. The nine-day trip was organized by a team of seniors (Alice Alpert ’09, Jena Johnson ’09, Shane Schoepfer ’09, Marc Mayes ’09) and accompanied by Assistant Professor Jessica Whiteside and postdoc Elisabeth Nadin. (Photo: Intrepid 2009 Spring Breakers pose under Delicate Arch, Arches National Park, UT.) Beyond simply admiring the region’s beautiful exposures of largely sedimentary rocks, we set out as detectives to study the rocks’ structural and mineralogical features, as well as fossils, all imprints of multifarious geologic processes and biological history. From seeing dinosaur fossil-bearing rocks up close to appreciating vistas of gorgeous arches, canyons and stratigraphy from afar, the trip brought us all closer to the science that fascinates us. Of no less import, the long hikes, cold nights and car rides also enabled us to get to know and appreciate our peers away from the stress and strain of the academic environment.
The trip was an adventure from the start. Once we arrived in Grand Junction, CO, we learned that the four Dodge Caravans reserved for our trip had been commandeered by another group that had extended its reservation. In their place, Hertz Rental Cars provided us a fleet of three Subaru Outback wagons, two Subaru Impreza hatchbacks, and a Mitsubishi Galant sedan, quite possibly the largest vehicle convoy in the history of Geo Department spring break field trips. As tough as it was to keep the convoy together on the roads as we shopped for supplies and drove on winding roads to the Colorado National Monment, the unique vehicle arrangement quickly fostered camaraderie among us. That night we pitched our tents on a cliff-side campground on the Monument, a thousand-foot drop only yards from our camp, and a panoramic, cross-section view of the local stratigraphy stretched before us in the monocline forming the east side of the Monument.
On our first full day, Dr. Andres Aslan and a faculty member at Mesa State University in Grand Junction, drove up to meet us and helped orient us to the rocks. The brick-red, fine-grained Wingate sandstone formed many of the sheer cliffs in the region; the coarser-grained Entrada sandstone formed many of the ledges we saw and the structures we would see in Arches National Park. Driving the Rim Trail around the National Monument, we observed how sandstone grain size variations led to the patterns of erosion that produced landmarks like Independence Monument, the Kissing Couple and the Coke Ovens. We also visited Dinosaur Hill in McInnis Canyon, where paleontologist Elmer Riggs first discovered the Brontosaurus in 1901 in an outcrop of the Morrison formation. During the afternoon we drove through Unaweep Canyon (photo above: Detective work at Unaweep Canyon, CO.); led by Andres and Shane Schoepfer ’09, we examined gravels to appreciate the latest research on the history of river incision through the canyon.
Next, we spent two days in Canyonlands National Park. Canyonlands offered us the chance to hike through immense canyons of some of the oldest sedimentary rocks in the region—the alternating red and white Cedar Mesa sandstones of the Cutler Group formation. Some of us hiked over twenty-six miles over the course of two days through the Needles district on the Peekaboo Canyon trail, the Elephant Trail and the Joint Trail (photo: on the Peekaboo Trail, Canyonlands National Park, UT. Spring breakers hike and scramble along the immense cliffs on the Peekaboo Canyon trail. On this day, many hiked over thirteen miles, examining features of the red and white Cedar Mesa sandstone formation and petroglyphs left by the Anasazi Indians). Surrounding us were exquisite examples of different rock competencies: the white Cedar Mesa member, made of material from coastal sands and beach deposits, capped the red member, made of coarser erosion products from terrestrial sandstones. Cross-bedding abounded. Blasted with winds while traversing the corners of rounded rock ledges high above the canyons, we felt the power of the Aeolian erosion first-hand. Later, we felt like extras in a Geology-oriented version of “Honey, I Shrunk the Kids,” as we hiked through parallel joint sets in the massive sandstones, thought to have been caused by stresses induced by the underlying Paradox Salt formation (photo, right). Canyonlands also offered us a first glimpse at cryptobiotic soils, mats of microbial communities on eroded sands that that planetary geologists think might exist on Mars or other dry planets, and petroglyphs left by the Anasazi Indians, who inhabited Canyonlands during a wetter climatic interval nearly a thousand years ago.
On our fifth day, while traveling from Canyonlands to Arches National Parks, we visited Upheaval Dome and the Island in the Sky (photo: Andy Nager and Tyler Lucero awestruck at Island in the Sky, Canyonlands National Park, UT. The picture is worth “1000!” words!). The formation of Upheaval Dome, a massive crater on the northern edge of Canyonlands Park, has been controversial for many decades. Some researchers believe the structure is the result of the region’s sedimentary strata sliding on underlying salt deposits via a process dubbed “salt tectonics”; others believe the crater has an “impact” origin, the result of a meteorite slamming the Earth’s surface. We inspected the site ourselves, and many of us believe that the discovery of shocked quartz and other mineralogical clues favor the meteorite hypothesis for the crater’s origin. At Island in the Sky, formed by millions of years of tectonic uplift, we took in some of the most beautiful vistas of the trip. From pastel-colored sandstone ledges dropping over two thousand feet, we saw the confluence of the Green and Colorado Rivers.
At Arches National Park, we explored a combination of tectonic and weathering-produced features. The park’s entrance sits in the Moab Fault along US-191; views from the park road allowed us to see textbook-quality examples of extensional faulting. Over the course of the day we took a series of short hikes to some of the most famous arches in the Entrada sandstone, including the breathtaking Delicate Arch (photo: Inspired by arches. Arches National Park, UT. Kelsey Peterson, Emily Tursack, Mana Tang and Jesse Bateman form an arch almost as beautiful as the hundreds blasted into form by aeoloian weathering at Arches National Park). Observing so many examples of arches helped us understand how the unique structures are formed. Eons of Aeolian erosion sand blasted the jointed rock into “fins and the continuous blasting of these rock fins at their weak points—often along shale-rich layers—formed small holes. Once formed, the holes were hollowed out, forming larger and larger natural arches. Possibly the greatest number of photographs per hour during the trip were taken around the photogenic arches.
During the final days of the trip, we traveled back to Colorado National Monument, staying at the same campground as our first night. We used the Monument as the jumping-off point for a day trip to the Black Canyon of the Gunnison, south and east of Grand Junction. Incorporated in the late 1990s and one of the newest National Parks, the Black Canyon is a V-shaped canyon with nearly 2000-foot sheer vertical relief from the cliffsides down to the Gunnison River. The canyon formed as a result of tectonic uplift, which accelerated the Gunnison River’s downcutting. The “Black” Canyon offered us the chance to see the oldest rock in the region: the Vishnu Schist, metamorphosed Proterozoic rock over a billion years old (photo: Black Canyon of the Gunnison under snow, Black Canyon of the Gunnison National Park, CO. The immense Black Canyon in all its haunting splendor—two thousand vertical feet of the Vishnu Schist, over a billion years old, stretching down to the Gunnison River). However, on the day of our visit, heavy snows made the Black Canyon quite white—poor exposure allowed us only to see the dark rock and patchy exposures of pegmatitic veins. Yet, we found fun ways to make use of the snow even if it obscured the Black Canyon’s famous rocks.
Finally, on our last evening of the trip, we took advantage of Colorado’s dark, clear night skies to stargaze with the Western Colorado Astronomy Club. We peered through high-power telescopes with club members as they conducted a “Messier Marathon”—an all-night stargazing session in which they hoped to identify all 100+ nebulae and galaxies that 18th-century astronomer Charles Messier saw in his lifetime. Besides the stargazing, those of us who stayed into the wee hours of the morning enjoyed meaningful conversations with club members about development pressures and the politics of environmental management around Grand Junction.
Though we observed over a billion years of Earth history in slightly more than a week, and camped in freezing temperatures for many nights, our collective curiosity about the history of the Colorado Plateau was still burning on the journey home. Window seats on the return plane-ride to Boston were more popular than the hot chocolate mix packets on the coldest nights of our trip—we all wanted to get one more map view of the beautiful Uncompaghre Plateau to the west. Then, as a group, we broke one final record: we had a time nearly -6 hr. between the end of the 2009 spring break trip and the start of discussions for Spring Break 2010. As soon as the rocks disappeared below the clouds, whispers about next year’s plans were tickling through the hush of the airplane cabin.
Each year, the costs of the Geology Spring Break trip are supported by a combination of student fundraising efforts, contributions from external organizations, and the Department of Geological Sciences. We would like to thank Professor Peter Schultz and The Rhode Island Space Grant and the Exxon Mobil Corporation for their generous contributions to our trip, as well as the Department of Geological Sciences. Many thanks to department administrative staff (Nancy Fjeldheim, Gloria Correra, Carolyn Sherman and Ruth Crane) for logistical support, to Bill Collins for help with organizing field equipment, and to Jan Tullis for insights on planning our itinerary. We also thank Dr. Andres Aslan and members of the Western Colorado Astronomy Club for being so generous with their time on the ground in Colorado!
Photo: Looking back: We deeply appreciate all those who helped us make the 2009 Spring Break trip possible—thanks!