This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: Unlike conventional glaciers, rock glaciers appear as piles of rock that obscure large masses of unaccounted-for ice. Rock glaciers are common in the Wasatch and Uinta ranges, even appearing on the Colorado Plateau in the La Sal Mountains near Moab.
Now, University of Utah geologists are bringing one of Utah's largest rock glaciers, located under the towering summit of Mount Timpanogos near Salt Lake City and Provo, into sharp focus. Two new studies document how Timpanogos Rock Glacier formed and how much ice it contains. By measuring minute differences in gravitational pull between rock and ice, the team created a novel technique to image the 3D ice body within a large rock glacier.
Timpanogos Rock Glacier stores enough frozen water to fill 600 Olympic swimming pools, or 1.5 million cubic meters (about 396 million gallons). That is also equivalent to the volume of the largest pyramid at Giza in Egypt, according to Bronson Cvijanovich, a former graduate student in the Department of Geology & Geophysics. "Timpanogos Rock Glacier is surprisingly ice-rich.
It is 83% ice and 17% loose rock," said Cvijanovich, the lead author of one of two studies overseen by geophysics professor Michael Thorne and glaciology professor Leif Anderson. "There's a lot of ice that's hidden in Utah's mountains," Anderson said. "When we are high in the mountains and walking across loose rocks or rubble, you don't realize there could be 120 feet (37 meters) of ice buried beneath your feet." Cvijanovich led field campaigns to Timpanogos Rock Glacier, hauling sensitive instruments, including a state-of-the-art gravimeter, to the ice buried above Emerald Lake in fall 2024.
Over the course of six forays, Cvijanovich took gravity readings at 232 locations, separated by 25 meters (about 80 feet), in a grid atop the rock glacier. The gravimeter measures density differences between rock and ice, enabling scientists to calculate the 3D shape of the buried ice body. "There is a large contrast in mass density between the rock that makes up Mount Timpanogos and the much lower-density ice that is in the rock glacier adjacent to it," Thorne said.
"When we measure the gravitational acceleration over the rock glacier, we see a larger decrease in that gravitational acceleration as we make measurements over areas with thicker ice." Once the gravity observations were collected, they still needed to be corrected for differences in gravity due to the position of the sun and moon, the location's terrain, latitude and elevation. After these corrections, the research broke new ground. The team developed a novel method for imaging the internal ice of the rock glacier in 3D using Bayesian statistics.
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