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GRAND CANYON, Ariz. (KDVR) – The Great Unconformity of the Grand Canyon has challenged geologists for over 150 years. Researchers, led by the University of Colorado Boulder, are finding missing events that may have caused the feature.

Rock in some areas of the canyon is almost 2 billion years old. More than 1 billion years’ worth of rocks at the Great Unconformity have disappeared, according to Barra Peak, a CU Boulder graduate student andlead author of a new study.

“The Great Unconformity is one of the first well-documented geologic features in North America,” Peak said. “But until recently, we didn’t have a lot of constraints on when or how it occurred.”

The team’s research, in a paper published in the journal Geology, suggests that a series of faulting events may have occurred during the breakup of an ancient supercontinent, causing rocks and sediment to wash away.

“It’s not a single block with the same temperature history,” Peak said.

Thermochronology, which tracks the history of heat in stone, is used determine the age of rock formations

“There are just so many things there that aren’t present anywhere else,” Peak said. “It’s a really amazing natural lab.”