(Newser)
– The Grand Canyon may be a geological marvel, but it is also a geological puzzle, which may have finally been broken. The puzzle is known as the Great Nonconformity, a statement told Phys.org. In some parts of the canyon, the 520 million-year-old rock layers lie directly on top of layers for about a billion more years. The cut, visible to the naked eye, was first noted by geologist and explorer John Wesley Powell in the 1860s. Since then, scientists have tried to answer a basic question: Where did a billion go? years of rocks?
Now, a University of Colorado study published in the journal Geology suggests an answer. We can blame Rodinia, an ancient supercontinent that, according to investigators, wreaked havoc on the landscape when it broke and washed away those “missing” rocks in the ocean. Forbes. “The Great Nonconformity is one of the first well-documented geological features in North America,” says lead author Barra Peak. Above the layers of rocks that have joined vertically to the bottom of the canyon, “you have these beautiful horizontal layers that form the mounds and peaks that you associate with the Grand Canyon.”
To find out what this was like, the Peak team used a method called “thermochronology,” which detects old heat signatures in rock formations caused by enormous pressure. They concluded that when Rodinia broke, “it may have broken in the eastern and western halves of the Grand Canyon in different ways and at slightly different times, producing great dissatisfaction in the process,” according to the statement. The great dissatisfaction is not exclusive to the Grand Canyon, but it makes the phenomenon easy to see. The Peak team is now looking at other Great Nonconformity sites in North America to see if their findings apply to them as well. (Read more Grand Canyon stories.)