A team of geologists led by the University of Colorado Boulder is digging into what may be Earth’s most famous case of geologic amnesia.
Researchers have spotted that phenomenon, called the “Great Unconformity,” at locations around North America, including in the Grand Canyon and at the base of Pikes Peak in Colorado. There lie sites of missing time, where relatively young rocks dating back about 550 million years sit right on top of much more ancient stone—in some cases more than 3 billion years old.
In other words, a huge chunk of geologic history has vanished from in between.
“Researchers have long seen this as a fundamental boundary in geologic history,” said Rebecca Flowers, an associate professor in the Department of Geological Sciences.
Rebecca Flowers stands near exposed rock on Pikes PeakA hiker walks past one site of the Great Unconformity near the town of Manitou Springs, Colorado.
For a study published today in the Proceedings of the National Academy of Sciences, she and her colleagues drew on a technique known as “thermochronology” to take a fresh look at that fundamental boundary.
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