Geologists have figured out where hundreds of millions of years of the Grand Canyon rock record disappeared

Scientists have been able to unravel the intricate riddle of one of the Grand Canyon’s most famous geologic features: the mysterious missing time span in the canyon’s geochronological record that spans hundreds of millions of years.

The “great mismatch” in the age of the Grand Canyon rock has plagued geologists for 150 years. Now researchers seem to have found an explanation for the lack of such a large geochronological gap.

The red cliffs and cliffs of the Grand Canyon are not only one of the main attractions of the United States, but also a kind of textbook on the history of the Earth, which spans billions of years of its geological history. If you go down the rocky slopes of the canyon, you can “jump” almost 2 billion years into the past of the planet. But this textbook also contains missing pages: In some areas, rocks with a total age of about a billion years have disappeared without a trace from the Grand Canyon.

This mystery was once called the “Great Discrepancy” – it has puzzled geologists since its discovery 150 years ago to the present day. The authors of the new work believe that they have come close to solving this mystery. They showed that a series of small but strong faults may have shaken the region during the collapse of an ancient supercontinent called Rodinia. As a result of this event, the land around the canyon tore apart, and the stones with sedimentary rocks were washed into the ocean.

The team’s findings could help scientists fill in the missing pieces of what happened during this critical period for the Grand Canyon. In their work, geologists used a method called “thermochronology”, which allows you to track the history of heat propagation in rocks. Scientists have shown that when geological formations are buried deep underground, pressure from above can cause them to begin to heat up and change. This heat, therefore, leaves a trace in the chemistry of minerals in such formations.

Using this approach, the researchers analyzed rock samples collected from around the Grand Canyon. They found that the history of this feature may be more confusing than previously thought. In particular, the western half of the canyon and its eastern part may have been subject to various geological distortions throughout the time. Researchers have yet to unravel this tangle of facts until the end.

The article was published in the journal Geology.

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