Reading this, the lower side of the North American continent drills a hole in the Earth’s melting mantle. And, according to researchers at the University of Texas at Austin, this may be the first time anyone has analyzed this geological phenomenon in real time, known as “craton thinning.” The team recently published their findings in the journal Natural Earth Science.
Cratons are huge ancient rock formations that form part of the planet’s continent. Although they often maintain stability for billions of years, geological areas change from time to time in a way that the entire rock formation can disappear during a process known as kratonic thinning or kratonic drip. Millions of years ago, one of the recorded examples occurred at the deepest roots of the craton in northern China. However, until recently, scientists had no opportunity to study the process when it happened. But it probably won’t be long.
During the development of a new full-wave seismic fault model in North America by UT Austin Geoscientist Junlin Hua and colleagues, we noticed strange behavior at the boundaries of the Earth’s deep mantle and its thin lithosphere.
“We’ve made the observation that there could be something under the craton,” says Hua, Hua, who is now a professor at the University of Science and Technology in China. said in a statement. “We’re lucky enough to have a new idea about this thinner drive.”
Their tomographic modelling suggests that the offshore tectonic plate, known as the Faralon plate, located beneath most of the Pacific Ocean, is responsible. The Faralon Plate, first imagined in the 1990s by research co-author Stephen Grand, spent the last 200 million years sinking under North America. It is about 370 miles separated from the craton question, but the Faralon plate appears to redirect the flow of mantle material into a path that melts from the bottom of the craton. The resulting activity potentially releases the volatile compound T, weakening the larger craton base.
“It’s a little thinner over a very wide area,” Hua says.
To test this theory, Hua and colleagues ran a computer model with or without the inclusion of a Faralon plate. When on the model, the craton drips.
“You look at the model and say, ‘Is that true? Are we over-interpreting data, or can we tell you something new about the Earth?” said Professor Solten Becker, a co-author of the study and professor of planetary science. “But it appears that these chunks come and go in many places. [showing us] Authentic. ”
Becker emphasized the importance of such discoveries by explaining how planetary scientists can help them to better understand the history of Earth’s evolution.
“It helps us understand how we make continents, how we break them, and how we recycle them. [into the Earth,]” he said.
The drip appears to focus primarily on the lower part of the US Midwest, but that doesn’t mean residents of places like Topeka and Cleveland don’t need to worry. Processes such as the drip of cratenics affect structural activity for millions of years. Not only that, but similar events generally halt when the remnants of the Faralon Plate sink deep into the mantle and stop affecting North American cratons.
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