Moon-forming cataclysm also could have triggered Earth’s plate tectonics

The Woodlands, Texas The remnants of the Moon-forming cataclysm could have kick-started plate tectonics on Earth.

The main explanation for the Moon’s origin proposes that a Mars-sized planet, called Theia, collided with the newborn Earth and ejected it. debris cloud in space which was later absorbed into a satellite (Sn: 3/2/18, New computer simulations suggest alleged remains of Theia lie deep inside the planet could also initiate the beginning of subductionA hallmark of modern plate tectonics, Caltech geoscientist Qian Yuan explained March 13 at the Lunar and Planetary Science Conference.

The story provides a coherent explanation for how Earth obtained both its moon and its moving tectonic plates, and it may aid in the search for other Earth-like worlds. But others caution that it is too early to say that this is exactly what happened.

Of all the worlds discovered so far, ours is the only one confirmed to exist. plate tectonics ,Sn: 1/13/21, For billions of yearsEarth’s creeping plates have spread, collided and slid beneath each other, birthing and split continentsuplift of mountain ranges and widening of oceans (Sn: 4/22/20, Sn: 1/11/17, But all this reshaping has also erased most of the clues to the planet’s early history, including how and when plate tectonics first began.

several hypothesis Stayed Proposed To explain the onset of subduction, a tectonic process in which a plate slide down the other ,Sn: 5/2/22; Sn: 6/5/19; Sn: 1/2/18, Yuan and his colleagues chose to focus on two continent-sized blobs of material in Earth’s lower mantle, known as large low shear velocity regions ,Sn: 5/12/16, These are areas through which seismic waves are known to travel unusually slowly. The researchers previously proposed that these regions may have formed from older, subducted plates., But in 2021, Yuan and his colleagues alternatively proposed that the mysterious mass may be a dense, sunken the remains of thea,

Building on that previous work, the researchers used computers to simulate how Theia’s impact, and its lingering remnant, would affect the flow of rock inside Earth.

They found that once these hot alien blobs sink into the lower part of the mantle, they can push large plumes of hot rock upward into Earth’s hard outer layer. As the upwelling continued to feed into the raised plumes, they would have ballooned and pushed the slab of Earth’s surface beneath them, triggering subduction about 200 million years after the Moon formed.

While simulations suggest that large low-shear velocity provinces may have had a hand in initiating the subduction, it is not yet clear whether these masses came from Theia. “The features … are a recent discovery,” says geophysicist Laurent Montesi of the University of Maryland in College Park. “They are very fascinating structures with very unknown origins.” As such, he says, it is too early to say that Theia triggered plate tectonics.

“It’s exciting. This material down there is something special,” Montesi says of the large low-shear velocity provinces. “But should it be supernatural in origin, I don’t think that’s made the case.”

However, if confirmed, the explanation could have implications that reach beyond our solar system. “If you have a big moon, you likely have a big impactor,” Yuan said. Scientists have not yet confirmed such a discovery. exomoon ,Sn: 4/30/19, But keeping an eye out, Yuan said, could help us uncover another world that is as tectonically active as our own.