Massive accident 4.5 billion years ago: Remnants of the celestial body Theia got stuck in the Earth’s mantle

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“Seismic studies of the Earth’s interior show two continent-sized regions where seismic waves propagate unusually slowly,” Qian Yuan of Arizona State University and colleagues write in the journal Nature. Therefore, areas deep within the Earth’s mantle differ in their composition from the material surrounding the Earth’s mantle and are two to three and a half percent denser. To date, there has been no generally accepted scientific explanation for these regions.

Using extensive computer simulations, Yuan and his colleagues found that such dense regions were a natural consequence of massive collisions during planet formation about 4.5 billion years ago, and that the two anomalies were located deep in the Earth’s mantle beneath the Pacific Ocean and Africa. It shows that it is under . It may be the remains of Theia. “Our impact simulations suggest that part of Theia’s mantle may migrate into the Earth’s lower mantle,” the researchers said.

Pieces up to 50 kilometers in size

Based on the Moon’s composition of Earth and Theia debris, Yuan and colleagues derived a density for these sinking pieces of Theia mantle that is two to three and a half percent higher than normal Earth mantle. It is in good agreement with the results obtained from seismic studies. As the team’s simulations show, these are fragments of the Theia mantle, up to fifty kilometers in size, that have sunk into the Earth’s interior and coalesced there to form larger structures above the Earth’s core.

Importantly, these larger concentrations have remained stable in the Earth’s mantle for four and a half billion years, until the present day, as computer models show. There is another piece of evidence that supports Yuan and his colleagues’ hypothesis: The Hawaiian Islands contain a type of volcanic basalt whose composition is surprisingly similar to rocks in lunar lava plains. This rock may have originated from the Theia material zone deep in Hawaii. (SDA)

Source : Blick