Large structure discovered beneath the Pacific Ocean challenges geophysical theories about the Earth’s interior

Evidence found ancient seabed Sunk deep underground during the age of dinosaurs, it challenges current theories about the Earth’s internal structure.

Located in East Pacific Ridge (a tectonic plate boundary on the floor of the southeastern Pacific Ocean), this previously unexplored section of the seafloor sheds new light on the interior of our planet and how its surface has changed over millions of years. The results of the research team from the University of Maryland were published in the journal. Achievements of science.

Under the supervision of a postdoctoral fellow in geology. Jingchuan Wangthe team used innovative seismic imaging techniques to further explore Earth’s mantlelayer between the crust and core of our planet. They discovered an unusually thick region in the mantle transition zone, an area located between 410 and 660 kilometers below the Earth’s surface. The zone separates the upper and lower mantle, expanding or contracting depending on temperature. The team believes the newly discovered seafloor could also explain the anomalous structure Low Shear Pacific Province

(LLSVP), a huge region in the Earth’s lower mantle, as the LLSVP appears to be divided by a plate.

“This thickened area looks like a fossilized imprint of an ancient piece of seafloor that sank toward Earth about 250 million years ago,” Wang said. “This gives us a glimpse into Earth’s past that we’ve never seen before.”

Process subduction This occurs when one tectonic plate slides under another, recycling surface material back into the Earth’s mantle. This process often leaves visible traces of movement, including volcanoes, earthquakes and deep-sea trenches. While geologists typically study subduction by examining samples of rocks and sediments found on the Earth’s surface, Wang worked with geology professor Vedran Lekic and assistant professor Nicholas Schmerr on using seismic waves to probe the ocean floor. By studying how seismic waves travel through different layers of the Earth, scientists have been able to create detailed maps of structures hidden deep in the mantle.

“You can think of seismic imaging as something similar to a CT scan. “Essentially, this allowed us to get a cross-section of the interior of our planet,” Wang said. “Typically, oceanic slabs of material are completely absorbed by the Earth, leaving no noticeable traces on the surface. “But observing the ancient subduction plate from this vantage point has given us new insights into the relationship between Earth’s very deep structures and surface geology that were not previously apparent.”

What the team discovered surprised them: material was moving through the Earth’s interior much more slowly than previously thought. Wang says the unusual thickness of the region the team found suggests the presence of cooler material in this part of the mantle transition zone, indicating that some oceanic plates They get stuck halfway, falling through the mantle.

“We found that in this region, material sank about twice as fast as we expected, suggesting that the mantle transition zone may act as a barrier and slow the movement of material through the Earth,” he explained. “Our opening opens doors. new questions about how the Earth’s depths influence what we see on the surface over great distances and time.”

Future vacancies

In the future, the team plans to expand their research to other areas of the Pacific Ocean and beyond. Wang hopes to create the most complete map ancient subduction zones and upwelling (a geological process that occurs when subducted material is heated and rises again to the surface), and their influence on both the deep and surface structures of the Earth. Using seismic data obtained from this research, Wang and other scientists are improving their models of how tectonic plates have moved throughout Earth’s history.

“This is just the beginning,” Wang said. “We believe that many ancient structures remain to be discovered in the deep interior of the Earth. “Each of them has the potential to reveal many new insights about our planet’s complex past and even lead to a better understanding of planets beyond our own.”