Imagine diving into the depths of the ocean and finding a ancient map of our planet, hidden under thousands of meters of water and rock. This is what a research group from the University of Maryland, in the United States, discovered.
This discovery, published in the journal Science Advanceschallenges theories about the internal structure of our planet and provides new clues about the processes that shaped the Earth’s surface.
Journey to the center of the Earth
To make this discovery, scientists used a technique similar to scanning, but applied to our planet.
They sent seismic waves through the Earth and analyzed how they reflected and distorted. They were thus able to create a sort of x-ray of the interior of our planet.
Thanks to this type of seismic imaging, which is similar to a scanner, the team was able to observe a mantle region beneath the Pacific Oceanmore precisely in the Eastern Pacific submarine ridgewhere she discovered a very thick area in the middle part of the Earthbetween the crust and the core.
This thick area was actually a ancient ocean floor that sank millions of years ago and who was trapped… 660 kilometers deep!
How did an ocean get trapped underground?
Around 250 million years ago, as dinosaurs began to populate the planet, a significant layer of ocean floor slowly sank into the mantlethe layer of rock located beneath the earth’s crust.
This process, called “subduction”, occurs when tectonic plates (giant fragments of the earth’s crust) slide under each other, dragging parts of the ocean floor with them. But what is surprising is that this ocean floor never completely disintegrated.
Jingchuan Wangprincipal investigator of this study, explains in a press release from the School of Computer, Mathematical and Natural Sciences at the University of Maryland that “ the rock appears to have been “trapped” in a region of the mantle called the transition zone, a place so cold and dense that it slowed its movement ».
According to the article, this transition zone that Wang speaks of is between 400 and 660 kilometers deep and appears to function as a natural barrierwhere materials move more slowly than expected.
A new geological enigma
This discovery helps us to better understand how matter moves inside the Earth and how mountains, volcanoes and oceans are formed.
It allows us also to better understand why earthquakes occurbecause many of them are linked to the movement of tectonic plates, like the one that sank and became trapped.
Jingchuan Wang, geologist and principal researcher.
The next steps will be to explore other areas of the Pacific looking for other “fossils” of this type, which would make it possible to complete the history of ancient plate tectonic movements.
“This is just the beginning,” Mr. Wang said, emphasizing that “we believe that many other ancient structures await discovery at the interior of the Earth.
Article references and sources:
– Jingchuan Wang., et all. Mesozoic intraoceanic subduction shaped the lower mantle beneath the East Pacific Rise.(2024). Science Advances.
– School of Computer Science, Mathematics and Natural Sciences at the University of Maryland. Ancient Sunken Seafloor Reveals Earth’s Deep Secrets. (2024) Published in the Faculty news section.
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