Scientists have identified deep "sunken worlds" within the Earth's mantle beneath the Pacific Ocean. These locations likely contain ancient tectonic plates that have been drawn beneath the surface.
This discovery was made by a team from the Geological Institute of the Swiss Federal Institute of Technology in Zurich, led by doctoral candidate Thomas Schouten, in collaboration with experts from the California Institute of Technology. Their research, published in Scientific Reports, revealed additional areas in the Earth's interior that appear to be remnants of submerged plates.
Using seismic records, researchers determine the positions of these submerged tectonic plates throughout the Earth's mantle. Typically, they are found in regions known as subduction zones, where two plates meet, and one descends beneath the other into the planet's interior.
Notably, during their study, scientists observed an unusual phenomenon: the submerged tectonic plates are not located where they are expected. Instead, they are situated beneath vast oceans or within continents.
One such anomaly was discovered beneath the western part of the Pacific Ocean. Researchers noted that according to current plate tectonic chronologies, there are no reasons for ancient fragments of plates to be found in that location.
Schouten remarked, "Clearly, such zones in the Earth's mantle are more widespread than previously thought." No geological data indicate historical subduction nearby, suggesting that these anomalies may not be pieces of plates at all, or at least not in the way scientists initially envisioned.
Questions have arisen regarding the origin and nature of these structures. One hypothesis is that they are ancient silicon-rich pockets left over from the early mantle. They could also be iron-rich accumulations that have drifted for billions of years.
This uncertainty implies a more diverse range of mantle compositions than previously believed, prompting scientists to continue their investigations to uncover answers to these new questions.