Mysterious structure in the Pacific Ocean may date back to the time of dinosaurs

A team of scientists studying the East Pacific Ridge, a major geological formation that forms a mid-ocean ridge, came across a strange landmass that may once have been an ancient seabed. This previously unstudied ocean floor provides new clues about the internal dynamics of our planet and the evolution of its surface over geological ages.

In a recent article published in the journal Science Advances, researchers explain how they used seismic data. Ancient oceanic plates hidden deep in Earth’s mantle, the middle layer between crust and core. This thick area was found approximately 410 to 660 kilometers below the surface.

The team now believes that this discovered piece of seafloor may shed light on the mysterious structure of the so-called Pacific Low Shear Velocity Region (LLSVP), a large region in the lower mantle. Known for inexplicably delaying the propagation of seismic waves that measure earthquakes.

A tectonic plate barrier in the Pacific Ocean

According to the study, the thickest transition zone area showed above-average seismic wave velocities based on new tomographic images. This suggests a change in mineral structure due to lower temperatures.

For writers, this situation It is the result of ancient oceanic subduction that occurred beneath the current Nazca Plate during the Mesozoic era (250 to 120 million years ago).. In this region the Nazca Plate is currently subducting (subducting) beneath the South American Plate.

However, on the western side there is a rapidly growing mid-ocean ridge and a hotspot (area of ​​intense volcanic activity) beneath the Easter Islands. In the central and eastern Pacific, the The team identified this mysterious structural gap.

The paper’s first author, geologist Jingchuan Wang from the University of Maryland in the US, explains: “We found that material in this region was sinking at half the rate we expected, indicating that the mantle transition zone can act as a barrier and slow the movement of material on Earth“.

How ancient seafloor produces ‘super plumes’ today

The team suggests that the ancient patch of seafloor (which sank into the Earth about 250 million years ago) may have functioned as a type of plate that was colder and denser than surrounding areas. Technically, it can be considered an ancient seabed fossil.

Submerged in a region of melting mantle, these dense remnants of what were once the Triassic seafloor are sinking deep into the hottest layers of the mantle. By passing through these high-temperature layers, the old material eventually It produces superplumes, large geological structures that can influence magma formation and reach the Earth’s surface.

The hot spot that forms Easter Island in Chile is believed to be directly above one of these clouds. This thermal anomaly point is characterized by intense volcanic activity. The system, consisting of a series of volcanic islands, developed as the Pacific Plate moved northwestward above the hotspot.

Implications of the research for other parts of the Pacific Ocean

With the seismic data collected in this research, the team is developing a new model to better understand the movement of tectonic plates throughout Earth history. The authors hope that in the future it will be possible to extend the essence of the current research to other parts of the Pacific Ocean and even beyond.

Wang’s hope is to create a broad map of ancient subduction and upwelling zones—places where sinking material was heated and returned to the Earth’s surface in its heated form. The idea is to investigate the effects of this material in both the deep and superficial layers of the planet.

Did you like the content? So stay up to date with more studies like this on TecMundo and take the opportunity to get to know the Cascadia subduction zone, where mega earthquakes and tsunamis occur. Until later!