We’ve had a rough idea of what the interior of our planet looks like for decades. However, it is not uncommon for geologists to discover new and unique aspects of what is covered by the surface we walk on. Now, something has been discovered that is intriguing the scientific community.
A hidden tectonic plate
A latest discovery announced by these scientists is that of a new tectonic plate. One that, unlike the known plates into which our planet's surface is divided, is hidden beneath another, larger plate, beneath the waters of the Pacific Ocean.
The most intriguing thing about this sign is its location, not because it is under another sign, but because it is far from the subduction zones known. To understand why, it might be helpful to remember what subduction zones are.
Diagram of the subduction zone existing under the Andes mountain range.
Subduction is a form of interaction between two tectonic plates. It occurs when the two plates push against each other. As a result of this pushing, one of the plates ends up sliding under the other. The upper plate moves along the surface, while the lower plate sinks into the Earth's mantle.
The area through which the sinking plate moves is called the subduction zone. It would not be unusual to find traces of a tectonic plate in these areas. However, the team behind the new study came across this debris in an area of the western Pacific, far from any of the known subduction zones.
Study of seismic waves
Studying what happens tens or hundreds of kilometers beneath our feet is a complex task. We cannot lift tectonic plates like a carpet. To the Humanity's deepest excavations can barely scratch the limits of the Earth's crust.
One of the most common tools for studying the planet's interior is based on seismic wave propagation. Waves travel differently depending on the characteristics of the material they pass through: their temperature, density and chemical composition are variables that affect the propagation of these waves.
The analysis uses a new high-resolution model to study these waves, which should allow us to better understand what is beneath the Earth's surface. In this case, the remains of a sunken tectonic plate were found far from the subduction zones, far from where it “should” be.
Details of the study were recently published in an article from Scientific Reports magazine.
Global distribution of seismic stations, receiver locations, and seismic wave velocity anomalies used to construct the FWI REVEAL model. Credit: TLA Schouten et al.
Discovery that is intriguing scientists
The discovery raises more questions than answers. According to the responsible team, the current knowledge about plate tectonics cannot explain how the material could have arrived at the location where it was found, in a place where recent geographic history has not seen subduction zones that could explain the presence of these remains.
It is not known for sure what type of materials are involved in this process, nor what geological dynamics led to the appearance of the remains in the remote location where they were found.
This is our dilemma. With the new high-resolution model, we can see these anomalies throughout the Earth's mantle. But we don't know exactly what they are or what material is creating the patterns we discovered.
Explained the team in a press release.
Source: pplware.sapo.pt
