A new study offers a new perspective of Earth’s mantle, highlighting quite the discovery.
Apparently, there are some “peanut chuncks” inside Earth’s middle layer right beneath East Asia. Researchers explained the whole process, and things are more complicated than previously believed.
Here is what you need to know.
How the Oceanic Crust Get There?
The new study focused on a region under China, right where the North China crust lays atop a part of oceanic Pacific crust underneath the mantle. The area is stagnant, and it doesn’t sink past the transition area.
Study insights and findings
Jikun Feng, the lead author of the study, and his team used an existing array of over 200 seismometers to identify ambient seismic noise or small, daily vibrations not tied to specific earthquakes.
“Earth is energetic, manifested by the tectonic movement of the lithosphere and underlying convenction in the deep mantle,” explains Feng.
Furthermore, the team stacked the seismometer readings to figure out how seismic waves acted in the mantle at the transition area, right where the upper and lower mantle meet. The findings are genuinely intriguing.
A sharp discontinuity, or variation in the seismic waves’ velocity, has been found within Earth’s mantle at 660 kilometres (410 miles). Based on those waves, the team determined that some of the oceanic plates had “bunched up.” What does it mean?
Researchers explained that as the oceanic plate faces denser rock at that depth, it halts its sinking into the mantle. Then, it flows laterally within the transitional mantle.
Finally, the stuck plate divides chemically into various mineral structures, creating a “chunky” area of the mantle with a compact construction.
“Our findings provide direct evidence of segregated oceanic crust trapped within the mantle transition zone,” stated Feng.
What’s more intriguingly is that the “chunky” region differs slightly from the rest of the mantle material, which is a rock, part basalt, three parts peridotite (pyrolite).