The crust, mantle, outer core (Earth’s core), and inner core were formerly thought to be the four layers that made up the structure of the Earth. However, a fifth layer was later found to exist inside the inner core. Now that a distinct, thin-but-dense layer has been discovered, researchers can better understand the planet’s interior.
A layer between the core and the mantle, which University of Alabama researchers discovered, is probably a sunken ocean floor that had previously only been observed in isolated spots. The information showed that the core-mantle boundary (CMB) under the surface may be covered by the old structure.
According to research results published in the journal Science Advances, the layer was found beneath a wide area of the Southern Hemisphere that had not been sampled.
Seismic wave scattering studies have discovered globally dispersed small-scale heterogeneities in the lowermost mantle, even though less than 20% of the CMB has been examined for the presence of these ultralow velocity zones, according to the paper.
According to geologists, the rocky mantle of Earth joins the metallic outer core 2,000 miles beneath the planet’s surface. Greater variations in physical characteristics occur across this border than between the air above and the solid rock on the surface.
Dr. Samantha Hansen, the paper’s primary author, said in a statement: “Seismic investigations, like ours, provide the greatest resolution imaging of the internal structure of our planet, and we are finding that this structure is considerably more convoluted than formerly assumed.
The crew installed a seismic network during four trips to Antarctica, and over the course of three years, collected data from it. These networks, which are buried in Antarctica, analyse seismic waves from worldwide earthquakes to produce a picture of the Earth’s interior.
“Our high-definition imaging technology discovered small anomalous zones of material at the CMB everywhere we examined after analysing thousands of seismic recordings from Antarctica. The material can be anywhere between a few and tens of km thick. Dr. Edward Garnero of Arizona State University continued, “This means we are witnessing mountains on the core, in some areas up to five times taller than Mt. Everest.
With heights ranging from less than about three miles to more than 25 miles, the region can be thought of as mountains along the core-mantle boundary. Analysis could reveal how this region contributes to heat escaping from the planet’s core, which powers its magnetic field.