An ancient ocean bottom that may wrap around the core of the planet has
been revealed by scientists after creating the highest resolution depiction
of the underlying geology of the Southern Hemisphere of the planet.
Around 2,900 kilometers (1,800 miles) under the surface, where the molten,
metallic outer core meets the rocky mantle above it, lies this thin but
thick layer. The core-mantle barrier is at this point. (CMB).
It is essential to fully comprehend what lies beneath our feet in order to
investigate anything from volcanic eruptions to changes in the Earth's
magnetic field, which shields us from solar radiation from space.
According
to geologist Samantha Hansen of the University of Alabama, "Seismic
investigations, like ours, provide the highest resolution imaging of the
interior structure of our planet, and we are finding that this structure is
vastly more complicated than previously thought."
Over the course of three years, Hansen and her colleagues mapped seismic
waves from earthquakes using 15 monitoring stations buried in Antarctica's
ice. The nature of the material inside the Earth is revealed by the way
those waves travel and bounce. These regions are referred to as ultralow
velocity zones because the sound waves move more slowly there.
(ULVZs).
According
to geophysicist Edward Garnero of Arizona State University, "[thousands] of
seismic recordings from Antarctica were analyzed, and our high-definition
imaging technology discovered small anomalous zones of material at the CMB
wherever we explored.
The material might be somewhere between a few kilometers and [tens] of
kilometers thick. This indicates that there are mountains on the core, some
of which are up to five times as tall as Mount Everest.
These ULVZs, according to the researchers, are most likely oceanic crust
that has been buried for millions of years.
Convection currents might have moved the old ocean bottom to its present
location, even though the buried crust isn't close to known subduction zones
on the surface, where changing tectonic plates force the rock down into
Earth's interior.
The researchers aren't excluding alternative possibilities since inferring
rock kinds and movement from seismic wave movement may be challenging. The
ocean floor theory, however, now appears to be the most plausible
explanation for these ULVZs.
There is also the possibility that the entire core may be covered by this
old ocean crust, however it is difficult to be certain given its thinness.
Future seismic studies ought to be able to improve the overall image even
further.
Geologists can use the discovery to better understand how heat escapes from
the denser, hotter core and rises into the mantle. In the area where we
live, the variations in composition between these two layers are higher than
those between the air above the solid surface rock.
According
to Hansen, "Our research offers significant links between shallow and deep
Earth structure and the fundamental processes governing our planet."
The research has been published in
Science Advances.
