Massive structures resembling two underground continents rising from the Earth’s core, which have puzzled scientists for many years, may be ancient gold and platinum from a “second moon.”
According to Live Science, a new study links two gigantic “spots” on the Earth’s mantle map to an ancient space collision, where one or more objects as large as the Moon, rich in gold and platinum, crashed directly into Earth.
This also explains the presence of these precious metals on our planet, with only a small fraction having been mined by humans from the surface.
One or more Moon-sized objects slammed into primordial Earth, leaving traces as two mysterious “continents” beneath the mantle – (Illustration from Live Science).
“These impacts could create large areas with a density slightly thicker than the planet’s material” – co-author Simone Marchi from the Southwest Research Institute (SwRI – USA) stated.
Space objects as large as the Moon, along with some smaller ones, brought abundant amounts of gold, platinum, palladium, and many other precious elements to Earth.
With their dense composition, these heavy metals dragged the dense region formed by the impacts gradually down into the planet’s interior.
According to models by SwRI researchers, the dense region initially formed by the space objects resembled a magma ocean distinct from Earth’s magma. This ocean consisted of semi-solid, semi-molten rock.
The precious metals gradually permeated into the semi-molten region, spreading around. Due to mixing, being no longer pure, instead of sinking into the core, these metals, along with the material they mixed with, reside in the area where we find the mysterious “underground continents” today.
The publication in the scientific journal Proceedings of the National Academy of Sciences also describes a billions-year history of convection, during which metals were mixed in the mantle, with part being brought to the surface, trapped in the crust, which are the valuable deposits of gold, platinum, and palladium that humans mine today.
The research results provide an intriguing explanation for the “ultra-low velocity zones” – one beneath Africa and one beneath the Pacific Ocean – commonly referred to as “spots” or “underground continents”.
These areas were discovered when many studies found that seismic waves passing through these regions slowed down, indicating the presence of something unusual and denser in the mantle’s core.
Another supported hypothesis suggests that they are remnants of Theia, a hypothetical planet the size of Mars, which collided with primordial Earth 5.4 billion years ago, causing the material from both to mix, ultimately creating the Earth and Moon we know today.
