the Yale University I mentioned in the research that With the Southwest Research Institute (SwRI) Together, A With people The magazine showed, based on model calculations, how the group of gold and other related metals came relatively close to the surface of our planet.
The story began with dramatic collisions that occurred in our planet’s youth, then continued into the semi-molten region of the Earth’s mantle, and finally ended surprisingly close to where precious metals rested on Earth’s surface. Gold, platinum, and a few other related metals are among the elements that are highly heliophilic, a term meaning they are attracted to iron, and these metals typically collect in the cores of celestial bodies. Based on this property alone, gold and its relatives should have ended up almost exclusively in the Earth’s iron interior, but due to impacts, that did not happen.
Impact and its consequences. Minerals marked with yellow dots first sink down into the mantle while still molten, then quickly solidify under increasing pressure. Later, mantle convection currents mix these minerals.
Source: Sweiri
These precious metals arrived here when the proto-Earth billions of years ago collided with smaller celestial bodies (which can be as large as our Moon), and planetary spores. The materials left here during the collisions slowly mixed with the original materials of our planet – but it is the method of mixing that gave us the gold mines we have today.
Screenshots of mantle mixing simulation. Lighter colors (yellowish, green) indicate a higher mineral content.
Source: Yale/Korinaga
The researchers’ theory is based on a thin transition zone in the Earth’s mantle, where the shallow part of the mantle melts, while the deeper part remains solid. The researchers found that this region has special dynamic properties, as a result of which metals entering the mantle are trapped and do not reach the core. The mantle convection currents are then mixed and brought partially closer to the surface. Without this process, the gold, platinum, osmium, iridium and other iron-loving elements found on our planet would have existed at the Earth’s core or in its immediate vicinity long ago. On the other hand, by remaining in the mantle, they could get closer to us, for example through volcanic activity.
According to the theory, mixing is still happening, and signs of this are the deep regions in the Earth’s mantle, which today we can clearly separate based on the speed of seismic waves. According to the researchers, so-called large-scale, low-shear wave velocity regions (LLSPV – in red in the video above) are created as a result of large impacts and collisions, and this is basically an argument in favor of the theory.
Specialists have found that what is most interesting is that these dynamic processes occurring in the transition zone of the Earth’s mantle are in themselves very fast, and yet their effects determine the evolution and geochemical composition of our planet for billions of years.
