Why are gold and platinum concentrated in the Earth's mantle?

Precious metals such as gold and platinum can accumulate in the Earth's mantle due to being trapped by a region with special dynamic characteristics.

Simulation of an asteroid crashing into proto-Earth. Photo: Simone Marchi

Scientists at Yale University and Southwest Research Institute (SRI) discovered some new information about the distribution of gold, platinum and many other precious metals. In research published October 9 in the journal Proceedings of the National Academy of Sciences, Jun Korenaga, professor of Earth and planetary sciences at Yale University, and Simone Marchi at SRI in Boulder, Colorado, propose an explanation. the process by which gold concentrates in shallow pockets within the Earth's mantle instead of sinking deep into the core. This hypothesis also provides more insight into the formation of planets in the universe, according to Phys.org .

Researchers know that violent collisions between large objects in space and movement in partially melted areas of the Earth's mantle cause precious metals to accumulate closer to the planet's surface than expected. Recent research from scientists around the world shows that metals like gold and platinum arrived on Earth billions of years ago after early proto-Earth collided with a Moon-sized object in space. , leaving physical ores in the ground. But that absorption process remains a mystery.

Not only highly valuable due to scarcity, aesthetic beauty and application in high-tech products, gold and platinum are known as iron-loving elements. They are so attracted to iron that researchers predict that almost all of the gold and platinum in the Earth's metal core can be collected because they merge directly into the metal core or sink quickly from the mantle to the core. Due to such reasoning, they did not expect to be able to collect gold or platinum near the Earth's surface, but in fact the opposite was true.

Korenaga and Marchi's hypothesis revolves around a thin transition zone in the mantle, where part of the mantle melts and the deeper part remains solid. The researchers found that this transition zone has strange dynamic properties that can effectively trap submerged metal components and slowly transfer them to the rest of the mantle.

According to the new hypothesis, the process is still ongoing. According to the research team, the transition zone almost always formed when a large impactor crashed into the early Earth. The new theory not only explains the mysterious aspect of Earth's geochemical and geophysical evolution but also highlights the breadth of the planet's formation time frame.

Theo Phys.org - An Khang (Theo Phys.org )

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