Precious metals such as gold and platinum can accumulate in the Earth’s mantle due to being retained by an area with unique dynamic characteristics.
Simulation of an asteroid impacting the early Earth. (Photo: Simone Marchi).
Scientists at Yale University and the Southwest Research Institute (SRI) have uncovered new information regarding the distribution of gold, platinum, and many other precious metals. In a study published on October 9 in the Proceedings of the National Academy of Sciences, Jun Korenaga, a professor of Earth and planetary sciences at Yale, and Simone Marchi from SRI in Boulder, Colorado presented a hypothesis explaining the process of gold concentration in shallow pockets within the Earth’s mantle instead of sinking deep into the core. This hypothesis also provides further insight into planetary formation in the universe, according to Phys.org.
Researchers are aware that intense collisions between large objects in space and movement in partially molten regions of the Earth’s mantle drive precious metals to accumulate closer to the planet’s surface than previously predicted. Recent studies from scientists worldwide indicate that metals such as gold and platinum arrived on Earth billions of years ago after the primordial Earth collided with a moon-sized celestial body, leaving behind mineral deposits within the Earth. However, the process of absorption remains a mystery.
Not only are gold and platinum highly valued due to their scarcity, aesthetic beauty, and applications in high-tech products, but they are also known as iron-loving elements. They are attracted to iron to such an extent that researchers predict that nearly all gold and platinum in Earth’s metallic core could have merged directly into the core or quickly sunk from the mantle to the core. Based on such reasoning, they did not expect to find gold or platinum near the Earth’s surface, but the reality is quite the opposite.
The hypothesis proposed by Korenaga and Marchi revolves around a thin transitional region of the mantle, where part of the mantle is molten and the deeper parts remain solid. The researchers found that this transitional area has unique dynamic characteristics that can effectively retain sinking metal components and slowly transfer them to the rest of the mantle.
According to the new hypothesis, this process is still ongoing. The research team states that the transitional area almost always forms when a large object collides with the primordial Earth. This new hypothesis not only explains the mysterious aspects of the geochemical and geophysical evolution of the Earth but also highlights the extensive timeframe of planetary formation.
