Gold rush from the Earth's core? Researchers reveal precious metals leak

Earth's core is rich with gold, and it's leaking out through the mantle and into the crust, new research has found.

A new study of isotopes found in the volcanic rock that oozed out from deep under the lithosphere has revealed precious metals in Earth's crust, including gold, initially leaked out of the core before beginning the long, long journey up to the surface, borne on convecting magma.

While we can mine gold from Earth's crust, it's just a tiny fraction of the planet's total gold reserves. Most of Earth's gold—over 99 percent—is believed to be locked deep in the metallic core, enough to blanket the entire land surface in a 50-centimeter (20-inch) thick layer.


This concentration makes sense. During Earth's formation, heavy elements like gold sank through the molten interior and settled in the core—a process known as the iron catastrophe. Later, asteroid impacts added more gold and heavy metals to the crust.

Although scientists have long known that elements like primordial helium and heavy iron isotopes leak from the core, it's remained uncertain how much of the gold and other heavy metals found on the surface actually originated from deep within Earth, rather than arriving via space debris.
Scientists have found a way to trace gold and other precious metals back to Earth's core—by studying isotopes of a rare metal called ruthenium.

Ruthenium exists in different isotopic forms, which are versions of the same element with varying numbers of neutrons. The isotopic makeup of ruthenium in Earth’s core differs slightly from that found near the surface. Until now, that difference had been too subtle to detect. But using advanced analytical techniques, researcher Nils Messling and his team at Göttingen University were able to identify it.

By analyzing volcanic rocks from Hawaii, the team detected unusually high levels of ruthenium-100, an isotope tied to the Earth's core. This finding confirms that ruthenium—and likely other siderophile elements (those drawn to iron, like palladium, rhodium, platinum, and gold)—are slowly leaking from the core into the mantle and eventually rising to the surface.

The process is extremely slow, and we can’t access these elements directly by drilling 2,900 kilometers down. But the discovery reveals a previously hidden connection between Earth’s surface and its deep interior, with implications for how we understand our planet and others like it.

“Our findings not only show that the Earth’s core is not as sealed off as we once thought,” said geochemist Matthias Willbold of Göttingen University. “We now have evidence that vast volumes of superheated rock—amounting to hundreds of quadrillions of metric tons—rise from the core-mantle boundary to the surface, forming volcanic islands like Hawaii.”

The study has been published in the journal Nature.