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Gold isn’t as rare as you may think—it’s just hard to reach. 99.999 percent of Earth’s precious metals lay hundreds of miles beneath the surface, trapped inside the planet’s molten core. If the sheer distance didn’t make accessing gold difficult enough, we’re also separated from the ore by (literal) tons of solid rock. Fortunately, Earth is making it easier for us humans. According to a new study published in the journal Nature, Earth’s core is “leaking” gold.
Now, don’t get too excited—gold isn’t spewing out of the ground in cartoon-esque fountains—but the researchers on the study did find evidence that precious metals are oozing out of Earth’s core and into the mantle. Unlike the core, the mantle is mostly solid, and makes up most of the planet (84 percent of the Earth’s volume to be exact). Comparatively, the mantle also has less of a platinum-group-metal called ruthenium, or Ru. Scientists discovered traces of Ru while studying samples of volcanic rocks from Hawaii and concluded that they must have come from Earth’s core.
“When the first results came in, we realized that we had literally struck gold,” first author of the study Nils Messling said in a press release. “Our data confirmed that material from the core, including gold and other precious metals, is leaking into the Earth’s mantle above.”
New procedures developed by the University of Göttingen allowed researchers to detect the microscopic markers that indicate the Ru actually came from the molten core. According to the paper, when Earth’s core formed 4.5 billion years ago, the Ru came from a different source than the trace amounts of the element that naturally occur in the mantle. The differences in the isotopes are so small, however, that it was previously impossible to distinguish them.
On top of procedural revolutions, the study is also notable in that it supports wider geological theories. Evidence from the study affirms the plate tectonics theory that oceanic islands formed from molten material.
“Our findings not only show that the Earth’s core is not as isolated as previously assumed,” Matthias Willbold, another author of the study, said in the release. “We can now also prove that huge volumes of super-heated mantle material–several hundreds of quadrillion metric tonnes of rock–originate at the core-mantle boundary and rise to the Earth’s surface to form ocean islands like Hawaii.”
As for the future, the researchers expressed that there is still much to learn, particularly when it comes to the timeline of the “leak.”
“Whether these processes that we observe today have also been operating in the past remains to be proven,” Messling explained. “Our findings open up an entirely new perspective on the evolution of the inner dynamics of our home planet.”