While global supplies of lithium are currently high, the expected surge in demand from electric carmakers could create a lithium shortage by as early as 2030.
More than 75 percent of the world’s lithium is mined in Chile and Australia, but geologists from Stanford University have discovered that vast stores of the valuable metal may be available at hundreds of sites across North America in the remains of ancient supervolcanoes.
In a paper published in Nature Communications, the researchers explained how these massive volcanoes — 10,000 times more powerful than most active volcanoes today — created the perfect thermodynamic conditions to produce thick deposits of lithium-rich clays.
“Lithium is the new oil,” lead author Thomas Benson, a recent Ph.D. graduate of Stanford’s School of Earth, Energy, and Environmental Sciences, told Seeker.
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As the price of lithium goes up, it will become increasingly risky to allow just a handful of countries and companies to control the global lithium supply. By tapping lithium deposits in the calderas of extinct supervolcanoes, many more countries — including the US, Canada, and Mexico — can help diversify lithium production.
Supervolcano isn’t a true scientific term, Benson explained, but generally refers to a volcanic eruption that produces at least 1,000 cubic kilometers of material. For comparison, the eruption of Mount St. Helens in 1980 produced only 4.2 cubic kilometers of material.
The best-known supervolcano site in America is probably Crater Lake in Oregon. At nearly 2,000 feet deep, it’s the deepest lake in the nation, filling a six-mile wide caldera left by the colossal eruption and collapse of Mount Mazama 7,700 years ago.
But when geologists go looking for lithium, places like Crater Lake don’t cut it. What they need is a caldera lakebed that’s long been drained of its water.
That’s why the McDermitt volcanic field in Nevada is just the type of place where America’s lithium boom might begin. Located 60 miles northwest of Winnemucca, Nevada, the ancient caldera was formed from a supervolcanic eruption more than 16 million years and looks today like nothing more than a rocky wasteland. But just 30 meters below the surface lies a seam of sedimentary clays with lithium concentrations of greater than 4,000 parts per million.
“The magma that originally erupted from the supervolcano had about 1,400 ppm lithium in it,” said Benson, describing a red-hot pyroclastic flow of pumice, ash, crystals, and rock that spread for 50 miles in all directions. “That’s not crazy levels of enrichment, but since there was this big hole in the ground and you had 200,000 to 300,000 years, that lithium was progressively leached from the nearby rock by rainwater and deposited in the caldera lake sediments.”
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Not all ancient caldera sediments are loaded with lithium. Benson and his colleagues analyzed tiny samples of crystallized magma called melt inclusions taken from supervolcano sites around the world. It turns out that the most lithium-rich magma is formed when a lot of continental crust is melted into the mix. Magma that’s mostly from the deeper mantle, however, doesn’t produce a lot of lithium, neither does magma melted from oceanic crust.
That’s why ancient magma samples from the Pantelleria caldera off the coast of Sicily showed only 100 ppm lithium, while the Hideaway Park supervolcano site in Colorado, sitting atop a thick layer of continental crust, registered at 5,990 ppm lithium on average. Even when the Crater Lake caldera does dry out hundreds of thousands of years from now, its near-coastal location would likely make it a lousy source of lithium.
The McDermitt volcanic site in Nevada is believed to be the largest lithium deposit in America with an estimated two megatons of the prized, but volatile metal. That’s a good cache, considering that the total amount of extractable lithium on the planet is estimated around 14 megatons.
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The problem is that mining technology hasn’t caught up with the geology. Lithium Americas Corp. owns large swaths of the McDermitt site and has been conducting feasibility studies since 2012, but according to a June 2016 report, the technology for processing and refining the lithium from the clay deposits was still being tested.
No lithium clay mines are currently in operation.
Benson said until recently the mining industry has focused its research and development on two other types of lithium deposits: the salt flats of South America and a lithium-rich mineral called spudomine in Australia.
“But now that money is being poured into the lithium industry,” said Benson, “I’m sure the technologies will catch up to meet the demand.”
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