Scientists have pinpointed what could be the world’s largest known lithium deposit, concealed beneath a long-extinct volcano straddling the Nevada-Oregon border, offering a potential boost to global supplies amid soaring demand for the battery metal.
The McDermitt caldera, formed by a massive eruption 16 million years ago, holds lithium-rich clay sediments created through a rare sequence of geological events, according to a study published in Science Advances by researchers Thomas Benson, Matthew Coble, and John Dilles from Lithium Americas Corporation, GNS Science, and Oregon State University.
Global lithium demand is projected to reach nearly 1 million metric tons by 2040 — roughly eight times 2022 output — as nations shift from gasoline-powered vehicles and coal power to electric alternatives reliant on batteries.
Unlike typical sources from brine in places like Chile or hard rock in Australia, the McDermitt site’s lithium is embedded in clay, with some samples showing concentrations over 70 times higher than in average rock.
The eruption expelled about 1,000 cubic kilometers of molten material, forming a crater wider than 40 kilometers [24.85 miles] and scattering ash and lava up to 80 kilometers [49.70miles] distant. The resulting basin cooled slowly, allowing rainwater and snowmelt to create a lake that trapped volcanic debris.
Without an outlet, the water turned increasingly saline and extracted lithium from the surrounding rock, depositing it in sediments at the lake bed. As the lake evaporated, it left layers of lithium-laden clay.
Further enrichment occurred in the southern section, including Thacker Pass, where later underground magma uplifted the terrain, fracturing the crust and allowing hot fluids to alter the clay into illite. This mineral locked in even more lithium.
Drill tests reveal up to 18,000 parts per million lithium in some cores, far exceeding typical Earth rock levels below 50 ppm. The study confirmed the element resides directly within the illite.
Two mining ventures in the area have identified at least 5.1 million metric tons of lithium, with around 3 million metric tons at Thacker Pass, which was flagged in 2017 as highly promising.
Lithium Americas Corporation advanced plans there, overcoming legal challenges from area ranchers and tribal communities concerned about sacred sites.
The site’s formation stemmed from lithium-enriched magma, a confined lake basin, prolonged chemical processes, and subsurface heating — conditions that set it apart and could guide searches for similar deposits in volcanic regions such as Mexico, Serbia, Nevada, and California.
If developed, the resource could establish a major U.S. lithium reserve, easing dependence on imports, reducing battery costs, accelerating electric-vehicle manufacturing, and curbing emissions from overseas transport.
Yet extraction poses risks to local water resources, ecosystems, and Indigenous lands, requiring balanced decisions by regulators and communities to support the shift from fossil fuels.
