Huge lithium deposits are in Nevada. Here's why.

In Clayton Valley, a broad basin in western Nevada's Esmeralda County, aquamarine pools lie between brown-toned mountains under a clear blue sky. Similar basins and ranges align like battalions from west to east across the state, though most are bone dry. Clayton's still ponds are artificial — and rich in lithium.

Silver Peak, a tiny former silver mining town in this remote valley, became Nevada's first lithium production facility in 1966, decades before the metal became a key to renewable energy and national security. The facility, operated by Albemarle Corporation, produces 5,512 tons (5,000 metric tons) of lithium carbonate annually.

Silver Peak is Nevada's only lithium-producing site, but that will soon change.

Historically, lithium had little economic significance, but surging demand for lithium-ion batteries has sharpened focus on these deposits. The U.S. Geological Survey reports that batteries, primarily for electric vehicles, comprise 87% of global lithium use. Analysts expect this share to rise to 95% by 2030. The United States produces a paltry 0.5% of global lithium, but Nevada could revise that statistic.

"Nevada clearly has more lithium than any other state," said Christopher Henry, an emeritus geologist at the Nevada Bureau of Mines and Geology (NBMG).

"That's thanks to our tectonic setting," added James Faulds, a geologist at NBMG.

The state's lithium deposits are a result of almost unimaginable geologic serendipity. Nearly everything relates to stretching crust: steep topography, abundant volcanic rocks, high heat flow, arid climate, and hydrologically closed basins, according to a new report from NBMG.

Related: Scientists just discovered an enormous lithium reservoir under Pennsylvania

From water comes lithium

The tectonic history of North America's Basin and Range Province, which comprises much of the western United States, including the entire state of Nevada, is complex. About 17 million years ago, crust previously thickened by ancient tectonic collisions began to stretch and thin, spreading like mounded Silly Putty, Henry explained.

Blocks of crust tilted like dominoes, forming basins where sediment and water pooled into shallow lakes and reservoirs. Magma rose through the thinning crust, spewing volcanic rocks to the surface to intermingle with cobbles, sand, and clay.

Most of Nevada's basins are now dry, with only curled mud cracks and salts remaining as vestiges of yesteryear's lakes. Crustal extension continues today and is key to the state's vast lithium reserves.

"Nevada is the fastest growing state, tectonically speaking," Faulds said.

Lithium's story begins with igneous rocks, explained Simon Jowitt, an economic geologist at the University of Nevada, Reno. Most lithium mined worldwide is extracted directly from these hard rocks, including at the world's largest lithium mine in Australia's Greenbushes pegmatite.

But Nevada's lithium source rocks, namely, rhyolite (the erupted form of granite), contain only trace amounts of lithium — not enough to economically mine directly. Here geologists are instead interested in "volcano sedimentary deposits," where the highly soluble metal is concentrated in nearby basins after being weathered out of its source rock.

Streams generally collect runoff and flow to the sea, but Nevada's arid climate and topography render most basins hydrologically closed. Streams instead bring water into internally drained basins, where it pools.

Runoff leaches lithium from rhyolites wherever they occur — from deep underground to slopes of steep ranges. The lithium-enriched runoff accumulates in basins and slowly concentrates into brines.

"You've got something almost like a sponge," Jowitt said. "The water comes, but there's no escape."

In Clayton Valley, lithium-rich brine is either pumped to the surface to evaporate or processed through still-emerging direct lithium extraction techniques.

Lithium clay potential

Beyond brine, what excites geologists is the potential of Nevada's lithium clay.

The McDermitt Caldera, which straddles the Nevada-Oregon border, marks an early manifestation of the Yellowstone hot spot, which ultimately formed a chain of volcanoes as the North American plate moved over a stationary heat source.

When McDermitt erupted 16.3 million years ago, a lake within the caldera filled with ash and smectite clay. As the lake evaporated, hydrothermal fluids transformed the lithium-rich smectite into even richer illite clay, especially at Thacker Pass at the southern end of the caldera. Today, McDermitt is one of the world's largest known lithium deposits.

Uranium prospectors stumbled upon McDermitt in the 1970s. "The behemoth there is lithium," said Tom Benson, a volcanologist at Lithium Argentina Corp. With lithium neither economically attractive nor easily mined, however, production at the site never began.

Today, the company's spin-off, Lithium Americas Corp, estimates that its Thacker Pass project contains 240 million tons (217.3 million metric tons) of the metal. The company plans to start production around 2028.

Nevada's other calderas haven't yet yielded similar amounts of lithium, leaving geologists puzzled. "We're trying to figure out what happened at McDermitt," Faulds said.

Benson thinks the key is McDermitt's uniquely enriched rhyolites, formed when hot, dry magma melted lithium-rich continental rocks. In contrast, Nevada's older calderas formed in colder, subduction-like settings or melted crust with less lithium. "The tectonic setting and type of crust matters," Benson said.

Just 268 miles (431 kilometers) to the south, Rhyolite Ridge's tilted strata rise along the Silver Peak Range — Nevada's next lithium clay frontier. Once believed to sit atop a McDermitt-type buried caldera, Rhyolite Ridge is better understood as a faulted and drained Clayton Valley, Faulds explained.

Initially, geologists think, lithium-rich rhyolitic tuff deposits accumulated in Rhyolite Ridge's tectonically active basin. As the basin developed, a lake formed, depositing clay-rich lake sediments over the volcanic rocks. Hydrothermal fluids seeped through faults and fissures, soaking the lake bed sediments with lithium from the rhyolites below. Later faulting uplifted and tilted these deposits, exposing the valuable clays.

To understand Rhyolite Ridge, "you take Clayton Valley, chop it up with faults, and uplift portions to expose enriched clays from lithium brines," Faulds said.

Ioneer USA Corporation is planning a lithium-boron mine and chemical processing plant at Rhyolite Ridge, with production expected by 2028.

Meanwhile, in the hills outside Reno, the Tesla Gigafactory has produced enough lithium battery cells to power 500,000 electric vehicles annually since 2017. With McDermitt and Rhyolite Ridge production set to start amid ongoing Clayton Valley operations, Nevada's lithium production is expected to rise.