World’s Largest Lithium Deposit, valued at $1.5 trillion, Lies Under a Supervolcano in the U.S

Buried beneath an ancient volcanic crater on the Nevada Oregon border sits an enormous deposit of lithium rich clay. Scientists now think this quiet landscape may hold enough lithium to influence the global battery market for decades.

A new study argues that McDermitt caldera may host about 20 to 40 million metric tons of lithium, likely the largest deposit yet identified.

Using the recent United States’ average contract price for lithium carbonate, about 37,000 dollars per ton, that estimate comes out to be nearly $1.5 trillion.

Supervolcano full of lithium

The deposit sits inside a caldera, a large volcanic crater formed when a magma chamber collapses. This particular basin spans roughly 28 miles north to south and 22 miles east to west along the Nevada Oregon line.

Work on this deposit was led by Thomas R. Benson, PhD, at Lithium Americas Corporation (LAC). His research focuses on how lithium rich minerals form in volcanic terrains.

About 16 million years ago, a huge eruption emptied much of the magma chamber beneath this area. That outburst left behind thick sheets of hot ash that later cooled into hard volcanic rock on the caldera floor.

Later, the crater held a long lived lake that collected volcanic ash and mud. Those sediments formed lacustrine, formed in a lake environment, claystones that now trap much of the lithium rich clay.

Hot magma turns to lithium clay

Deep below the basin, magma continued to release hydrothermal, hot water rich in dissolved minerals circulating underground, fluids long after the main eruption.

Those fluids leached lithium and other elements from volcanic glass and carried them upward into the wet lake sediments.

As that chemistry played out, the lake mud first turned into smectite, magnesium rich clay that can absorb lithium into its layers.

Later, hotter fluids altered parts of that smectite into another clay called illite that locks in much more lithium.

In the lithium rich zone at Thacker Pass, illite, potassium rich clay that holds lithium tightly, forms a band about 100 feet thick.

Analyses show that this clay can contain around 1.3 to 2.4 percent lithium by weight, roughly double typical claystone deposits.

A recent feature noted that the high grade illite layer sits close to the surface, which makes large pit mining possible.

It also stated that investigators had reported lithium concentrations reaching about 1 percent by weight, according to Thomas R. Benson, a geologist at Lithium Americas Corporation.

Why this lithium deposit matters

Lithium today is best known as the heart of the lithium ion battery, a rechargeable battery that moves lithium ions between two electrodes.

These batteries power phones, laptops, electric cars, and storage packs that balance wind and solar energy on the grid.

The same research group notes that global demand for lithium could reach one million tons per year by 2040, eight times the 2022 output.

That is why such a concentrated deposit in a single basin draws so much attention from governments and companies planning long term energy transitions.

Volcanic lake deposits like this are shallow and wide, which lowers the strip ratio, amount of waste rock per ton of ore.

Compared with deeper hard rock mines, that often means less blasted rock and lower energy use per ton of lithium.

Because the richest clays sit near the land surface at Thacker Pass, miners can target the most lithium dense layers directly.

The combination of huge tonnage, high grades, and relatively simple geometry makes this deposit unusual among known clay hosted lithium resources.

Environmental questions in the clay

Such a giant deposit also raises difficult questions about water, wildlife, and the cultural meaning of this landscape.

Local tribes and ranching communities have voiced concerns about how a large mine might change springs, grazing areas, and sacred sites.

Supporters point out that a shallow clay deposit can disturb less land than multiple smaller mines spread across distant regions.

Critics respond that even a single large pit can alter groundwater, produce dust, and fragment habitat if not carefully managed.

Processing clay-hosted lithium is technically tricky because the metal is bound inside minerals rather than sitting in salty brines.

Engineers must grind the clay, use leaching, chemical washing with carefully chosen solutions, and then recover lithium while limiting water use and waste.

What geologists look for next

Geologists studying McDermitt now see a recipe for rich volcanic lithium deposits that blends magma chemistry, basin shape, and long lasting heat.

The magmas here were peralkaline, igneous composition unusually rich in sodium and potassium, which tend to hold on to lithium as they cool.

Later, magma rose again beneath the caldera in a phase called resurgence, renewed uplift driven by fresh magma pushing upward.

That movement fractured the overlying rocks, opened pathways for hot fluids, and focused lithium rich illite formation along the southern rim of the basin.

Armed with this model, exploration teams scan volcanic basins for matching chemistry, preserved lake beds, and signs of past hot fluid circulation.

Only a few places worldwide seem to share McDermitt’s mix of large size, closed basin setting, and long lived magmatic activity.

Lessons from this lithium deposit

The McDermitt caldera lithium deposit is vast, shallow, and chemically unusual, qualities that set it apart from most other known sources. At the same time, it sits within a lived landscape where people, wildlife, and water all have prior claims.

Decisions made over the next few years will determine whether this lithium mostly stays locked in clay or moves into batteries and power grids.

Either way, McDermitt has already changed how scientists think about where critical minerals can hide inside old volcanic systems.

For those thinking about climate and technology, this story makes the link between distant geologic events and the batteries in their daily lives clear.

Learning how minerals form in Earth’s crust becomes directly connected to questions about cars, phones, and power grids.