An unprecedented lithium find on the Nevada-Oregon border could meet growing demand for the metal, according to a new analysis.
It is estimated that between 20 and 40 million tons of lithium are contained within a volcano that was formed about 16 million years ago. This find is much larger than the lithium deposits found under a salt flat in Bolivia, which was once considered the largest deposit in the world.
A discovery that will change the global outlook for lithium
If we believe their rough estimate, this is an extremely important lithium deposit. This could change the dynamics of lithium globally in terms of price, supply security and geopolitics.
Anouk Borst, geologist at KU Leuven University
New in situ analysis reveals that a rare clay, composed of the mineral illite, contains between 1.3% and 2.4% of volcanic lithium. This is almost double the lithium found in the main lithium-bearing clay mineral, magnesium smectite, which is more common than illite.
Unusual conditions for a very rich volcanic deposit
Some unusual conditions have created what could be a very rich volcanic deposit.
The crater, known as the McDermitt caldera, was formed 16.4 million years ago when it was approximately 1000 km.3 of magma erupted outside. The caldera is filled with products expelled from alkaline magma rich in sodium, potassium, lithium, chlorine and boron. It cooled rapidly to form a fine crystalline glassy volcanic rock, called ignimbrite, which weathered to produce lithium-rich particles.
A lake subsequently formed in the crater, which persisted for hundreds of thousands of years, with eroded and surrounding volcanic materials forming a mud-filled crater beneath it. The new analysis suggests that after the lake was emptied, another burst of volcanic activity exposed the sediments to a hot, alkaline brine rich in lithium and potassium.
A rare change in mineral
Previous research has suggested that illite exists deep within the crater, and formed when high temperatures and pressures transformed smectite into illite.
Thomas Benson, geologist at Lithium Americas Corporation
Benson’s group suggested that a layer of illite about 40 m thick formed in the lake sediments thanks to the hot brine. The liquid migrated upward along fractures formed as volcanic activity continued, changing smectite to illite in the southern part of the crater, Thacker Pass. The result is a clay rich in lithium.
This is a multi-step transformation from lithium-rich smectite to illite, where hydrothermal fluids enrich the clays with potassium, lithium and fluorine. They seem to have found the sweet spot where the clays are preserved near the surface, so they don’t have to take too much rock, but it hasn’t broken yet.
Anouk Borst
A hidden treasure under a simple appearance
The material can best be described as “somewhat like potter’s clay” according to Christopher Henry, professor emeritus of geology at the University of Nevada, Reno.”It is not very interesting, except for the amount of lithium in it“.
“There is a huge search for more lithium deposits” Henry added. “The United States has very few lithium production operations in Nevada“.
Henry does not fully agree with the proposed new story about the crater, because isotopic dating shows that there was a lake there until 15.7 million years ago, but the volcanic system died 16.1 million years ago. . The new timeline requires volcanic activity longer than the evidence suggests, he explained.
Extraction and its impact on the economy
Benson’s company hopes to begin mining in 2026. It will remove the clay with water and then separate the small lithium-rich particles from the larger minerals by centrifugation. The clay is poured into tanks of sulfuric acid to extract the lithium.
If they can extract the lithium in a less energy-intensive way or in a process that doesn’t use as much acid, it could have a significant economic impact. The United States has its own supply of lithium and industries are less concerned about a supply shortage.
Anouk Borst
Benson considers the lithium-rich clay at Thacker Pass “unique” among volcanic sedimentary deposits.
