United States: A new study suggests that an ancient supervolcano named McDermitt Caldera in the US may contain the largest lithium deposit in the world. The volcano sits on the border between Nevada and Oregon.
The study was funded by a mining company, Lithium Nevada, a subsidiary of Lithium Americas Corporation (LAC). There were contentious plans to extract the soft, silvery metal, but it is all steeped in controversy.
According to the company’s latest review, the caldera’s southernmost rim, including Thacker Pass, contains the highest concentrations of lithium in the region.
The recent approval of the Thacker Pass lithium mine by the US government in the McDermitt Caldera has raised concerns among scientists, environmentalists, ranchers, and First Nations people. This land is sacred to several Indigenous tribes and hosts valuable wildlife habitats.
Lithium mining can harm ecosystems, reduce groundwater, and generate significant waste. The US largely depends on China for its lithium. America is currently suspending relations, especially trading, with China. So there is a push to mine more on federal lands.
Experts from Lithium Nevada, the University of Oregon, and the New Zealand research institute GNS Science said that when the ancient supervolcano erupted around 16 million years ago, hot liquid magma gushed through the ground’s cracks and fissures and enriched the clay soil with lithium.
The majority of the caldera’s clay is identified as magnesium smectite, a well-known lithium source in other parts of the world. Towards the southernmost edge of the caldera, scientists have discovered an unusual clay type called illite, which contains a particularly high concentration of lithium.
The team suggests that this lithium-rich mining area likely formed due to another eruption of magma after the ancient caldera lake had dried up.
As a result of this event, a chemical reaction would have occurred, replacing lithium-smectite in the lake sediment with even more lithium-rich illite clay. But this transformation appears to be limited to the Thacker Pass area, not the entire caldera.