Enormous Reserve of ‘Hidden Treasure’ Found Under Arkansas

A U.S. Geological Survey (USGS)-led study has revealed an enormous lithium deposit in southwestern Arkansas that could potentially revolutionize the global electric vehicle industry.

Using innovative water testing methods combined with machine learning, researchers estimate the region contains between 5 and 19 million tons of lithium reserves—enough to meet projected 2030 world demand for lithium in car batteries nine times over.

The discovery focuses on lithium-rich brines within the Smackover Formation, an ancient seabed that extends across several Southern states. The finding is particularly significant as it could reduce U.S. reliance on imports of the raw material.

“Lithium is a critical mineral for the energy transition, and the potential for increased U.S. production to replace imports has implications for employment, manufacturing and supply-chain resilience,” David Applegate, the USGS director, said in a statement. “This study illustrates the value of science in addressing economically important issues.”

Back in the 1990s, the U.S. was the world’s largest producer of lithium, according to the World Economic Forum. However, by 2021, it accounted for just 1 percent of global production, despite lithium’s critical role in powering the coming electric vehicle boom.

Lithium is often referred to as the “white gold” of the energy transition—or, as the USGS put it, “hidden treasure”—because of its crucial role in battery technology that will drive the green revolution.

“Our research was able to estimate total lithium present in the southwestern portion of the Smackover in Arkansas for the first time,” Katherine Knierim, the study’s principal researcher, said in a statement. “We estimate there is enough dissolved lithium present in that region to replace U.S. imports of lithium and more.”

But Knierim urged caution, stating that “these estimates are an in-place assessment. We have not estimated what is technically recoverable based on newer methods to extract lithium from brines.”

The discovery comes at a crucial time as global demand for lithium continues to surge, driven by the rapid adoption of electric vehicles and renewable energy technologies. Currently, the U.S. relies on imports for more than 25 percent of its lithium needs.

Energy company Exxon Mobil has already taken steps to tap into this promising resource. The company has drilled exploratory wells in Arkansas and is actively evaluating the economic viability of lithium extraction in the region.

The company has set ambitious production targets, aiming to begin lithium extraction by 2027. By 2030, Exxon plans to produce enough lithium to supply more than a million electric vehicles annually.

The Smackover Formation, dating back to the Jurassic period, is already known for its oil and bromine deposits. It extends beyond Arkansas under parts of Louisiana, Texas, Alabama, Mississippi and Florida.

The potential extraction of lithium from brines co-produced during oil and gas operations presents an opportunity to harvest valuable resources from what would otherwise be considered waste material.

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Reference

Knierim, K. J., Blondes, M. S., Masterson, A., Freeman, P., McDevitt, B., Herzberg, A., Li, P., Mills, C., Doolan, C., Jubb, A. M., Ausbrooks, S. M., & Chenault, J. (2024). Evaluation of the lithium resource in the Smackover Formation brines of southern Arkansas using machine learning. ScienceAdvances, 10(39). https://doi.org/10.1126/sciadv.adp8149