A U.S. Geological Survey (USGS)-led study has estimated that between 5 and 19 million tons of lithium are located beneath southwestern Arkansas, potentially meeting global lithium demand for electric vehicle batteries multiple times over by 2030. The findings, based on water testing and machine learning, offer significant implications for U.S. lithium production and the global transition to clean energy.
The study, conducted by the USGS in collaboration with the Arkansas Department of Energy and Environment’s Office of the State Geologist, used an innovative approach to quantify lithium present in brines from the Smackover Formation. This geological unit, a remnant of an ancient sea, is located beneath Arkansas, Louisiana, and several other southern U.S. states. It has long been known for its rich oil and bromine deposits, but recent research has highlighted its potential for lithium extraction from brines co-produced during oil and gas operations.
The significance of this discovery was underscored by USGS Director David Applegate: “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.”
The study’s estimates suggest that the lithium reserves in the southwestern portion of the Smackover Formation could be sufficient to replace U.S. lithium imports and potentially supply even more. The USGS estimates that even the low-end figure of 5 million tons of lithium could meet projected 2030 global lithium demand for electric vehicle batteries nine times over, according to figures from the International Energy Agency.
However, the researchers caution that these numbers represent in-place lithium reserves, not what is necessarily recoverable using current extraction technologies. "We estimate there is enough dissolved lithium present in that region to replace U.S. imports of lithium and more," said Katherine Knierim, the study’s principal researcher and USGS hydrologist. She also noted that further advancements in lithium extraction methods would be needed to determine what percentage of these reserves could be commercially viable.
The study represents the first attempt to estimate total lithium concentrations across the Smackover Formation in Arkansas using a machine learning model. By analyzing samples from the region and comparing them with data from the USGS’s Produced Waters Database, the model was able to predict lithium concentrations in areas where no previous samples had been collected. This predictive model offers a critical tool for mapping potential lithium resources across a wide geographic area.
"The USGS – and science as well-- works best as a partnership, and this important research was possible because of our strong partnership with the Office of the Arkansas State Geologist," said Knierim.
Global demand for lithium, essential for producing batteries in electric and hybrid vehicles, has skyrocketed in recent years. As the world transitions away from fossil fuels, lithium’s role in energy technology has become increasingly significant. Currently, the U.S. relies on imports for more than 25% of its lithium supply, making domestic sources like those identified in the Smackover Formation vital for supply chain resilience and national energy security.
The potential of this reserve to significantly reduce reliance on foreign lithium underscores the importance of continued research and development in lithium extraction methods, particularly those that can efficiently harvest lithium from oil and gas production waste streams.
The USGS study highlights the enormous potential of the Smackover Formation to contribute to the global supply of lithium, especially as the demand for electric vehicles continues to grow. While more work is needed to determine how much of this lithium can be commercially extracted, the findings are an encouraging step toward greater U.S. self-sufficiency in this critical mineral.
The full study, published in Science Advances, is available here.
