Smackover Formation

Smackover Formation
Stratigraphic range: Oxfordian
Wells reporting Smackover Formation tops are indicated by a black point, and extend from Texas to Florida. Formation top depths measured in 6,764 wells range from 1,394 to 23,554 feet.
Type	Formation
Underlies	Buckner Formation
Overlies	Norphlet Formation
Location
Region	Arkansas, Louisiana, Texas, Alabama, Mississippi, and Florida
Country	United States

The Smackover Formation is a geologic formation that extends under parts of Arkansas, Louisiana, Texas, Alabama, Mississippi, and Florida. ^[1] It preserves fossils dating back to the Jurassic period. The formation is a relic of an ancient sea that left an extensive, porous, and permeable limestone geologic unit.

The Smackover Formation consists of oolitic limestones and silty limestones. ^{[2] [3]}

Mineral resources

Smackover Formation stratigraphic column for Texas

The Smackover Formation has been a prolific source of petroleum since the 1920s and, since the 2000s, brine has been refined to extract bromine. In the 2020s, feasibility studies to extract commercial quantities of lithium are underway.

The 1922 discovery of the Smackover oil field, after which the Smackover Formation is named, resulted in a sizeable oil boom in southern Arkansas.^{[ citation needed ]}

In addition to being a petroleum reservoir, as of 2015, the brine from the Smackover Formation is the only source of commercial bromine in the United States. ^[4]

Smackover and Bossier Formations geologic cross section

A 2022 report estimated that the lithium brine in the formation has "sufficient lithium to produce enough batteries for 50 million electric vehicles." ^[5] In October 2024, federal and state researchers announced the formation may hold five to 19 million tons of lithium, which is about nine times the annual worldwide demand for electric vehicles projected for 2030. ^[6] Results from multiple exploration wells in Lafayette County, Arkansas had found an average lithium concentration of 582 mg/L (4,860 lb/million US gal) in the subsurface brine of the upper Smackover Formation including one exploration well with the highest lithium concentration yet reported in the Southwest Arkansas Smackover formation, 616 mg/L (5,140 lb/million US gal). ^[7]

See also

• Earth sciences portal
• United States portal
• Paleontology portal

• List of fossiliferous stratigraphic units in Arkansas
• Paleontology in Arkansas
• Smackover, Arkansas
• Bromine production in the United States
• Lithium production
• Brine mining

References

1. U.S. Geological Survey (October 21, 2024). "USGS Uses Machine Learning to Show Large Lithium Potential in the Smackover Formation" . Retrieved October 24, 2024.
2. Dickinson, Kendell (1968). Upper Jurassic Stratigraphy of Some Adjacent Parts of Texas, Louisiana, and Arkansas. USGS. p. E9.
3. Chimene, Calvin (1976). Braunstein, Jules (ed.). Upper Smackover Reservoirs, Walker Creek Field Area, Lafayette and Columbia Counties, Arkansas, in North American Oil and Gas Fields. Tulsa: The American Association of Petroleum Geologists. pp. 177–204. ISBN   0891813004.
4. Various Contributors to the Paleobiology Database. "Fossilworks: Gateway to the Paleobiology Database" . Retrieved 17 December 2021.
5. "Resource report concludes Galvanic's lithium prospect among most prolific in North America". Green Car Congress. 2022-07-13. Retrieved 2022-08-27.
6. Penn, Ivan; Elliott, Rebecca F. (October 21, 2024). "Arkansas May Have Vast Lithium Reserves, Researchers Say". New York Times . Retrieved 23 October 2024.
7. "Smackover Lithium reports highest lithium brine grade in SWA Project Area as FEED studies nearing completion". Magnolia Banner-News . 18 July 2025. Retrieved 26 July 2025.