Bonneville basin playas and salt lakes

Region West, Southwest
Mineral systems
Deposit types
Critical minerals
Other minerals

Information leading to the delineation of this focus area

Basis for focus area Focus area covers salt lakes, playas, and mud flats in the Bonneville Basin having surface or subsurface brines. Mud flat of the Great Salt Lake Desert is from Hintze and others (2000). Great Salt Lake is represented at an elevation of 4200 feet above seal level, its historical average elevation. Sevier Lake/Playa is a digitization of the current playa/mudflat.
Identified resources Identified resources of lithium and potash. Historical production of lithium, magnesium, potash, and salt.
Production Extensive potash and magnesium production has occurred at Great Salt Lake and Bonneville Salt Flats. Potash (as potassium chloride) has been produced intermittently from the Bonneville Salt Flats since 1916. Potash (as potassium sulfate) has been produced at Great Salt Lake since 1968. Magnesium metal at Great Salt Lake has been produced since 1972 (Gwynn, 2002). Magnesium chloride is produced at the Bonneville Salt Flats and at Great Salt Lake. Lithium production from Great Salt Lake brine began in 2020.
Status Past and current lithium, magnesium, and potash mining; current lithium exploration.
Estimated resources Great Salt Lake has estimated In-place resources of 110 Mt of K, 140 Mt of Mg, and 2.4 Mt of Li in the lake brine (SWCA Environmental Consultants, 2013; Compass Minerals, 2021); Intrepid Potash (2021) estimated that the Bonneville Salt Flats has a Probable reserve of at least 3 million stu of KCl in shallow and deep subsurface brines; Sevier Lake has an estimated In-place resource of 36 Mt of potassium sulfate in shallow brine (Brebner and others, 2018).
Geologic maps Hintze (1980), scale 1:500,000.
Geophysical data Inadequate aeromagnetic and aeroradiometric coverage.
Favorable rocks and structures Surface brines, shallow and deep subsurface brines.
Deposits Great Salt Lake (potash as potassium sulfate, magnesium metal, magnesium chloride, lithium, salt) (USMIN Site_ID: UT00001), Bonneville Salt Flats (potash, magnesium chloride, salt), Sevier Lake/Playa (potash as potassium sulfate).
Evidence from mineral occurrences USMIN; UMOS (Utah Geological Survey, 2021); Utah Geological Survey's Great Salt Lake Brine Chemistry Database (
Geochemical evidence Extensive brine analytical data are available for Great Salt Lake, the Bonneville Salt Flats, and Sevier Lake/Playa. Significant publications include the Utah Geological Survey's Great Salt Lake Brine Chemistry Database (, Lines (1978), Mason and others (1995), Gwynn (2006), Rupke and McDonald (2012), Brebner and others (2018), Rupke and Boden (2020); Concentrations of over 100 ppm Li are present at the Bonneville Salt Flats and up to about 80 ppm Li at Great Salt Lake (Mason and others, 1995; Rupke and McDonald, 2012; Rupke and Boden, 2020).
Geophysical evidence Unknown.
Evidence from other sources Unknown.
Comments Extensive literature beyond what is cited in this table is available on the Bonneville basin and its related deposits. Great Salt Lake and the Bonneville Salt Flats have been major producers of brine-related commodities for decades. Another deposit that has received some attention for potash and Li is Pilot Valley.
Cover thickness and description Resource at the surface, and within basins.
Authors Jane M. Hammarstrom, Andrew Rupke.
New data needs New geochemical analysis of brines for prospective areas; a complete compilation of existing brine analytical data.
Geologic mapping and modeling needs None requested at this time.
Geophysical survey and modeling needs None requested at this time.
Digital elevation data needs Lidar inadequate; need lidar for playa areas and bathymetric lidar of Great Salt Lake.