Great Salt Lake Lithium Sourcing and Groundwater Inflow Investigation (RI-294)

By:  Elliot Jagniecki, Andrew Rupke, Taylor Boden, Erin Brinkman, and Jake Alexander

Summary: This Report of Investigation focused on identifying sources of lithium recharge of Great Salt Lake (GSL). Endorheic basins, like GSL, are chemical repositories for continental brines that evolve from long-term evaporative concentration of surface and groundwater. Lithium (Li) accumulation in these basins is a product of water-rock interaction, ambient groundwater and hydrothermal input, and mobilization by phyllosilicate ion exchange under certain chemical conditions. Since 1966, GSL has sustained average Li concentrations ranging from ~15 to 25 mg/L in the south arm (SA) (Gilbert Bay) and ~45 to 60 mg/L in the north arm (NA) (Gunnison Bay), despite probable industrial removal of ~200,000 metric tons from 1988 to 2021 via brine extraction for various mineral commodities. Lithium residence time in GSL is estimated to be ~1400 to 1600 years in the NA and 630 to 670 years in the SA. However, this estimate does not account for groundwater seepage contributions along the lake margins, as well as recycled Li that is ionically adsorbed to clay-bearing sediments and occluded within chemical sediments. Climate and lacustrine thermochemical dynamics also play a temporal role in Li concentration within the GSL brine. Spatially, point sources of elevated Li concentrations from modern playa clay-oolitic-bearing sediments and sulfate-rich groundwater spring seeps show a causal link between the supply of Li and its presence in the lake brine. For example, a single spring in the NA has a Li concentration of 5.86 mg/L with a discharge of 0.0062 m3/s that equates to an input rate of ~1.15 metric tons/yr of Li into the GSL system. Whole rock geochemistry from playa and lake sediments show higher Li concentrations (23–125 ppm) than fringing groundwater (~0.02–30 mg/L) and lake brines (20–80 mg/L). These observations provide unambiguous evidence of localized sourcing of Li that is not accounted for in resource assessments, let alone as solute sources that influence GSL salinity during low lake elevations.

Other Information:
Published: 2026
Pages: 16
Plates: 2
Location: Utah
Appendices: 1
Media Type: Paper Publication