Senior Geologist
Utah Geological Survey
Bio:
Elliot Jagniecki is a senior geologist with the Utah Geological Survey (UGS) specializing in sedimentology, chemical sediments (evaporites and carbonates), geochemistry, and paleoclimatology of modern and ancient saline systems. He received a Ph.D. from Binghamton University, NY in 2014 and worked five years on various international oil and gas basins as a petroleum geologist at ConocoPhillips prior to joining the UGS in 2018. At the UGS, he conducts limnological and hydrologic research on Great Salt Lake, particularly salinity dynamics, groundwater contribution and chemistry, and salt precipitation. Other UGS roles include resource evaluation of outcrop and subsurface geology for hydrocarbon and CO2 storage for the state of Utah.
Title: Great Salt Lake Lithium Sourcing and Groundwater Inflow Investigation
Abstract: Endorheic basins are chemical repositories for continental brines that evolve from long-term evaporative concentration of runoff, riverine, groundwater, and lacustrine sources. Lithium (Li) accumulation is a product of water-rock interaction, ambient groundwater and hydrothermal input, and mobilized by phyllosilicate ion exchange under certain chemical conditions. Great Salt Lake (GSL), Utah, has sustained average Li concentrations from ~15 to 25 mg/L in the South Arm (SA) and ~45 to 60 mg/L in the North Arm (NA) since 1966 despite probable industrial removal of ~200,000 metric tons from 1988 to 2021 via brine extraction for various mineral commodities, implying cryptic Li recharge into the GSL system. 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 of 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 provide a causal connection between the supply and destination of Li in the lake brine. For example, a single spring (~4.5 m diameter) 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 GSL or sequestered in the lakebed. 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.
