By: Elliot Jagniecki, Andrew Rupke, Stefan Kirby, and Paul Inkenbrandt
Understanding the dynamics of the salt cycle and salt balance of Great Salt Lake (GSL) continues to be a challenge and several aspects of the system remain poorly constrained. The salt cycle and balance are important for the lake's ecosystem and industries, both of which hinge on salinity levels. The halite (NaCl) salt crust in the north arm of Great Salt Lake, Utah has existed on the lake floor since the construction of the railroad rock causeway in 1959 due to restricted flow through the causeway. Immediately prior to the opening of a new bridge in the causeway in early December 2016 when north arm lake elevation was at a historical low (just above 4189 feet), the north arm lake brine was at halite saturation. After the opening, inflow of less saline south arm water mixed with north arm water, raised lake elevation, and diluted the north arm lake brine to undersaturation with respect to halite. This study compiles field and laboratory data from 2019 to 2021 and geochemical modelling to document and understand the chemodynamic and hydrodynamic factors that influence the degree of halite saturation on a seasonal and annual basis.