"The Great Salt Lake (GSL) of Utah, USA, is the largest saline lake in North
America, and its brines are some of the most concentrated anywhere in the world. The lake
occupies a closed basin system whose chemistry reflects solute inputs from the weathering
of a diverse suite of rocks in its drainage basin. GSL is the remnant of a much larger
lacustrine body, Lake Bonneville, and it has a long history of carbonate deposition. Inflow
to the lake is from three major rivers that drain mountain ranges to the east and empty into
the southern arm of the lake, from precipitation directly on the lake, and from minor
groundwater inflow. Outflow is by evaporation. The greatest solute inputs are from calcium
bicarbonate river waters mixed with sodium chloride-type springs and groundwaters. Prior
to 1930 the lake concentration inversely tracked lake volume, which reflected climatic
variation in the drainage, but since then salt precipitation and re-solution, primarily halite
and mirabilite, have periodically modified lake-brine chemistry through density stratification
and compositional differentiation. In addition, construction of a railway causeway
has restricted circulation, nearly isolating the northern from the southern part of the lake,
leading to halite precipitation in the north. These and other conditions have created brine
differentiation, mixing, and fractional precipitation of salts as major factors in solute
evolution. Pore fluids and diagenetic reactions have been identified as important sources
and especially sinks for CaCO3, Mg, and K in the lake, depending on the concentration
gradient and clays."
