Great Salt Lake

The Lake Bonneville shorelines are evidence of an extensive Pleistocene freshwater lake in the Basin and Range province in western Utah. The Bonneville shoreline expressions are vanishing due to urbanization. Antelope Island State Park hosts pristine records of these ancient shorelines. America’s renowned geologist, G.K. Gilbert, deduced that valley floors were once covered by water, and isolated mountain ranges were islands. Gilbert used this area to propose the idea of isostasy (equilibrium adjustments of Earth’s crust) because individual shorelines vary in elevation; highest elevations occur where the lake was deepest. This work was the case example for illustrating the methodology of multiple working hypotheses to overcome bias in human reasoning.
Drying of Lake Bonneville left the Great Salt Lake (Gwynn, 2022). This is the largest saline lake in the Western Hemisphere, and hosts an extreme ecosystem. Distinctive ooids, microbialites, and evaporite minerals (e.g., halite, mirabilite) of this modern lake have implications for astrobiology and understanding life in extreme environments. The dynamic responses to climate change are preserved in the sedimentary records of the lake deposits. The surprising biodiversity and geodiversity of the Great Salt Lake make this a remarkable jewel of the desert.