This makes it possible to interpret the geochemical history of a lake from its chemical sediments. Carbonates and gypsum are the first minerals to precipitate out. The Dead Sea is at this stage. Halite precipitates out after even more evaporation. Carbonate does not precipitation because of evaporation, but is primarily inorganic.
Calcite is the most abundant carbonate in freshwater environments.
Diatoms contribute most of the silica. The largest lacustrine sequence in the world. Basins are in Wyoming, Colorado and Utah. These are well developed horizontal rhythmites. Fossils include ostracods, gastropods, pelecypods, fish and algae.