Seasonal lakes fill during the wet season, and dry up during the dry season. Each time the water dries up, the minerals it has carried from afar are deposited at the bottom of the lake. Over the centuries, this cycle accumulates significant mineral deposits on the lake bed. Geologica assumes that the lakes have since completely disappeared in deserts and wastelands, where the evaporite deposits persist, ready for exploitation. Like marine evaporites, lake evaporite deposits generally consist of gypsum and rock salt, as well as some minerals specific to lake evaporites: trona, mirabilite and borax, which occur in these proportions:

Mineral Percent
Trona (soda ash) 70%
Mirabilite 15%
Borax 15%