Making Salt from Water: The Unique Mineralogy of Alkaline Lakes

Abstract

Alkaline lakes have some of the most unique and diverse known mineral assemblages as a result of their very high pH and dissolved inorganic carbon concentrations. In these closed-basin systems, aqueous geochemistry and mineralogy are intimately linked, whereby the removal of elements through mineral precipitation controls the lake water geochemistry. The resulting extreme water chemistry of alkaline lakes produces minerals that are rare in other environments, including low-temperature minerals that record valuable environmental information and that are commonly extracted as mineral resources. Alkaline lakes are also excellent environments to study various processes in mineral crystallization, growth, and transformation, including the formation of metastable phases, precipitation after extreme supersaturation, co-precipitation of minerals, and the influence of dynamic conditions.