Geochemistry of Evaporites and Evolution of Seawater

The chemistry of modern and ancient evaporites, and their parent waters, is reflected in the mineralogy and facies distribution remaining in the geologic record. The evaporation of modern seawater and the order of precipitated salts, as well as the environment in which marine evaporites are deposited, together are the key for the understanding of the fossil record. The chemical evolution of the ocean has influenced the mineralogy of the K–Mg salts, and these changes are recorded in primary fluid inclusions remaining in unaltered halite. This chapter reviews these problematic sediments, describing in detail how the evaporite mineralogy and halite fluid inclusions have been used to estimate the chemical composition of ancient oceans. Here, we present and discuss the evaporite record in the Precambrian as well as the Phanerozoic and the general geologic significance of evaporites.