Constraints of fluid inclusions and C, O isotopic compositions on the origin of the dolomites in the Xisha Islands, South China Sea

The study shows that the dolomitizing fluid of the dolomites in the Xisha Islands is the high salinities brine formed by seawater evaporation in the surface environment. The dolomitizing process of dolomites in the study area can be summarized as: Sea level fell down in the glacial period, and the high salinities, Mg enriched brine formed by the evaporation of seawater in the lagoon environment seeped into underlying biogenic limestone through the pores of the carbonates, and then the dolomites were formed by metasomatism.179