Research progress in carbonate associated sulfate

Carbonate associated sulfate, or CAS in brief, is one of the important indicators for paleoenvironmental restoration. Trace sulfate may enter carbonate lattice and replaces the carbonate during diagenesis. The CAS has the capability to preserve the isotopic composition of seawater sulfate and to record the sulfate concentration of seawater, as well as the changes in the paleoenvironment. In recent years, CAS has attracted great interest and attention from the geological society. In this paper, attempt has been made to address CAS with emphases on its pre-treatment methods, influencing factors, isotopic composition and its significance in paleoenvironmental reconstruction. The application of CAS to the restoration of different sedimentary environments is discussed, in addition to the future research directions. We hope that the introduction may raise interests and attentions from researchers.