Precipitation of calcian dolomites and magnesian calcites in the southeast of South Australia

Abstract

Magnesian calcites and calcian dolomites have been observed in active simultaneous precipitation from shallow saline waters. The total magnesium precipitating varies with geographic location. "Protodolomite" and stoichiometric dolomite found in suspension in the accumulated lagoonal sediments are discussed at length. Celestite, SrSO ₄ is also found to precipitate along with the carbonate phases. The area appears to be a high-strontium locality. The precipitation is suggested to be controlled by plant photosynthesis.