Exsolution in natural carbonate systems

The paper is concerned with exsolution in 23 natural carbonate systems: CaC O3 + MgCO3; CaCO3 + SrCO3; CaCO3 + REE2(CO3)(3); CaCO3 + BaCO3; SrCO3 + BaC O3; CaCO3 + MgCO3 + FeCO3; CaCO3 + MgCO3 + SrCO3: CaCO3 + SrCO3 + MnCO3: Ca CO3 + MgCO3 + BaCO3: CaCO3 + SrCO3 + BaC3; CaCO3 + SrCO3 + REE2(CO3)(3); Ca CO3 + SrCO3 + BaCO3 + REE2(CO3)(3); CaCO3 + SrCO3 + MgCO3 + FeCO3 + BaCO3; CaCO3 + MgCO3 + SrCO3 + BaCO3 + CaCO3 + MgCo3 + SrCO3 + Na2CO3 + REE2(CO3)( 3) CaCO3 MgCO3 + SrCO3 + BaCO3 + FeCO3; CaCO3 + FeCO3 + [S]; CaCO3 + BaCO3 + [SO4]; CaCO3 + [SO4]; CaCO3 + REE2(CO3)(3) + Na2CO3 + SrCO3 + [PO4]; CaCO 3 + SrCO3 + Na2CO3 + REE2(CO3)(3) + [PO4. 2F]; CaCO3 + SrCO3 + REE2(CO3)(3) + [2F]. The type of system was determined from the composition of exsolution produc ts and qualify spectrum of elements occupying particular positions in the s tructures of minerals of final exsolution parageneses. The major types of e xsolution are recognized from the composition of the initial phase and fina l exsolution parageneses. Each of the systems has one or more types of exso lution. We consider 38 types and several subtypes of exsolution In carbonat es, For most of them we present the geochemical compositions of the initial and exsolved phases. Decomposition of carbonates produces not only carbonate mineralization but also minerals of other types: phosphate-carbonates, fluorine-carbonates, ph osphates, sulfides, sulfates, and oxides, Among all known groups of mineral s, carbonates (particularly calcite) show the greatest number of exsolution types. Among carbonates, the most frequent and diverse exsolution processes are ob served in carbonatites. In metamorphic rocks and skarns these processes are less abundant, and in hydrothermalites they are rare.