Marbles from Highland complex in Sri Lanka, contained calcite-dolomite-graphite assemblage, where were metamorphosed under ultra-high temperatures. We calibrate these ultra-high temperature assemblages with calcite-dolomite solvus temperature for carbon isotopic geothermometry. Solid inclusions of maganesian calcite in forsterite and spinel in marbles showed a close system in mineralogically and have a possibility of representation of the ultra-high temperature chemical equilibrium. Then these solvus temperatures give us the best opportunity of reservation of the maximum temperatures attained. These sulvus temperatures gave us the high-temperature region of 770-890 °C . We obtained a consistent relationship between empirical carbon isotopic signature (calcite-graphite, dolomite-garphite) and the solvus temperatures of the inclusion.
