XRD graphitization degrees: a review of the published data and new calculations, correlations, and applications

A system for transformation, correlation, and unification of subordinations between d002 (Å) of semi-graphite and graphite, graphitization degrees and metamorphic temperature was created. The existing equations in the literature were analyzed and new equations, which determine correlation relationships between these parameters, were formulated. The effect of factors that control graphitization processes (temperature, general pressure and tectonic stress, structure and origin of primary carbon matter, orientation of carbon formations, fluids, mineral and chemical composition, and duration of processes) was also considered. It was concluded that the structural state of semi-graphite and graphite is reversible, and this can be used for facies diagnostics and studying of metamorphic history of graphite-bearing metamorphic rocks. A new scale for graphitization degrees was proposed.