Extending the applicability of the Raman carbonaceous-material geothermometer using data from contact metamorphic rocks

The degree of graphitization of carbonaceous material (CM) has been widely used as an indicator of metamorphic grade. Previous work has demonstrated that peak metamorphic temperature (T) of regional metamorphic rocks can be estimated by an area ratio (R2) of peaks recognized in Raman spectra of CM. The applicability of this method to low‐pressure ( 50) that adequately reflects the range of sample heterogeneity. Using this procedure (with 532‐nm laser) and adapting our new calibratio