Mapping observation of residual pressure around an inclusion in sapphire by fluorescence spectroscopy

Abstract

Three dimensional mapping observations of fluorescence spectra were carried out around a mineral inclusion in sapphire. The fluorescence spectra attributable to Cr³⁺ ions every 5 micrometers or 10 micrometers and residual pressure of each measurement point was determined from the peak shift of the fluorescence line using a pressure calibration curve (Mao et al. 1986). Maximum residual pressures around the zircon and albite were 0.60GPa and 0.25GPa, respectively. The observed pressure distribution can be resulted from not only difference between thermal expansion of sapphire and inclusion, but also shape of inclusion and deformation mechanism.