In situ observation of the decomposition of kyanite at high pressures and high temperatures

Abstract

In situ observations of the decomposition of kyanite, Al 2 SiO 5 , were carried out in a multi-anvil high-pressure apparatus using synchrotron radiation, where the phase change from kyanite to stishovite + corundum was observed at high pressures and high temperatures. The phase boundary of this decomposition at T = 1200–1900 K and P = 5–15 GPa was determined to be, P (GPa) = 10.2 + 0.0016 × T (K). Previous studies using the quench method showed a discrepancy in the transition pressure of the decomposition. Our results using in-situ observations resolve this dispute.