A new thermal analysis technique for detecting the melting of silicates under high pressure: Application to the melting of pyrope up to 9 GPa

A new thermal analysis for the Kawai-type high-pressure apparatus has been developed for determining the melting temperatures of silicates. The thermal analysis system consists of a heating system and a temperature measurement system: the former enables us to control heating and cooling accurately through a personal computer, and the latter measures the highest and lowest temperatures of the sample precisely with two independent thermocouples. The signal of melting is detected by monitoring dΔT/dt, where ΔT is the temperature difference across the sample, and t is time. The performance of this thermal analysis method has been tested by re-determining the melting curve of pyrope up to 9 GPa. The resulting melting curve agrees well with previous results determined by quenching experiments. Further, the proposed method improves the efficiency of determining the melting curve-it has taken only three runs to construct the curve, while previous quenching experiments required thirty runs to yield similar results.