Compressional wave velocity of granite and amphibolite up to melting temperatures at 1 GPa

Compressional wave velocities (V_P) at above-solidus temperatures and at 1 GPa were obtained for a granite and amphibolite, which are considered to be major constituents of the continental crust. The temperature variation of velocities showed that the V_P values of granite decreased with rising temperature, but substantially increased beyond the melting temperature (850–900 °C). Such an increase may be caused by the α–β transition of quartz. The velocities of amphibolite decreased linearly with increasing temperature and dropped sharply at temperatures above the solidus (700 °C), indicating that partial melting of amphibolite acts to significantly lower the seismic velocities.