Effect of the Crystal Size Distribution on the Compression Wave Velocity in Rocks at High Pressure: A Preliminary Result

The olivine crystal size distribution and compression wave velocity of trachybasalt from the Qinling-Dabie orogenic belt are measured. The samples are divided into two groups. Although the samples of each groups show similar chemical composition, mineral assemblage and mineral orientation, their olivine crystal size distributions are different. However, the compression wave velocities of trachybasalt at high pressure are similar. Based on the experiment data, it is believed that if 94% minerals in a rock is less than 0.54 mm in diameter, the crystal size distribution has no effect on the compression wave velocity measured by used the lead zirconate titanate transducer (PZT) with the resonant frequency of 1 MHz. Therefore, the compression wave velocity in rock measured at laboratory can be compared with the results gained by the seismic method (such as seismic refraction survey and seismic reflection survey).