晶体大小分布对高压下岩石纵波速度影响的初步研究

 对化学成分、矿物成分、矿物含量及矿物定向性相近的4块新生代粗面玄武岩样品进行了橄榄石晶体大小分布和高压条件下纵波速度测量，讨论了晶体大小分布对高压条件下岩石纵波速度测量的影响。初步认为，如果岩石中有94%的矿物颗粒小于0.54 mm，那么，在高压条件下使用谐振频率为1 MHz的换能器（PZT）测量的岩石纵波波速不受岩石中矿物晶体大小分布的影响，所得的岩石纵波速度实验测量结果可以严格地与地球物理资料进行对比。

EFFECT OF THE CRYSTAL SIZE DISTRIBUTION ON THE COMPRESSIONAL WAVE VELOCITY IN ROCKS AT HIGH PRESSURE: A PRELIMINARY RESULT

The olivine crystal size distribution and compressional 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 compressional 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. 54mad in diameter, the crystal size distribution has no effect on the compressional wave velocity measured by used the lead zirconate titanate transducer (PZT) with the resonant frequency of 1MHz. Therefore, the compressional 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).