高温高压下闪长岩弹性纵波速度的实验研究  

Experimental Reserches on Compressional Elastic Wave Velocities of Diorite at High Pressures and Temperatures

作　　者：刘巍[1] 杜建国[1] 白利平[1] 郭捷[2] 

机构地区：[1]中国地震局分析预报中心,北京100036 [2]中国科学院地球化学所,贵州贵阳550002

出　　处：《地球学报》2004年第6期683-687,共5页Acta Geoscientica Sinica

基　　金：国家自然科学基金项目 (编号 :10 2 990 40 );青年地震联合基金项目 (编号 :60 3 0 0 7)资助

摘　　要：利用YJ - 30 0 0吨压力机 ,在 1.0GPa、室温至 10 0 0℃条件下采用超声波脉冲透射 反射法就位测量了闪长岩的纵波速度 (VP) ,并在 72 0℃、780℃、870℃和 980℃获得了 4个实验产物。在 1.0GPa恒定压力下 ,闪长岩的VP 随温度升高呈线性缓慢降低 ;当温度大于 75 0℃时 ,波速开始大幅度下降。显微镜观察和电子探针鉴定结果表明 :在不同温度下闪长岩内部的矿物发生了不同程度的脱水和部分熔融等反应。波速随温度升高呈线性和非线性下降 ,主要是由于在高温高压条件下岩石内部矿物发生热膨胀、脱水和部分熔融等反应引起了岩石内部结构和成分的变化而造成的。Ultrasonic laboratory measurements of compressional velocities (V P) were carried out for diorite at 1.0 GPa from room temperature to 980 ℃ in a multi-anvil pressure apparatus. Four products were obtained at the temperatures of 720 ℃、780 ℃、870 ℃ and 980 ℃ respectively. At the constant pressure of 1.0 GPa, the V P showed an almost linear decrease with the increasing temperature. At temperature beyond 750 ℃, the V P began to decrease remarkably. The analysis result under a microscope and with an electron microprobe analyzer proves that the minerals in diorite were dehydrated and partially melted to various extents at different temperatures. The linear and nonlinear declines of velocity are attributed to the changes of rock fabrics and components in diorite due to thermal expansion of minerals, dehydration and partial melting.

关 键 词：闪长岩 部分熔融 纵波速度 矿物 温度升高 岩石 下降 显微镜观察 发生 利用 

分 类 号：P588[天文地球—岩石学] P58[天文地球—地质学]