关键词: 波速, 高压－高温试验, 地壳, 延庆－怀来盆地

Abstract: According to the deep PT-conditions of the Yanhuai basin,the compressional and shear wave velocities of the representative rocks in this area were measured. Variations of wave velocities induced by phase transition of quartz and hornblende are found at certain depths. It is suggested that in the middle crust the material with both low velocity and high conductivity may not be the quartzite or rich quartz bearing rocks,but may be the rocks with aqueous minerals. The upper part of the upper crust may be composed of rocks of argillaceous limestone or its kinds,while the lower part of the upper crust may be composed of granodiorite or its kinds. In the areas without high conductivity and low velocity layer,the middle crust may be composed of granodiorite and quartzite,and in the areas with high conductivity and low velocity layer,the middle crust may be composed of rocks of hornblendite facies. The lower crust may be composed of hornblende gneiss,andesine-granulite and augite-granulite.

Key words: Wave velocities, High pressure-high temperature test, Crust, Yanqing-Huailai basin