摘要
本文对采自广东台山地区和云开大山地区早古生代两类花岗岩的定向标本在常温常压、加温（最高达１０５℃）或加压（最高达５．０６×１０７Ｐａ）下对花岗岩的波速（Ｖｐ、Ｖｓｈ和Ｖｓｖ）进行了精确的测量，获得广东两类花岗岩常温常压下三种波速的平均值、Ｖｐ／Ｖｓｈ比值和油松比以及在不同温压条件下的波速变化曲线；用数理统计方法获得两类花岗岩的各向异性参数。结合岩石学、地球化学及岩石磁性的研究，分拆了广东省两类花岗岩在微观结构和成岩条件等方面的差别，并进一步揭示了两者形成时不同的大地构造背景。这一研究对花岗岩成因、岩石圈内部的结构构造研究具有十分重要的意义。
The compressional-wave velocities(Vp) and shear-wave velocities(Vsh and Vsv) of early Paleozoic S-type and I-type granitoid samples collected from the central and west part of Guangdong province were measured accurately both at atmospheric pressure and room temperature and during heating(up to 105℃) and pressuring(up to 5.06×107Pa).Through systematic Calculation,we obtained the average values of wave velocities(Vp,Vsh and Vsv),the ratio of compressional-wave velocities and shear-wave velocities(Vp/Vsh) and Poisson's ratio under atmospheric pressure and room temperature and the curves of p-wave and S-wave velocities at various pressures and temperatures. The values of wave velocities(Vp, Vsh and Vsv), Vp/Vsh and Poisson's ratio are different obviously between S-type and I-type Granitoids.The average values of wave velocities(Vp, Vsh and Vsv), Vp/Vsh and Poisson's ratio of S-type granitoids are 5005m/s,2897m/s,2591m/s and 0.25 and smaller than those of I-type granitoids(5512m/s,2937m/s, 2671m/s and 0.30); especially in compressional-wave velocities,the difference is 507m/s and is 10% of wave velocity value of S-type granitoids.The values of Vp/Vsh for S-type and I-type granitoids are larger than 1.70 and located in the normal range of granitoids, but the values of I-type granitoids are larger than that of S-type granitoids.The values of wave velocities of S-type and I-type granitoids increase gradually with increasing pressure and decrease Sradually with increasing temperature,but the range of S-type granitoids is larger than that of I-type granitoids obviously.The anisotropy of S-type granitoids is up to 1.10 and larger than that of I-type granitoids.From the elastic properties of S-type and I-type granitoids,we can conclude that the structure and porosity in S-type granitoids are better developed than those in I-type granitoids,and the granite body was intensely compressed in the direction of NNW-SSE during the process of formation.
出处
《高校地质学报》
CAS
CSCD
1995年第1期34-40,共7页
Geological Journal of China Universities
基金
国家自然科学基金
优秀中青年人才专项基金
国家教委博士点专项基金
关键词
Ⅰ型花岗岩
S型花岗岩
大地构造意义
花岗岩
I-type granitioids,S-type granitoids,elastic wave velocities(Vp,Vsh and Vsv,Guangdong province
