高压下含水玄武岩熔体的结构研究

发布时间：2018-06-18 12:57

本文选题：高压 + 阻抗谱　；参考：《吉林大学》2015年硕士论文

【摘要】：关于克拉通破坏的机制通常有两种观点：拆沉机制和热侵蚀机制，无论是哪种破坏机制都会涉及到下附的软流层熔体的物理性质。本文利用高压原位测量技术测量了高压下含水玄武岩玻璃的布里渊散射光谱和拉曼光谱以及交流阻抗谱，系统的研究了高压下含水玄武岩玻璃的结构。（1）我们以氩气为传压介质测得了含水玄武岩玻璃的高压布里渊散射图谱，可以看到随着压力的增大横波和纵波都向高频移动，压力的增大使波速增加。在压力为7.1GPa左右声速随压力变化关系的曲线斜率发生了明显变化，样品的绝热剪切模量（G）、压缩率（KS）以及密度随压力的变化关系符合二阶相变特点。（2）为了验证含水玄武岩玻璃的高压布里渊散射实验中得到的二阶相变点，，我们对含水玄武岩玻璃样品进行了拉曼光谱测量。从测得含水玄武岩玻璃的拉曼光谱和拉曼峰位随压力变化关系图中可以看到：所加压力达到8GPa左右时，O-Si(Al)-O伸缩振动峰和弯曲振动峰消失了，同时新的Si-O(nb)非桥氧振动峰出现，证明含水玄武岩玻璃在8GPa左右发生了二阶相变。（3）通过测量不同压力下含水玄武岩玻璃的阻抗谱，研究了含水玄武岩玻璃在高压下的电学性质。从不同压力下含水玄武岩玻璃的的阻抗谱图中可以看出实验中没有测到晶界传导的信号，所以总电阻也就是晶粒的电阻。7.8-8.9GPa的压力范围内，样品的电阻发生了突变，这与样品在7.1GPa左右发生的二阶相变对应。
[Abstract]:There are usually two viewpoints on the mechanism of craton failure: delamination mechanism and thermal erosion mechanism, no matter which kind of failure mechanism is concerned with the physical properties of the underlying soft flow melt. Brillouin scattering spectra, Raman spectra and AC impedance spectra of aqueous basalt glasses under high pressure have been measured by high pressure in situ measurement technique. The structure of water-bearing basalt glass under high pressure is systematically studied. It can be seen that both the shear wave and the longitudinal wave move to high frequency with the increase of pressure, and the wave velocity increases with the increase of pressure. When the pressure is about 7.1 GPA, the slope of the curve of the relationship between the velocity of sound and the pressure changes obviously. The relation of the adiabatic shear modulus, compression ratio (KS) and density with pressure is in accord with the second order phase transition characteristic. In order to verify the second order phase transition point obtained in the high pressure Brillouin scattering experiment of water-bearing basalt glass, We have measured the Raman spectra of aqueous basalt glass samples. The Raman spectrum and Raman peak position of water-bearing basalt glass are measured. It can be seen that when the applied pressure reaches about 8 GPA, the stretching and bending vibration peaks of O-Si-Si-Al-O are disappeared, and the new Si-Onnb) non-bridged oxygen vibration peak appears. It is proved that the second order phase transition occurs in the water-bearing basalt glass at about 8 GPA. (3) the electrical properties of the water-bearing basalt glass under high pressure are studied by measuring the impedance spectra of the water-bearing basalt glass under different pressures. From the impedance spectra of water-bearing basalt glass under different pressures, we can see that there is no signal of grain boundary conduction in the experiment, so the total resistance, that is, the resistance of the grain is within the pressure range of 7.8-8.9 GPA, the resistance of the sample has a sudden change. This corresponds to the second order phase transition of the sample at about 7.1 GPA.
【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB332

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