压力高达27GPa下天然奥长石的XRD分析（英文）  

XRD Investigation of a Natural Oligoclase at Pressure Up to 27 GPa

作　　者：杜建国[1,2] 马艳章[3,4] 祝洪洋 谢超[2] 后东斌 李营[2] 孙凤霞[2] 

机构地区：[1]防灾科技学院,河北燕郊065201 [2]中国地震局地震预测重点实验室(中国地震局地震预测研究所),北京100036 [3]Department of Mechanical Engineering,Texas Tech University [4]吉林大学超硬材料国家重点实验室,吉林长春130012 [5]高压科学技术研究中心,吉林长春130112

出　　处：《光谱学与光谱分析》2017年第4期1314-1321,共8页Spectroscopy and Spectral Analysis

基　　金：the Natural Science Foundation of China(41373059)

摘　　要：在室温高达27GPa压力下对天然奥长石(Na_(0.86)K_(0.02)Ca_(0.12)Mg_(0.01)(Fe_(0.01)Al_(1.12)Si_(2.87)O_8))粉晶进行了原位同步辐射X光衍射(XRD)测量,获得了样品的状态方程。实验数据表明随着压力增大奥长石样品在大约3.5GPa发生了三斜向单斜的相变(P1→C2)和在大约10.0GPa发生了单斜对称相变(C2→C2/m)。样品三个相的体模量计算值分别为K_0=73.8GPa(K′=10.98),K_((C2))=124GPa(K′=1.05)和K_((C2/m))=272GPa(K′=0.625)。样品的元素组成影响其T—O—T键角的刚度、M—O键的强度和Si—O—Al键角的弯曲,从而导致奥长石样品在高压行为的特殊变化。三斜相的奥长石晶胞压缩性具明显的各向异性。实验结果表明在冷俯冲带奥长石可能是碱金属和碱土金属深循环的载体。The volume compressibility of natural oligoclase （Na0. 86 K0.02 Ca0.12 Mg0.01 （Fe0.01 All. 12 Si2.87 08 ） ） was investigated by in situ powder synchrotron X-ray diffraction （XRD） methods at pressure up to 27 GPa, and the equations of state （EoS） of the oligoclase were obtained. The experimental data indicate that the oligoclase specimen underwent triclinic to monoclinic phase transition （P1 to C2） at about 3.5 GPa and a further phase transition from C2 to C2/m in monoclinic symmetry at about 10 GPa with increasing pressure. The bulk modu- lus of the triclinic phase was calculated to be K0 = 73.8 GPa, and those of monoclinic phases with C2 symmetry and C2/m symmetry to be K〈c2） = 124 GPa and K（c2/m） =272 GPa, respectively. The stiffness of the T-O-T angle, the strength of the M-O bond and bending of Si-O-A1 angle are as a function of the chemical composi- tions of feldspars. The substitution of mingled ions for main ions in the crystal structure of the oligoclase modi- fied T-O-T angle and the strength of the M-O bonds, resulting in variation of high pressure behavior of the oli- goclase. Unit cell compression of triclinic phase oligoclase is obviously anisotropic. The results indicate that oligoclase may probably contribute to the deep recycle of alkali and alkaline-earth elements in the cool subduction zone.

关 键 词：COMPRESSIBILITY BULK MODULUS Natural oligoclase XRD High pressure 

分 类 号：O657.3[理学—分析化学]