大别山榴辉岩中石榴石拉曼光谱特征及其地质学意义  

RAMAN SPECTRA FEATURES OF THE GARNET IN ELCOGITE FROM THE DABIE MOUNTAIN AND ITS GEOLOGICAL SIGNIFICANCES

作　　者：李静[1] 陆丽娜[1] 崔月菊[2] 谢超[2] 杜建国[2] 司志森[1] 

机构地区：[1]防灾科技学院,河北三河065201 [2]中国地震局地震预测研究所,北京100036

出　　处：《矿物岩石》2016年第1期17-21,共5页Mineralogy and Petrology

基　　金：中央高校基本科研业务(ZY20130202);国家自然科学基金(41373059;41403099)

摘　　要：利用拉曼分析技术测定大别山榴辉岩中石榴石的拉曼谱峰,测试结果表明榴辉岩中石榴子石的类型为镁铝-鉄铝石榴子石系列,与电子探针所得结果一致。石榴石高频区的拉曼位移与半高宽表现出反相关关系,并且从颗粒边部至中部再至边部呈现有规律的变化,具体表现为中部拉曼位移较小,在912.4cm^(-1)~913.9cm^(-1)之间,而边部拉曼位移较大,在914.6cm^(-1)~917.0cm^(-1)之间;半高宽则体现为中部较大,在23.46cm^(-1)~24.04cm^(-1)之间,而边部较小,在21.19cm^(-1)~23.11cm^(-1)之间。拉曼位移的变化体现了晶体结构的变化。说明榴辉岩折返过程中,因外部压力变化导致的矿物的晶格变形首先从颗粒中部开始,而中部及边部拉曼位移与半高宽的明显差异,说明晶格变形未达到均一化,很可能与榴辉岩的折返速率较快有关。研究榴辉岩中石榴石的拉曼谱峰特征可为探讨高压矿物在构造环境变化时的拉曼响应以及板块的俯冲及折返机制提供一定的依据。Garnet in eclogite from high pressure metamorphic belt of Dabie Mountain is investi- gated by micro-Raman spectroscopic measurement. It shows that the garnet belongs to the pyrope and almandine groups, consistent with the results obtained by electron probe analysis. The high frequency region of the Raman shift and the full width at half maximum （FWTH） of the garnet shows inverse relationship and changes regularly from the middle of the particles to the edge. Raman shift is lower in the middle ranging from 912.4 cm-1 to 913.9 cm-1 and higher in the edge ranging from 914. 6 cm-1 -to 917.0 cm-1. Conversely, FWTH in the middle changes from 23.46 cm-1 to 24.04 cm-1 while FWTH in the middle from 21.19 cm-1 to 23.11 cm-1 ,a consequence of changes of crystal structure. All of theses phenomena indicate that the lattice deformation of the garnet caused by the changes of external pressure starts from the middle of the particle during the exhumation of the eclogites. The significant differences of the Raman shift and FWHM from the middle to the edge shows that the lattice deformation is not uniform duo to the rapid exhumation of the Dabie elcogites. The study of the Rman characteristics of garnets in ectogites provides some information on discussion of Raman response of the high pressure mineral experienced the tectonic environment changes and the mechanism of the plate subduction and exhumation.

关 键 词：大别山 榴辉岩 石榴石 拉曼光谱 

分 类 号：P574.1[天文地球—矿物学] O657.37[天文地球—地质学]