含次生流体包裹体的石英和长石内的微量水及其地质意义  

The trace amount water in quartz and feldspar with secondary fluid inclusions and its geological significance

作　　者：韩亮[1,2] 周永胜[2] 李海兵[1] 

机构地区：[1]中国地质科学院地质研究所大陆构造与动力学国家重点实验室,北京100037 [2]中国地震局地质研究所地震动力学国家重点实验室,北京100029

出　　处：《地球物理学进展》2015年第5期1981-1989,共9页Progress in Geophysics

基　　金：自然科学基金项目(41302169,40972146)资助

摘　　要：本文采集了龙门山逆冲推覆构造带内三种不同变形程度的长英质岩石,利用傅里叶红外吸收光谱仪（FITR）,测试了包含次生流体包裹体石英和长石内的微量水,并与干净石英样品测试结果进行比较.研究表明,含次生流体包裹体的石英和长石的吸收峰基底宽缓,曲线平滑,主要吸收峰出现在3380-3450cm-1附近,造成次要吸收峰难以识别,吸收强度整体大幅提高,其中3200cm-1、3650cm-1和3730cm-1附近的微弱吸收峰更容易见到.三个样品中含次生流体包裹体的长石的水含量（0.022-0.103wt%H2O）高于石英（0.011-0.031wt%H2O）的水含量,水含量随变形程度的增加先升高后降低.含次生流体包裹体的石英和长石的水含量不能代表矿物内的结构水,但能够反映出微裂隙内流体的多少.因此,这间接指示了震后快速蠕变时期断层带边缘水含量高于中心的流体分布特征.We collected three kinds of felsic rocks with different deformation in the Longmen Shan thrust tectonic belt,and measured water contents in quartz and feldspar including some secondary fluid inclusions using Fourier transform infrared spectroscopy（FTIR）,as well as comparison with the results without secondary fluid inclusions.The absorbance spectra including secondary fluid inclusions show broadband absorbance with strong peaks ranging from 3380 to 3450cm-1,and the absorbance coefficient are higher than those without secondary fluid inclusions.The curves are very smooth that most of other peaks are difficult to be distinguished except for weak peaks at3200cm-1,3650 cm-1 and 3730 cm-1. Water content of feldspar with secondary fluid inclusions in three samples is0.022 to 0.103wt% H2 O,which is higher than that of 0.011 to 0.031wt%in quartz,and water content increase with rock deformation firstly and reduce subsequently.The water content of quartz and feldspar with secondary fluid inclusions is not precise and could not represent the trace amount water in minerals,but it agrees with the fluid flow in micro-cracks.Therefore,it indirectly indicates that the fluid flow in the fault margin is higher than that in the fault center during the postseismic creep period.

关 键 词：龙门山逆冲推覆构造带 傅里叶红外吸收光谱仪(FTIR) 石英和长石 次生流体包裹体 

分 类 号：P541[天文地球—构造地质学]