一种潜在的地质压力计:流体包裹体子矿物的激光拉曼光谱测压法  

A POTENTIAL GEOLOGICAL BAROMETER:NEW METHOD TO DETERMINE THE PRESSURE WITH DAUGHTER MINERALS IN FLUID INCLUSION BY RAMAN SPECTROSCOPY

作　　者：郑海飞[1] 段体玉[1] 孙樯[1] 乔二伟[1] 

机构地区：[1]北京大学地质学系,北京100871

出　　处：《地球科学进展》2005年第7期804-808,共5页Advances in Earth Science

基　　金：国家自然科学基金项目"地球内部水的突变性质及其地质作用的实验研究"(编号:40173019);教育部博士点基金项目"包裹体拉曼光谱压力计的实验研究"(编号:20030001053)资助

摘　　要：高温高压下矿物的拉曼原位测量表明,某些拉曼活性的物质其拉曼位移与压力之间具有良好的线性关系。这一特性使我们能够通过测量矿物包裹体中含有这些子矿物的拉曼位移以确定矿物的形成压力。与目前常采用的共存矿物对压力计以及流体包裹体的CO2等容线法等压力测定方法相比,该方法具有快速、方便和准确的特点。由于包裹体中可以存在各种不同的子矿物以及不同的溶液物质,因此系统研究包裹体中一切可能存在的矿物或物质的拉曼位移与温度和压力之间的关系将可以提供一种方便、准确的地质压力测量手段。In situ measurement of Raman spectroscopy at high temperature and high pressure indicates that the frequency of the Raman peak of some materials, including minerals, molecules and ions, shifts systematically with increasing pressure and temperature. This property has been used as a pressure gauge for high pressure experiment with diamond anvil cell(DAC). Since the system of fluid inclusion is similar to that of DAC, we propose that it also be used to determine the formation pressure for mineral by measuring the Raman shift of the daughter mineral and ion in fluid inclusion in geological and geochemical studies. The method is firstly to increase the temperature of the fluid inclusion to homogeneous temperature heated by heat stage and then to measure the Raman shift for the mineral or ion with Raman active mode of vibration. For ion there is no problem to get the data of the Raman shift at homogeneous temperature. As for the mineral disappearance at homogeneous temperature, the data of Raman shift can be obtained before the mineral disappears by measuring Raman shift at several lower temperatures and then extrapolating them to the homogeneous temperature. By comparing with the previous geological barometer, such as the barometer based on two co-existing minerals or the barometer on the state function of CO2 volume in fluid inclusion, we believe that the proposed method might be a more rapid, convenient and precise method for determining the geological pressure. Because there exist many possible minerals or materials with Raman active mode in the fluid inclusion in minerals, systematic measurement and study should be done to obtain the relationship between the Raman shift of minerals and the temperature and/or pressure by carrying out in situ experimental study at high temperature and high pressure.

关 键 词：流体包裹体 子矿物 拉曼光谱 压力计 

分 类 号：P59[天文地球—地球化学]