镜质组反射率测试及其所反映的构造应力场

为了利用煤镜质组反射率推断豫北构造应力场，基于构造应力是造成镜质组反射率各向异性（VRA）的主要控制因素，对在豫北焦作、安阳、鹤壁三个矿区井下取的定向煤样品进行了室内显微镜下反射率测试，对测试数据按有关公式进行计算后就得出了由最大反射率值、中间反射率值、最小反射率值为轴组成的镜质组反射率椭球体（VRI）.结果表明，研究区煤样显示二轴晶正光性，它们经过了强烈的构造变形，研究区煤样镜质组反射率各向异性是由构造应力所引起；由镜质组反射率椭球体（VRI）得出的豫北构造应力场与钻探、节理统计、河南省区域构造应力场分析等方法得出的应力场基本上是吻合的，但也有一定的区别，主要体现在应力场到安阳、鹤壁矿区后发生了向左的偏转.总之，利用煤镜质组反射率各向异性推断构造应力场的方法是可行的、是有效的.

Tests on vitrinite reflectance of coal and analysis of tectonic stress field

In order to deduce the tectonic stress field in North Henan by coal vitrinite reflectance,based on the principle that the tectonic stress is the main controlling factor of the vitrinite reflectance anisotropy(VRA),we have performed tests of coal vitrinite reflectance under microscope for directional coal specimen collected from Jiaozuo,Anyang,Hebi mining field in Henan province,and gained vitrinite reflectance ellipsoids(VRI) made up of reflectance maximum,reflectance middle value and reflectance minimum through some calculation to testing data.The results show that coal specimen in studied area indicate indicatrix of optical biaxial crystal,which suffered from intense tectonic deformation and the vitrinite reflectance anisotropy(VRA) is induced by tectonic stress.The tectonic stress field of North Henan obtained from vitrinite reflectance ellipsoids(VRI) is accordant basically with the tectonic stress field acquired from other methods,such as drilling,joint statistics and Henan province territorial tectonic stress field analysis,but there is small difference that the tectonic stress field has left deflexion in Anyang and Hebi.In short,the method deducing tectonic stress field by vitrinite reflectance anisotropy(VRA) is feasible and effective.