柴达木北缘煤镜质组光性组构及应力-应变分析

Vitrinite Optical Fabric and Stress-Strain Analysis of Northern Margin of Chaidamu Basin

应用应变椭球体对柴达木盆地北缘进行了应力 -应变分析 .结果表明 ,在区域构造应力场的长期作用下 ,该区以逆冲推覆构造的发育为典型特征 .强烈的构造挤压与剪切应力作用不仅使煤级提高 ,而且煤镜质组反射率光性组构的规律性十分显著 .煤镜质组反射率光性组构反映了区域上 NNE- SSW向近水平的挤压应力作用 ;盆地北缘构造煤大部分样品的镜质组反射率的弗林参数 K值大于 1 ,变形类型为缩颈型 ,仅个别样品为扁平型应变 ,反映了较高的应力 -应变环境 .

Under a long action of regional tectonic stress, the thrust and nappe were well developed, that is a typical characteristic in the northern margin of Chaidamu basin. Strong compressive and shear action of tectonic stress not only raised the coal rank but also made a remarkable regularity of reflectance and optical fabric of vitrinite. The feature of vitrinite reflectance optical fabric reflects the action of NNE SSW regional compressive force that is nearly horizontal .The Flinn parameter of most samples of tectonic coal of the northern margin of Chaidamu basin is larger than 1 and their strain type is contraction, with only a few sample being a type of flat strain. All of these have proved an high stress-strain environment in the northern margin of Chaidamu basin.