鄂尔多斯煤盆地西缘古构造应力场演化分析

Paleotectonic Stress Field Evolutional Analysis in West Margin of Ordos Coal Basin

通过野外节理、断层等构造形变的观测分析,恢复了鄂尔多斯盆地西缘古构造应力场分布特征。自中生代以来,研究区南、北段古构造应力场在不同时期均有所不同:印支期,北段最大主压应力方向为NW-SE向,南段为NE—SW向;燕山期,北段最大主压应力方向为NWW-SEE向,南段为NEE-SWW向;喜马拉雅期,北段主要受拉张应力,方向为NNW-SSE向;南段最大主压应力方向为NNE-SSW向。据研究区所处特殊的大地构造位置以及地球动力学背景,分析了研究区构造应力场演化的主控因素。

Through observation and analysis of field structural deformation of joints and faults, restored paleotectonic stress field distribution features in western margin of the Ordos Basin. Since Mesozoic, paleotectonic stress fields in south and north sectors of the study area were different during different periods. During Indosinian, direction of maximum principal compressive stress in north sector was NW-SE, in south sector NE-SW;during Yanshanian, in north sector, NWW-SEE, in south sector NEE-SWW;during Himalayan, in north sector was mainly controlled by tensile stress with direction of NNW-SSE, while in south sector maximum principal compressive stress with direction of NNE-SSW. Based on study area special tectonic and geodynamic settings, have analyzed study area main controlling factors of tectonic stress field evolution.