鄂尔多斯盆地构造应力场特征及其构造背景

通过大量断层和褶皱的野外观测以及构造形成序列的确定,同时考虑盆地形成演化过程中板块动力学背景,并结合前人的研究成果,开展了鄂尔多斯盆地古构造应力场的研究。研究表明盆地区域主压应力场方向在加里东期呈NNE-SSW向和近SN向,主要是晚奥陶世以来秦岭洋盆向北俯冲并与华北板块碰撞的结果;印支期主要呈NW-SE向和NNE-SSW向、SN向,主要受中特提斯构造动力体系中羌塘地块与欧亚大陆碰撞拼贴产生的远程构造效应影响;燕山期主要呈NW-SE向,主要受古太平洋大陆板块与欧亚大陆板块碰撞远程构造效应影响,盆地西南缘呈NE-SW向;喜马拉雅期呈NNE-SSW向,主要受新特提斯构造动力体系和今太平洋构造动力体系联合作用影响,即今太平洋板块和印度板块与欧亚板块俯冲碰撞有关。

CHARACTERISTICS AND TECTONIC SETTING OF TECTONO-STRESS FIELD OF ORDOS BASIN

On the basis of observation of a great number of joints, faults, folds in the field and classification of the formation sequences of structures, the paleo-tectonic stress fields of the Ordos Basin were studied by taking into account the plate dynamics background of formation and evolution of the Ordos Basin and the previous achievements made in this field. The directions of the major tectonic stress fields for the basin are NNE-SSW and SN respectively during the Caledonian movement, and this was resulted from the northward subduction of the Qinling ocean basin and its collision with the North China plate since late Ordovician. During the Indosinian movement, the directions of the major tectonic stress fields are along NW-SE, NNE-SSW and SN, which were basically resulted from the collision between the Qiangtang block, a part of the Tethyan dynamic system, and the Eurasian plate. During the Yanshanian movement, the direction of the major tectonic stress field is NW-SE, and this is obviously resulted from the collision between the paleo-Pacific continental plate and the Eurasian plate. During the Himalayan movement, the stress direction becomes NNE-SSW, and this is a result of the collision between both present Pacific plate and Indian plate with the Eurasian plate.