辽西钓鱼台海岸基岩节理特征及构造解析

通过对辽西兴城钓鱼台地区海岸基岩500多组节理产状的观测,运用构造解析方法,结合岩体的新老关系、节理空间组合特征,分析了节理的产状、分期及与区域构造的关系,并对节理构造破裂古应力场进行了反演。研究区节理面倾角较陡,共发育三组平面X共轭剪节理,按其展布方向分为:NW-SE与NEE-SWW向节理组、NW-SE与NWW-SEE向节理组、NW-SE与NE-SW向节理组。节理所处的古应力状态以走滑型为主,正断型次之。根据岩体侵位顺序,将构造运动分成五个阶段,对应的古应力场分别为NE-SW向拉张;NW-SE向挤压,NE-SW向拉张;NNE-SSW向挤压,NWW-SEE向拉张;NNW-SSE向挤压,NWW-SEE向拉张;近E-W向拉张,初步推断上述五个构造阶段均属于燕山期。

Characteristic and Tectonic Analysis for Joints of Coastline Bedrock in Diaoyutai, Western Liaoning

By observing the attitude of more than 500 groups of joints in coastline bedrock in Diaoyutai, Xingcheng, Western Liaoning, applying the structural analysis methods, and considering the order of rock masses and the spatial combination characteristics of joints, their relationship among attitude, staging and regional structure was analyzed. Furthermore, the paleo-stress field was also researched. It was indicated that there were three sets of plan conjugate joints, and their strikes were NW-SE and NEE-SWW, NW-SE and NWW-SEE, NW-SE and NE-SW, in which NE direction of the joints were the most development. The main type of paleo-stress field of joints is strike-slip, and the following type is fracture. According to the sequence of pluton emplacement, tectonic movement is divided into five stages, they were: NE-SW extensional movement, NW-SE compressive movement and NE-SW extensional movement, NNE-SSW compressive movement and NWW-SEE compressive movement, NNW compressive movement and NWW extensional movement,NNW-SSE compressive movement and NWW-SEE extensional movement, nearly E-W extensional movement. On the basis of the preliminary deduction, all of the five stages of tectonic movement were belonged to Yanshanian Period.