铜官山S状背斜构造综合解析

通过褶皱、断裂、节理、线理等构造形迹的系统观测对铜官山S状背斜的形成过程和机制进行了综合构造解析,发现该背斜经过了3次构造变形,2次构造叠加复合.早期NE向褶皱的S状弯曲是由于前期EW向断裂限制的结果;晚期S状弯曲是由于新华夏构造应力场导致轴近水平的麻花状旋扭的结果;还通过物理模拟和数字模拟验证了限制型及麻花型S状构造形成机制.值得注意的是,通过铜官山S状背斜的综合构造解析可以扩大到整体下扬子台褶带的构造演化力学解析.从而证明根据局部地区的构造综合解析才是认识区域大地构造运动方式、方向及其变化最直接、最可靠的证据.

Structural Synthesis Analysis of S-Shaped Anticline in Tongguanshan

In this paper, comprehensive structural analysis of the formation process and formation mechanism of the S-shaped anticline of Tongguanshan is carried out through systematical observation of folds, faults, joints and lineation. It is found that there have been three stages of structural deformation and two structures superimposed and compounded. The S-bend of the early NE-fold is due to the limitation of the EW-direction faults. Late S-shaped bending is the result of the near-horizontal twisting due to the Newcathaysian tectonic stress field. It also verifies the formation mechanics of restricted and twisted S-shaped structures by physical simulation and numerical simulation. It is worth noting that the structural synthesis analysis of the S-shaped anticline of Tongguanshan can be expanded to the geomechanics analysis of the formation and evolution of the whole Lower Yangtze platform fold belt, showing that the detailed structural synthesis analysis of the local typical structures is the scientific basis for studying the manner and direction of the movements.