太原掀斜构造特征及其成因分析

在对太原掀斜构造形迹分析的基础上,通过节理统计,以板块构造和大陆动力学理论为基础,研究了古构造应力场特征和构造演化历程。结果表明:太原掀斜构造由东山背斜、西山向斜和太原断陷组成。中生代以来的构造演化可分为中生代晚期、古近纪及新生代晚期三个阶段。主体构造,即东山背斜、西山向斜以及相伴生的南北向褶曲等都是在中生代晚期北东—南西向右旋力偶作用下形成。区内等距分布的北东东向至东西向的正断层组等次级构造及太原断陷的雏形形成于古近纪北东—南西向左旋力偶。在新生代晚期北西—南东向拉张应力作用下,太原断陷进一步拉张下陷,形成现今构造格局。不同时期应力场和板块构造动力系统不尽相同,但它们之间有继承的特点,其形成演化与区域大陆动力学条件转化和演化一致。

Characteristics and Its Formation Analysis of Taiyuan Tilting Structure

Based on the analysis of the structural features of Taiyuan tilting and joint statistics,and the plate tectonics and continental dynamics theory,the characteristics of the ancient tectonic stress field and its evolutionary process are analyzed.It show that Taiyuan tilting is composed of Dongshan anticline,Xishan syncline and Taiyuan rift.Since the Mesozoic era,the tectonic evolution process can be divided into three stages：the late Mesozoic,Paleogene and the Late Cenozoic.The main structure,including the Dongshan anticline,Xishan syncline and the accompanying north-south fold,was formed under the function of the northeast-southwest dextral couple in the late Mesozoic.The sub-structures of the normal faults and the prototype,distributed equidistantly in the east of the northeast to westeast in the region,were formed under the function of the northeast-southwest L-couple in Paleogene.In the Late Cenozoic,as the northwest-southeast tensile stress,tensile and subsidence further formed the current tectonic pattern of Taiyuan rift.The stress field is different from plate tectonic dynamic system in different periods,while they have the characteristics of hereditary,and its formation and evolution process agree with conditional transformation and evolution of regional continental dynamics.