低序次韧性断裂的负反转构造研究

A Study on Negative Inverse Structure of the Subordinate Ductile Fault

赣湘地区的变质核杂岩和变质穹窿构造中,晚期脆性断裂与早期低序次韧性构造间存在着明显的相关联系。这是由于韧性断裂中的面理(S_2),经劈理、节理多次转化,由压性构造转化为张性构造并形成伸展型的脆性断裂。其演化机制在宏观上是碰撞造山形变后期的引张作用;微观上是岩石物体加工硬化的方向性等缘故。并综合分析了在荷载、边界变化的条件下,应力、应变在宏—微观上的重新分配(partitioning),导致低序次韧性构造向脆性断裂负反转的必然趋势。这方面的研究,不论在资源或是环境地质调查中均有实践意义。

In the metamorphic core complex (MCC) and the metamorphic arch, Jiangxi and Hunan area, there is an obvious correlation between the late brittle fault and the early subordinate ductile structure. It is considered that extensional type brittle faults could be generated through multiple transformations from ductile foliations (S2) to cleavages and joints, and mainly owing to the tectonic deformation from compressive to tensile. The evolution mechanism is due to a lot of causes not only a tensile action of the late period in the collision orogenic deformation in the macroscopic scale, but also a direction character of the process hardening of the rock body in the microscopic scale. A new partitioning of the stress and strain in a condition of load and boundary has been synthetically analysed in the macroscopic and microscopic scales, thus it will be inevitable trend that the subordinate ductile structure can transform into the brittle fault in the MCC, metamorphic arch and collision orogenic deformation. In this research as mentioned above, there is the important significance of practice investigation both the mineral resources and the environment geology.