安徽省淮南煤田颍凤区推覆构造微观变形特征及其形成机制

本文通过微观、超微观变形特征的研究,论述了颍（上）凤（台）区推覆构造是在近南北向挤压应力作用下形成的以脆性变形为主的中浅层次的上叠式推覆构造,它发生于印支末期,强烈推覆期为燕山早期,而燕山晚期—喜山早期为推覆终止和改造期。利用位错密度、亚颗粒大小等进行古构造应力的计算,说明了颍凤区推覆构造是在高应力、高应变速率的构造环境中形成和发展的。

CHARACTERISTICS OF MICROSCOPIC DEFORMATION AND MECHANISM OF THE FENGYANG-FENGTAI NAPPE IN THE YINGSHAN-FENGTAI AREA,HUAINAN COALFIELD,ANHUI

According to the study of the characteristics of microscopic and supermicroscopic deformation of the Fengyang-Fengtai nappe of the Ying- shang-Fentai area,Huainan coalfield,Anhui,it has been revealed that the nappe is a shallow-and middle-level superimposed nappe and that the main deformation of the nappe is brittle.The nappe was formed in the late stage of the Indosinian movement and best developed during the early Yanshan- ian.In the kate stage of the Yanshanian and the early stage of the Hima- layan movement,the motion of the nappe gradually stopped and then the nappe was reformed.The values of the ancient tectonic stress obtained from calculations of the dislocation density and size of the sub-grains show that the nappe was formed and developed in the tectonic environment with a high stress and high strain rate.