大陆逃逸构造研究现状

ADVANCES IN CONTINENTAL SCAPE STRUCTURES

大陆逃逸构造是陆内构造变形主要方式之一,系统总结分析逃逸构造形成机制,对建立大陆构造模式、认识大陆构造变形机理具有重要意义。基于目前发现的大陆逃逸构造,总结并提出了其力学机制、构造模型以及研究方法。大陆逃逸构造是板块碰撞后期在共轭的"V"字形构造控制下发展而来的重要构造形式,协调了构造应力机制的转变。在力学机制方面,逃逸构造"V"字型断裂带符合PGS模型(paired general-shear model)和先存构造活动性准则,该准则是基于库伦—摩尔准则和摩擦滑动律的扩展;构造模型方面,侧向逃逸和斜向挤出模式是逃逸构造的基本模型;研究方法方面,构造解析仍然是建立逃逸构造的基本方法,利用构造模拟进一步再现其变形过程与动力学机制是其必要的研究方法。

The continental scape structure,as one of the important structural styles to accommodate intracontinental deformation,is of great significance to understand intracontinental deformation,strain partitioning and formation mechanism during tectonic evolution of the continent.Based on the previous continental escape structures defined in structural belt,this paper synthesizes the formation mechanism,tectonic models and methods of continental scape structures.The structure is generally formed due to the limitation of conjugate V-shaped structure at the end stage of continental collision,and it plays a key role in coordinating the transformation of stress regime.Mechanically,the formation of V-shaped fracture zones coincides with the paired general-shear model and the preexisting structure activity criterion according to the Byerlee law and the Coulomb-Mohr fracture criterion.The escape models essentially include lateral escape and oblique extrusion.Structural analysis is essentially necessary in the definition of an escape structure,and tectonic modeling is a reliable tool to reconstruct and understand tectonic processes of continental lateral extrusion.