燕山运动与东亚构造体制的转变

构造体制转变的本质是动力学体系的转变。东亚构造体制的转变是从一个汇聚碰撞的动力学体系转变为一个活动大陆边缘的动力学体系。其核心问题是古太平洋板块开始向新生的亚洲大陆下俯冲。在这一独特的动力学体系转变过程中 ,产生了陆缘俯冲消减增生杂岩带 ,火山弧和相关的表壳变形等一系列标志。文中强调以自然的、显著的、易于识别的标志———火山弧的出现代表东亚构造域动力学体系的转变 ;指出翁文灏命名的燕山运动A幕———髫髻山组火山岩下的不整合 ( ( 16 0± 5 )Ma前 )和B幕———张家口组火山岩下的不整合 ( ( 13 5± 1)Ma前 )代表这一转变。也就是说 ,燕山运动是东亚构造体制转变的产物 ,其出现有着深刻的地球动力学背景

Yanshanian movement and conversion of tectonic regimes in East Asia

The conversion of tectonic regimes in East Asia is essentially the transformation of its geodynamic systems, that is, the transformation from one collision process to one subduction process. The core issue is that when the inception of Palaeo-Pacific subduction along the eastern Eurasian margin occurred, the earliest accretionary complexes resulted from the inception, continental volcanic arc and the related surface deformation successively took place during this unique tectonic process. This paper emphasizes the natural, notable and recognizable marker that is the emergence of a continental volcanic arc on the East Asia margin, which represents the conversion of the geodynamic systems. The Episode A and Episode B of the Yanshan Movement proposed by Wong (1929), are marked by the unconformity beneath the andesite volcanic rocks of the Tiaojishan formation with an age of 160±5 Ma and the unconformity beneath volcanic rocks of the Zhangjiakou formation with an age of 135±1 Ma for their bases, respectively. That is, the Yanshan Movement is the result of the conversion of tectonic regimes in East Asia, which has profound global geodynamic settings.