动态“盆山”耦合关系及其层序响应过程:以滇西兰坪—思茅盆地为例

Dynamic Basin-Orogen Coupling and Sequence Response Process:Taking Lanping-Simao Basin,Western Yunnan as a Case

动态的盆山耦合模型是伴随造山带从主碰撞阶段、后碰撞阶段到陆内阶段的演化,与之耦合的盆地会发生从前陆盆地到伸展盆地、走滑构造盆地的转换,滇西三江地区中新生代盆山耦合关系就是该概念模型的典型实例。在认识三江造山带构造演化属性和盆山转换性质的基础上,综合地层、露头和沉积资料,在各时期构造体制内探讨三江地区中生代以来动态盆山耦合过程的层序响应关系。兰坪—思茅盆地中新生界共划分出3个二级层序和11个三级层序。3个二级层序对应于前陆盆地、伸展盆地和走滑构造盆地演化阶段,代表了单一原型盆地的沉积充填。11个三级层序受非周期性的盆地基底活动控制,包括多次逆冲载荷的挠曲反应、基底幕式断陷和走滑构造活动。

Accompanied with the orogenic belt evolution stage from collision to post-collision and intraplate stage,the coupled basins transform from foreland basin to extensional basin and strike-slip structural basin,which is considered as the dynamical basin-orogen coupling model.The Mesozoic-Cenozoic basin-orogen coupling of Sanjiang region of western Yunnan is a typical example of this conceptual model.Based on strata and outcrops,we divide Mesozoic strata of Lanping-Simao basin into 3 second sequences and 11 third sequences.The 3 second sequences corresponded to the evolutional stage of foreland basin,extensional basin and strike-slip structural basin,on behalf of each single prototype of the sedimentary basin filling.The growth of 11 third sequences controlled by several times non-cyclical basin basement activities including repeatedly deflection response to thrust load,episodic faulting activity of basement,and strike-slip structural function.