试论"盆""山"的耦合和脱耦及其运动学

AN APPROACH TO OROGENESIS-COUPLED/DECOUPLED BASIN DEVELOPMENT AND ITS KINEMATICS

"盆""山"耦合和脱耦基于中国大陆是一个经多期碰撞-拼合形成的复合大陆、因而盆地演化与造山作用息息相关而提出,其核心是盆地研究的活动论构造观,包括用造山带地层学的理论和方法研究建造的序列和用造山带古地理学的理论和方法正确进行古构造-古地理的重建,并采用地质构造的力学分析与历史分析相结合的方法和盆地动力学分析的方法。以造山作用为主线,在给予时间约束后,从4个方面(挤压与拉张空间上互为依存、走滑断裂的转换作用、深部过程的制约和构造逸脱)研究了"盆""山"的耦合特征及其运动学。文中以中国大陆中—新生代的构造演化为例分析了"盆""山"脱耦的运动学,提出认识东、西两部侏罗纪以来的分异是理解印支期"盆""山"关系解脱的关键。

Orogenesiscoupled/decoupled basin development was represented as a new thinking for study on oil and gasbearing basins. The soul of the new thinking was a tectonic outlook of mobilism on basin study, which called for two newemerging academic branches: orogenstratigraphy and orogenpaleogeography. Two methods should be emphasized: the mechanical and historical synthetic analysis of geological structures and the analysis of basin geodynamics. Because of the complexity and multiplicity of relations between 'basin' and 'orogen', the prerequisite of basinorogen analysis was to give a time restriction, namely, a unified kinematic process and geodynamic mechanics between orogenesis and basin development would be discussed within a relatively short interval. The kinematics of 'basin''orogen' coupling could be explored from four aspects. 1)Compression and tension should be interdependent spatially, and the attention be paid to some large or superlarge basins related to collision and postorogenic basins. 2)There were two kinds of strikeslip faults: one was a part of the global shearing net, whose importance in tectonics of China Continent was once neglected; another was what was in the same kinematic system with tensile or compressional faults. 3) The contrains of deep seated courses resulted in tectonic overfly, the 'basin' (or 'orogen') of shallow structural layers being coexisted with the 'orogen' (or 'basin') of deeper structural layers. 4)Tectonic escape might be regarded as a combination of the transformation of strikeslip faulting and the affection of deepseated courses, but the extension and strikeslipping in escaping areas should have some distinct characters. The key to understanding the inheritance or decoupling of the Indosinian 'basin''orogen' relation was a tectonic differentiation between the west and east parts of the ChinaSE Asia Subcontinent occurred from the Jurassic. The east part became a wide Yanshanides, where the Indosinian 'basin''orogen' relation was decoupled. A subductiontype orogeny occurred in the west part in the Early Cretaceous, which did not decouple the Indosinian 'basin''orogen' relation. Sandwiched in between the both Yanshanides, there existed a relatively stable zone not involved in the Yanshanian orogeny, where the reformation of the Himalayan movement was the crux if basins were reserved and oilgas accumulation was formed.