燕山中、新元古代裂陷槽构造旋回层序研究──兼论裂陷槽构造旋回概念及级序的划分

Tectonic Cyclic Sequences in the Mesoproterozoic and Neoproterozoic Aulacogen of Yanshan A Concept of Aulacogen Tectonic Cycle and Its Hierarchy

本文依据裂陷槽构造控制及演化规律的原则提出了裂陷槽构造旋回层序的概念，并同时给出了相应的三级划分方案。应用裂陷槽构造旋回层序的概念研讨了燕山地区中、新元古代裂陷槽构造旋回层序的发育特征。燕山裂陷槽发育４个构造阶段旋回层序，即裂张断陷、裂张均衡、均衡负载和盖层构造阶段旋回层序，其中又有序叠加了１８个构造期和８２个构造幕旋回层序。前一类层序主要受控于导致裂陷槽形成、发育的区域构造；

A typical aulacogen was presented around the Yanshan areas during Mesoproterozoic and Neoproterozoic,which is filled with marine and terrigenouc sediments with thousands of meters thick and highly effected by the tectonic stages and episodes of aulacogen development.The tradational sequence strtigraphy theory by Vail,P.R.(1977,1991) failed to give a satisfied interpretations to the sequences developed within aulacogen basins because of the interplays of tectonic variations, complex sediment filles and sedimentary history.Based on the tectonic evolution of aulacogen and its effections on the filles,a concept of tectonic cycle of aulacogen is worked out,and meantime a hierarchy of tectonic cycle,with three orders,is build up.In terms of aulacogen tectonic cycle the features of Mesoproterozoic and Neoproterozoic tectonic cycles of Yanshan aulacogen are reviewed in the paper.Four tectonic stage cycles,i.e.,rifting-faulting,rifting equilibrium,sediment equilibrium and stable sedimentation stages are divided,and within them 18 tectonic epoch and 82 tectonic episode subsequences are stacked orderly.According to study,the tectonic stage cycles are forced by regional or global tectonic possibly,and the tectonic epoch and episode sequences are indeed dual controls of the tectonic evolution of aulacogen and tectonic eustacy fluctuations within the rifting basins.