右江盆地层序充填动力学初探

在盆地分析及层序地层研究成果基础上,采用层序 -盆地 -地球系统的动态成因分析方法,对右江盆地进行了初步的层序充填动力学研究。首次识别出 5个级别的层序界面及相应的沉积层序,讨论了层序界面与地质事件、层序级别与盆地类型等的关系,进而建立了右江盆地层序地层格架。通过对裂谷盆地层序发育明显受同沉积断裂及基底沉降控制的分析,建立了层序成因与盆地构造活动的关系模型。在此基础上,探讨了层序充填动力学过程及其与盆地演化的关系。右江盆地层序充填过程包括陆内裂陷、陆缘裂谷、弧后裂谷和前陆造山四个阶段,经历了海西 -印支期由拉张到挤压的完整构造旋回。

Sequence Filling Dynamics of Youjiang Basin,Southern China

In the light of sequence basin earth theory in conjunction with previous stratigraphy,sedimentology,basin analysis and sequence stratigraphy,the sequence filling dynamics of Youjiang Basin has been studied in detail.Five hierachies of sequence boundaries and corresponding five hierachies of depositional sequences,1 super-order sequence,4 1st-order sequences,6 2nd-order sequences,11 sequence sets,47 3rd-order sequences and a certain amount of 4th-and 5th-order sequences have been recognized for the first time.Relationship between sequence boundary and geological events,and that of sequence hierachy and basin type have been discussed,and then sequence stratigraphic framework of Youjiang Basin has also been established.By the cognition that sequence development of rifting basin is mainly controlled by synsedimentary fault and fundamental subsidence,relationship between sequence genesis and basin structure has been set up. The sequence framework and filling proccess are obviously distinct within different genetic basins. Finally,the author delibrated the sequence filling dynamic process and related basin evolution of the Youjiang Basin.On the basis of the research result mentioned above,this paper suggests that the sequence filling process of the Youjiang Basin can be subdivided into four stages:intracontinental rifting,marginal rifting,retroarc rifting and foreland basin,constituting a complete tectonic cycles during Hercynian Indosinian stage.