西准噶尔前陆盆地二叠纪火山—沉积序列与盆地演化耦合

Coupling Between the Permian Volcanic- Sedimentary Sequences and the Basin Evolution in the Western Junggar Foreland Basin

本文探讨了西准噶尔前陆盆地二叠系层序界面属性及层序的内部构成,识别并标定了6类层序界面:削截角度不整合、削截不整合、削蚀不整合、削蚀上超不整合、侵蚀上超不整合和上超界面,在此研究的基础上,二叠系被划分为6个三级层序。建立了区内二叠纪火山—沉积盆地演化的序列模型。下二叠统的4个三级层序是火山沉积盆地演化的结果,与前陆盆地早期残余海的演化耦合;中、上二叠统发育的两个三级层序的时空堆叠与前陆盆地晚期的盆地演化耦合。层序的堆叠是火山—沉积盆地演化的物质记录和响应,盆地演化伴随火山 沉积层序的形成与分布。

The paper discusses the attributes of the Permian sequence boundaries and the inner architectures of the sequences in the western Junggar Basin. Six types of sequence boundaries have been identified and described, which are: (1) truncation angular unconformity, (2) truncation unconformity, (3) erosional truncation unconformity, (4) erosional truncation onlap unconformity, (5) erosion onlap unconformity, and (6) onlap boundary. Based on the above study, six third-order sequences have been identified, and a model of the evolutionary succession of the Permian volcanic-sedimentary basin of the study area is suggested. Four third-order sequences in the Early Permian are the result of the evolution of the volcanic-sedimentary basin, which was coupled with the evolution of the residual sea (i. e. the early-stage foreland basin). The time-space stacking of two third-order sequences developed in the Middle and Late Permian was coupled with the late evolution of the foreland basin. The stacking of the third-order sequences is a material record of the foreland basin evolution as well as its response, while the basin evolution will accompany the formation and distribution of the volcanic-sedimentary sequences.