札达盆地属陆相沉积盆地, 行政区划位于西藏自治区西南部, 盆地内发育别具一格的“土林”, 且沉积序列较为完备; 前人对札达盆地的演化史及地层层序有一定的研究, 但未能归纳系统总结; 本文总结相关资料文献及野外实地调查, 通过对区内进行层序地层和成因地层分析的研究方法, 为研究陆相沉积盆地提供了一条新的途径, 通过对札达盆地演化形成-发展-闭合整个过程的阐述, 搭建札达盆地沉积演化史的“格架”, 系统研究了地层垂向系列展布到沉积体系中成因相、生成环境、沉积过程、几何形态、空间展布等方面; 从而较好的展示了札达盆地演化史; 经过分析, 札达盆地可分为三个阶段: 盆地萌芽阶段、盆地发展阶段以及盆地萎缩封闭阶段; 札达盆地自上新世—早更新世期间, 盆地发展演化总体经历了由早期到晚期压陷作用发生弱—强—弱的状态变化和沉积物发生冲积—湖积—冲积的演化过程; 通过对不同阶段札达盆地演化历史细致详实的阐述, 可以了解高原地区陆相盆地产生、发展及消亡的整个过程, 对研究高原区域地貌环境以及区内生态变迁有参考作用。

Zanda Basin is a continental sedimentary basin, the administrative division is in the southwest of Xizang Autonomous Region, the basin developed a unique “soil forest”, and the sedimentary sequence is relatively complete. There have been some researches on the evolutionary history and stratigraphic sequence of Zanda Basin, yet a systematic summary remains lacking. By integrating relevant data, literature and field investigation, this paper provides a new approach for the study of continental sedimentary basins through the research methods of sequence stratigraphy and genetic stratigraphy analysis in the area. Through the description of the whole process of evolution, formation, development and closure of Zanda Basin, a “framework” of the sedimentary evolution history of Zanda Basin is built. The genetic facies, forming environment, sedimentary process, geometric form. and spatial distribution of vertical strata in sedimentary system are systematically studied. Thus, it shows the evolution history of Zanda basin. The analysis shows that the Zanda Basin can be divided into three stages: the germination stage, the development stage and the shrinking and sealing stage. During the Pliocene-Early Pleistocene period, the development and evolution of the Zanda Basin have generally experienced weak-to-strong-to-weak geological activity, accompanied by sedimentary processes transitioning from initial alluvial deposition, through lacustrine sedimentation, and back to alluvial deposition, as the basin evolved from early to late stages of depression. By elaborating the evolution history of Zanda Basin in different stages in detail, we can understand the whole process of the formation, development and extinction of continental basins in the plateau area, and provide reference for the study of geomorphic environment and ecological changes in the plateau area.