柴达木盆地北缘下、中侏罗统古地理及盆地类型研究

Paleogeography and basin type of the early and middle Jurassic in the northern margin of Qaidam Basin

柴达木盆地北缘侏罗系后期改造强烈,地层赋存复杂,从地面露头、钻井、地震等资料入手,采用单因素分析多因素综合作图法,对下、中侏罗统岩相古地理进行了定量研究.认为早中、侏罗世时期该区主要发育湖泊相,以滨浅湖-半深湖相为主;现今下、中侏罗统的分布范围并不代表其原始沉积盆地的边界,原始沉积盆地的北边界在南祁连山边界大断裂附近;北缘早、中侏罗世时期为伸展断陷盆地.

In the late stage of the Jurassic,the northern margin of Qaidam Basin is intensely remade,and its formation occurrence is complex.Based on core data,outcrop data,drilling data,seismic data and so on,the paleogeography of the early and middle Jurassic is quantitatively studied by using single-factor analysis and multi-factor mapping method.It is held that in the early and middle Jurassic,lake facies develop in the region,and it is mainly shore shallow-half-deep lake facies;its recent distribution range is not the boundary of primary sedimentary basin,and the northern border of the primary sedimentary basin is near the thrust faults of the Southern Qilian Mountains;the northern margin of Qaidam Basin is extensional faulted depression basin during the early and middle Jurassic.