摘要：The sedimentary and structural features of the marginal zone of the sedimentary basin are very complicated.In addition,strong erosion in such areas is generally considered to be detrimental to the preservation of oil and gas,so the degree of oil and gas exploration in such areas is very low.In this paper,taking the Mesozoic and Cenozoic in the northwestern margin of the Junggar Basin,China as an example,we use the abundant seismic,logging,and core data in this area to study the mesozoic and Cenozoic tectonic evolution,and calculate the tectonic shortening in this area.The results show that the Mesozoic and Cenozoic tectonic evolution in the area since the Triassic can be divided into four stages: (1) Compression-torsional deformation stage of the Indosinian period (T); (2) During the Jurassic sedimentary period,namely the early Yanshanian period,the northwestern margin of the Junggar Basin is still in a compression-torsional deformation stage; (3) During the Cretaceous sedimentary period,namely the late Yanshanian period,the basin was in a relatively stable compression and deformation stage; (4) After the Paleogene,the Junggar Basin gradually entered the Himalayan period,during which the basin was in the tensile and shear deformation stage.Based on the principle of area conservation,the structural shortening of the seismic profile was calculated.The amount of shortening before K deposition is 3.1% ~ 4.1%; the amount of shortening before E deposition is 5.9% ~ 6.7%; the amount of shortening before N deposition is 8.2% ~ 8.4%; and the current amount of shortening is 11.4% — 11.8%.The research in this paper has certain reference value for promoting the Meso-Cenozoic oil and gas exploration in this area.
关键词：Junggar Basin;tectonic evolution;tectonic shortening;erosion thickness;hydrocarbon distribution
