Meso-Cenozoic Tectonic Deformation And Its Relationship With Sandstone-type Uranium Deposits In Yili-Zhaosu Basin,Xinjiang

Since the beginning of the Mesozoic and Cenozoic,the West Tianshan Mountains in China,including the Yili Basin,have been influenced by the Indo-Chinese Movement,the Yanshan Movement,and the Himalayan Movement,forming a distinctly different topographical landform.The Yili-Zhaosu basin is located on the Yili micro-block supported by the Tarim plate and the Kazakhstan plate in the western Tianshan orogenic belt of China.Guided by tectonic geology and metallogenic theory of sandstone-type uranium deposits,through field investigation of Yili-Zhaosu basin,combined with measured profiles,logging data and satellite remote sensing interpretation,this paper discussed the structural deformation characteristics of Yili-Zhaosu basin,established the Mesozoic-Cenozoic tectonic evolution framework of Yili-Zhaosu basin,and discussed the migration and enrichment of uranium deposits under the effect of the structural deformation pattern.And the ore-forming period is divided according to the Cenozoic red layer.The main achievements of this paper are as follows:(1)Identify the basic characteristics of tectonic deformation in the Yili-Zhaosu Basin,and investigate their spatial distribution,geometry and kinematics.Combined with the fold deformation of the Mesozoic and Cenozoic sedimentary strata and the characteristics of tectonic geomorphology,the Yili Basin can be roughly divided into the northern fault zone,the central depression zone and the southern slope zone.Piedmont fault has two-stage motion characteristics.In the eastern part of the southern margin of the Yili Basin,there are strongly deformed folds and fault structures,the west is a weakly deformed slope zone,the middle part is the transition zone of the structural deformation strong zone,and the west is the soothing anticline and syncline combination.The thrust fault is developed in the northern part of the Zhaosu Basin,and the back-type structural uplift is in the middle.The structural features of the northern Zhaosu can be compared with the southern part of the Yili Basin.(2)The continental red layer distributed in the Ili-Zhaosu Basin was discussed.The age of the strata was tentatively defined as the Miocene.The deformation characteristics of the red layer were identified in the field,which provided a reference for the deformation of the Mesozoic and Cenozoic.The red layer covers and the evolution of the late Cenozoic tectonic framework,which divides three different metallogenic stages and a metallogenic calm period,demonstrating that the red layer has an important influence on the mineralization of sandstone-type uranium deposits.(3)The structural prototype restoration of the basin was carried out in the YiliZhaosu Basin.It is believed that the current Yili Basin is a composite product of composite stacking of different basin basins.(4)By classifying and analyzing the characteristics of faults and folds in the basin,the migration of uranium deposits is discussed,and the relationship between normal faults,reverse faults,folds,basin prototypes,Miocene red layer and groundwater migration are summarized.Thus,the role of various forms in uranium enrichment is determined and the metallogenic model is discussed.According to the enrichment characteristics of uranium deposits in Yili Basin,it has a guiding role for uranium exploration in Zhaosu Basin.