| The Qinghai-Tibet Plateau has always been a hot area studied by the international academia.Many scholars have studied the uplift mechanism of the plateau,the genesis of massive crust,the process of the subduction of the collision between India and the Eurasian plate,the deep deformation characteristics of the Qinghai-Tibetan lithosphere,and superficial responses.A lot of research has been done on the issue.People have proposed a series of structural models,such as subduction thickening mode,injection mode,horizontal shortening thickening mode,extrusion-escape model,Asian plate southward dive-retreat model.These models basically involve the overlap or subduction relationship between the Indian and Asian lithospheres,but there are many differences.It can be said that none of the current models can explain the complex uplifting process of the Tibetan Plateau in a relatively satisfactory manner.The reason for this is still due to the lack of support for a comprehensive and in-depth study of the plateau shells,mantle structures,thermal structures,and material states.Reliable geophysical exploration data.In particular,in the western part of the Tibetan Plateau,the terrain is complex,the topography is difficult,the transportation is very difficult,and the climate and environmental conditions are extremely harsh.Therefore,the depth of the deep geophysical exploration work of the predecessors is relatively low;and the Brahmaputra,Bangong-Nujiang and Jinsha Rivers within the plateau are three major sutures are gathered here,and the three major blocks of the Tethys Himalayas,LhasaGangdese and Qiangtang shrunk to be narrow corridors in the western part of the Qinghai-Tibet Plateau.The strong deformation characteristics of the deep lithosphere undoubtedly discuss the collision between India and Asia.The dive process and its superficial response are of great significance.Therefore,this paper selects the western part of the Tibetan Plateau as a research area and relies on the “sinoProbe-01” project under the “deep exploration technology and experimental research” special project to use the magnetotelluric sounding set in the western part of the Qinghai-Tibet Plateau.Using the standard point array observation data,193 magnetotelluric sounding data points were intercepted along E80°,E81°,E82°,and E83°,forming four MT-depth profiles that span the western part of the Qinghai-Tibet Plateau and selected with known basic geological phenomena.A more consistent and relatively reliable lithospheric electrical structure model.The model characteristics show that the lithospheric conductive structures in the western Tibetan Plateau are characterized by “horizontal zoning and vertical delamination.” The Lhasa-Gangdise block and the Qiangtang block exhibit “high-resistance body-high-conductor-middle-high resistance in the longitudinal direction.“The characteristics of stratification are that there are many obvious electrical gradients in the lateral direction.Their spatial location is basically consistent with the two sutures and other deep fractures in the area.Based on the geological and predecessor geophysical research results in the area,the paper analyzes from the perspective of electrical characteristics and believes that along the north-south direction,the Lhasa-Gandise parcel is divided into Shiquanhe-Shangzha-Cali and Longjer-The division of the Gongbuta fault is divided into three patterns of tectonic belts in the south,middle,and north;the Qiangtang block presents the structural pattern of “two ridges and one ridge”;the occurrence of the Bangong Lake-Nujiang suture belt is inclined to the north and is located The Lhasa-Gandise block on the south side subducted northward along the suture belt to the south of the Qiangtang block,which also seems to indicate that the northward dive of the Indian plate is the main mechanism of the deformation of the lithosphere in the Tibetan Plateau. |
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