Study For Electrical Structure Of Xuefeng Mountain Basement Uplift And Its Western Margin

The Xuefeng mountain area is located at the junction of Hu'nan,Guizhou and Chongqing provinces.It belongs to the middle-upper Yangtze block in structure and it is the core of South China block at the same time.The Xuefeng mountain intracontinental tectonic system experienced Caledonian movement,Indosinian movement and Yanshan movement.It has complex space-time structure.The basement of Xuefeng Mountain slipped off due to gravity during the uplift process,and there were several sets of slip-off strata in the research area.Later,the tectonic forces in the southeast direction produced a series of folds.Because of its complex structural style,it has been a hot topic for geologists for a long time.This paper relies on the "Deep Exploration Technology and Experimental Research" project(Sinoprobe 02-04)and "the Deep Geological Survey of the Qinzhou Bay-Hangzhou Bay juncture belt" while establishes three sections of SE trending magnetotelluric sounding profiles in the Xuefeng mountain area,totaling 64 observation points.We get the 2D and 3D electrical structure models of Xuefeng Mountain after data screening,processing,analysis and inversion.The depth reliability of the model was verified by taking the Line1 as an example.The results show that the Xuefengshan has the characteristics of transverse block,and the vertical stratification is not obvious.The study area is divided into three different blocks by three faults,including Hefeng-Laifeng fault,Cili-Baojing fault and Anhua-Xupu fault called trough fold zone,Xuefeng western margin extension zone and Xuefeng mountain basement uplift zone.The electrical structure in the eastern part of the study area is obviously complex,reflecting that the thrust force in the SE is greater than that in the NW.This is because the thrust force from the SE direction is blocked by the ancient crystalline basement in the Xuefeng mountain area,and the deformation range decreases gradually from SE to NW.The Xuefengshan area was in the marine sedimentary stage in the early Caledonian movement,which is conducive to the generation of oil and gas resources.At the same time,folds are propitious to the storage of oil and gas resources.So the west of Hunan area has a good prospect of oil and gas resources.The eastern margin of the study area is subject to frequent tectonic activities,a large number of faults,metal deposits were distributed in low resistivity areas near large faults,and mineralization acts on magmatic activities.It is inseparable,and the existence of faults controls the distribution of ore deposits.