内蒙古额济纳旗东北部雅干断裂带深部构造特征分析OACSTPCD

There exists a continued debate concerning the spatial distribution and deep structural characteristics of the Yagan fault zone in northeastern Ejina Banner,Inner Mongolia.Adhering to the known-to-unknown research approach,this study completed five magne-totelluric sounding(MT)profiles.First,it delved into the relationship between the electrical structure characteristics of a MT profile(MT01)on the west side of the study area and the geological structure information of the Yagan fault zone within the profile.In terms of electrical characteristics,the Yagan fault zone was determined as a resistivity gradient zone characterized by northward dip,high dip angles,and deep depths.Based on these characteristics,and combined with the inversion interpretation results of four MT profiles(MT02～MT05)on the east side,this study identified the deep positions and structural characteristics of the Yagan fault zone within all the MT profiles.Moreover,it determined the major electrical directions of all the MT profiles using the impedance tensor decomposition technique,and the spatial trend of the Yagan fault zone based on the two-dimensional inversion interpretation results.As revealed by the results,the Yagan fault zone within the study area exhibits an overall nearly EW strike at the shallow surface and a strike of NE45° in the deep part,with an average width of approximately 6.8 km.It is a reverse fault with a gradual arc deflection to the north from west to east,manifesting a generally northward dip direction,dip angles ranging from 60° to 67°,and a fault depth of about 20 km.The obtained deep electrical structure model effectively reveals the deep structural characteristics of the study area.providing certain reference significance for the study of regional tectonic evolution.