Study On Geoelectric Characteristics Of Bayingebi Formation And Identification Of Sand Body In Tamusu Area Of Inner Mongoria

Tamusu area,Alxa Right Banner,Inner Mongolia,is located in Yinggejing Depression of Bayingebi Basin.A super-large uranium deposit in Tolegai area has been discovered.It is difficult to obtain the stratum structure,sand body distribution,the development of fault structures and water-bearing strata in the study area by using the regional small-scale geophysical data due to the low degree of hydrogeological investigation,the lack of largescale geophysical data and the complex hydrological and geological structure background.Based on the project of "Advance Study on Complex Hydrogeological Conditions and Mining Technology of Tamusu Super Large Uranium Deposit",this paper has carried out a research on CSAMT in Tamusu area,Inner Mongolia.Based on the analysis of geological,hydrological and geophysical characteristics of the research area,one-dimensional,twodimensional and typical geological models are constructed,and two-dimensional OCCAM inversion is carried out.The feasibility of using CSAMT method to obtain the electrical structure of Bayingebi Formation is demonstrated.Two dimensional Occam inversion method is used to compare different inversion parameters of CSAMT data,the best parameters of two-dimensional inversion in this area are obtained,and the measured data are inversed.The vertical derivative method is used to identify the high resistivity layer boundary of layered model and borehole geological model,and it's applied to the measured CSAMT data processing.The results show that the abnormal position and the rock mass boundary corresponds well,which further proves the effectiveness of the first derivative boundary identification method.The CSAMT inversion results are inferred and interpreted by combining the known geological,geophysical and drilling data,This paper studies.the resistivity characteristics of the stratigraphic structure on typical profile,summarizes the geoelectric characteristics of "low-high-low" from top to bottom in the upper section of Bayingebi Formation,finds out that the sand body in the second section of the upper section of Bayingebi Formation is generally distributed in nearly north-south direction,and in the west is distributed in northwest-southeast direction,which is fan delta facies deposition.The results show that the large-scale CSAMT method can effectively identify the stratigraphic structure,sand body distribution and tectonic developmen in Tamusu area,which provides basic data for subsequent uranium prospecting in Tamusu area.