The Comprehensive Interpretation Of Geology And Geophysical Data In Xiaohui,Yanbian

Yanbian is rich in mineral resources,and the reserves of metal minerals play an important role in Jilin Province,especially in gold,iron,tungsten,molybdenum and other mineral resources.The Xiaohuitun area is located in the south-west of Yanbian eugeosynclinal fold belt(II),the Jilin Heilongjiang Variscan fold system(I),in the Tianshan-Xingan Varisca fold area(I).The southwest side which is bordered by the Huifa River and Gudong River deep fault zone is bounded on the Helong fault block,China-North Korean paraplatform.The east side is adjacent to the Yanji graben basin.Therefore,it has a great potential in finding mineral in the area of Xiaohuitun.And it is of great significance to comprehensively interpret the data which is about mineral resource in Xiaohuitun area from the aspact of geophysical and geology.This paper focuses on a mature method which is the finite element numerical simulation method.Variational principle and weighted residual method are the theoretical basis of finite element method.When using the finite element method to solve the partial differential equation,the functional is constructed so that the extremum can be determined.Solving the extremum of functional means transforming the problem of boundary value into variation,which is called variational principle.The study area is divided into many small units that are linear interpolated and analyzed,and then the linear equations of each node in the study area are deduced.Finally the values of geophysical field in each node can be obtained by the linear equations.When the electric field simulates,by using fundamental formula of the stable current and starting from the stable currentthe 2D point source of geoelectric field is deduced.And then the equations are constructed by using the boundary conditions.Finally the finite element method is used to continue the the electrical numerical simulation.When solving the problem of magnetic anomaly,the basic equation of magnetic potential can be deduced and the boundary conditions and initial conditions in the problems of boundary value are specified.Next the magnetic potential is calculated through solving the extreme value problems of functional following the precondition that the energy function which is so-called functional is constructed.Finally the magnetic abnormality can be worked out by using the relationship between magnetic potential and magnetic anomaly.Last but not least,the forward modeling to the typical geophysical profiles in xiaohuitun district is carried out by using the finite element method,the magnetic model and geoelectric model are established based on the real geophysical data measured by the survey.By using the software of forward fitting,the typical abnormal magnetic profile and abnormal electrical profile are forward fitted.Though systematically studing of the geological and geophysical data in this area,and combining those geological and geophysical achievement magnetic and electrical anomaly in survey regions can be interpreted.