Application Of Bi-dimensional Empirical Mode Decomposition(BEMD) In Extraction For Gravity Anomaly Of Ore-forming Information

Geological system is a highly complexed system.The continuous superposition of geological factors and geological process in the long time and huge spatial scale led to the earth system become very complex,and the data sets which record the complex process and the superposition phenomenon often have nonlinear structure and non-stationary characteristics.Therefore,it has very important research significance to process geological data by using nonlinear and non-stationary mathematical method.On the other hand,geophysical method has played an important role in deep geological prospecting work along with the increasing prospecting depth in recent years.Therefore,high precision,high resolution and large detection depth of gravity data have important instruction meaning on predicting underground concealed deposits as well as determing the structural ore-controlling space structure due to geophysical data can indirectly provide the earth's internal information.This article obtains the anomaly information between the different scales of geological structure in the study area and the spatial distribution relationship of its Sn-Cu polymetallic mineralization by adopting the method of bi-dimensional empirical mode decomposition(BEMD)and then extrating abnormal information on the 1:50000 gravity data in GeJiu area.Research results are as follows:1.Obtained three gravity compoents under different frequency space by using the method of bi-dimensional empirical mode decomposition(BEMD),namely,high-pass filter BIMF2,bandpass filter BIMF3 and low pass filtering BIMF4 which represent the original gravity data.Among them,the BIMF4 gravity component reflects the rock mass density of the study area,the BIMF3 gravity component reflects the regional structure in the study area,the BIMF2 gravity component reflects the local structure in the study area.2.According to the geological characteristics which represented by the gravity anomaly,we speculated that the rock mass in the deep of GeJiu mining may be a large batholith,and the rock mass of the west and concealed rock mass of the east of GeJiu mining are consanguineous,as well as invaded time may be different.The rock mass of the west and the east have certain differences on invasion deep,size,shape,lithology under an old fracture control.It has a close relation between mineralization enrichment activities and the late YanShan biotite granite in the study area,whereas the fracture and anticline structure had control effect to the Sn-Cu polymetallic mineralization.3.The deep of E-W trending structural belt in reaserch area is the prospe cting key area in the future.The E-W trending fault zone has the dual nature of ore-transporting and ore-containing structure,and fold belt is an important ore structure.As a result,the extension area and the deep of E-W trending fault zone hasa good prospecting potential.