Experiment Research of Electromagnetic Exploration Method in Shujiadian Copper Deposit,Tongling,Anhui Province

TheTongling area in Anhui province is one of the important deposits for Copper-Gold-Iron-Sulfur metallogenic belt in the middle and lower reaches of the Yangtze river.In this area,there are two main metallogenic types,the porphyry type and the hydrothermal type,and the mineralization is closely related with magmatic activities.Shujiadian porphyry copper deposit is a new type of copper deposit discovered in Tongling in recent years.The ore body is mainly aboudant in the rock mass which is adjacent to the northwest-contact-zone,and is closely related with the pyroxene diorite.The effective experiment of electromagnetic exploration method for this type of ore deposit is of great significance for searching the same type of deposit in this area.In this paper,Controlled Source Audio Magnetotelluric(CSAMT)and Complex Resistivity(CR)were firstly carried out,and then the measured data were inverted.Combined with geological and drilling data,we interpreted the inversion results.The CSAMT result basically reflects the geoelectric structure in this area.the corresponding resistivity,from high to low,is granodiorite-porphyry,diorite,pyroxene-diorite,quartz-diorite-porphyry,and sandstone and siltstone strata in the Silurian Fentou formation.The copper ore body is in the transitional zone from high resistivity(diorite)to low resistivity(pyroxene diorite)and is located on the right side of the diorite.Although the CSAMT result cannot directly give response to the copper ore body,it can roughly predict the position and trend of ore body according to the high resistivity(diorite)position in each line of the CSAMT result.It can obtainρ0,m,c,τparameters from complex resistivity method.In the results of zero frequency resistivity,the resistivity of pyroxene-diorite is medium,and the resistivity of granodiorite-porphyry and diorite are high,which have the same result with CSMAT,but in the ore body,zero frequency resistivity is relatively low,polarization coefficient is medium,frequency correlation coefficient and time constant are high.Finally,the following conclusions in this paper are that CSAMT can obtain deep resistivity structure,but it can not find porphyry copper deposit directly,Whereas,it can directly find the porphyry copper deposit usingρ0,m,c,τparameters obtained from complex resistivity method.