Prediction Of Deep And Peripheral Ore-Bodies In Shipenggou Gold Deposit,Jilin Province

The study area situated in Archean metamorphic terranes in the southern part of the Dunmi fault,a matching belt between the northern margin of the North China craton and the Xingmeng orogenic zone,is located in the Tieling-Jingyu Fe-Au-Ag-Cu-Pb-Zn metallogenic belt and Huinan-Fumin Au-Fe prospecting area.Au-bearing quartz vein is the main characteristic of Au mineralization.Compared with Jiapigou mining district,regional strata of the study area are well developed relatively and is mainly constituted of Archaean Jiapigou Group being closely related to Au mineralization,the regional magmatic activity is strong,but with the absence of the Mesozoic igneous rock in the mining area,fold and fault structures is well developed,making the study area being rich in Au resources.More than 20 gold deposits such as Sandaocha,Bajiazi,Banmiaozi,Haigou,Jinchengdong gold deposits with scale ranging from small to medium to large occur in the region,making it a favorable concentration area for Au mineralization.The outcropping strata units in Shipenggou gold deposit are constituted of Yangjiadian Formation and Sandaogou Formation of Archaean Jiapigou Group.The northeast,northwest,and nearly north-south trending structures are developed,with the absence of the Mesozoic magmatism.Au mineralization are mainly hosted in Sandaogou Formation in vein shape(Au-bearing quartz vein).The ore control structure is mainly in NE direction.The wall rock alteration is mainly constituted of silicification,sericite,chloritization and carbonatization.The Shipenggou gold deposit is considered as an orogenic gold deposit according to geological characteristics and geochemical signature of deposit.Based on the analysis of 1:10000 soil geochemical data in the study area,Au and Ag elements were determined to be the main metallogenic elements with high standard deviation,coefficient of variation,and concentration Clark values.In the term of factor loading of ore-forming elements,the elements in the study area are well categorized into four factor combinations,and the ore-forming process exhibits the characteristics of multi-period and multi-stage superposition.Moreover,the elements anomalies of Au,Ag,Hg,Zn,the combination anomalies of Au-Ag,and the abnormal superposition area of element combinations at different mineralization stages are important geochemical prospecting indicators in the study area.The magnetic anomaly in the study area is generally distributed in the northeast direction,and the gradient zone is distributed in the northeast direction.The mineralization development section shows a low and gentle negative field area,with a series of low and gentle positive anomaly areas mixed.Based on the interpretation of high-precision magnetic survey data,the structure of the study area is constituted of NEE and NWW trending structures,forming the main structural framework.Mineralization and alteration are comprehensively controlled by the shape of the ore-forming geological body,the location of occurrence changes,and the ore-forming fault structure and ore-forming structural plane.The measurement results of IP medium gradient show that the high resistivity anomalies and high polarization anomalies are mostly distributed in NE trending strips,and there are no relatively concentrated zones of anomalies.The changes of morphology and occurrence of geological body,especially the intersection and composite positions of geological body boundaries(structural planes)and ore control structures,as well as mid low resistivity and high polarizability anomalies are determined to be the main prospecting indicators.The synthetic information mineral prediction model of Shipenggou gold deposit was established based on geological,geophysical,and geochemical data in this study,which delineated 10 prediction areas including one ClassⅠprediction area,three ClassⅡprediction areas,and six ClassⅢ prediction areas.Furthermore,based on the prediction of the deep part of the ore body,it is believed that there is further prospecting potential in the deep part of the Shipenggou I-IV mining area,providing a basis for subsequent exploration work deployment.