Metallogenic Conditions And Prospecting Direction Of Erdaogaoligou Gold And Silver Deposit In Huadian City

Erdaogaoligou gold-silver deposit is located in the composite part of North China Platform and Jihei Orogenic Belt,belonging to the Archean high-grade metamorphic Area;it is located in the North China metallogenic province,Liaodong metallogenic belt,Tieling-Jingyu?secondary uplift?Fe-Au-Cu-Pb-Zn metallogenic subzone and the south-east extension of Jiapigou gold field.The main strata exposed in the study Area are Archean Majiadian upper crust rock?Ms?,Cambrian sandstone slate,crystalline limestone??₁?,Triassic conglomerate?T₃a?and sandstone section?T₃b?of Xiaoyingzi,Cretaceous acidic lava tuff?K₁?of Naerhun Formation,and Quaternary basalt.Magmatic activities are frequent in the Area.The early Archean magmatic rocks have undergone multiple metamorphism and deformation,and have become grey gneisses;the large-scale granite intrusion in the late Archean has transformed the early metamorphic rocks.The Phanerozoic magmatic activity has been manifested from Paleozoic to Mesozoic.The structural framework in this region is dominated by faults with strikes of EW,NW,NE and NS.Of these,NW and NE-trending fault are most developed.The NW-trending fault controls the distribution of cryptoexplosive breccias and production of orebody in the study Area,which are both ore-conducting and ore-hosting structures.One mineralized alteration zone and two mineralized breccia pipe structure have been discovered in the mining Area.No.2 mineralized breccia pipe structure is located in the central part of the mining Area,which is the most important metallogenic section in the Area.The orebody occurs in the contact part of the monzogranite,tonalite,and trondhjemite.At present,there are 15 ore bodies with industrial significance.They mainly exhibit idiomorphic,subhedral-xenomorphic,cataclastic,exsolu-tion,and metasomatic texture.The ore structure is dominated by breccias,massive,fine-vein,and mesh-vein etc.They show silicification,carbonation and chloritization.Metallic mineralization such as pyrite,galena,and sphalerite in breccia pipe structure and mineralization alteration such as silicification,sericitization,carbonatation and chloritization have been taken as important prospecting indicator in gold mine.The characteristics of low resistivity and high polarization of the methods-IP intermediate gradient and IP sounding have been taken as geophysical indicator.Soil geochemical anomalies with large scale,good combination of elements,high intensity and obvious concentration center characteristics are geochemical prospecting indicators.The metallogenic conditions and prospecting criteria of No.3mineralized breccia pipe structure are similar to those of No.2 in structure,geophysics and geochemistry,which is the main direction for further prospecting.The depth of the orebody in No.2 mineralized breccia pipe structure is not completely controlled,and has certain prospecting potential.