Geological Characteristics And Prospecting Direction Of Altered Granite Type Gold Deposit In Baizhangzi,Liaoning Province

The Baizhangzi gold deposit in Liaoning Province is located in the northern margin of the Sino-Korean paraplatform,the south-central part of the Yanliaotai fold belt,the junction of the Liaoxi sag and the Shanhaiguan paleo-uplift,the intersection of the Qinglong-Jinxi fault zone and the Xifengkou-Lingyuan fault zone,the eastern margin of the Dushan complex and the Maojiadian-Baizhangzi gold polymetallic ore concentration area in the eastern part of the Xifengkou-Lingyuan gold polymetallic ore belt.The complex geological structure evolution process makes the geological structure of this region very developed,with complex metamorphic and deformation characteristics and frequent magmatism,which provides a good geological structure background and geological conditions for regional gold mineralization.The outcrop strata in the Baizhangzi gold deposit are dominated by the Proterozoic Changcheng system and Jixian system.The Mesozoic Jurassic,Aarchean Badaohe group and Cenozoic Quaternary are scattered.The structure of the mining area is dominated by faults,followed by folds,and the main part is NE-NNE.Regional magmatic activity is intense and spanning a large time domain,mainly in Yanshanian period.The lithology is mainly medium-acidic,and the morphology is dominated by bedrock and dike rocks.The emplacement is mostly medium-shallow and ejective facies,which plays a role of thermal power source for the formation of gold deposits.More than 50 gold ore bodies have been circled in the mining area,and the ore bodies are produced in the internal and external contact zone of Baizhangzi granite.The spatial distribution of ore belt and ore body is restricted by the shape of rock mass,fault structure and the nature of surrounding rock.According to the mineralization characteristics,it is divided into quartz vein type and altered granite type ore body.Quartz vein type ore body is the main mining object in the early stage of mine production.The morphological characteristics of the shallow ore body are controlled by the development of the F2 secondary fault,while the deep ore body is controlled by the development of the rock mass and the structure in the rock mass.They are mainly distributed between 111 and 127 lines,occurring in the fractured zones of quartz sandstone and granite body of Dahongyu Formation,and the ore bodies are veinlet-like.The altered granite type,characterized by thick and large ore bodies,is the main object of mine production.The altered granitic orebody gradually becomes smaller from the upper middle section to the lower middle section,but it is still thick and large in the middle section of 0m deep,and there is no obvious pinching trend.Structure is the main ore-controlling factor of Baizhangzi gold deposit.Most of the delineated orebodies occur in NE-trending ductile shear zones,and a few occur in NW-trending and nearly EW-trending fault structures.Influenced by the nature of controlled ore structure,the NE-trending veins are large in scale and stable in extension and extension,which constitute the main body of the deposit,while the NE,NW and nearly EW-trending veins are mostly extended and extended in tens of meters,with a small scale.The main prospecting indicators of Baizhangzi gold deposit are summarized and the further prospecting direction is determined by comparing the output characteristics of known ore bodies with the data of existing prospecting results.According to the statistical results of rock electrical properties in the area,the gold-bearing quartz veins show the characteristics of medium and high resistivity,and the gold-bearing altered granites show the characteristics of medium and low resistivity.There are obvious electrical differences between the gold-bearing altered granites and the surrounding rocks and other Yanshanian magmatic rocks.The shallow part of the mining area has strong multi-level structure,which makes the resistivity reflect the alternating state of high and low resistivity in local area,and has certain influence on the identification of mineralization development sites,but the deep interpretation results show that the resistivity prospecting marks are obvious.According to the metallogenic geological conditions and electrical characteristics of mineralized altered granite,five target areas have been delineated in the deep metallogenic area of the elevation-200 line,including two I target areas and three II target areas,which provide the basis for the following exploration deployment.