Geological Characteristics And Periphey Potential Prediction Of Lujiaogou Gold Deposit In Hudian City Of Jilin Province

The Jiling Huadian Lujiaogou gold deposit is located in the east of Gaoxin Village,Hongshilizi Town,Huadian City.In recent years,through a large number of geological,geophysical and geochemical exploration work,several small gold deposits has been found in the study area,with good prospecting prospects.The study area is located in the border structure of the east boundary of the northern part of North China platform,in the middle of the compounding area of the ne-trending Huifa River fault zone,nw-trending Huiquan Warehouse and the Qingchaguan-Jinyinbie fault zone,west of the Dalazi-Jiapigou polymetallic mineralization tectonic belt.The main strata exposed in the study area are: Archaeozoic Jiapigou Group Laoniugou Formation Gneissic Rocks,Neoproterozoic Seluohe Group Epimetamorphic Rocks and Cretaceous System Andesite Rocks,and there are Quaternary Holocene series developed on both sides of the river and in the valley.The orebodies are mainly present in the strata of Neoproterozoic Seluohe Group,so the strata of Seluohe Group is the stratigraphic marker condition to find the gold ore bodies.The early metamorphic deformation of the study area is manifested by the epicrustal median plates,the felsic band,the rootless folds and the gneiss median plates.In the late stage,it is influenced by the strong activity of the platform margin fault zone,forming the nw-trending tectonic structure,and developing the fault structure of the ne-trending and the trending near ns direction.The magmatic rocks in the study area are not developed.The mineralization types of the gold deposits in the study area are mainly micro-disseminated type,followed by auriferous quartz vein type and alteration(crushing)zone.Micro-disseminated is distributed unevenly from the natural gold,which is present in the contact area of the dolomitic marbleof the Seluohe Group with the sericite quartz schist or metamorphic sandstone,or is sometimes produced separately in marble,metamorphic,and metamorphic sandstone.Mineralization is obviously controlled by stratigraphic bedding,schistosity and shear cracks.The ore-bearing structure is often developed on the basis of the original bedding and schistosity,and develop to the torsional deformation and brittle deformation superposition structure,the production is consistent with the production of the formation.The alteration of the surrounding rock is characterized by strong silicification.The alteration has a large scale and a wide range,the ore body on both sides of the erosion width of 10 ~ 50 m above,the intensity of alteration and gold mineralization is proportional.Other secondary wall alterations are: sericitization,chloritization,carbonation,mylonitization,cataclastication and so on.The alteration of surrounding rock is mainly the product of dynamic metamorphism and magmatic(vein rock)activity.In the study area,the three polarizability zones and 17 local anomalous zones were identified in IP intermediate gradient sweeping.The apparent polarization value is greater than 2%,generally higher,the highest value of 13.21%.Multiple anomalies coincided with the Au-biochemical secondary halo anomalies and the discovered mineralization.13 fracture structures are inferred by apparent resistivity anomaly and high precision magnetic method,and many of them are in good agreement with known fracture structures and mineralized alteration zones,which play a guiding role in finding gold mines.The soil geochemical measurements in the study area circled 22 gold anomalies with a maximum of 161 ppb.Many anomalies and geophysical anomalies are in good agreement with the known mineralization and mineralization zones,which are the main prospecting signs for finding gold deposits.Through the above research,summed up the following prospecting signs:(1)Seluohe group sericite quartz schist,metamorphic sandstone,marble and its contact with each other is a favorable part of gold mineralization;(2)NW trending shear zone,interlayer fracture zone;(3)diorite,porphyry and other veins;(4)strong silicification,pyritization,chloritization,sericitization;(5)ore containing quartz vein with quartz + pyrite + chalcopyrite(+ galena);(6)Au,Ag,Bi,As,Mo complex anomalies or Cu,Pb anomalies.Based on the comprehensive prospecting and prospecting geologic models,a similar analogy study was carried out on the periphery of the Lujiaogou gold deposit,and the external metallogenic prediction and the potential area were divided,a total of two I-level potential area are marked,and pointed out the direction of the future prospecting.