| The geotectonic location of the study area is located in the Qinling-Qikun orogenic system-East Kunlun Mountains arc basin system-North Kunlun Mountains magmatic arc zone,and is located on the north side of the East KunShan Middle School of JiangSu Province fault zone.The regional structure is complex,faults are developed,magmatism is intense,and the main tectonic line is spread from northwest to near east-west.The strata are discontinuous and are greatly influenced by structures and rock masses.The strata in the structural belt are mostly exposed in the form of fault blocks and rock fragments.It is a set of disordered tectonic melange cliff belt,which has the characteristics of orogenic belt strata structure and is of great significance for prospecting and research.The study area is located in the Caleb-Xiangride Indosinian metallogenic belt in eastern Kunlun Mountains.Deep and large faults are relatively developed and magmatic rocks are widely distributed.It has favorable geological conditions for the formation of gold,silver,lead,zinc,copper and molybdenum polymetallic deposits.A number of gold,silver,copper,molybdenum and lead-zinc deposits(spots)have been found around this area.The mineralized areas have certain zoning.Therefore,this area has great prospecting potential,but the working degree and research degree are generally low.Although previous investigations and studies have made a relatively comprehensive study of mineralization in the integrated exploration area of inside in East Kunlun Mountains Gully,the research level in that area is obviously insufficient,especially the analysis of silver deposits.The distribution of various magmatic rocks and volcanic rocks in this area and their relationship with mineralization,the distribution of ore(chemical)zones and the genesis of ore deposits need further investigation and study.The outcropping strata in the study area are mainly Paleoproterozoic Jinshuikou cliff Group and Late Triassic Elashan Group,which are the main ore-bearing strata.Magmatic rocks are mainly granodiorite,monzonitic granite,basalt and rhyolite of late Triassic,which are closely related to the genesis of silver deposits in this area.The main faults are NW,NNW,NEW,NNW,NNW and NNE.The NW fault in the central and western part of the study area,the NE fault in the central part and the NNW fault in the northern part are the main ore-controlling faults in the study area.The main ore species is silver ore,and some gold mineralization and lead-zinc mineralization are also found.Silver ore bodies occur in the fractured breccia in the Jinshuikou Group stratum and the E 'La mountain stratum.Through the deep geological Engineering Verification Test,the ore bodies are mainly controlled by the fracture zone of the fracture structure in the deep,with certain extension and good continuity of the ore bodies.A total of 10 silver(mineralized)zones have been delineated in the study area.The silver(mineralized)zones in the central part of the area are mainly distributed in the northwest-southeast direction,and the width of the ore zone tends to increase in the south-east direction.There are strong limonitization,silicification,pyritization,yellow-potassium-iron-vanadium,manganese mineralization and strong kaolinization in the mineralized zone.The direction of the mineralized zone is about 155,which changes from north west to south east to north east with an inclination of 55 ~ 87.The occurrence of the mineralized zone varies greatly.TheNo.IV silver mine zone is located in the northern part of the research area.According to the surface fragmentation degree and alteration characteristics,the boundary of the silver mine zone is consistent with that of the fault fracture zone.The ore belt is distributed around the Yingan porphyry body as a whole.The main body in the ore belt iscataclastic rhyolite,rhyolite breccia lava,and structural breccia.The occurrence of the ore belt varies greatly.Through geological work,it is found that the ore characteristics in jinshuikou rock group are different from those in elashan rhyolite and the prospecting criteria on the surface.the surface of jinshuikou rock group is mainly composed of yellow-potassium-containing ferrovanadium-manganese mineralized structural breccia and cataclastic rocks,which are grayish brown to yellowish brown,with certain alteration phenomena such as limonitization,carbonation and silicification,and the oxidation degree of the ore is slightly higher.Ores in the formation of Elashan Formation mainly occur in rhyolite.The ores have strong silicification.The silicification features are mainly vein-like,cluster-like and surface-like and occur at the same time.The surface has weak limonitization,which is light yellow brown to light yellow green.The internal oxidation degree of the rocks is low.The content of primary minerals is high.The main silicification features are pyrite,arsenopyrite,chalcopyrite,galena,tetrahedrite,bornite and malachite,etc.They contain natural silver,argentite,etc.The wall rocks of the upper and lower walls of the ore(mineralized)bodies in the Jinshuikou rock group are mainly plagiogranite,granodiorite,schist and gneiss.The wall rocks have such alteration phenomena as pyritization,silicification,carbonation,epidotization,chloritization,sericitization,limonitization and kaolinization.The alteration type characteristics of surrounding rock of each ore(chemical)body are basically the same.The surrounding rocks of the upper and lower walls of the ore(chemical)bodies in the Ora mountain layer are mainly cataclastic rhyolite,breccia rhyolite and locally dacite.The rocks in the surrounding rocks near the ore are generally broken and have strong alteration.The tectonic plates in the periphery of the fracture zone are physically and chemically developed.The surrounding rocks have alteration phenomena such as silicification,pyritization,sericitization,strong kaolinization and weak epidotization,especially the kaolinization and sericitization of surface alteration.Based on the micro-temperature measurement of fluid inclusions in Shi Ying by taking samples from the main ore zone in the strata of Jinshuikou Group and the ore zone in the strata of Elashan Mountain,the temperature measurement results are as follows: the homogeneous temperature of fluid inclusions in Shi Ying of Jinshuikou Group is mainly concentrated in 275 ~ 295?,the homogeneous temperature peak value of fluid inclusions in Shi Ying of Elashan Group is mainly concentrated in 155~ 215?,and the metallogenic environment is a medium-low temperature deposit.Through the sampling of rhyolite porphyry,which is the surrounding rock on both sides of the orebody in volcanic rocks of E 'lashan Formation in the northern part of the study area,and zircon U-Pb testing and analysis of rock age,it is concluded that the rhyolite porphyry age in the study area is 217.4±3.1Ma,belonging to the Late Triassic(Guoxianzheng et al.,2018).Many experts and scholars have conducted LA-ICP-MS zircon U-Pb isotopic chronology studies on granite in the eastern section of the East Kunlun orogenic belt.The crystallization age of granite bodies in this region is about 220 Ma,and magmatic rocks in this region were relatively active in Indo-Chinese epoch.Therefore,it is presumed that intrusive rocks and extrusive rocks in this area were formed at the same time.According to the ore-forming geological characteristics of this area,ore-controlling structures occur in jinshuikou group and elashan group,and the ore-bearing rocks are related to the rocks in this area.It is inferred that the genetic type of the deposit is a medium-low temperature magmatic hydrothermal silver deposit. |
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