The Metallogenic And Metallogenic Regularity Of The Yi Dun Island Arcbelt

The Yi dun island arc is located in the southwestern Sanjiang tectonic belt,adjacent to the Ganzi Litang suture zone on the East,and the boundary of the Jinsha River suture zone in the West.It is located between the Songpan Ganzi and the Qiangtang block,which roughly distributes in the north and south direction of the pods.A large number of different types of ore deposits have been formed in the area with strong tectonic movement and multiple stages of magma activity.These deposits are very different in size,and the ore controlling factors are complex and diverse.The mineralization and metallogenic regularity of the whole Yi Dun island arc belt are rarely studied.The age of mineralization is concentrated in 237-208 Ma and 135-65Ma(Hou Zengqian et al,2003)on the Baiyu-YiDun arc basin.This age is close to the two granite belts,which are widely exposed in the region(at the measure of the CuoJiaoMa-DongCuo granite belt and the QueShan-GeNie granite zone).Mineralization is closely related to magmatic activity.In this paper,7 typical ore deposits of different regions and different metallogenic types(Xia Cun,GA Yi Qiong,such as Jin Gou,Chang Da Gou,Ji Xue Ping,Cuo Mo Long,Sha Xi)are selected by the time-oriented demarcation scale,Based on the systematic collection of previous research results,the ore deposits are systematically sampled and light slice grinding,and some isotopes of sulphur and lead are carried out in some deposits.The experimental research and data analysis on the rock mass,trace,rare earth and zircon hafnium isotope dating of the rock mass closely related to the genesis of the deposit are analyzed,and the characteristics of the deposit characteristics,ore fabric,rock alteration and ore genesis are compared,and the relationship between the major geological events and ore formation is discussed,and the following understanding of the mineralization and metallogenic regularity in the region is obtained:1)the first stage mineralization: the interarc rift caused by different oceanic crust subduction angles in the Indosinian subduction orogenic process,that is,the Shuangfeng type volcanic rocks related to Shuangfeng type volcanic rocks(Xia Cun),jet deposit + hydrothermal metasomatism(Ga Yi Qiong),subvolcanic hydrothermal deposits(such as Jin Gou),and low angle oceanic subduction caused by the high angle oceanic subduction.The rock type deposit(Xue Ji ping),while the southern Xue Ji ping and Chang Da Gou in the north are porphyry type deposits.The location of the area is different,the depth of the magma depth is deeper.The Chang Da Gou is located in a tensional environment,and the environment of the Xue Ji Ping is a compressional environment,so it leads to the difference in the geochemistry.2)the second mineralization: the mineralization related to the tectonic environment controlled by the orogenic extensional tectonic environment after the late Yanshan arc collision,the representative deposit is a skarn type deposit related to the tin polymetallic deposit(Cuo Mo Long and Hai Long),as well as the silver lead zinc polymetallic deposit related to the hydrothermal vein(Sha Xi and Xia Sai).3)From the east to the west,the principle of spatial zoning in the Yi Dun island arc is: the central,the copper lead,zinc and silver polymetallic metallogenic belt controlled by the main arc zone in the De Ge – Xiang Cheng;in the west,the skarn-type tin polymetallic metallogenic belt and the hydrothermal vein type silver polymetallic metallogenic belt,controlled by the Bai Yu-Yi Dun arc basin,are related to the crust and mantle granite.From south to north,the regularity is mainly in the De Ge-Xiang Cheng main arc zone,and the deposit in the south is dominated by porphyry copper deposits,and the central copper lead,zinc and silver polymetallic deposits(such as Ru Jinggou and Xi Lagou)are found in the middle of the middle subvolcanic hydrothermal type.The northern part is the main(Xia Cun)and the quack poor jet sedimentary hydrothermal fluid in the northern part of the deposit type copper lead zinc deposit.The filling type copper lead zinc deposit and Chang Dagou porphyry copper deposit are represented.From the south to the north,the epiporphyry type-the supershallow subvolcanic hydrothermal type-the volcanic eruption hydrothermal type-the supershallow subvolcanic hydrothermal type-the epiporphyry type,the type of the ore deposit has a symmetrical distribution.The metallogenic elements in the Yi Dun arc zone are zoning from north to south,showing Cu polymetallic(epiporphyry type)-Pb,Zn,Cu(jet-sedimentary-hydrothermal filling)-Ag,Pb,Zn,Cu,Au(jet-deposition)-Cu,Pb,Ag,(subvolcanic type)-polymetallic(epiporphyry type).