Alteration-Mineralization Zoning And Metallogeny Of Hutouya Copper-Zinc-Lead Polymetallic Ore Deposit,Qimantage Area, Qinghai Province

Hutouya Copper-Zinc-Lead Polymetallic Ore deposit is one of the largest and most typical skarn deposits in Qimantage region.Not only the strong activities of magma intrusion, the various exposed carbonate strata of different era, and the complex ore-forming elements combination such as iron, copper, zinc, tin, molybdenum,but also both ortho-contact and exocontact substyles exist in this mine area.The skarn of ortho-contact substyle (Ⅰ、Ⅱ、Ⅲ mineral belt) mainly lies between granite and carbonate-bearing strata, and the main mineralization is Fe、Sn、Mo、Cu; the skarn of exocontact substyle (Ⅳ、Ⅴ、Ⅵ、 VII mineral belt) mainly lies in the contact zone or discortant contact bctween strata of different epochs and the lithologic boundaries,dominated by Pb、Zn、(Cu).The miner area shows obvious zonation of mineralization and alteration from the intrusive rock outwards:the metal ore-forming elements variation is Mo�'FeSnCuCo�'CuMo(PbZn)�'PbZnAg,and the appropriate alteration changes from potassium, garnetization,diopsidization to epidotization,choritization,choritization.The LA-ICP-MS zircon U-Pb dating shows that the age of granodiorite is (235.4±1.8) Ma (n=24,MSWD=1.7), the SHRIMP zircon U-Pb dating shows that the age of monzonite is (219.2±1.4)Ma(n=11,MSWD=0.83). The copper-molybdenite skarn ores and molybdenite skarn ore dating by molybdenite yield the Re-Os isochron age of (225.0±4.0)Ma(n=7,MSWD=0.24)and (230.1±4.7)Ma(n=5,MSWD=0.12), diagenesis and metallogeny age were confined in middle-late Triassic.Research on geochemical characteristics of metallogenic granite shows it’s aluminum-peraluminous, high potassium, Calc-alkaline granite,the geochemical characteristics of granite are as follows:rich in LREE,obviously negative Eu anomaly, enrichment of LILE (Rb、K、Th、U) and depletion of HFSE (Ba、Nb、Ti、P). Combination of the geochronology, petrological geochemistry and ecolutionary of regional structure characteristics,the author holds that a large-scale magma intrusion activities and polymetallic mineralization formed during post-collisional tectonic evolution stages are the production of late palaeozoic-early mesozoic tectonic cycle of East Kunlun orogenic belt.The research on sulfur lead isotope of ore mineral in mine area suggest that the34S value of metal sulfide such as chalcopyrite,galena, sphalerite,pyrite,spans among+0.6‰～+8.3‰(concentrates mainly on3‰-7‰),and the average is+4.4%o. which suggest the composition of the sulfur isotope in the ores is mainly from deep seated magmatic source, coupled with surrounding-rock Sulfur.The lead isotope ratio of metal sulfide is little(206Pb/204Pb=18.333～18.728,207Pb/204Pb=15.523～15.718,208Pb/204Pb=38.040～38.815). most Pb isotope data are plot in the area between mantle evolution-trend line and upper-crustal evolution-trend, indicating the mixation of mantle and upper crust by magmaism. The type of fluid inclusions are mainly vapor-liquid phase inclusions and daughter minerals-bearing polyphase inclusions. The variation range of the uniform temperature and salinity from fluid inclusions of different metallogenic phase are big. the uniform temperature peak concentrates on250-270℃,320-360℃and420-460℃The paper summarizes the mainly ore-controlling factors and important ore-controlling factors of Hutouya Polymetallic Ore deposit, discusses the metallogenic types, Ore-forming process and mechanism, in the end build the mineralization model.