He-Ar isotope geochemistry of the Yaoling-Meiziwo tungsten deposit,North Guangdong Province:Constraints on Yanshanian crust-mantle interaction and metallogenesis in SE China  

作　　者：ZHAI Wei SUN XiaoMing WU YunShan SUN YanYan HUA RenMin YE XianRen 

机构地区：[1]Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering, Guangzhou 510006, China [2]School of Marine Sciences, Sun Yat-sen University, Guangzhou 510275, China [3]Department of Earth Sciences, Sun Yat-sen University, Guangzhou 510275, China [4]Geological Survey Institute of Guangdong Nonferrous Metals Geological Survey Bureau, Guangzhou 510080, China [5]State Key Laboratory of Mineral Deposit Research, Nanjing University, Nanjing 210093, China [6]Institute of Geology and Geophysics, Chinese Academy of Sciences, Lanzhou 730000, China

出　　处：《Chinese Science Bulletin》2012年第10期1150-1159,共10页

基　　金：the National Basic Research Program of China (2007CB411404);the National Natural Science Foundation of China (40873034);the Guangdong Province Universities and Colleges Pearl River Scholar Funded Scheme (2011)

摘　　要：Isotopic abundances and ratios of He and Ar found in inclusion fluids in pyrites formed in the Yaoling-Meiziwo tungsten miner-alization epoch show that the concentration of 4He varies widely,from 1.54×10-7 cm3 STP/g to 2609×10-7 cm3 STP/g.3He is 0.759×10-12 cm3 STP/g-3.463×10-12 cm3 STP/g.3He/4He is 0.0043-4.362 Ra,varying from crustal to mantle values.The concen-tration of 40Ar ranges from 0.624×10-7 cm3 STP/g to 8.89×10-7 cm3 STP/g.The 40Ar/36Ar varies extensively,from 330 to 2952,between atmospheric and crustal or mantle radiogenic values.Mantle-derived He is present in ore-forming fluids and the calcu-lated average proportion of the mantle He is 22%;the maximum is 67%.Our research results show that mantle-derived fluids play a significant role in tungsten mineralization.The fractionation of He and Ar indicate that there was 4He-enriched air-saturated water(MSAW) in the ore-forming fluid.The ore-forming fluid was a mixture of mantle fluid,crustal magmatic fluid and MSAW.The occurrence of a mantle component in ore-forming fluid indicates the large-scale W and Sn mineralization,including Yaol-ing-Meiziwo,in southeastern China was the result of crust and mantle interaction.The underplating or intrusion of voluminous basaltic magma formed by partial melting of the upper mantle provided the necessary heat to cause partial melting of the crust and the generation of voluminous S-type granitic magmas.Crustal magmatic fluid and mantle fluid with high 3He/4He were released from magma crystallization and fractionation,mixed with the circulating modified air-saturated water,and filled the extensional tectonic fractures,leading to the formation of world-class W and Sn deposits in southeastern China.Isotopic abundances and ratios of He and Ar found in inclusion fluids in pyrites formed in the Yaoling-Meiziwo tungsten miner- alization epoch show that the concentration of 4He varies widely, from 1.54×10-7 cm3 STP/g to 2609×10-7 cm3 STP/g. 3He is 0.759×10-12 cm3 STP/g-3.463×10-12 cm3 STP/g. 3He/4He is 0.0043-4.362 Ra, varying from crustal to mantle values. The concen- tration of 40Ar ranges from 0.624×10-v cm3 STP/g to 8.89×10-7 cm3 STP/g. The 40Ar/36Ar varies extensively, from 330 to 2952, between atmospheric and crustal or mantle radiogenic values. Mantle-derived He is present in ore-forming fluids and the calcu- lated average proportion of the mantle He is 22%; the maximum is 67%. Our research results show that mantle-derived fluids play a significant role in tungsten mineralization. The fractionation of He and Ar indicate that there was 4He-enriched air-saturated water （MSAW） in the ore-forming fluid. The ore-forming fluid was a mixture of mantle fluid, crustal magmatic fluid and MSAW. The occurrence of a mantle component in ore-forming fluid indicates the large-scale W and Sn mineralization, including Yaol- ing-Meiziwo, in southeastern China was the result of crust and mantle interaction. The underplating or intrusion of voluminous basaltic magma formed by partial melting of the upper mantle provided the necessary heat to cause partial melting of the crust and the generation of voluminous S-type granitic magmas. Crustal magmatic fluid and mantle fluid with high 3He/4He were released from magma crystallization and fractionation, mixed with the circulating modified air-saturated water, and filled the extensional tectonic fractures, leading to the formation of world-class W and Sn deposits in southeastern China.

关 键 词：中国东南部 壳幔相互作用 成矿流体 同位素地球化学 钨矿 AR 广东省 地幔流体 

分 类 号：P597[天文地球—地球化学]