华南南岭地区中生代花岗岩体年代学及氧逸度特征  

Geochronology and Oxygen Fugacity of Mesozoic Granites in Nanling Area of South China

作　　者：孙占亮[1] 

机构地区：[1]山西省地质调查院,山西太原030006

出　　处：《地球科学与环境学报》2014年第1期141-151,共11页Journal of Earth Sciences and Environment

基　　金：中国科学院知识创新工程重大项目(KZCX1-YW-15-1);国家自然科学基金项目(41203028)

摘　　要：华南南岭地区中生代花岗岩钨锡成矿活动十分剧烈。采集了南岭地区清湖岩体、姑婆山岩体（锡矿）、雪花顶岩体、骑田岭岩体（锡钨矿）和九峰岩体5处出露花岗岩锆石样品，并进行锆石 U-Pb年代学和微量元素分析。结果表明：花岗岩年龄主要集中在146～166 Ma之间，与前人所测年龄在误差范围内一致；其锆石Ce^4＋/Ce^3＋值总体偏低（低于200），EuN/EuN^＊值均小于0．4，无论是与锡（钨）矿有关的花岗岩还是普通花岗岩，都显示较低的氧逸度特征，明显低于年龄较老的大宝山铜钼矿、德兴斑岩铜矿的锆石Ce、Eu异常。因此，南岭地区中生代时可能离古太平洋板块俯冲带较远，受到俯冲流体影响较弱，可能形成于古太平洋板块 SW向俯冲背景下。W-Sn mineralization of Mesozoic granites in Nanling area of South China is very strong. Five granite zircon samples from Qinghu,Guposhan （Sn deposit）,Xuehuading,Qitianling （Sn-W deposit）and Jiufeng plutons in Nanling area were conducted and measured by zircon U-Pb geochronology and trace element analysis.The results show that granite ages are mainly formed at 146-166 Ma,consistent with previous measured ages within errors;all the calculated zircon Ce^4＋/Ce^3＋ values are lower than 200,the EuN/EuN^＊ values are less than 0.4,and granites related with W （Sn）deposit or barren granites have lower oxygen fuga city than that of the older Dabaoshan Mo-Cu-W deposit and Dexing porphyry Cu deposit.Therefore, Nanling area is possible far from subduction zone of Paleo-Pacific Plate in Mesozoic,is weakly influenced by subduction fluids,and is affected by SW-trending subduction of Paleo-Pacific Plate.

关 键 词：花岗岩 氧逸度 锆石U-PB年龄 钨锡矿 中生代 太平洋板块俯冲 南岭地区 

分 类 号：P588.121[天文地球—岩石学]