湘南新田岭白钨矿床He，Ar同位素特征及Rb-Sr测年  

He,Ar Isotope Characteristics and Rb-Sr Dating of the Xintianling Skarn Scheelite Deposit in Southern Hunan, China

作　　者：蔡明海[1] 韩凤彬[1] 何龙清[2] 刘国庆[2] 陈开旭[2] 付建明[2] 

机构地区：[1]广西大学资源与环境学院,广西南宁530004 [2]宜昌地质矿产研究所,湖北宜昌443003

出　　处：《地球学报》2008年第2期167-173,共7页Acta Geoscientica Sinica

基　　金：国土资源大调查项目“南岭锡矿成矿规律研究”(编号:200310200072)资助

摘　　要：新田岭白钨矿床是湘南W-Sn多金属矿集区中的一个大型矽卡岩型矿床,产于骑田岭岩体北接触带。本文对矽卡岩矿石中1件黄铁矿样品进行了流体包裹体He、Ar同位素测定,获得3He/4He值为4.08Ra,40Ar/36Ar为342,反映了在矽卡岩矿床的成矿流体中亦有地幔流体的显著参与;运用石英Rb-Sr法获得成矿等时线年龄为(157.4±3.2)Ma(2σ)(MSWD=1.6),87Sr/86Sr初始值为0.71044±0.00012,该年龄值与柿竹园超大型钨多金属矿床及芙蓉大型锡矿等的成矿年龄在测试误差范围内基本一致,表明中侏罗世是湘南地区钨锡成矿的高峰期。The Xintinling scheelite deposit, located in the northern contact zone of the Qitinling pluton, is a large-size skarn deposit. So far only very insufficient work has been done in this deposit. In this paper, He and Ar isotopes of fluid inclusions in pyrite was studied, and the ratio of 3He/4He obtained is 4.08 Ra （Ra = 1.4 x 10- 6, modem atmospheric ratio）, which is significantly higher than that of crustal fluids （0.01 -0.05 Ra）, suggesting that ore-forming fluids contain not only crustal-derived He but also abundant mantle-derived He. The Rb-Sr isochron dating of quartz from scheelite- quartz veins is （157.4 ± 3, 2）Ma（2o）, which indicates the ore-forming epoch of the Xintinling deposit belongs to early Yanshanian （Middle Cretaceous）. This age is consistent with that of the Shizhuyuan superlarge W-Sn polyrnetallic deposit and the Furong large Sn polymetallic deposit, implying that Middle Cretaceous is a major metallogenic epoch of W-Sn polymetallic detposits in southern Hunan.

关 键 词：HE-AR同位素 Rb-St测年 新田岭白钨矿床 湘南地区 

分 类 号：P597.1[天文地球—地球化学]