赣南中生代淘锡坑钨矿区花岗岩锆石SHRIMP年龄及石英脉Rb-Sr年龄测定 |
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引用本文:.2007.Precise zircon SHRIMP U-Pb and quartz vein Rb_Sr dating of Mesozoic Taoxikeng tungsten polymetallic deposit in southern Jiangxi[J].Mineral Deposits,26(4):432~442 |
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基金项目:国家科技支撑计划“南岭地区有色_贵重金属成矿潜力及综合探测技术示范研究”课题、中国地质调查局“中国成矿体系综合研究”项目、“我国重要矿产和区域成矿规律研究”项目和国家重点基础研究发展计划课题(2007CB411407) |
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中文摘要:江西省崇义县淘锡坑钨矿区位于南岭东西向构造带东段与武夷山北东—北北东向构造带南段的复合部位,属于以石英脉型黑钨矿为主的钨多金属矿床。矿床形成与燕山期中酸性岩浆作用有密切关系,石英矿脉受北西向断裂控制,穿切新元古代地层。文章选取钻孔揭露的底部新鲜花岗岩样品2件,用SHRIMP方法测定锆石的结晶年龄,结果分别为(158.7±3.9 )Ma和(157.6±3.5)Ma;对3件含黑钨矿石英脉样品中石英的流体包裹体进行了Rb-Sr等时线年龄测定,结果分别为(154±4)Ma、(157±3)Ma和(161±4)Ma。与前人用Re_Os法测定的辉钼矿(154 Ma)比较,发现花岗岩的成岩年龄与含矿石英脉、钨矿的形成年龄相同,成岩成矿作用几乎同时完成。综合前人研究资料,认为南岭地区160~150 Ma成岩成矿作用主要分布于南岭中东段,可能与岩石圈大规模伸展的构造动力学背景有关。 |
中文关键词:地球化学 淘锡坑钨矿 锆石SHRIMP年龄 石英脉Rb_Sr等时线年龄 南岭 |
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Precise zircon SHRIMP U-Pb and quartz vein Rb_Sr dating of Mesozoic Taoxikeng tungsten polymetallic deposit in southern Jiangxi |
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Abstract:The Taoxikeng tungsten deposit in central Nanling region of South China consists of vein_type ore bodies hosted in Cambrian to Jurassic strata and is closely related to Mesozoic granitic intrusions. Wolframite is the dominant ore mineral intergrown with such gangue minerals as quartz, feldspar, phlogopite and muscovite. The authors conducted zircon SHRIMP and quartz Rb_Sr dating for the purpose of better understanding the timing and genesis of the mineralization. Zircon SHRIMP dating of two granite samples yielded ages of (158.7±3.9) Ma and (157.6±3..5) Ma. Rb_Sr analyses gave a well_defined 87Rb/86Sr isochron with ages of (154±4) Ma,(157±3) Ma and (161±4) Ma. Compared with known molybdenite Re_Os dating (154 Ma), it is found that the granite and the mineralization were formed at the same time. These new data, combined with available geochronological data from other major deposits in Nanling region, suggest that large_scale W, Sn, Mo, Bi, Nb, Ta, Pb, Zn mineralization took place throughout central and eastern Nanling region at 160~150 Ma, suggesting a geodynamic setting of crustal extension during the Middle_Late Jurassic transformation of tectonic regimes. |
keywords:geochemistry, Taoxikeng tungsten deposit, zircon SHRIMP dating, quartz vein Rb_Sr dating, Nanling region |
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