投稿时间:2017-05-16
修订日期:2017-12-27
网络发布日期:2018-07-12
中文摘要:南秧田矿床是滇东南地区最大的以钨为主的金属矿床。文章以含电气石花岗片麻岩、无矿电气石石英脉和白钨矿矿化电气石石英脉样品为研究对象,结合地质特征、电气石元素地球化学及B同位素,对电气石成因开展研究。研究显示三类电气石均属于碱性电气石中的镁电气石,以富Mg及Y位中无Al或低Al为特征,具有相对高的FeO/(FeO+MgO)比值(平均0.53);其稀土元素(REE)配分曲线与晚白垩世花岗岩稀土元素配分曲线相似;δ11B值集中在-14‰,与地壳平均值非常接近,这些特征表明其与岩浆期后热液成因的电气石特征一致。电气石石英脉中广泛的钨矿化表明晚白垩世岩浆期后热液对矿区主矿体的叠加富集作用明显,据此提出距晚白垩世花岗岩体数百米至一千米的中源距离为有利矿化区,为矿区外围及深部勘查评价指明了找矿方向。
Abstract:The Nanyangtian deposit is the largest W-polymetallic deposit in southeastern Yunnan. Tourmaline-bearing granitic gneiss, quartz vein, and scheelite-bearing tourmaline-quartz vein were emphatically studied in this paper. The genesis of tourmaline was identified by the combination of geological characteristics, geochemistry and B isotope. The result reveals that the tourmalines of three types belong to dravite characterized by high-Mg, no or low Al in Y-site, and relatively high FeO/(FeO+MgO) ratios (0.53 on average). The chondrite-normalized REE patterns are comparable with those of the Late Cretaceous granite. The δ11B values are concentrated on -14‰, approximate to the value of average crust. These features show the post-magmatic hydrothermal fluid after magmatism. Extensive W-mineralization in tourmaline quartzite shows that the hydrothermal fluid after Late Cretaceous magmatism was beneficial to re-enrichment for the major orebody in the ore district. Hence, the authors hold that the beneficial mineralized location should be located at the medium distance (from a hundred meters to 1 km) from the Late Cretaceous granite. This study provides the direction for exploration and evaluation of deep ore district.
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基金项目:本研究得到中国地质调查局地质调查项目(编号:DD20160015,1212010880402)的资助
引用文本:
张林奎,张彬,张斌辉,李光明,陈敏华,石洪召,曹华文,张寿庭.2018.云南南秧田钨矿床电气石的成分和硼同位素特征及成矿意义[J].矿床地质,37(3):481~501ZHANG LinKui,ZHANG Bin,ZHANG BinHui,LI GuangMing,CHEN MinHua,SHI HongZhao,CAO HuaWen,ZHANG ShouTing.2018.Chemical and boron isotopic composition of hydrothermal tourmaline from Nanyangtian tungsten deposit, Yunnan: Implications for ore genesis[J].Mineral Deposits37(3):481~501
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