投稿时间：2013-11-25
修订日期：2015-04-05
网络发布日期：2015-07-02
中文摘要:湘东南宝峰仙地区发育3个小规模花岗岩体,岩性均为黑云母二长花岗岩,与南岭产有大型-超大型钨锡多金属矿床的骑田岭和千里山岩体位于同一成矿带内,相距不远。文章通过对宝峰仙岩体进行锆石SHRIMP U-Pb测年,获得(细)中粒斑状黑云母二长花岗岩(早期)和细粒黑云母花岗岩(晚期)的形成年龄分别为(147.0±4.0) Ma(MSWD=1.6)和(141.3±3.3) Ma(MSWD=1.09),为燕山期构造岩浆活动的产物。这2种花岗岩具有高w(Si)(平均75.11%)、富w(K2O)(平均5.07%)、低w(TiO2)、w(MgO)、w(CaO),10000×Ga／Al值(大于2.6)较高、δEu较小的特点,为铝质A型花岗岩的岩石地球化学特征。宝峰仙花岗岩的εNd(t)偏高,T2DM偏小,显示在花岗岩成岩过程中有幔源组分参与,与千里山和骑田岭相似。花岗岩石成矿元素W、Sn、Pb、Zn等含量偏高,且岩体与围岩接触带的岩石蚀变较强、钨锡矿化点广泛分布。综合分析宝峰仙地区花岗岩成岩年龄、岩石地球化学特征及其所处构造位置,认为该区具有较大的钨锡多金属找矿潜力。
Abstract:This study focuses on the rock-forming age and geochemistry of Baofengxian granite stocks. The results show that these stocks are exactly similar to famous Qitianling and Qianlishan Sn(W)-forming granite in adjacent areas. Zircon SHRIMP U-Pb dating of granites reveals that two stage's intrusion took place in these stocks, with the earlier medium-grained granite formed at(147.0±4.0) Ma(MSWD=1.6) and the later fine-grained granite formed at (141.3±3.3) Ma(MSWD=1.09).The granitic samples are characterized by high SiO2(>75.11% on average) and K2O, low TiO2, MgO and CaO, and negative δEu anormalies, with high 10000×Ga／Al ratios(>2.6) like alumineous A-type granite. T2DM values of the granitic samples are obviously lower than the average value of normal granite in this area, which is consistent with regional linear distribution of lower TDM of Yanshanian granites, suggesting that mantle-crust interaction probably occurred during the anatectic event of these stocks. Ore-forming elements such as W, Sn, Pb and Zn are slightly concentrated in these samples; these features, combined with extensive distribution of numerous small W (Sn) deposits and ore spots around this stocks, imply that W (Sn) metallogenic potential perhaps exists in the Baofengxian area.
文章编号：
中图分类号：P618.44;P618.67
文献标志码：
基金项目:本文得到中国地质调查局南岭地区重要金属矿床成矿规律研究及选区评价项目(编号: 1212011120804)资助
引用文本：
陈希清,付建明,程顺波,马丽艳,卢友月.2015.湖南宝峰仙花岗岩地球化学特征与锆石 SHRIMP U-Pb定年[J].矿床地质,34(3):602~616CHEN XiQing,FU JianMing,CHENG ShunBo,MA LiYan,LU YouYue.2015.Geochemical characteristics and Zircon SHRIMP U-Pb dating of Baofengxian stocks in southern Hunan[J].Mineral Deposits34(3):602~616
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