投稿时间：2013-02-03
修订日期：2013-11-02
网络发布日期：2013-12-29
中文摘要:东天山黑峰山铁矿床、双峰山铁矿床以及沙泉子铜铁矿床位于新疆哈密盆地以南，是东天山阿齐山-雅满苏构造带的重要矿床。文章利用磁铁矿、黄铁矿和方解石的微量元素及稀土元素组成示踪了这些矿床的成矿流体来源和性质，初步探讨了矿床的成因类型。激光剥蚀（LA）-ICP-MS磁铁矿微量元素分析表明，三个矿床的磁铁矿具有非常低的w（V）、w（Cr）和w（Ti）（平均分别为68×10-6、13×10-6和237×10-6），指示磁铁矿形成于热液过程而不是岩浆分异。黄铁矿中较高的Cu含量可能反映了含Cu矿物微颗粒的存在。黄铁矿中较低的Pb、Zn含量可能反映了成矿流体中较低的Pb2+和Zn2+浓度。黄铁矿中的Co/Ni比值表明这些矿床均为火山-热液成因。三个矿床黄铁矿的稀土元素总量都很低（ΣREE为0.58×10-6~3.02×10-6），黑峰山铁矿中的黄铁矿轻、重稀土元素分馏不明显，双峰山铁矿和沙泉子铜铁矿中的黄铁矿均为轻稀土元素富集型，（La/Yb）N分别为3.51~13.4和2.76~17.2。三个矿床略有差别的方解石稀土元素配分模式，反映了其流体组成和形成机制的差别。黑峰山铁矿中的重稀土元素富集型的方解石稀土元素配分模式为方解石Sm-Nd定年提供了依据。三个矿床的黄铁矿和方解石均无Ce异常，黑峰山铁矿中的黄铁矿和方解石表现为负Eu异常，而双峰山铁矿和沙泉子铜铁矿中的黄铁矿和方解石表现为正Eu异常，反映了三个矿床均形成于较高的温度，前者成矿流体可能为碱性，后两者成矿流体为酸性、还原性。结合前人研究成果认为，黑峰山铁矿、双峰山铁矿及沙泉子铜铁矿均为火山热液-充填（交代）矿床。
Abstract:Located in the south of Hami basin of Xinjiang, the Heifengshan, Shuangfengshan and Shaquanzi (Cu-)Fe deposits are important deposits in the Aqishan-Yamansu belt of eastern Tianshan. Based on trace element and REE geochemistry, this paper deals with the source and nature of the ore-forming fluid and also discusses ore genesis of theses deposits. LA-ICP-MS analyses show that magnetite contains low V, Cr and Ti (68×10-6, 13×10-6 and 237×10-6 on average, respectively), indicating that magnetite was derived from the hydrothermal process rather than from the magmatic differentiation. The relatively high Cu content in pyrite probably indicates Cu-bearing inclusions in pyrite, whereas low Pb and Zn concentrations in pyrite may indicate the low abundances of Pb2+ and Zn2+ in the ore-forming fluids. The Co/Ni ratios of pyrite indicate that these deposits are of volcanic-hydrothermal origin. Pyrite from these deposits is characterized by very low REE content (ΣREE=0.07×10-6~3.02×10-6). Pyrite from the Heifengshan Fe deposit shows no obvious fractionation between LREE and HREE, whereas pyrite from the Shuangfengshan Fe deposit and Shaquanzi Fe-Cu deposit shows significant LREE enrichment, with (La/Yb)N values being 3.51~13.4 and 2.76~17.2, respectively. The different REE patterns of calcite for these deposits indicate different fluid compositions and mechanisms responsible for the formation of calcite. There are no Ce anomalies for both pyrite and calcite, indicating the high-T formation of these deposits. Pyrite and calcite from the Heifengshan Fe deposit show REE patterns with negative Eu anomalies, whereas those from the Shuangfengshan and Shaquanzi deposits show positive Eu anomalies, indicating that the ore-forming fluids responsible for the Heifengshan Fe deposit were alkaline and those for the Shuangfengshan and Shaquanzi deposits were acid and reductive. Combined with previous studies, the authors hold that these deposits may be of the volcanic hydrothermal infilling/replacement type.
keywords:geochemistry trace elements rare earth elements magnetite pyrite calcite Fe deposit eastern Tianshan Mountains Xinjiang
文章编号：
中图分类号：P618.31;P618.41
文献标志码：
基金项目:本文得到国家973项目（编号：2012CB416804）和中国科学院“百人计划”项目（编号：KZCX2-YW-BR-09）的联合资助
引用文本：
黄小文,漆亮,孟郁苗.2013.东天山黑峰山、双峰山及沙泉子(铜)铁矿床的矿物微量和稀土元素地球化学特征[J].矿床地质,32(6):1188~1210HUANG XiaoWen,QI Liang,MENG YuMiao.2013.Trace element and REE geochemistry of minerals from Heifengshan, Shuangfengshan and Shaquanzi (Cu-)Fe deposits, eastern Tianshan Mountains[J].Mineral Deposits32(6):1188~1210
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