摘要:
西藏哈姆曲锑（金）矿床位于雅鲁藏布江结合带西缘,矿体主要赋存于晚白垩世侵入岩中,糜棱岩化闪长玢岩是其主要的赋矿围岩。矿体受NNE—SSW向断裂控制,主要呈脉状、层状、透镜状产出。在野外地质调查和分析矿床成矿地质条件的基础上,对矿床辉锑矿进行了S、Pb同位素研究,探讨了矿床的成矿物质来源。辉锑矿δ34S值在–4.7‰～–3.2‰之间,均值为（–3.97±0.05）‰,硫同位素组成分布较为集中,近似于岩浆硫（花岗岩）的范围（–4‰～9‰）,指示硫同位素具有岩浆硫的特征。辉锑矿中206Pb/204Pb的变化范围为18.557～18.690,平均值为18.622±0.002;207Pb/204Pb的变化范围为15.607～15.681,平均值为15.647±0.002;208Pb/204Pb的变化范围为38.793～39.147,平均值为38.967±0.002。矿床铅同位素组成稳定,为非放射性成因的正常铅;结合其特征值μ（9.46～9.59）以及铅同位素构造演化图解,判断矿床铅同位素组成具有壳幔混源的特征。
Abstract:
The Hamuqu antimony deposit in Tibet is located in the western margin of the Yarlung Zangbo suture zone,and ore bodies are mainly found in the Late Cretaceous mylonitized diorite porphyrite.The ore bodies in the Quzhen mineralization section,which are mainly veined,layered and lenticular-like are controlled by NNE–SSW trending faults.On the basis of field geological investigation and analysis of ore-forming geological conditions,the S and Pb isotopes of stibnite in the deposit were studied,and the sources of metallogenic materials of the deposit were discussed.Theδ34S values of stibnite range from–4.7‰to–3.2‰,with an average of–3.97‰.The distribution of sulfur isotope composition is relatively concentrated and similar to the range of magmatic sulfur（–4‰to 9‰）,indicating that sulfur isotope has the characteristics of magmatic sulfur.206Pb/204Pb isotope compositions of stibnite ranges from 18.557 to 18.690,with an average value of 18.622;207Pb/204Pb ranges from15.607 to 15.681,with an average of 15.647;208Pb/204Pb isotope value ranges from 38.793 to 39.147,with an average of 38.967.The lead isotope composition of the deposit is little variable and shows normal lead features.Combined with theμvalues （9.46～9.59） of lead isotope and the lead isotopic tectonic evolution features,we propose that the lead isotope of the deposit has the characteristics of crust-mantle mixed sources.
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