【摘要】 位于西藏班公湖-怒江成矿带西段多龙矿集区内的拿厅斑岩Cu（Au）矿床是近年来开展勘查取得重大找矿突破的矿床之一,控制Cu资源量已达到大型规模。但目前对该矿床的地质特征、成矿岩石成因及成矿物质来源还缺乏深入的了解和研究。本文基于系统的野外地质观察、岩相学研究,结合精细的锆石SIMS U-Pb定年、锆石Hf-O同位素、岩石地球化学和蚀变-矿石矿物的H-O-S同位素分析,认为该矿床是形成于121～118Ma的斑岩型Cu（Au）矿床,与多龙Cu（Au）矿集区内多不杂、波龙、拿顿、色那、拿若和铁格隆南（荣那）矿床为同一期岩浆-热液成矿事件,其成岩-成矿峰期为120～118Ma。拿厅斑岩铜（金）矿床成矿岩体显示轻稀土富集的分配型式和缺少Eu异常,且富集大离子亲石元素（如Rb、Ba等）,而亏损高场强元素（如Nb、Ta等）,显示弧岩浆的特征,形成于班公湖-怒江洋向北俯冲的大陆边缘弧背景。锆石Hf-O同位素模拟结果显示,矿区早期的安山-英安质次火山岩(ε_Hf（t）=-2. 0～10. 3;δ¹⁸O=5. 07‰～6. 77‰)具有早期幔源岩浆和经历MASH过程混入壳源的岩浆（10%～20%壳源物质）的特征;而二长花岗斑岩和成矿花岗闪长斑岩(ε_Hf（t）=1. 7～3. 3;δ¹⁸O=6. 40‰～6. 95‰)则是MASH过程逐渐演化（壳源-幔源混合,约20%～40%壳源物质）的产物。在形成拿厅斑岩铜金矿成矿岩浆的过程中,没有发生陆壳加厚的过程;岩浆演化过程中有较少斜长石分离结晶,主要为角闪石和钛铁氧化物结晶分异。另外,热液蚀变（石英、磁铁矿）和硫酸盐-硫化物（硬石膏、黄铜矿、黄铁矿）的H-O-S同位素结果显示,拿厅成矿流体和成矿物质主要来源于岩浆,与岩浆流体出溶过程密切有关。更多还原

【Abstract】 The large Nating porphyry Cu（ Au） deposit in the Duolong ore district is one of the most significant deposits newly discovered in the western section of the Bangong Co-Nujiang metallogenic belt（ Tibet）. However,there is still no deep understanding on geological characteristics of the deposit,the genesis of its ore-forming rocks,and ore-forming material sources. Based on systemic field geological survey and petrographic studying upon rocks of this deposit,combined with precise zircon SIMS U-Pb dating and Hf-O isotopic analysis,petrochemistry analysis,and H-O-S isotope study of the hydrothermal minerals of this deposit,it is concluded that the Nating deposit is a Cretaceous（ ca. 121 ～ 118 Ma） porphyry Cu（ Au） deposit. The age is consistent with those of other deposits（ e. g.,Bolong,Nadun,Sena,Naruo,and Teglongnan/Rongna deposits） in the Duolong Cu（ Au） ore district,suggesting that they belong to the same period of magmatic-hydrothermal event with peak period of mineralization of 120 ～ 118 Ma. The magmatic rocks show LREE enrichment patterns with absent of Eu anomalies,and enrichment in large ion lithophile elements（ e. g.,Ba,Rb） and depletion in high-field strength elements（ e. g.,Nb,Ta）,showing geochemical characteristics of arc-type magma. All these evidences indicate that this deposit was likely formed in a continental marginal arc during the Bangong Co-Nujiang Ocean subduction. Moreover,zircon Hf-O isotopic compositions indicate that the early-stage andesitic-dacitic volcanic rocks( ε_Hf（ t） =-2. 0 ～ 10. 29; δ¹⁸O = 5. 07‰ ～6. 77‰) were likely derived from magma mixing（ 10% ～ 20% crustal material） between mantle-derived mafic and crust-derived melts during the MASH process. Whereas the ore-forming granodiorite porphyry and the monzonitic granite porphyry( ε_Hf（ t） = 1. 72 ～ 3. 26;δ¹⁸O = 6. 40‰ ～ 6. 95‰) are possibly formed by evolution of the MASH process with 20% ～ 40% crustal material addition. During the period of ore-forming magma formation,there is no thickening of the continental crust occurred in this area,but a few plagioclases fractional crystallization,mainly amphibole and Fe-Ti oxide,does happen in this region. In addition,the H-O-S isotope results of hydrothermal minerals（ quartz,magnetite） and sulfate-sulfide（ anhydrite,pyrite,and chalcopyrite） show that ore-forming fluids and materials are mainly derived from magma,which is closely related to magma degassing（ fluid exsolution）.更多还原