| 冈底斯造山带两套不同成矿体系的含矿斑岩对比研究 |
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| 引用本文：杨竹森,黄智龙,田世洪,钱志宽.2010.A comparison of porphyries between Pb-Zn-Ag metallogenic system and Cu-Mo-Au metallogenic system in Gangdese orogen, Tibet[J].Mineral Deposits,29(2):195~206 |
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| 基金项目:国家支撑计划项目（2006BAB01A04）和国家自然科学基金项目（40672053，40603013） |
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| 中文摘要:Cu（Mo、Au）矿化和Pb-Zn-Ag矿化分别是冈底斯成矿带南缘和北缘最重要的成矿作用，目前在冈底斯南缘发现了长达350 km、宽40 km的斑岩铜矿带，对该成矿带铜矿化及相关斑岩已有深入研究，而北缘的Pb-Zn-Ag矿化及相关斑岩还刚为人们所认识。纳如松多银铅锌矿是冈底斯北缘Pb-Zn-Ag矿化带的典型矿床之一，并出露未风化的斑岩。与冈底斯南部铜矿带斑岩相比较，纳如松多斑岩具有高Si，低Ti、Ca、Mg和极度贫Na的特点；总体上富集Th、U等大离子亲石元素，而Ba、Sr、P等元素则明显亏损；稀土元素配分模式为略微右倾的燕型模式，轻、重稀土元素分异不明显，具有明显的Eu负异常。纳如松多斑岩与林子宗群典中组火山岩在空间上和时间上具有非常紧密的联系，整体上也具有较为相似的地球化学特征，应与典中组火山岩具有相同的岩浆起源，即主碰撞期后仍然残留的新特提斯洋板片及卷入的陆源沉积物的部分熔融形成的原始岩浆；原始岩浆经过约75%的斜长石分离结晶后，在主碰撞期典中组火山岩喷发后上侵形成纳如松多斑岩。 |
| 中文关键词:地球化学 斑岩 纳如松多银铅锌矿床 典中组火山岩 冈底斯 西藏 |
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| A comparison of porphyries between Pb-Zn-Ag metallogenic system and Cu-Mo-Au metallogenic system in Gangdese orogen, Tibet |
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| Abstract:Two important polymetallic ore belts, i.e., Cu-Mo-Au ore belt and Pb-Zn-Ag ore belt, occur respectively in the southern part and the northern part of Gandese or ogen, south Tibet. Much research work has been devoted to the Cu-Mo-Au ore-forming process and related porphyry in southern Gandese, but researches on the Pb-Zn-Ag polymetallic ore belt in northern Gandese remain very insufficient. The Narusongduo ore deposit is one of the representative ore deposits in the Pb-Zn-Ag polymetallic ore belt, with outcrop of fresh porphyry. Compared with the porphyry in southern Gangdese, Narusongduo porphyry is characterized by enriched Si,lower Ti and depleted Ca, Mg and Na, as well as enriched Th and U and relatively depleted Ba, Sr and P. The Narusongduo porphyry also shows inconspicuous fractionat ion of LREE/HREE and distinct negative Eu anomaly. The Narusongduo porphyry is similar to Linzizong volcanic rocks of Dianzhong Formation in geochemical features and has close spatial_temporal relationship with the latter, suggesting that they have the same magmatic origin, with their magma derived from the partial melting of the subducted Neo-Tethyan oceanic slab and sediments during the Indo-Asian collision. Moreover, through crystal fractionation of 75% plagioclase, the original magma formed the Narusongduo porphyry. |
| keywords:geochemistry, porphyry, Narusongduo Ag-Pb-Zn ore deposit, volcanic rocks of Dianzhong Formation, Gandese, Tibet |
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