| 滇西北中甸弧成矿岩体中榍石化学成分特征及其成岩成矿标识 |
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| 引用本文： | 李华伟,董国臣,董朋生,汤家辉,王树树.滇西北中甸弧成矿岩体中榍石化学成分特征及其成岩成矿标识[J].地球科学,2020,45(6):1999-2010. |
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| 作者姓名： | 李华伟 董国臣 董朋生 汤家辉 王树树 |
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| 作者单位： | 中国地质大学地球科学与资源学院, 北京 100083 |
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| 基金项目： | 国家“973”项目2015CB452604国家重点研发项目2016YFC0600502111引智计划B18048 |
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| 摘 要： | 位于西南三江构造火成岩带义敦弧南段的中甸弧，以发育印支期斑岩型铜矿床和燕山期矽卡岩-热液石英脉型钼-钨-铜矿而著称.针对普朗、地苏嘎和休瓦促成矿岩体中的榍石单矿物，利用EMPA和LA-ICP-MS测定化学成分，探讨化学成分对成岩成矿的指示意义.普朗、地苏嘎和休瓦促岩体榍石均为岩浆来源.普朗岩体榍石形成温度为743~754℃，休瓦促岩体榍石形成温度为702~753℃.根据榍石的δCe、δEu推断三个岩体氧逸度高低顺序为:普朗>地苏嘎>休瓦促，榍石中的Cu含量对母岩浆中的Cu金属量变化不敏感，不能单独作为母岩浆Cu金属量的判别标志；钼成矿对岩体的氧逸度要求不高，在利用榍石中的Mo含量判断母岩浆中的Mo金属量时要综合考虑氧逸度和辉钼矿结晶的影响；岩体中的F含量能降低岩浆粘度，对钼成矿有促进作用，可以作为Mo成矿的指标；榍石中的W、Sn含量对Mo-W矿床具有指示作用，休瓦促Mo-W矿岩体中榍石的W、Sn含量要高于普朗和地苏嘎不成Mo-W矿的岩体.
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| 关 键 词： | 义敦 中甸弧 榍石 成岩成矿 矿床地质 |
| 收稿时间： | 2019-04-01 |
Titanite Chemical Compositions and Their Implications for Petrogenesis and Mineralization in Zhongdian Arc,NW Yunnan,China |
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| Abstract: | Zhongdian arc is located in the southern section of the Yidun arc at the Sanjiang Tethys, Southwest China. It is known as the Indosinian porphyry copper deposits and the Yanshanian skarn-hydrothermal quartz vein Mo-W-Cu deposits. In this paper, it was measured the titanite chemical compositions from ore-forming rocks of Pulang, Disuga and Xiuwacu with EMPA and LA-ICP-MS to discuss their implications for petrogenesis and mineralization. The titanites from Pulang, Disuga and Xiuwacu are all of magmatic origin. The titanite formation temperature from Pulang pluton is 743-754 ℃, and 702-753 ℃ from Xiuwacu pluton. Based on the δCe, δEu from titanites, it can be inferred that the order of oxygen fugacity of these plutons is: Pulang > Disuga > Xiuwacu. It requires high magma oxygen fugacity for Cu mineralization, but the Cu contents in titanite are insensitive to the content variations of Cu in magma, which can not be used as an indication of the Cu contents in magma. Mo mineralization does not require high magma oxygen fugacity, and the magma oxygen fugacity and crystalization of molybdenite need to be thought when we use the Mo contents of titanite to determine the Mo fertility in magma. The F contents in magma can reduce magma viscosity and promote Mo mineralization which can be an indication for Mo mineralization. The W and Sn contents in the titanite is a good indication of the Mo-W mineralization, and the W and Sn contents in the Xiuwacu Mo-W deposit are higher than those in the Pulang and Disuga. |
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