| 东天山西滩浅成低温热液金矿床地球化学 |
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| 引用本文：.2000.Geochemistry of the Xitan epithermal gold-silver deposit, east Tianshan Mountains[J].Mineral Deposits,19(4):322~329 |
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| 基金项目:国家科技攻关305项目（85-902-05） |
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| 中文摘要:对东天山西滩金矿床稀土元素地球化学、流体包裹体和H、O、S、Pb、Sr、C、Si等稳定同位素组成的研究表明，该金矿床成矿元素来自赋矿围岩：成矿流体主要为大气降水，显示出低温、低压、低-中等盐度、弱酸-中性等特征：成矿作用发生在碰撞造山期，多期次热液叠加和幕式特征显著：矿床成因应属冰长石-绢云母型浅成低温热液金矿床。 |
| 中文关键词:浅成低温热液 地球化学 金矿床 新疆西滩 |
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| Geochemistry of the Xitan epithermal gold-silver deposit, east Tianshan Mountains |
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| Abstract:Hosted by Lower Carboniferous Aqishan Group, the Xitan gold deposit is controlled by arcuate faults related to paleo-caldera. ∑REE values in this deposit decrease from wall rocks through altered rock type ores to quartz vein ores. The REE pattern of the altered rock type ores is similar to that of the wall rocks, while the partition curves of the quartz vein ores are relatively steep. Fluid inclusion studies of quartz yield homogenization temperature of 137℃ to 250℃, mainly from 150℃ to 200℃ and fluid pressure of (268~ 326)×l05Pa. Salinities of primary fluid inclusions range from 0.8% to 6.7% NaCIequivalent. Isotopic geochemical studies show that δD and δ18OH2O values of the ore-forming fluids are -119 to - 90 permil and -12.7 to -1.6 perm il, respectively. δ34S values of pyrite and whole rock vary from 0.1 to 1.3 permil and from l.4 to 2.3 permil, respectively. (87S r/86S r)i values of ores and wallrock determined by Rb-Sr isochron technique are very close to each other, being 0.7049 to 0.7059 and 0.7046 respectively. δ13C volume of calcite from the ore is -5.47 permil, and δ30Si volumes of wall rock and ores are from 0.1 to 0.3 permil. In addition, the main gold mineralization took place at (244+ 9)×l06 a based on the Rb-Sr isochron dating. All the REE and isotopic geochemical characteristics indicate that the ore- forming substance of this gold deposit w as directly de rived from wall rock, the ore-forming fluids were dominantly meteoric water and were characterized by low-temperature, low-pressure and low to medium salinity, and the ore-forming process took place in collision and orogenic period, with very obvious multistage super imposition and episodic mineralization. It is concluded that the Xitan gold deposit is a kind of adularia-sericite type epithermal gold- silver deposit according to P Heald' s classification. |
| keywords:epithermal solution, geochemistry, gold deposit, Xitan, Xinjiang |
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