云南因民铁铜矿区辉长岩类中黑云母-金红石化特征及其指示意义  

Mineralization Characteristics and Indication Significance of Biotite-Rutile from the Gabbro Intrusions in the Yinmin Iron-Copper District,Yunnan Province

作　　者：孙紫坚 方维萱[2] 鲁佳[2,3] 王同荣 郭玉乾[2] 宋丽红[2] 

机构地区：[1]北京矿产地质研究院,北京100012 [2]有色金属矿产地质调查中心,北京100012 [3]昆明理工大学国土资源工程学院,云南昆明650093 [4]昆明风景矿业有限公司,云南昆明654102

出　　处：《现代地质》2017年第2期267-277,共11页Geoscience

基　　金：国家科技部转制院所专项资金项目"铁氧化物铜金型矿床元素赋存状态及构造岩相学填图技术研发"(2011EG115022;2013EG115018)

摘　　要：对云南因民铁铜矿区深部辉长岩类中金红石、黑云母、碳酸盐和绿泥石的矿物地球化学特征进行研究,以探讨赋存于辉长岩类中的铁氧化物铜金型矿(化)体的成岩成矿环境。金红石由岩浆结晶和多期蚀变作用形成,其结晶温度为820~1 082℃,多期蚀变温度为444~730℃,金红石与黑云母密切共生;黑云母可划分为原生高钛镁质黑云母、热液蚀变镁质黑云母和铁质黑云母,形成温度分别为653~750℃、525~619℃和551~577℃,氧逸度均位于Ni-Ni O缓冲剂附近,表明黑云母形成于高温强氧化环境,有利于金红石化;铁白云石-菱铁矿化揭示了强还原环境,交代蚀变金红石;绿泥石多由铁镁矿物蚀变形成,形成于中低温(174~243℃)、低氧逸度(-44.68^-51.42)和高硫逸度(-14.42^-19.76)的强还原环境,有利于金属硫化物形成。本区岩浆结晶演化和黑云母-金红石化蚀变具有高温强氧化地球化学岩相学特征,有利于钛、铁矿化,后期叠加中低温强还原地球化学岩相,为IOCG矿床成矿的有利地球化学岩相学类型。In order to discuss the metallogenetic and diagenetic environment of iron oxide-copper-gold type deposit, the mineral-geochemical characteristics of biotites, rutiles, chlorites and ankerites of gabbro intrusions in the depth of Yinmin iron-copper district, Yunnan Province were analysed. Ruffles were derived from magmatic crystallization and multiple-stages alteration. The crystallization temperature of ruffles ranged from 820 to 1,082 ℃, and the multi-phases alteration temperature of rutiles ranged from 444 to 730 ℃. Rutiles had a symbiotic relationship with biotites. The biotites were divided into three types： Ti-rich magnesial biotites crystallised from magma, magnesial biotite and ferruginous biotite due to hydrothermal alteration. The crystallization temperature of the primary Ti-rich magnesial biotites ranged from 653 to 750 ℃, the alteration temperature of hydrothermal magnesial biotites ranged from 525 to 619 ℃, and that of hydrothermal ferruginous biotites ranged from 551 to 577 ℃. The oxygen fugacity of all the biotites was near Ni-NiO, indicating that biotites formed in the high oxygen fugacity environment, which was conducive to the formation of rutiles. In conclusion, both of biotites and rutiles formed in the environment with high temperature and oxygen fugacity. Ankerite-siderite alteration was developed in the later stage, forming in the strongly reduced and alkaline environment, playing a corrosive role to rutiles. The alteration temperature of chlorites, which were altered from ferromagnesian, such as biotites, hornblende and pyroxene, ranged from 174 to 243 ℃. The oxygen fugacity was from -44. 68 to -51.42, and the sulphur fugacity was from - 14.42 to - 19.76, showing that chlorites formed in an environment with low-medi- um temperature, low oxygen fugacity and high sulphur fugacity, which was benefit to the formation of metal sulfide. In sum, the stages of magmatic crystallization, biotitization and rutiles mineralization were characterized by geochemical lithofacies with high te

关 键 词：因民铁铜矿区 辉长岩类岩体 黑云母化 金红石化 云南 

分 类 号：P588[天文地球—岩石学]