滇西北甭哥碱性杂岩体地球化学与成矿作用分析  

An analysis of geochemistry and metallogenesis of Bengge alkaline igneous complex in northwestern Yunnan Province

作　　者：黄玉蓬[1,2] 刘显凡[1] 邓江红[1] 董毅[1] 邹金汐[1] 

机构地区：[1]成都理工大学地球科学学院,四川成都610000 [2]四川省冶金地质勘查局成都地质调查所,四川成都610203

出　　处：《中国地质》2013年第3期885-894,共10页Geology in China

基　　金：中国地调局地调项目(1212011120587);成都理工大学矿物学;岩石学;矿床学国家重点(培育)学科建设项目(SZD0407)联合资助

摘　　要：透岩浆流体成矿理论和地幔流体交代引发壳幔混染叠加成矿的机理,为"小岩体成大矿"这一事实提供了理论依据。滇西北甭哥碱性杂岩体岩石地球化学特征表明其受到强烈的深部流体作用,且成矿物质并非岩浆本身所携带,相应引发矿质富集的流体作用与岩浆作用分属不同的体系,初步推测甭哥金矿成矿受制于透岩浆流体与壳幔混染叠加这一深部流体作用过程。其机制可以理解为含矿地幔流体与岩浆互不混溶并同步运移,伴随岩浆结晶成岩而交代岩体成矿,或在一定条件下与岩体分离,运移至物理化学边界层等有利部位聚集成矿,在此过程中,含矿地幔流体也可沿途交代、活化围岩,导致壳幔混染叠加使成矿元素进一步富集。基于此,该岩体具有良好的深部成矿潜力。The metallogenic theory of trans-magrnatic fluid and mechanism of the interaction between mande fluid and crustal hydrothermal fluid provides a credible explanation for the idea ＂little intrusion could form large deposit＂. The geochemical characteristics suggest that the Bengge alkaline complex had been strongly affected by deep fluid and the ore-forming elements were not provided by the magma or melt which formed the Bengge complex. The ore-forming fluid system and the magma were independent of each other. It is believed that the mineralizing process was controUed by the tram-magmatic fluid and the mechanism of interaction between mantle fluid and crustal hydrothennal fluid. The ore-forming mantle fluid was not mixed with the alkaline magma but they could move together. During the crystallization of the alkaline magma, on the one hand, the mantle fluid could alter the alkaline body; on the other hand, the mantle fluid might escape from the magma and move to the physical-chemical boundary layer which was favorable for the enrichment of the ore-forming elements. During this process, the mantle fluid could react and extract the ore-forming elements in the crust, which was helpful to the formation of a large ore deposit. Based on the above analysis, the authors hold that Bengge alkaline complex has attractive ore potential.

关 键 词：甭哥碱性杂岩体 透岩浆流体 地幔流体 壳幔混染叠加成矿 滇西北 

分 类 号：P584[天文地球—岩石学] P611[天文地球—地质学]