个旧西凹铜-锡多金属矿床花岗岩蚀变带稀土元素特征及意义  

REE characteristics and significance of granite alteration zone of Xi'ao copper-tin polymetallic deposit in Gejiu area

作　　者：廖时理[1,2] 陈守余[1,2] 邓小虎[1,2] 李培[3] 

机构地区：[1]中国地质大学(武汉)资源学院,湖北武汉430074 [2]地质过程与矿产资源国家重点实验室,湖北武汉430074 [3]中国国土资源经济研究院,北京101149

出　　处：《中南大学学报（自然科学版）》2014年第5期1555-1565,共11页Journal of Central South University:Science and Technology

基　　金：国家自然科学基金资助项目(41302264);国土资源部公益性行业科研专项(201011002-10);中国博士后基金资助项目(2013M531766);中央高校新青年教师科研基金资助项目(CUG120841)

摘　　要：通过分析西凹铜-锡多金属矿床蚀变岩的稀土元素特征,研究该矿的成矿物质、成矿流体来源及成矿环境等。研究结果表明:蚀变花岗岩的稀土元素配分模式与未蚀变花岗岩类似,但也存在一定的差异。相对于未蚀变花岗岩,钾化花岗岩稀土总量增高,重稀土元素(HREE)的富集程度比轻稀土元素(LREE)的大,轻稀土元素中的La,Ce的富集程度比Pr和Nd的大,次生钾长石继承了蚀变流体的稀土元素特征,可能与蚀变流体温度较高有关,且富含F,Cl和CO2有关,成矿流体来源于岩浆期后热液。绿帘石-绿泥石化花岗岩稀土总量略有降低,LREE亏损而HREE略微富集,由流体蚀变、云母类矿物的吸附作用及早期钾化蚀变共同造成。Eu异常和Ce异常,表明钾化处于相对高温氧化条件下,而绿帘石-绿泥石化则处于相对低温和还原的环境中。蚀变花岗岩中REE与成矿元素关系密切,对岩体内部找矿具有一定的指示意义。The rare earth element （REE） features of Xi＇ao copper-tin polymetallic deposit were analyzed to discuss the forming source and environment. The results show that REE distribution patterns of altered granites are similar to unaltered granite, suggesting that the ore forming fluid probably derived from magma. Compared with unaltered granite, the content of total REE of potassic alteration granite increases, and the HREE rises higher than LREE. Besides, La and Ce of the LREE increase more than Pr and Nd. Secondary potassium feldspar inherits the REE characteristics of the alteration fluid. These probably result from high temperature and F, C1, CO2 rich features of the fluid. The content of total REE of epidotization-chloritization granite is relatively unchanged. The decease of LREE and slight increase of HREE perhaps are caused by the combination of factors of alteration, absorption of mica and early potassium alteration. Eu and Ce anomaly indicate that potassic alteration occurs at relatively high temperature in oxidation conditions, and epidotization- chloritization occurs at relatively low temperature in reducing conditions. REE are closely related to main ore-forming elements in the altered granites, providing relevant information for ore prediction in inner granite acteration zone.

关 键 词：云南个旧 铜-锡多金属矿床 稀土元素特征 蚀变花岗岩 

分 类 号：P611.1[天文地球—矿床学]