大石棚铁锰矿区磁铁矿稀土元素地球化学特征及地质意义  

Rare Earth Elements Characteristics and Geological Significance of Iron Deposit in Dashipeng Ore Field of Huili County,Sichuan Province,China

作　　者：李曦[1,2] 刘继顺[1,2] 王天国[1,2] 刘彪[1,2] 

机构地区：[1]中南大学有色金属成矿预测教育部重点实验室,湖南长沙410083 [2]中南大学地球科学与信息物理学院,湖南长沙410083

出　　处：《南方金属》2015年第5期17-21,共5页Southern Metals

摘　　要：大地构造上位于南北向延伸的川滇被动陆缘裂谷系昆阳裂谷是我国重要的元古代铜、铁成矿带,其中,大石棚铁锰矿床是典型的代表.为了探讨大石棚磁铁矿矿质来源及成因的异同及其所代表的地质意义,利用ICPMS对磁铁矿及其围岩和岩体进行了稀土元素测试.结果表明,所有样品均具有轻稀土元素(LREE)富集和明显分异的特点.磁铁矿具有Eu正异常和较弱的Ce负异常,表明其成矿物质均来自上升的深部热液,在高温、还原环境下及围岩参与下成矿.文章认为大石棚磁铁矿是由一种高温、铕强烈富集的流体在还原环境下形成的;成矿物质来源主要来自后期热液,围岩也提供了部分成矿物质来源,岩体不仅提供了部分物质来源还为成矿提供了所需温度,引起了Eu负异常和局部Ce正异常的出现以及稀土元素总量的增加.From the view point of the ear structure, Sichuan - Yunnan passive margin rift system of kunyang rift is located in the tectonic extension of the north and south, which is the important proterozoic copper and iron metallogenic belt in Chi- na, among them, the stone iron manganese deposit is a typical representative. To investigate the stone tents magnetite ore sources and the causes of the similarities and differences and the geological significance represented, ICP - MS is used to analyze the magnetite and its surrounding rock and the rock mass for the rare earth elements. The results show that all sam- ples have light rare earth elements （LREE） concentration and the characteristics of obvious differentiation. Magnetite with Eu is positively abnormal and weaker Ce is negatively abnormal, showing that its minerals are from rising deep hot fluid, and are mineralized under the environment of high temperature, reduction and the surrounding rock. It is thought that the stone tents magnetite is a kind of high temperature, strong enrichment of europium fluid in the formation of reductive envi- ronment ; It is mainly from the late hydrothermal ore - forming material source which does not only provide part of the source of ore - forming materials of surrounding rock and rock body, but also provide the temperature needed for ore - forming ma- terial sources, causing that the Eu is negatively anomaly, the emergence of the local Ce is abnormal and the amount of rare earth elements increases.

关 键 词：大石棚铁锰矿区 地球化学 磁铁矿 稀土元素 

分 类 号：P595[天文地球—地球化学] P618.7[天文地球—地质学]