青海省洪水河铁矿床岩石学、地球化学特征及其成因  

Petrologic and Geochemical Characteristics of the Hongshuihe Iron Deposit in Qinghai Province:Implication for Ore Genesis

作　　者：廖鹏程[1] 吕新彪[1,2] 贾启元 高学鹏[2] 张帅[1] 毛晨[1] 

机构地区：[1]中国地质大学(武汉)资源学院,武汉430074 [2]中国地质大学地质过程与矿产资源国家重点实验室,武汉430074

出　　处：《矿物岩石地球化学通报》2016年第2期285-294,共10页Bulletin of Mineralogy, Petrology and Geochemistry

基　　金：中国地质调查局地质大调查项目(12120114018001)

摘　　要：为探讨青海洪水河铁矿床的成矿物质来源及形成环境,选取典型铁矿石和赋矿围岩进行主量元素、微量元素和稀土元素分析测试。结果表明,铁矿石富SiO_2和TFe_2O_3,其Zr(Nb)-Al_2O_3,Zr(Nb)-TiO_2具强相关性,稀土元素呈现轻稀土元素亏损、重稀土元素富集的特征,具La、Y正异常,无明显Eu异常,无Ce负异常。分析认为,洪水河铁矿矿质来源于远离火山口的地幔源区热液,在形成过程中有较多陆源碎屑的加入,而最终形成于海底低温热液和海水混合的还原环境。结合东昆仑地区构造演化历史可认为洪水河铁矿形成于元古宙大陆裂谷边缘环境,为幔源岩浆活动的热水沉积产物。In order to discuss the origin of ore-forming material and metallogenie environment of the Hongshuihe iron de- posit, which is located in the Qinghai Province, major, trace and rare earth elements of typical iron ores and host rocks have been analyzed in this paper. The data indicate that iron ores are enriched in SiO2 and TFe2O3, with strong positive correlations between Zr（Nb）and TiO2, Zr（Nb）and Al2O3, features of LREE depletion and HREE enrichment, La and Y positive anomalies, but without pronounced Eu and Ce negative anomalies. These features mean that the ore-forming mate- rial of the Hongshuihe iron deposit comes from mantle-sourced hydrothermal solutions far away from crater, with the addi- tion of continental elastic components. The deposit was finally formed in reduced environment which was due to the mixing of low-temperature hydrothermal solutions and seawater. Considering the tectonic evolution of the Eastern Kunlun region, it is suggested that the Hongshuihe iron deposit was formed in the Proterozoic continental rift environment through sedimenta- tion of hydrothermal fluid associated with mantle-derived magmatic activities.

关 键 词：地球化学特征 成因 洪水河铁矿 青海 

分 类 号：P618.31[天文地球—矿床学]