摘要
海南石碌铁多金属矿床是以铁矿为主,共生或伴生有钴、铜等多金属和白云岩等非金属矿产的超大型矿床。碳酸盐岩作为新元古代石碌群的重要组成部分,是主要的赋矿围岩之一。开展了石碌群第六层上、中、下段的碳酸盐岩主、微量元素地球化学研究。结果表明,主量元素以CaO、MgO为主,除SiO2含量变化较大外,其它成分基本小于1%。碳酸盐岩∑REE含量为1.34×10-6~29.06×10-6(平均为10.89×10-6),明显低于PAAS,稀土配分型式主要呈左倾或向上凸起,蛛网图中亏损高场强元素,富集大离子亲石元素。根据地球化学性质可将样品分为两组:一组具正Eu异常、无Ce异常,Y/Ho值较低(平均为29.49);另一组Eu无异常,具Ce负异常,Y/Ho值较高,为38.28~63.88(平均为44.65)。该特征表明微量元素继承于海水和海底高温热液两个源区,暗示了海底高温热液可能是铁、钴铜多金属的重要来源。根据Ce异常变化规律所揭示的第六层从下段到中、上段氧化性逐渐增强的特征,认为石碌群第六层沉积环境为受限的弧后海盆,石碌群经历了从浅海相到海湾-泻湖相的沉积演化。
Shilu iron polymetallic deposit,situated in western Hainan Province,has great reputation for its large-scale iron ores and associated cobalt,copper metals and dolostones,etc.nonmetals resources.The Neoproterozoic Shilu Group,the host of Shilu deposit,consists of submarine siliciclastic and carbonate sedimentary succession with greenschist facies.Here we present major and trace elements data of carbonatite from the sixth sequence of the Shilu Group.The results show that carbonatite is characterized by high CaO and MgO,and minor but variable SiO2 contents.With LREE depletion relative to HREE or upward-convex PAAS-normalized REE patterns,carbonatite samples have REE contents ranging from 1.34×10-6 to 29.06×10-6(av.10.89×10-6),which are obviously lower than that of PAAS.The trace element results reveal variable depletion in HFSEs and relatively enrichment in LILEs,relative to the PAAS.All samples can be classified into two groups:one characterized by positive Eu and no Ce anomalies,and low Y/Ho ratios with an average of 29.49,the other featured by no Eu and negative Ce anomalies,and high Y/Ho ratios with an average of 44.65.The geochemical data suggested that carbonatite deposited from both seawater and seafloor high-temperature hydrothermal fluids which also contributed to the Fe,Co and Cu metals.The progressive oxygenation revealed by Ce anomalies of carbonatite from the lower segment to upper segment indicated that the depositional environment of the sixth sequence is a restricted back-arc basin,and the Shilu Group experienced the sedimentary evolution from the neritic facies to barrier-bay-lagoon facies.
作者
王展
王智琳
许德如
王力
彭尔柯
伍杨
WANG Zhan;WANG Zhi-lin;XU De-ru;WANG Li;PENG Er-ke;WU Yang(Key Laboratory of Metallogenic Prediction of Nonferrous Metalsand Geological Environment Monitoring(Central South University),Ministry of Education,School of Geosciences and Info-Physics,Central South University,Changsha 410083,China;State Key Laboratory for Nuclear Resources and Environment,East China University of Technology,Nanchang 330013,China;CAS Key Laboratory of Mineralogy and Metallogeny,Guangzhou Institute of Geochemistry,Chinese Academy of Sciences,Guangzhou 510640,China;Hainan Resources and Environment Survey Institute,Haikou 570206,China)
出处
《东华理工大学学报（自然科学版）》
CAS
2020年第1期1-11,共11页
Journal of East China University of Technology(Natural Science)
基金
国家自然科学基金项目(41302049,41672077)
国家重点研发计划“深地资源勘查开采”重点专项(2016YFC0600401).
关键词
碳酸盐岩
主微量元素
沉积环境
石碌铁多金属矿床
海南省
carbonatite
major and trace elements
deposit setting
Shilu iron polymetallic deposit
Hainan Province
作者简介
王展(1992—),男,硕士研究生,主要从事地球化学研究。E-mail:1454489686@qq.com;通信作者:王智琳(1984—),女,副教授,主要从事成因矿物学与矿床地球化学研究。Email:wangzhilin1025@163.com
