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| 宁芜矿集区凹山铁矿床磁铁矿元素地球化学特征及其对成矿作用的制约 | |
| 引用本文： | 段超,李延河,袁顺达,胡明月,赵令浩,陈小丹,张成,刘佳林.宁芜矿集区凹山铁矿床磁铁矿元素地球化学特征及其对成矿作用的制约[J].岩石学报,2012,28(1):243-257. |
| 作者姓名： | 段超 李延河 袁顺达 胡明月 赵令浩 陈小丹 张成 刘佳林 |
| 作者单位： | 1. 地质过程与矿产资源国家重点实验室,中国地质大学地球科学与资源学院,北京100083 2. 中国地质科学院矿产资源研究所,国土资源部成矿作用和资源评价重点实验室,北京100037 3. 国家地质实验测试中心,北京,100037 |
| 基金项目： | 本文受公益性行业科研专项项目(200911007、200811114)、国家自然科学重点基金项目(40930419)、国家重点基础研究发展计划项目(2007CB411405)和地质过程与矿产资源国家重点实验室开放基金项目(GPMR201029)联合资助. |
| 摘 要： | 凹山铁矿床是一个典型的玢岩型铁矿床,成矿过程具有多阶段的特征,是宁芜矿集区凹山矿田成矿作用演化的典型代表。本次研究工作,在详细的野外地质调查研究和室内研究的基础上,将主要矿石矿物磁铁矿的形成划分为4个世代,分别为浸染状磁铁矿、角砾状磁铁矿、粗粒脉状磁铁矿和伟晶状磁铁矿,它们是四个成矿阶段的产物。电子探针和LA-ICP-MS原位分析表明,随着成矿作用的演化,磁铁矿主量元素中Ti、Mn、V含量变化微弱,Al、Mg含量增高;微量元素中Ga、Sn及高场强元素Zr、Hf、Nd、Ta含量变化较小;从角砾状矿石到伟晶状矿石Co含量逐渐增高、Sc含量逐渐降低。根据以上成矿各阶段中磁铁矿成分的变化,并结合前人研究成果得出,凹山铁矿床作为一个高温气液充填矿床,其成矿物质主要来自于岩浆演化晚期形成的高温富铁流体。在成矿过程中磁铁矿具有同源连续演化的特征,其中隐爆作用诱发了大规模铁沉淀,并为成矿提供了空间,形成了早期的浸染状和角砾状矿石;成矿过程中流体成分不断变化,后期大量挥发份的累积和外源流体的逐渐加入,形成了伟晶状矿石并使得磁铁矿具有了热液成因的特征。 |
| 关 键 词： | 玢岩型铁矿床 磁铁矿 电子探针 LA-ICP-MS 凹山 宁芜矿集区 |
| 收稿时间： | 9/4/2011 12:00:00 AM |
| 修稿时间： | 2011/11/25 0:00:00 |
Geochemical characteristics of magnetite from Washan iron deposit in Ningwu ore district and its constraints on ore-forming |
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| DUAN Chao,LI YanHe,YUAN ShunD,HU MingYue,ZHAO LingHao,CHEN XiaoDan,ZHANG Cheng and LIU JiaLin.Geochemical characteristics of magnetite from Washan iron deposit in Ningwu ore district and its constraints on ore-forming[J].Acta Petrologica Sinica,2012,28(1):243-257. | |
| Authors: | DUAN Chao LI YanHe YUAN ShunD HU MingYue ZHAO LingHao CHEN XiaoDan ZHANG Cheng and LIU JiaLin |
| Institution: | State Key Laboratory of Geological Processes and Mineral Resources, School of the Earth Sciences and Resources, China University of Geosciences, Beijing 100083, China;MLR Key Laboratory of Metallogeny and Mineral Assessment, Institute of Mineral Resources, Chinese Academy of Geological Sciences, Beijing 100037, China;MLR Key Laboratory of Metallogeny and Mineral Assessment, Institute of Mineral Resources, Chinese Academy of Geological Sciences, Beijing 100037, China;National Research Center for Geoanalysis, Beijing 100037, China;National Research Center for Geoanalysis, Beijing 100037, China;State Key Laboratory of Geological Processes and Mineral Resources, School of the Earth Sciences and Resources, China University of Geosciences, Beijing 100083, China;State Key Laboratory of Geological Processes and Mineral Resources, School of the Earth Sciences and Resources, China University of Geosciences, Beijing 100083, China;State Key Laboratory of Geological Processes and Mineral Resources, School of the Earth Sciences and Resources, China University of Geosciences, Beijing 100083, China |
| Abstract: | Washan iron deposit is a typical porphyry-type iron deposit, with a multi-stage ore-forming process. It displays the iron mineralization evolution of the Washan ore field. Based on the detailed field geological investigation, mineralogy and petrology study, the magnetite formation is divided into four stages, namely, disseminated magnetite, magnetite in breccia, coarse-grained vein magnetite and pegmatitic vein magnetite. In situ electron microprobe and LA-ICP-MS analysis of the magnetite from Washan iron deposit show that with the evolution of mineralization, the contents of Ti, Mn, V in magnetite are consistent; the Al and Mg contents increased; the contents of Ga, Sn and high field strength elements (Zr, Hf, Nd, Ta) change in a small range; from magnetite in breccia to pegmatitic vein magnetite, Co content gradually increased and Sc decreased gradually. The compositions of magnetite in various stages indicate that the process of magnetite mineralization has a continuous evolution with a similar source. Combined with previous studies, the mineralization formed from the iron-rich melt in the later of magmatic evolution. The large-scale iron precipitation triggered by cryptoexplosion and the corresponding breccia pipes provide available space for the mineralization. The disseminated ores and brecciated ores formed in the early stage. With the magmatic-hydrothermal evolution, magnetite showed more hydrothermal likely signature in the later stage. |
| Keywords: | Porphyry-type iron deposit Magnetite Electron microprobe LA-ICP-MS Washan Ningwu ore district |
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