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| 新疆坡北镁铁-超镁铁杂岩体中橄榄石成分特征及其成因意义 | |
| 引用本文： | 刘艳荣,吕新彪,梅微,代玉才.新疆坡北镁铁-超镁铁杂岩体中橄榄石成分特征及其成因意义[J].矿物岩石地球化学通报,2012,31(3):249-256. |
| 作者姓名： | 刘艳荣 吕新彪 梅微 代玉才 |
| 作者单位： | 1. 中国地质大学资源学院,武汉430074;长安大学西部矿产资源与地质工程教育部重点实验室,西安710054 2. 中国地质大学资源学院,武汉,430074 3. 新疆地矿局第六地质大队,新疆哈密,839000 |
| 基金项目： | "十二五"国家科技支撑计划资助项目，西部矿产资源与地质工程教育部重点实验室开放基金资助项目 |
| 摘 要： | 橄榄石的矿物化学成分可以很好的反映母岩浆成分、岩浆分异结晶及硫化物熔离作用等信息.坡北镁铁-超镁铁杂岩体中橄榄石电子探针成分分析表明:橄榄石均为贵橄榄石,其化学成分与寄主岩石类型密切相关,其中橄榄辉长岩中橄榄石的Fo值在74～81之间,橄长岩或橄榄单斜辉石岩中橄榄石Fo=75～82.7,异剥橄榄岩或橄榄岩中橄榄石Fo值为83.6～86.3,暗示橄榄岩结晶早于橄榄辉长岩.橄榄石Ni含量变化范围为(174～2281)×10-6.利用最高Fo含量的橄榄石成分计算得到坡北岩体母岩浆MgO=14.38％,为高镁玄武岩浆.橄榄石分离结晶和硫化物熔离模拟显示:坡北岩体主要发生了～25％的橄榄石分离结晶,在橄榄石结晶程度为2％～4％的过程中,发生过硫化物熔离作用,但熔离程度较低(～0.2％).总体来看,该区成矿远景不佳. |
| 关 键 词： | 坡北镁铁-超镁铁杂岩体 橄榄石分离结晶 硫化物熔离 |
Genetic Significances and Composition Characteristics of Olivine from Pobei Mafic-Ultramafic Complex, Xinjiang |
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| LIU Yan-rong , LV Xin-biao , MEI Wei , DAI Yu-cai.Genetic Significances and Composition Characteristics of Olivine from Pobei Mafic-Ultramafic Complex, Xinjiang[J].Bulletin of Mineralogy Petrology and Geochemistry,2012,31(3):249-256. | |
| Authors: | LIU Yan-rong LV Xin-biao MEI Wei DAI Yu-cai |
| Institution: | 1.Faculty of Resource Department,China University of Geosciences,Wuhan 430074,China;2.Key Laboratory of Western Mineral Resources and Geological Engineering of Ministry of Education,Chang’an University,Xi’an 710054,China; 3.No.6 Geological Party,Xinjiang Bureau of Geology and Mineral Exploration and Development,Hami 839000,China |
| Abstract: | The composition of olivine can directly give the messages of parental magma composition,magmatic fractional crystallization,and sulfide segregation.Electron microprobe analyses show that all olivine grains in the Pobei complex are chrysolite and their chemical compositions are closely related to the types of host rocks.The Fo values of the olivines in olivine-gabbro,troctolite or olivine-clinopyroxenite,wehrlite or peridotite are in the ranges of 74 to 81,75 to 82.7,and 83.6 to 86.3,respectively,indicating that peridotite was crystallized earlier than olivine-gabbro.Ni contents of the olivines vary from 308×10-6 to 1762×10-6.The MgO content of the parent magma,which contains the highest Fo olivine,was estimated to be 14.38%,indicating that the parent magma of the Pobei complex is a high-MgO basalt.Modeling results of olivine fractional crystallization and sulfide segregation show that ~25% olivine in the parental magma of the Pobei complex was fractionated and crystallized.A slight sulfide segregation(~0.2%) occurred during the period of olivine fractional crystallization proceeding from 2% to 4% suggests that the metallogenic potential of the Pobei complex is limited. |
| Keywords: | Pobei mafic-ultramafic complex olivine fractional crystallization sulfide segregation |
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