新疆北山地区罗东镁铁超镁铁质岩体地球化学特征及找矿潜力分析  

Analysis on Geochemical Characterisics and Prospecting Potentia of Luodong Mafic-ultramafic Intrusion in Beishan,Xinjiang

作　　者：呼冬强 张强 孟和 HU Dongqiang;ZHANG Qiang;MENG He(School of Mines and Geology,Xinjiang Institute of Engineering,Urumqi 830023,Xinjiang,China;Key Laboratory of Geological Hazard Prevention,College of Mining Engineering and Geology,Urmqi 830023,Xinjiang,China;No.2 Geological Party,Xinjiang Bureau of Geology and Mineral Resources Exploration,Kashgar 844000,Xinjiang,China)

机构地区：[1]新疆工程学院矿业工程与地质学院,新疆乌鲁木齐830023 [2]新疆地质灾害防治重点实验室,新疆乌鲁木齐830023 [3]新疆地矿局第二地质大队,新疆喀什844000

出　　处：《西北地质》2021年第3期91-107,共17页Northwestern Geology

基　　金：新疆维吾尔自治区地质勘查基金项目“新疆若羌县黑山岭一带1∶5万区域地质矿产调查”(K141-L006)。

摘　　要：罗东镁铁超镁铁质岩体位于新疆东部北山地区,呈眼球状出露于白地洼淤泥河断裂北侧,主要岩石类型包括辉长岩、橄榄岩、辉石橄榄岩和橄榄辉石岩等,具有明显的堆晶结构。岩相学、全岩主微量地球化学研究表明罗东岩体属于拉斑玄武岩系列且经历了早期橄榄石、辉石和斜长石的分离结晶作用,以及岩浆演化过程中上地壳混染作用,具有良好的铜镍矿形成条件。罗东岩体的母岩浆应该为高镁高温苦橄质岩浆,是地幔软流圈在尖晶石矿物稳定区域较高程度部分熔融后产物。岩石MgO为7%~33.7%,属含铜镍中等镁铁质岩石,镁铁比(m/f)为1.70~6.80,主体属于铁质超镁铁岩,综合分析罗东地区地、物、化信息显示岩体具有良好的找矿潜力,综合找矿模型的构建为北山地区经济、快速地从众多镁铁质超镁铁质岩体中筛选出有利的赋矿岩体提供了经验和方向。The Luodong mafic-ultramafic intrusion is located in eastern Beishan of Xinjiang and exposed on the north of the Baidiwa-Suihehe fault with an eyeball-shape.The intrusion is composed of gabbros,peridotite,harzburgite and olivine pyroxenite.Many of them have a cumulate texture.Petrography and geochemistry of the Luodong mafic-ultramafic intrusion indicate that the intrusion belongs to tholeiitic affinity series and has undergone early fractional crystallization of olivine,pyroxene and plagioclase,as well as the mixed dyeing of the upper crust during magmatic evolution,showing good formation conditions of copper-nickel ore.The primary magma was the high-mg and high-temperature picritic and was derived from the higher degree of partial melting of the asthenosphere mantle in the spinel stable region.The MgO contents of these inrusions vary from 7%to 33.7%and the m/f ratios range from 1.7 to 6.8,indicating that they belong to copper-nickel sulfide-bearing medium mafic rock and ferruginous ultramafic rock.The geological,geophysical,and geochemical analysis of Luodong region shows that these intrusions have good prospecting potential.The construction of a comprehensive prospecting model provides experience to select the favorable ore-forming intrusions from the mafic-ultramafic intrusions in Beishan.

关 键 词：镁铁超镁铁质岩 地球化学 找矿潜力 北山地区 

分 类 号：P595[天文地球—地球化学]