东天山垄西镁铁-超镁铁质岩地球化学特征及成矿潜力分析  

Geochemical Characteristics and Metallogenic Potential of the Mafi-cultramafic Rocks Form Longxi in the Eastern Tianshan Mountains

作　　者：米宝昕 李平 靳刘圆 王洪刚 王晓晨 Mi Baoxin;Li Ping;Jin Liuyuan(The Geological Society of Xinjiang,Urumqi,Xinjiang,830046,China;Geological Survey Academy of Xinjiang,Urumqi,Xinjiang,830000,China)

机构地区：[1]新疆地质学会,新疆乌鲁木齐830046 [2]新疆维吾尔自治区地质调查院,新疆乌鲁木齐830000 [3]内蒙古自治区第二水文地质工程地质勘查院

出　　处：《新疆地质》2019年第4期498-504,共7页Xinjiang Geology

基　　金：国家重点研发计划项目(2018YFC0604001-04);新疆地质勘查基金项目(Y15-1-LQ05)共同资助

摘　　要：东天山二叠纪镁铁-超镁铁质岩发育一系列铜镍硫化物矿床,近年来沙垄以西地区铜镍矿床的发现,大大提高了该地区镁铁-超镁铁质岩的关注度。垄西岩体主要由橄榄辉长岩和辉长岩组成,通过LA-ICP-MS锆石U-Pb测年,获得橄榄辉长岩成岩年龄为(288.9±1.8)Ma(n=16,MSWD=2.3),与东天山典型铜镍矿成岩成矿时代一致。岩石地球化学特征显示,源区主体为亏损地幔,可能遭少量俯冲流体改造的富集岩石圈地幔组分加入或地壳物质混染作用。由于同化混染作用较弱,可能仅在深部经部分硫化物熔离作用,关键成矿指标与区域上典型铜镍矿存在明显差异,不同程度制约了成矿潜力,岩体浅部找矿难度较大。The Permian mafic-ultramafic rocks in the eastern Tianshan Mountains have developed a series of coppernickel sulphide deposits,especially the discovery of copper-nickel deposits in Longxi area in recent years,which greatly improved the attention of the mafic-ultramafic rocks in this area.The Longxi rocks mainly consist of olive gabbro and gabbro.The diagenetic age of olive gabbro tested on zircon by LA-ICP-MS is(288.9±1.8)Ma(n=16,MSWD=2.3),which is consistent with the diagenesis and mineralization age of the typical copper-nickel deposit in the eastern Tianshan Mountains.The geochemical characteristics of the Longxi rocks indicate that the source is dominated by the depleted mantle,which may be affected by the mixing of crustal materials.Because of the assimilation and mixing effect is weak,it is possible that only part of sulfide is melted away in the deep part.The key metallogenic indicators are significantly different from the typical copper-nickel deposits in the region,which in varying degrees restricts the metallogenic potential and makes it difficult to find ore in the shallow part of the rocks.

关 键 词：东天山 年代学 镁铁-超镁铁质 成矿潜力 

分 类 号：P618.31[天文地球—矿床学] P618.46[天文地球—地质学]