投稿时间：2021-05-21
修订日期：2021-11-14
网络发布日期：2022-07-07
中文摘要:查明矿床形成后的变化保存情况对提高成矿预测能力十分重要。文章通过金云母的矿物化学和ArAr年代学研究来探析天宇铜镍硫化物矿床形成后的变化保存问题。研究发现，该矿床的云母有2种产状：一种呈他形片状分布在橄榄石与辉石颗粒之间；另一种是产在块状硫化物矿体与围岩的接触面上，呈叶片状集合体。2种云母种属为铁质黑云母、镁质黑云母和金云母。前者与角闪石近同期结晶，结晶后受到了晚期硫化物熔体的影响，后者为炽热的硫化物矿浆侵位时与围岩相互作用新生成的云母。云母结晶温度为609.6~646.2℃，2个金云母样品的Ar-Ar坪年龄分别为（250.4±1.5） Ma和（247.7±1.5） Ma。该2个坪年龄比岩体的锆石U-Pb年龄晚了约30 Ma，文章推测是由于区内晚二叠世—早三叠世的走滑断裂活动使该Ar-Ar年龄发生了重置。
中文关键词:地球化学 铜镍硫化物矿床 镁铁-超镁铁质杂岩体 金云母Ar-Ar年代学 天宇 东天山
Abstract:The change and preservation of ore deposits after their formation is also a key aspect of metallogenic prediction. In this study, we disscuss the preservation of the Tianyu Cu-Ni sulfide deposit based on the mineralogical chemistry and Ar-Ar geochronology of phlogopite. Two kinds of biotite are distinguished in the deposit, one is distributed between olivine and pyroxene, and the other is developed as leaf-like aggregates on the contact surface between massive sulfide ore and wallrocks. The former crystallizes with amphibole, and is influenced by later period sulfide melt. The latter is newly crystallized biotite when hot sulfide pulp interactes with wallrocks. The crystallization temperature of biotite is 609.6~646.2℃ estimated using the biotite Ti saturation geothermometer. Ar-Ar plateau ages of the two phlogopite samples are (250.4±1.5)Ma and (247.7±1.5)Ma respectively, which are about 30 Ma later than the zircon U-Pb age of the intrusion. It is speculated that the Ar-Ar age was reset due to the strike slip fault activity during Late Permian to Early Triassic in the area.
keywords:geochemistry copper-nickel sulfide deposit mafic-ultramafic complex phlogopite Ar-Ar geochronology Tianyu eastern Tianshan
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基金项目:本文得到“深地资源勘查开采”项目课题（编号：2017YFC0601202）、成矿作用与矿产预测重点实验室基本科研业务费项目（编号：K1202、KK2014）和科技成果转化项目（编号：HE2013）联合资助
引用文本：
王晓青,段士刚,陈小龙,高坡.2022.新疆东天山天宇铜镍硫化物矿床金云母Ar-Ar年代学及其地质意义[J].矿床地质,41(3):598~610WANG XiaoQing,DUAN ShiGang,CHEN XiaoLong,GAO Po.2022.Ar-Ar geochronology of phlogopite and its geological significance from Tianyu Cu-Ni sulfide depost in eastern Tianshan, Xinjiang Province, China[J].Mineral Deposits41(3):598~610
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