投稿时间：2021-06-13
修订日期：2021-10-30
网络发布日期：2022-05-06
中文摘要:中山沟金矿床是产出在冀北水泉沟碱性杂岩体西段的一处中型金矿床，受区域E-W向深大断裂控制。文章对矿区的碱性侵入岩体开展了年代学和岩体地球化学研究。LA-MC-ICP-MS锆石测年结果表明，矿区新鲜角闪石英二长岩与蚀变角闪石英二长岩样品的锆石谐和年龄分别为(390±2) Ma和(392±3) Ma，均为泥盆世。锆石稀土元素总量相对较高，轻稀土元素相对亏损，重稀土元素则相对富集，并伴随着中等-强烈的Ce异常和不明显的Eu异常。2件样品锆石的178Lu/177Hf比值相对均一，176Hf/177Hf比值呈现低值且变化浮动小，二阶段Hf模式年龄平均值为2424 Ma和2465 Ma。研究区侵入岩全岩分析显示其均为富SiO2、富碱、准铝的钙碱性岩石，为高钾钙碱性A2-型花岗岩，具有LREE、LILE元素（Sr、Rb、Ba）富集和高场强元素（Nb、Ta、Hf）、放射性元素（Th、U）、HREE和Ti相对亏损特征，稀土元素总量较低且变化范围较大，显示了右倾的稀土元素配分模式，并伴随着弱负-正Eu异常，相对富集轻稀土元素，亏损重稀土元素。岩体源区可能较老（太古代桑干群），可能为榴辉岩或角闪榴辉岩相，并含有一定量的富集地幔的物质。年代学和岩石学特征表明，碱性岩浆的侵位可能为西伯利亚板块和华北克拉通微地块发生碰撞后伸展的产物，是区域拉张构造背景下岩浆活动的产物。
Abstract:The Zhongshangou Au deposit, located in the west section of the Shuiquangou alkaline complex, northern Hebei Province, is a vein-type mineralization and is obviously controlled by near E-W trending regional deep faults. This paper summarizes the study on geochronology and geochemistry of the main intrusive rocks from the Zhongshangou Au deposit. LA-MC-ICP-MS zircon U-Pb dating yielded a concordia age of (390±2)Ma (MSWD =0.026) and (392±3)Ma (MSWD=0.016) for fresh and altered amphibolite monzonite, respectively, indicating the emplacement age of the intrusive rocks is constrained in Early Devonian. The whole rock geochemistry show that the intrusive rocks from the Zhongshangou Au deposit are characterized by high SiO2, alkali-rich，meta-/ per-aluminum, which belongs to calc-alkaline A2-type granite, characterized by LREE and LILE (large ion lithophile elements) enrichment, HFSE (e.g. Nb, Ta, Hf), HREE and radioactive elements (Th, U) depletion and Ti slight depletion, accompanied by slight negative or weak positive Eu anomaly. The source area of the intrusive rocks may be old (Archean Sanggan Group), and may be eclogite or hornblende eclogite facies, contains a certain amount of enriched mantle material. The geochronological and petrological characteristics indicate that the emplacement of alkaline magma may be the product of extension after the collision between the Siberian Plate and a micro-blak of the North China Craton, and it is the product of magmatic activity under the regional extensional setting.
keywords:geochemistry zircon LA-MC-ICP-MS dating Hf isotope A2-type granite alkaline rock gold deposit North margin of the North China Craton
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基金项目:河北省自然科学基金面上项目(编号:D2019403015)、河北省青年科学基金项目(编号:D2020403101)、河北省高等学校科学技术研究项目(编号:ZD2019003)、河北省"三三三人才工程"项目(编号:A202001014)和河北地质矿产勘查开发局科研项目(编号:13000022P00329410103R)联合资助
引用文本：
王丰翔,陈超,张福祥,于灵艳,冯云磊,马奎,王云静.2022.冀西北中山沟金矿区泥盆世A-型碱性杂岩侵位时代、岩石地球化学以及地质意义[J].矿床地质,41(2):403~425WANG FengXiang,CHEN Chao,ZHANG FuXiang,YU LingYan,FENG YunLei,MA Kui,WANG YunJing.2022.Emplacement age, petrogeochemistry and geological significance of Devonian A-type alkaline complex in Zhongshangou Au deposit, northwest Hebei Province[J].Mineral Deposits41(2):403~425
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