| 王光,张兴康,孙志伟,陈薇,刘广宇,刘树兴.冀西北东沟含铷岩体年代学、地球化学及对铷成矿的约束[J].矿产勘查,2026,17(8):1345-1357 |
| 冀西北东沟含铷岩体年代学、地球化学及对铷成矿的约束 |
| Geochronology and geochemistry of the Donggou Rb-bearing granite, northwestern Hebei and its constraints on Rb mineralization |
| 投稿时间：2025-07-06 |
| DOI：10.20008/j.kckc.202608005 |
| 中文关键词: 锆石 U-Pb年龄 岩石地球化学 岩石成因 东沟含铷岩体 冀西北 |
| 英文关键词: ziron U-Pb dating geochemistry petrogenesis the Donggou granitoid pluton northwestern Hebei |
| 基金项目:本文受河北省自然资源厅科研项目(13000021GM5KG6TOH871W)、河北省地矿局科研项目(454-0502-JBN-G9RL)和河北省地质矿产资源与环境调查专项资金项目(454-0502-YBN-NOVE)联合资助。 |
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| 中文摘要: |
| 东沟铷矿位于冀西北康保县东沟一带，为近年来冀西北地区新发现的铷矿床，Rb2O平均品位为 0.078%，有望达到中大型规模。铷矿主要赋存于东沟岩体内，该岩体主要由中细粒碱长花岗岩和细粒碱长花岗岩组成。本文通过开展东沟含铷岩体的 LA-ICP-MS锆石 U-Pb定年，获得的细粒碱长花岗岩年龄为(225.8±2.1) Ma，形成于晚三叠世。东沟含铷岩体具有高硅(SiO2=74.52%~76.58%)、富碱(K2O+Na2O=8.63%~9.50%)、低镁(MgO=0.03%~0.08%)、低钙(CaO=0.14%~0.74%)和高分异(DI=95.63~97.98)的特征，其稀土分配曲线呈右倾“海鸥”型特征，具有明显的负 Eu异常，富集 K、Rb、Th等大离子亲石元素，亏损 Ba、Sr、Ti、P等高场强元素，具壳源花岗岩的特征。岩石学、矿物学和地球化学特征指示，东沟含铷岩体为高分异 A型花岗岩，Rb等稀有金属富集成矿是强烈分离结晶作用的结果。东沟含铷岩体形成于中—晚三叠世华北克拉通北缘后碰撞的伸展环境，该时期形成的高分异花岗岩为冀西北地区铷等稀有金属矿找矿勘查提供了新方向。 |
| 英文摘要: |
| The Donggou Rb deposit is located in the Donggou area of Kangbao County, Northwest Hebei Prov.ince, which is a newly discovered rubidium deposit. The average Rb2O content is 0.078%, and it is expected to reach medium to large-scale. Rubidium mineralization occurs mainly in the Donggou granitoid pluton, and its lithol.ogy is mainly fine-grained alkali-feldspar granite and medium-fine-grained alkali-feldspar granite. LA-ICP-MSzircon U-Pb dating of the Donggou rubidium-bearing pluton shows that the weighted average age of fine-grainedalkali-feldspar granite is (225.8±2.1) Ma, belonging to the Late Triassic. The Donggou granitoid pluton is enrichedin silica (SiO2=74.52%-76.58%) and alkali (K2O+Na2O=8.63%-9.50%), lower in Mg (MgO=0.03%-0.08%), Ca(CaO=0.14%-0.74%) and high differentiation. Its REE distribution curve is right-leaning, with obviously negativeEu anomalies. It is enriched in LILE, including K, Rb, Th and depleted in HFSE, including Ba, Sr, Ti, P, with thecharacteristics of crust-derived granite. The petrological, mineralogical and geochemical characteristics indicatethat the Donggou granitoid pluton is a highly differentiated A-type granite, and intensive fractional crystallization isthe key factor for the enrichment and mineralization of rubidium and other rare metals. The Donggou granitoid plu.ton was formed in the extension environment of the North China Craton post-collision of the northern margin in theMiddle to Late Triassic. And the highly differentiated granites formed in this period will provide a new direction forthe prospecting of rubidium and other rare metals in northwestern Hebei. |
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