| 内蒙古半拉山钼矿LA-ICP-MS锆石U-Pb与辉钼矿Re-Os年龄及其成矿动力学背景 |
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| 引用本文：闫聪,孙艺,赖勇,马星华.2011.LA-ICP-MS zircon U-Pb and molybdenite Re-Os isotope ages and metallogenic geodynamic setting of Banlashan Mo deposit, Inner Mongolia[J].Mineral Deposits,30(4):616~634 |
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| 基金项目:本文得到中国地质调查局项目（1212010813045）资助 |
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| 中文摘要:内蒙古阿鲁科尔沁旗半拉山钼矿床位于大兴安岭南段，是新发现的中型爆破角砾岩型钼矿床。半拉山钼矿区内流纹岩围岩和花岗斑岩岩脉的LA-ICP-MS锆石U-Pb年龄分别是（157.5±3.3）Ma和（126.3±2.1）Ma，而辉钼矿样品的Re-Os同位素等时线年龄为（136.1±6.6）Ma（MSWD=0.42），表明成矿作用与流纹岩或花岗斑岩岩脉没有直接的成因联系，成矿侵入体在矿区深部，这一认识与野外地质考察结果一致。本文研究结果和大兴安岭南段岩浆热液矿床的成矿年代学资料显示大规模成岩成矿作用发生在150～130 Ma，即晚侏罗世与早白垩世之交，构造背景是中亚造山带古生代地壳增生和三叠纪—侏罗纪碰撞加厚之后的太平洋板块俯冲有关的弧后伸展。半拉山钼矿床爆破角砾岩矿床类型的确定表明，爆破角砾岩型钼矿化之下可能存在斑岩型钼矿化，值得进一步勘查。 |
| 中文关键词:地球化学 爆破角砾岩型钼矿床 LA-ICP-MS 锆石U-Pb年龄 辉钼矿Re-Os同位素 半拉山钼矿 西拉沐沦钼多金属成矿带 |
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| LA-ICP-MS zircon U-Pb and molybdenite Re-Os isotope ages and metallogenic geodynamic setting of Banlashan Mo deposit, Inner Mongolia |
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| Abstract:Located in the southern part of the Da Hinggan Mountains, the newly discovered Banlashan Mo deposit in Ar Horqin Banner of Inner Mongolia is a medium-size explosive breccia-type Mo deposit. The rhyolite host rocks and post-ore granite-porphyry dikes yield LA-ICP-MS zircon U-Pb ages of （157.5±3.3）Ma and （126.3±2.1）Ma, respectively. Five Re-Os isotopic analyses of molybdenite separates yield an isochron age of （136.1±6.6）Ma (MSWD=0.42). These ages show that both the rhyolite rocks and the granite-porphyry dikes have no genetic relation with the Mo-mineralization, which has been proved by field investigation, and that the mineralization-related intrusion that resulted in hydraulic brecciation of the rhyolite was possibly seated in the depth. These new data, together with the published isotope ages for the mineralizations and their related intrusions in southern Da Hinggan Mountains, suggest that the majority of the intrusion-related mineral systems (comprising porphyry, skarn and veins) were formed in the period of 150～130 Ma, i.e., the transition from Late Jurassic to Early Cretaceous. This major metallogenic event occurred in a back-arc extensional regime related to Pacific plate subduction, following Paleozoic subduction-related accretion and Triassic-Jurassic collision-related crustal thickening of the Central Asian Orogenic Belt. The definition of the Banlashan explosive breccia-type molybdenum deposit indicates that a porphyry-type Mo mineralization possibly exists below the breccia-type Mo-mineralization, which is of significance for future exploration in the Banlashan Mo deposit. |
| keywords:geochemistry, explosive breccia-type molybdenum deposit, LA-ICP-MS, zircon U-Pb dating, molybdenite Rs-Os isotope, Banlashan Mo deposit, Xilamulun molybdenum metallogenic belt |
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