| 九瑞矿集区鸡笼山铜金矿床含矿岩体成因和地球动力学背景 |
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| 引用本文： | 詹小飞,魏俊浩.九瑞矿集区鸡笼山铜金矿床含矿岩体成因和地球动力学背景[J].地质科技通报,2021,40(3):109-123. |
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| 作者姓名： | 詹小飞 魏俊浩 |
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| 基金项目： | 国家自然科学基金项目41772071 |
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| 摘 要： | 为了研究九瑞矿集区鸡笼山铜金矿床含矿岩体成因和地球动力学背景，对矿集区内成矿关系十分密切的花岗闪长斑岩体进行了主微量元素、锆石U-Pb年代学和Sr-Nd同位素测试。鸡笼山花岗闪长斑岩具有相对较高的SiO2含量和碱质，相对富集Al2O3、CaO，贫MgO、TiO2和P2O5。LREE相对富集、HREE较为亏损的右倾特征，无明显的负Eu异常，相对富集Rb、Ba、K、Sr等大离子亲石元素（LILE）和亏损Ta、Nb等高场强元素（HFSE），获得样品的形成年龄为（140±1）Ma（MSWD=1.02），表明其均为高钾钙碱性准铝质系列，属于壳幔混合成因的I型花岗岩，岩体可能为富集岩石圈地幔在部分熔融过程中混染了一定程度的古老下地壳物质的产物。岩体侵入年代与长江中下游地区中生代大规模岩浆活动时限一致，可能与古太平洋板块的俯冲作用和区域岩石圈伸展减薄条件下深部壳幔物质相互作用有关。
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| 关 键 词： | 鸡笼山矽卡型铜金矿床 花岗闪长斑岩 锆石U-Pb年龄 地球化学特征 九瑞矿集区 |
| 收稿时间： | 2020-10-17 |
Genesis and geodynamic background of the ore-bearing granodiotite porphyry of the Jilongshan copper-gold deposit in Jiurui district,Hubei Province |
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| Abstract: | Jilongshan copper-gold deposit is located in the Jiurui metallogenic district in the middle and lower Yangtze River metallogenic belt. Cu-Au mineralization of Jilongshan deposit is closely related to granodiotite porphyry. The petrogenesis of the rock is still controversially discussed. In this study, we report the U-Pb zircon chronology, major and trace geochemistry, Sr-Nd-Hf isotopic compositions of the ore-related granodiorite porphyry in Jilongshan. LA-ICP-MS zircon U-Pb geochronology of Jilongshan granodiorite porphyry is 140±1 Ma(MSWD=1.02). Geochemical results show that Jilongshan granodiorite porphyry has a relatively high content of SiO2 (62.33%~63.90%) and Al2O3 (15.24%~15.74%), and alkalis(w(K2O + Na2O) is 6.99%-7.73%). The trace elements are characterized by the relative enrichment of Rb, Ba, K, Sr, depletion of Ta, Nb. The REE characteristics show rightist features with relatively LREE enrichment with (La/Yb)N ratio of 10.55~15.95, and no obvious negative Eu anomaly. The ziron Hf isotope analysis shows low εHf (t) values, and low εNd (t) (-8.2~-9.7). These data suggested that the Jilongshan granodiorite porphyry may be derived from partial melting of enriched lithospheric mantle, mixed with ancient crustal material to a certain extent. |
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