锆石微量元素对铜陵侵入岩成因和铜、金成矿的制约.docVIP

  锆石微量元素对铜陵侵入岩成因和铜、金成 矿的制约# 方德，陈思，谢建成，李全忠** 5 10 15 20 25 30 35 40 （合肥工业大学资源与环境工程学院） 摘要：安徽铜陵地区是我国最著名的铜金产地之一，成矿与岩浆作用关系密切。近十年来， 铜陵中生代侵入岩的成因仍然存在分歧。本次我们报道了铜陵地区侵入岩新的锆石原位微量 元素数据。铜陵地区侵入岩具有典型的岩浆锆石特征：一致的重稀土富集、Ce 正异常和弱 Eu 负异常的稀土配分模式，高 Th/U 比值和(Sm/La)N 值，低 La 含量。高 Eu/Eu*比值、较 低锆石 Ti 温度、Yb-U-Y 和 Ti-Hf 相关关系等锆石微量元素特征暗示本区侵入岩来源于俯冲 洋壳部分熔融，在其上升过程中与富集地幔发生结晶分异作用。高锆石 Ce+4/Ce+3 比值（100） 反映了高氧逸度特征。这些明显的锆石地球化学特征表明铜陵地区侵入岩和大规模 Cu、Au 成矿作用是俯冲洋壳部分熔融结果。 关键词：锆石；原位微量元素；Ce+4/Ce+3；洋壳部分熔融；铜陵 中图分类号：P59 Petrogenesis of Mesozoic intrusive rocks and Cu-Au mineralization in Tongling region: In-situ zircon geochemical constraints FANG De, CHEN Si, XIE Jiancheng, LI Quanzhong (School of Resources and Environmental Engineering, Hefei University of Technology) Abstract: Tongling region is one of the most important non-ferrous metal producers where the formation of Cu-Au deposits has closely genetic relations with Mesozoic intrusions. However, petrogenesis of intrusions has been hotly debated in the past decade. Here we report new in-situ trace element data of zircon from the intrusive rocks in Tongling region. The Tongling intrusive rocks have typical characteristics of magmatic zircon: consistent REE patterns with HREE enrichment, Ce positive anomaly, weak Eu negative anomaly, high Th/U and (Sm/La)N ratios, low La contents. The trace element characteristics of zircon have high Eu/Eu* values, lower Ti-in-zircon temperature, Yb-U-Y and Ti-Hf relationship, indicating that the Tongling intrusive rocks were genetically related to slab melting and subsequent interaction with the enriched mantle. High zircon Ce+4/Ce+3 values (100) reflect high oxygen fugacity. These distinctly geochemistry characteristics of zircon indicate the intrusive rocks and the large-scale Cu-Au mineralization of Tongling region result from partial melting of the subducting oceanic crust. +4 +3 region. 0 引言 安徽铜陵地区地处中国东部中生代长江中下游铜、金、铁、多金属成矿带，是国内为数 不多的大型铜、金矿集区之一，也是中国东部燕山晚期一个重要的岩浆活动带，成矿作用和 岩浆作用关系密切。 铜陵地区中生代侵入岩一直以来是地质学者研究的重点内容，并取得了丰硕的成果，但 基金