十行带南带圆珠顶花岗质斑岩年代学、地球化学及对Cu-Mo矿化的意义

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• 作者：钟立峰李杰彭头平夏斌刘立文
• 会议时间：2013-10-01
• 关键词：岩石学 ; 花岗质斑岩 ; 年代学 ; 地球化学 ; Cu-Mo矿化
• 作者单位：钟立峰(中国科学院南海海洋研究所,中国科学院边缘海地质重点实验室,广州 510301)李杰,彭头平(中国科学院广州地球化学研究所,同位素地球化学国家重点实验室,广州 510640)夏斌(中山大学,海洋石油勘探开发广东普通高校重点室验室,广州 510006)刘立文(广东省地质局第五地质大队,肇庆 526020)
• 母体文献：2013年全国岩石学与地球动力学研讨会论文集
• 会议名称：2013年全国岩石学与地球动力学研讨会
• 会议地点：广州
• 主办单位：中国地质学会
• 语种：chi
• 分类号：P61

摘要

The Shi-Hang zone is an important NE-SW-trending Mesozoic magmatic belt inSouth China,which is dominated by granites with relativelyhigh εNd(t)values andyoung TDM model ages.Here,we present laser ablation inductively coupled plasmamass spectrometry(LA-ICP-MS)zircon U–Pb ages,major and trace elementcompositions,and Sr-Nd-Hf isotope data for the Yuanzhuding porphyritic granitoidswithin the southwestern Shi-Hang zone,and use these data to determine the origin ofthis granitoid and its relationship with Cu–Mo mineralization.Zircon U–Pb datingindicates that these granitoids were emplaced at 157.8±1.1Ma. They have initial87Sr/86Sr ratios of 0.70941-0.71398,εNd(t) values of -3.15 to -2.02, and in situ zirconεHf(t) values of +1.71 to +6.17.Geochemically,most of them are high-K calc-alkalineand show an adakitic affinity.They are more likely to emplace in a continental arcsetting related to westward subduction of the palaeo-Pacific plate. Their parentalmagmaoriginated chiefly from the overlying sediments of the downgoing slab,andsubsequently interacted withthe lithospheric mantle wedge at the temperatures of~790℃.High oxygen fugacity during magmatic evolution played a crucial role in thedevelopment of Cu–Mo mineralization within the Yuanzhuding.The discovery of theYuanzhuding deposit implies that theChenzhou–Huaiji fault belt is most likely prospective for mineral exploration for porphyry Cu–Mo deposits.