今天是2018年10月18日

多龙矿集区色那东岩体年龄、成因与动力学背景

DOI:10.3799/dqkx.2017.613

作者:王勤,林彬,唐菊兴,宋扬,李彦波,侯俊富,李玉彬,卫鲁杰

联系地址:成都理工大学地球科学学院,四川成都 610059

摘要:多龙矿集区是我国首个铜金属资源量达到2 000万t以上的世界级铜金矿集区,外围找矿潜力依然十分巨大.首次报道矿集区东部色那东地区花岗斑岩体和闪长玢岩体的地质年代学及地球化学测试结果,为总结区域成矿规律提供基础数据.通过精确的锆石测年,全岩主、微量元素和锆石Hf同位素测试发现,上述岩体的成岩年龄均为123±2 Ma,岩石的形成与俯冲洋壳板片部分熔融有关,源区有明显幔源组分加入.色那东地区侵入岩与矿集区含矿斑岩空间上集中侵入,且同属早白垩世岩浆活动产物,暗示其具有相同动力学背景,是班公湖-怒江洋俯冲末期-碰撞初期弧-弧“软”碰撞的产物,其侵入过程为成矿提供了热量和流体来源,显示该地区仍有较好的成矿潜力.

关键字:锆石U-Pb年龄;岩石学;地球化学;Hf同位素组成;色那东;西藏

Diagenesis, Lithogenesis and Geodynamic Setting of Intrusions in Senadong Area, Duolong District, Tibet

Author:Wang Qin, Lin Bin, Tang Juxing, Song Yang, Li Yanbo, Hou Junfu, Li Yubin, Wei Lujie

Author Address:College of Earth Sciences, Chengdu University of Technology, Chengdu 610059, China

Abstract:Duolong district has more than 20 million tons of copper resources, which is the top large-scale Cu-Au mineral district in China. However, the prospecting potential in its peripheral region is still huge. This paper reports the geochronology and geochemical test results of the granite porphyry and diorite porphyry in the Senadong area for the first time, providing data for regional metallogenic regularity. In this study, the accurate zircon isotopic dating, Hf isotopic and whole rock major and trace elements reveal that emplacement ages of granitic and dioritic porphyries 123±2 Ma, respectively; the formation of rocks is related to partial melting of subducted oceanic plate, and the magma contains significant mantle source component. Based on these results, it is proposed that the intrusions of the Senadong area adjacent to ore-bearing porphyry in Duolong district formed during the period of the Early Cretaceous magmatic activity, suggesting that they possibly have the same geodynamic background. All these intrusions are the products of Bangongco-Nujiang ocean arc-arc “soft” collision, which occurred in the end of subduction transform to the beginning of the collision. These magmas provide heat and fluid for mineralization, which suggests that the Senadong area could be a potential district to find the new porphyry deposits.

Keyword:U-Pb dating of zircon; petrology; geochemistry; Hf isotope; Senadong; Tibet

 

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作者简介:王勤(1983-),男,博士研究生,工程师,从事固体矿产勘查与评价相关工作,主要从事区域成矿学研究.ORCID: 0000-0003-1507-9316. E-mail: wagchin@163.com

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