摘要
塞尔维亚博尔(Bor)地区具有悠久的采矿历史及丰富的矿产资源。Jama铜矿床位于Bor地区,隶属于蒂莫克(Timok)矿集区,为了探讨该区典型容矿安山岩的成因及成矿指示意义,文章对Jama矿床的容矿安山岩开展了锆石U-Pb定年、微量元素及Hf同位素特征研究。研究结果表明:安山岩LA-ICP-MS锆石U-Pb年龄约为86 Ma,形成于晚白垩世。锆石Ti温度计估算结果显示岩浆结晶温度为663~806℃(平均724℃),锆石氧逸度计估算结果显示log_(fO2)值介于-14.86~-7.60(平均-11.07),ΔFMQ值介于+2.11~+7.62(平均+5.04),暗示了岩石形成于相对低温和较高氧逸度条件。锆石的ε_(Hf)(t)值较高,介于+12.6~+16.5,对应的二阶段模式年龄T_(DM2)介于88~344 Ma,结合锆石微量元素特征,指示了该安山岩形成于活动大陆边缘弧环境,岩浆主要来源于俯冲交代的亏损地幔楔的部分熔融。综合前人对区域构造-岩浆活动的认识,研究认为Jama矿区安山岩形成于Vardar洋板块向北俯冲的活动大陆边缘弧环境,晚白垩世俯冲板块回卷产生弧后伸展环境,导致高氧逸度的幔源岩浆上升,并在适当的条件下发生了成岩成矿作用。
The Bor region of Serbia has a long history of mining and abundant mineral resources.The Jama copper deposit is located in the Bor region and belongs to the Timok mining area.To investigate the genesis and mineralization significance of the host andesite in the Jama deposit,we analyzed its zircon U-Pb ages,trace elements,and Hf isotopes.LA-ICP-MS zircon U-Pb age is approximately 86 Ma in the Late Cretaceous.Calculated Ti-in-zircon temperatures range from 663℃to 806℃(average 724℃),and zircon oxygen fugacity shows that the log_(fO2)=-14.86--7.60(average-11.07),ΔFMQ=+2.11-+7.62(average+5.04),suggesting magmas with relatively high oxygen fugacity and low crystallization temperatures.The andesite is characterized by highε_(Hf)(t)value(+12.6-+16.5),and young second-stage model ages(T_(DM2)=88-344 Ma).Based on the trace element characteristics of zircon,the andesite was formed in an active continental margin arc environment and magma genesis was linked to partial melting of the depleted mantle wedges metasomatized by the subducted plate fluids.Synthesizing our findings with prior research on regional tectonic-magmatic evolution,we propose that the Jama andesite was formed in an active continental margin arc during the northward subduction of the Vardar oceanic plate.The late Cretaceous rollback of the subducted plate likely triggered back-arc extension,facilitating the ascent of oxygen-rich mantle-derived magma and subsequent diagenesis and mineralization.
作者
林木森
徐楷
王力圆
刘文元
LIN Musen;XU Kai;WANG Liyuan;LIU Wenyuan(Zijin School of Geology and Minging,Fuzhou University,Fuzhou 350108,China)
出处
《高校地质学报》
北大核心
2025年第4期439-450,共12页
Geological Journal of China Universities
基金
紫金矿业集团股份有限公司委托重大横向课题(01612012)
国家自然科学基金项目(42230807,41903007)联合资助。
