汉诺坝新生代玄武岩中金云母单斜辉石岩包体的LA-ICP-MS/MS原位Rb-Sr年代学研究

含金云母地幔包体作为岩石圈深部富钾含水交代作用的直接记录者，对理解富钾幔源岩浆以及相关的金矿床的形成至关重要，其中的金云母具有对交代作用进行定年的潜力。近些年来，对于华北岩石圈交代作用过程的研究虽已取得良好的研究基础，但在交代作用的定年问题上难有较大突破。本项目选择华北北缘汉诺坝地区的新生代玄武岩中的金云母单斜辉石岩包体进行系统的LA-ICP-MS/MS原位Rb-Sr定年，并结合岩石学、矿物学及同位素地球化学特征，确定金云母单斜辉石岩包体的成因和交代作用发生的时间，以及交代介质的性质和来源，探讨引起华北北缘岩石圈金云母交代作用的地球动力学机制。该研究对于揭示华北克拉通岩石圈深部富挥发分物质的再循环过程具有重要意义。

Phlogopite-bearing mantle xenoliths, as the direct recorder of potassic hydrous metasomatism in the deep lithosphere, are very important for understanding the formation of mantle derived potassic magma and related gold deposits. In particular, phlogopite in these rocks have the potential for dating metasomatism events. In the past, lithospheric metasomatism of the north China have been well-studied, while time constraints on these processes remain unclear. This project selects phlogopite-bearing clinopyroxenite xenoliths from the Hannuoba Cenozoic basalts in the northern margin of north China for systemic LA-ICP-MS/MS in-situ Rb-Sr dating. Together with petrology, mineralogy, and isotopic geochemistry of these samples, this project will directly date the phlogopites related metasomatic events, constrain the petrogenesis of these xenoliths, study the nature and derivation of the metasomatic agents, and finally discuss the related geodynamic causes. This research is of great importance for revealing the deep volatile-rich material cycle in the lithosphere of North China Craton.