A long-lived tectono-metamorphic event in the late Paleoproterozoic: Evidence from SIMS U–Th–Pb dating of monazite from metapelite in centralsouth Trans-North China Orogen
A long-lived tectono-metamorphic event in the late Paleoproterozoic: Evidence from SIMS U–Th–Pb dating of monazite from metapelite in centralsouth Trans-North China Orogen
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古元古代晚期一次长期的构造变质事件——来自跨华北造山带中南部变泥岩中独居石的SIMS U-Th-Pb定年证据
DOI：
10.1016/j.precamres.2019.105497
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发表时间：
2020
影响因子：
3.8
通讯作者：
Wu Chunming
中科院分区：
文献类型：
--
作者：
Chen Hongxu;Liu Jiahui;Zhang Qian WL;Wang Hao YC;Wu Chunming
独居石作为变岩中重要的副矿物，形成于变质事件中，对构造变质事件的发生时间有着重要的直接制约作用。本文采用独居石二次离子质谱（西姆斯）U-Th-Pb定年方法，对华北造山带中南部不同变质带中的4个典型变岩进行了研究。测年结果表明，花山、洛宁、赞皇和五台变质杂岩中的独居石记录的变质年龄分别为1.83Ga、1.95Ga、1.85Ga和1.91 ~ 1.83Ga。结合有关TNCO内离散岩系的变质年代学资料，认为华北东西陆块沿近南北走向的TNCO沿着伸展，早于1.97 Ga，晚于1.80 Ga，是一次长期的构造变质事件。
As a key accessory mineral in metapelite, monazite forms in the metamorphic event and therefore, places important direct constraint on the timing of the tectono-metamorphic event. In this study, we investigate four representative metapelites from different metamorphic terranes in the central-south Trans-North China Orogen (TNCO), applying secondary ion mass spectrometry (SIMS) U–Th–Pb dating on monazite. The dating results reveal that monazite collected from the Huashan, Luoning, Zanhuang and Wutai metamorphic complexes record the metamorphic ages of ~1.83 Ga, ~1.95 Ga, ~1.85 Ga and ~1.91 to 1.83 Ga, respectively. Combined with the literature data of metamorphic geochronology on the discrete terranes within the TNCO, it is suggested that the amalgamation between the Western and Eastern Blocks of the North China Craton along the nearly NS-trending TNCO stared as earlier as ~1.97 Ga and continued to as late as ~1.80 Ga, which was in fact a long-lived tectono-metamorphic event.