The northern margin of the North China Craton (NCC) contains widespread Permian magmatic rocks, but the origin of these rocks remains controversial. This uncertainty hampers us from better understanding of tectonic framework and evolution of the eastern Paleo–Asian Ocean, particularly with respect to its final–stage subduction and closure time. To address these questions, this study presents petrological, zircon U–Pb geochronological, whole–rock geochemical, and in situ zircon Hf isotopic data for these Permian mafic intrusions in the northern margin of the NCC. Precise zircon U–Pb dating results indicate that these mafic intrusions were emplaced in the middle Permian (ca. 260 Ma). Geochemically, the studied mafic intrusions have high MgO and transition metals element contents, with high Mg^# values, indicating a mantle origin. These mafic intrusions are characterized by enrichment of large ion lithophile elements (LILEs; e.g., Rb, Ba, and K) and light rare earth elements (LREEs), and depletion of high field strength elements (HFSEs; e.g., Nb, Ta, and Ti) and heavy rare earth elements (HREEs), indicating that they formed in a subduction–related setting. These geochemical features, together with zircon ε_Hf(t) values (–1.1 to +11.2), indicate that their parental magmas were derived from partial melting of heterogeneous mantle wedge metasomatized by subduction–related fluids, with the contributions of slab sediments. The studied mafic intrusions also show wide range of major and trace elements contents, and variable Mg^# values, Eu and Sr anomalies, suggesting that the primary magmas had undergone variable degrees of fractional crystallization. Together with the E–W trending Permian continental arc along the northern margin of the NCC, we confirm that the generation of the middle Permian mafic intrusions was related to southward subduction of the Paleo–Asian oceanic lithosphere beneath the NCC and the Paleo–Asian Ocean had not closed prior to the middle Permian.

中文翻译：

---

东古亚洲洋最后阶段向南俯冲：来自华北克拉通北缘中二叠纪基性侵入体的证据

华北克拉通 (NCC) 北缘包含广泛分布的二叠纪岩浆岩，但这些岩石的起源仍存在争议。这种不确定性阻碍了我们更好地了解东古亚洲洋的构造框架和演化，特别是在其最后阶段俯冲和闭合时间方面。为了解决这些问题，本研究提供了 NCC 北缘这些二叠纪基性侵入体的岩石学、锆石 U-Pb 年代学、全岩地球化学和原位锆石 Hf 同位素数据。精确的锆石 U-Pb 测年结果表明这些镁铁质侵入体位于二叠纪中期（约 260 Ma）。在地球化学上，研究的镁铁质侵入体具有高 MgO 和过渡金属元素含量，具有高 Mg ^#值，表明地幔起源。这些镁铁质侵入体的特征是大离子亲石元素（LILE；例如 Rb、Ba 和 K）和轻稀土元素（LREE）的富集，以及高场强元素（HFSE；例如 Nb、Ta 和Ti）和重稀土元素（HREE），表明它们是在与俯冲相关的环境中形成的。这些地球化学特征，连同锆石 ε _Hf (t) 值（–1.1 至 +11.2），表明它们的母岩浆来自俯冲相关流体交代的异质地幔楔的部分熔融，并有板状沉积物的贡献。研究的镁铁质侵入体还显示出广泛的主要和微量元素含量，以及可变的 Mg ^#值，Eu 和 Sr 异常，表明原生岩浆经历了不同程度的分步结晶。连同沿华北克拉通北缘的东西向二叠纪大陆弧，我们证实中二叠世基性侵入体的产生与华北克拉通下方古亚洲大洋岩石圈和古亚洲洋向南俯冲有关在二叠纪中期之前没有关闭。