JING Yan
1 College of Earth Sciences, Jilin University, Changchun 130061, China 2 Key Laboratory of Mineral Resources Evaluation in Northeast Asia, Ministry of Land and Resources of China, Changchun 130026, ChinaGE Wenchun
1 College of Earth Sciences, Jilin University, Changchun 130061, China 2 Key Laboratory of Mineral Resources Evaluation in Northeast Asia, Ministry of Land and Resources of China, Changchun 130026, ChinaDONG Yu
1 College of Earth Sciences, Jilin University, Changchun 130061, China 2 Key Laboratory of Mineral Resources Evaluation in Northeast Asia, Ministry of Land and Resources of China, Changchun 130026, ChinaYANG Hao
1 College of Earth Sciences, Jilin University, Changchun 130061, China 2 Key Laboratory of Mineral Resources Evaluation in Northeast Asia, Ministry of Land and Resources of China, Changchun 130026, ChinaJI Zheng
1 College of Earth Sciences, Jilin University, Changchun 130061, China 2 Key Laboratory of Mineral Resources Evaluation in Northeast Asia, Ministry of Land and Resources of China, Changchun 130026, ChinaBI Junhui
3 Tianjin Center, China Geological Survey, Tianjin 300170, ChinaZHOU Hongying
3 Tianjin Center, China Geological Survey, Tianjin 300170, ChinaXING Dehe
4 Shenyang Center, China Geological Survey, Shenyang 110034, ChinaReviews by two anonymous reviewers are gratefully acknowledged for their constructive comments and suggestions that led to a major improvement of the manuscript. We are sincerely grateful to the staff of the Geological Lab Center at China University of Geosciences, Beijing and the Institute of Geology and Mineral Resources in Tianjin, China, for their advice and assistance during the bulk rock major and trace elements, zircon U-Pb dating and Lu-Hf isotope analyses. We also appreciate the Wuhan SampleSolution Analytical Technology Co., Ltd., Wuhan, China, for their aid and suggestions in the analyses of major and trace elements. This study was financially supported by the National Natural Science Foundation of China (Grant No. 41872056).
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 enrichments in large ion lithophile elements (LILEs; e.g., Rb, Ba, and K) and light rare earth elements (LREEs), and depletions in high field strength elements (HFSEs; e.g., Nb, Ta, and Ti) and heavy rare earth elements (HREEs), indicating that they were formed in a subduction-related setting. These geochemical features, together with zircon εHf(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 their parental 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.
JING Yan, GE Wenchun, DONG Yu, YANG Hao, JI Zheng, BI Junhui, ZHOU Hongying, XING Dehe.2022. Final-stage Southward Subduction of the Eastern Paleo-Asian Ocean: Evidence from the Middle Permian Mafic Intrusions in the Northern Margin of the North China Craton[J]. Acta Geologica Sinica(),96(1):81-99
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