Fresh insights into the onset of big mantle wedge beneath the North China Craton  

作　　者：Yingpeng Wang Xuance Wang Wen Zhang Xiaowei Yu Ligong Wang Jinhui Wang Peigang Zhu Yongbin Wang 

机构地区：[1]Shandong Institute of Geological Survey,Ji’nan 250014,People’s Republic of China [2]Yunnan Key Laboratory of Earth System Science,Yunnan University,East Outer Ring Road,Chenggong District,Kunming 650500,Yunnan Province,People’s Republic of China [3]Key Laboratory of Critical Minerals Metallogeny in Universities of Yunnan Province,Yunnan University,Kunming 650500,People’s Republic of China [4]Radiogenic Isotope Facility,School of Earth and Environment Sciences,University of Queensland,Brisbane,QLD 4072,Australia

出　　处：《Acta Geochimica》2025年第1期145-162,共18页地球化学学报(英文)

基　　金：supported by the Geological Survey Program of Shandong Province(Yingpeng Wang);Yunnan Fundamental Research Projects(Yongbin Wang)。

摘　　要：The onset of the big mantle wedge(BMW)structure beneath the North China Craton remains debated.Research on the genesis of Late Mesozoic granites associated with gold deposits in the Jiaodong Peninsula above the BMW could provide fresh insights into this question.The monzogranite from the Zhaoxian-Shaling gold district was intruded during 154-148 Ma.This I-type granite has high-K calc-alkaline and metaluminous characteristics.The monzogranite formed at medium temperatures(718-770℃)and was generated in a thickened lower crust at depths within the stability field of garnet.The monzogranite’s high zircon Ce^(4+)/Ce^(3+)and Eu_(N)/Eu_(N)^(*)values and low FeOT/MgO ratios,suggest that it formed in a high oxygen environment.Its variableε_(Hf)(t)values with T_(DM2)of 1.93-2.87 Ga imply that it originated from the melting of ancient crust basement,with contributions from mantle-derived materials.The granite’s enrichment in LREEs and LILEs,and depletion in HREEs and HFSEs,along with its trace element tectonic discrimination diagrams and medium Sr/Y,indicate an adakite affinity in an active continental margin setting.The transition from S-type granites to I-type granites and finally to A-type granites observed in the eastern part of North China Craton suggests a shift in the tectonic environment from compression to extension.This change is also reflected in the transition from flat subduction to steep subduction.Therefore,the monzogranite was formed in a tectonic transition setting triggered by a change in the subduction angle of the PaleoPacific Ocean slab during the Late Jurassic.This event may have marked the initiation of the BMW above the North China Craton.

关 键 词：Zircon U-Pb age Hf isotopic composition Jiaodong Peninsula North China Craton 

分 类 号：P597[天文地球—地球化学] P541[天文地球—地质学]