Genesis of High Ba-Sr Yashan Intrusion from the Jiaodong Peninsula, Eastern China: Implications for the Destruction of the North China Craton
Guozhi Xie, Lipeng Zhang, Jie Li, Zhongyi Bao, Kun Wang, Qian Chen, Li Wang, Jingwei Wang
Journal of Earth Science ›› 2022, Vol. 33 ›› Issue (3) : 567-580.
Genesis of High Ba-Sr Yashan Intrusion from the Jiaodong Peninsula, Eastern China: Implications for the Destruction of the North China Craton
The origin of the Mesozoic high Ba-Sr (HBS) granitic magmatism in the Jiaodong Peninsula remains controversial in petrogenesis models and geodynamic settings. Here, we report zircon U-Pb age, trace element and oxygen isotope compositions, and whole-rock major-trace element and Sr-Nd isotope compositions of the HBS Yashan granodiorite. The zircon U-Pb age of ∼118 Ma denotes that the Yashan granodiorite belongs to the Weideshan-stage magmatic activity, which is consistent with the age of Mo mineralization in the Yashan intrusion. The low Sr/Y (48.8–115) and high (La/Yb)N (23.8–50.4) ratios of the Yashan granodiorite are analogous to adakitic features derived from the lower-crust. This is also supported by the whole-rock initial 87Sr/86Sr ratios (0.709 6–0.710 3) and zircon δ8O values (6.79‰–8.03‰). Contemporaneous mantle-derived mafic microgranular enclaves indicate the involvement of the metasomatized lithospheric mantle. The high magma oxygen fugacity of the Yashan intrusion as indicated by high zircon Ce4+/Ce3+ values suggests the involvement of plate subduction. The obviously lower Dy/Yb, La/Yb and Sr/Y ratios of magmatic rocks in the Weideshan-stage than those in the early-stage imply lithospheric thinning of the eastern North China Craton. We propose that the Yashan HBS granodiorite was formed by crust-mantle interactions during slab rollback.
Yashan / magmatic intrusion / high Ba-Sr / Jiaodong Peninsula / crust-mantle interaction / North China Craton
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