Geochemistry, zircon U–Pb chronology and Hf isotope of the Weideshan high Ba–Sr granites in Jiaodong Peninsula of the North China Craton: Constraints on their petrogenesis and tectonic implications

Abstract

The lithospheric thinning and huge gold mineralization in the Jiaodong Peninsula is intensively studied, aiming to better understand the geodynamic setting of the magmatic petrogenesis and the relationship between magmatism and large-scale mineralization. Thus, we conducted detailed research on the Weideshan intrusions in the Jiaodong region, including field investigations, geochemical, geochronological and Hf isotope analysis, to reveal the tectonic implications for the destruction of the eastern North China Craton (NCC). The Weideshan intrusions consist of quartz monzodiorite, quartz monzonite and monzogranite. The SHRIMP zircon U-Pb dating results show that the Weideshan intrusions are emplaced at 115–112 Ma, namely, in the late Early Cretaceous period. Rocks of Weideshan intrusions are high-K calc-alkaline series and metaluminous granites. The trace elements are characterized by enrichment of Rb, Ba, Sr and LREE, with unobvious Eu anomalies and depletion of Nb, Ta, Zr, Hf and Ti. The contents of Ba and Sr are (913.00–1562.00)/1199.29 μg/g and (373.00–793.00)/536.71 μg/g, respectively, showing the features of high Ba–Sr granites (HBS). Development of numerous dark enclaves and negative εHf(t) values (− 17.93 to − 12.19) indicate that the Weideshan granites originate from the mixture of crustal-derived felsic magma from partial melting of the Paleoproterozoic crust and alkali-rich magma from the enriched mantle. The generation of the Weideshan granites was closely related to the asthenospheric upwelling during the lithosphere thinning of the NCC in the late Mesozoic.