Early Jurassic granodiorite‐monzogranite‐granite suite in the Zhangguangcai Range, NE China: Implications for melting of newly accreted arc crust

Abstract

High‐K calc‐alkaline granitoids play a key role in understanding the formation and evolution of the continental crust. Herein, we present new laser ablation inductively coupled plasma mass spectrometry zircon U–Pb and Lu–Hf isotopic, whole‐rock geochemical and Sr–Nd isotopic data of early Jurassic high‐K calc‐alkaline granitoids in the Zhanggunagcai Range, NE China. In situ zircon U–Pb dating shows that the granodiorite‐monzogranite‐granite (GMG) suite was emplaced at ca. 192–187 Ma. They are high‐K calc‐alkaline and weakly peraluminous, similar to the geochemical characteristics of I‐type granites. The GMG suite has lower bulk‐rock initial 87Sr/86Sr ratios of 0.7037–0.7042, slightly positive εNd(t) values of +1.10 to +1.87 and highly positive zircon εHf(t) values of +5.3 to +10.9. This result suggests a major contribution of juvenile crust to the magma source. The tetrad rare earth element patterns and highly negative Eu anomalies of samples with high SiO2 contents indicate that fractional crystallization plays an important role in the genesis. Together with data in the literature, we infer that the early Jurassic granitic rocks have been formed by partial melting of juvenile arc crust associated with the westward subduction of the Paleo‐Pacific Plate.