Objective Previous studies of mafic microgranular enclaves (MMEs) and host granite have revealed that crust–mantle interaction plays an important role in the formation of granitic magma. However, whether MMEs and host granite are the products of different evolutionary stages of homologous magmas needs further exploration.

Methods After petrography study, the MMEs from the Ziyunshan pluton were selected for zircon U−Pb and Hf−O isotopic compositions analyses to reveal their petrogenesis and genetic relationship with the host granite.

Results U–Pb age of the MMEs is 225.1±5.3 Ma, which is in general agreement with the age (225.2±1.7 Ma to 227.0±2.2 Ma) of their host granites. The ε_Hf(t) and δ¹⁸O values of the MMEs are −6.4 to −1.6 and 7.6‰ to 9.9‰, respectively, and those are consistent with Hf−O isotope composition of their host granite. Two–stage model ages (T_DM2) of the MMEs range from 1.35 Ga to 1.65 Ga (average at 1.51 Ga), which is slightly higher than that of the host granite (1.22 Ga to 1.79 Ga, average at 1.36 Ga).

Conclusions The results indicate that the Ziyunshan MMEs and host granite are formed in post–collision tectonic setting. The initial magma chamber was firstly formed by the mantle magma and the anatectic magma in the lower crust. In the early stage, mixing of felsic magma and enriched mantle derived magma formed the host granite rich in MMEs. In the late stage, the more evolved and acidic residual magma emplaced into the host granite and mixed with a small amount of mantle–derived magma to form the complement granite and a small amount of MMEs. This study would provide a new perspective for understanding the genetic relationship between MMEs and their host granites.