Petrogenesis of Early Cretaceous adakites in Tongguanshan Cu–Au polymetallic deposit, Tongling region, Eastern China

•Tongguanshan intrusive rocks can be divided into high silica adakite and low silica adakite.•Tongguanshan adakites are products of partial melting of subducted oceanic crust, with magma mixing and crustal assimilation.•The oxidized and slab-derived volatile enriched environment favor for regional large-scale Cu mineralization.