Middle Permian adakitic granite dikes in the Sumdo region, central Lhasa terrane, central Tibet: Implications for the subduction of the Sumdo Paleo-Tethys Ocean

•The newly discovered Middle Permian granite dikes are adakitic in composition.•The adakitic magma was generated by partial melting of subducted oceanic slab.•The granite dikes were related to the subduction of the Sumdo Paleo-Tethys Ocean.