Petrogenesis of Archean TTGs and potassic granites in the southern Yangtze Block: Constraints on the early formation of the Yangtze Block

•Mesoarchean trondhjemite and potassic granite occur in the Kunming area, southern Yangtze Block.•Trondhjemite formed by partial melting of juvenile mafic crust at low pressure.•Potassic granite formed by partial melting of preexisting TTGs at high pressure.•Yangtze Block is subdivided into northwestern, northeastern and southern domains, which came together in late Paleoproterozoic to form the Yangtze Block.