Archaean TTGs as sources of younger granitic magmas: melting of sodic metatonalites at 0.6–1.2?GPa

Abstract  Two natural, low K2O/Na2O, TTG tonalitic gneisses (one hornblende-bearing and the other biotite-bearing) were partially melted at 0.8–1.2 GPa (fluid-absent). The chief melting reactions involve the breakdown of the b