Prograde metamorphic assemblage evolution during partial melting of metasedimentary rocks at low pressures: Migmatites from Mt Stafford, central Australia

Abstract

The Mt Stafford area in central Australia preserves a low-pressure greenschist - to granulite-facies regional aureole. The metasedimentary sequence has been divided into five zones from greenschist (Zone 1) to granulite facies (Zone 4) and a zone of hybrid diatexite formed from the introduction of granitic magma into the high-grade migmatites (Zone 5). Melt production was dominated by a series of multivariant biotite breakdown reactions, not the univariant reactions suggested by previous studies. Although the three main metasedimentary rock types produced similar amounts of melt at the highest grades, their melt production histories differed markedly as a function of temperature. Aluminous m..