Contrasting metamorphic P – T path between Schirmacher Hills and Mühlig-Hofmannfjella, central Dronning Maud Land, East Antarctica

Abstract

Abstract Retrograde metamorphic P – T paths of garnet–pyroxene-bearing mafic gneisses from three regions in central Dronning Maud Land (CDML) were examined. No difference in P – T conditions estimated from rocks of the three regions was recognized, and they are within the range of c. 6–8 kbar, 750–830 °C. However, localities in the Mühlig-Hofmann Range (Filchnerfjella and Jutulsessen) preserve rocks with mineral textures that indicate near-isothermal decompressional histories. In the Schirmacher Hills, an isolated exposure on the Princess Astrid Coast, metamorphic texture observed in mafic gneiss is indicative of an isobaric cooling history. Combining their P – T paths and age determinations suggests that the Schirmacher Hills was a separate terrane, together with present-day SE Africa, whereas the Grenvillian-age east–west-trending CDML inland nunatak regions are characterized by an isothermal decompressional metamorphic history related to the final amalgamation of Gondwana.