Metamorphism, structural evolution and experimental petrology of Lambert Glacier granulites, Antarctica

The preserved peak and post-peak metamorphic evolution culminating around 1000 Ma ago, which affected granulite-facies rocks from adjacent East Antarctic regions, the Reinbolt Hills and the Prince Charles Mountains, is described and quantified here for the first time. The derived pressure-temperature paths from these regions display a continuum in both the maximum preserved conditions and in the gradients of their trajectories, passing from higher pressures (=8 kbar) along the eastern margin of the Lambert Glacier, to low pressures (=4.5 kbar)in the north-west Prince Charles Mountains. The maximum preserved temperatures along the east Lambert Glacier (=700C) differ by a maximum of 250C from those in the west (=450C). This retrograde temperature differential is best explained by warning deformation promoting re-equilibration during retrogression in the Prince Charles Mountains.