Thermotectonic evolution of the Rauer Group and Vestfold Hills in Prydz Bay: implications for Neoproterozoic assembly of the East Antarctic Shield

Abstract

The Rauer Group and Vestfold Hills are critical components of the East Antarctic Shield and are believed to have been parts of the supercontinents Rodinia and Gondwana. The Rauer Group is characterized by Archean to Pan-African thermal history, while the Pan-African signature in the Vestfold Hills is restricted to its southwestern margin. The correlation between the Rauer Group and Vestfold Hills remains controversial, while the significance of amalgamation between these two terranes remains unclear. Most importantly, the precise nature and timing of the Rauer-Vestfold contact is disputed. In this review, we compare the available structural, metamorphic, geochronological and geophysical data in these two East Antarctic terranes and suggest that (i) the Rauer Group and Vestfold Hills of East Antarctica were amalgamated during the late Mesoproterozoic to early Neoproterozoic (∼1000 Ma), and (ii) the Rauer-Vestfold contact is located beneath the Sørsdal Glacier in the East Antarctic Shield. Finally, we argue that juxtaposition of the Rauer-Vestfold contiguous crustal unit with the Eastern Ghats Province (EGP)-Rayner amalgam took place in the Pan-African time (∼500 Ma).