Abstract: The Prydz Bay region of East Antarctica consists of different terrains including the Vestfold Hills, the Rauer Group, the Larsemann Hills, and Søstrene Island. The Prydz Bay region has undergone high to ultra-high temperature (UHT) metamorphism, with the Rauer Group typically experiencing UHT conditions. Recent studies suggest that UHT metamorphism may occur more widespread, and the Larsemann Hills, Søstrene Island may also have undergone UHT metamorphism. The UHT metamorphism in the Prydz Bay region resulted in various mineral assemblages. The assemblages of orthopyroxene+sillimanite and sapphirine+
quartz can reliably indicate UHT metamorphism in the region. Mineral assemblages including sapphirine (without quartz), spinel-quartz, or corundum may indicate UHT conditions, but whether these mineral assemblages reflect UHT conditions need to be further constrained by reliable thermometry or phase equilibrium modelling based on mineral composition analysis. Different heat sources for UHT metamorphism have been proposed and can be generally classified into two types: autogenic heat and external heat. Autogenic heat mainly includes radioactive heat and mechanical heat, whereas external heat can be provided through conduction and/or convection of a deep heat source. UHT may occur in different tectonic settings including ridge subduction, back-arc basins, and delamination of the lower crust. Previous studies have shown that the Prydz Bay region is a typical orogenic belt with overprinting of different metamorphic events. Recent studies support that UHT metamorphism occurred during the Pan-African period. However, the exact timing, evolutional process, tectonic setting, and heat source of UHT metamorphism are still controversial and thus call for further study.

Key words: the Prydz Bay region, ultra-high temperature metamorphism, mineral assemblage, tectonic setting, heat source