Abstract The Archaean to Palaeoproterozoic Khanfous area from the Archaean In Ouzzal granulite terrane (Western Hoggar, Algeria) preserves exceptional thermal-peak (1150< T < 1300 °C) mineral parageneses, consisting of orthopyroxene+spinel+quartz, sapphirine+spinel+quartz and sapphirine+orthopyroxene+quartz, in quartz-rich Al–Mg granulites. Reaction textures coupled with P – T FMASH pseudosections indicate that rocks experienced complex multi-stage evolution. Our results suggest that the Khanfous area, as well as the entire northern In Ouzzal metacraton, experienced ultrahigh-temperature crustal metamorphism attributed to a 2 Ga Palaeoproterozoic event, followed by exhumation along a clockwise P – T path. The extreme temperatures attained suggest delamination of the lithosphere and ascent of the asthenosphere after crustal thickening.