Abstract The Sverdrupfjella Group in western Dronning Maud Land is a 1200 to 900 Ma orogenic belt that experienced a thermal overprint in the early Cambrian. Evidence for distinct episodes of fluid–rock interaction is found in calc-silicate rocks, veins and retrograde mineral assemblages. A sequence of altered but undeformed basalts exhibit extreme 18 O depletion ( δ 18 O as low as −1.8‰) apparently due to interaction with meteoric water during regional (possibly early Cambrian) metamorphism. In the central Kirwanveggen, metasomatic calc-silicates, and retrograde mineral assemblages are associated with late high-strain zones of probable Cambrian age. The former have δ 13 C values which overlap those of massive metacarbonate units 150 km to the NE, and imply regional scale movement of fluids. The latter record 18 O depletion relative to unretrogressed equivalent rocks and suggest interaction with externally derived fluids.