THE formation of the high-pressure, high-temperature rocks known as granulites has traditionally been attributed to metamorphism in the deeper parts of continental collision zones and magmatic arcs(1-3). More recently, greater consideration has been given to the arcs possibility of granulite formation during continental rifting(4-6), and in particular(4) to whether granulites are forming today beneath the North American Basin and Range province. Here we report thermobarometric data and single-zircon U-Pb ages for an analogous, but much more deeply exhumed, extensional terrain in Fiordland, New Zealand(7,8), where Early Cretaceous granulites underwent renewed granulite-facies metamorphism at significantly shallower crustal levels following the extensional collapse of magmatically thickened continental crust. Our data show that granulite-facies metamorphism can take place during continental extension, and demonstrate that in western New Zealand it was accompanied at higher structural levels by the emplacement of one or more metamorphic core complexes(7-9), in keeping with the model postulated(4) for the Basin and Range province.