New electron microprobe monazite geochronological constraints on the timing of Proterozoic granulite facies metamorphism from the western Gawler Craton are presented. Monazite grain geochronological data obtained from samples of basement rocks penetrated in diamond drillhole Ooldea 1 constrain the timing of granulite facies metamorphism to c. 1700 Ma. The presence of two texturally distinct metamorphic assemblages within samples of the basement penetrated in nearby diamond drillhole Ooldea 2 suggests that the Moondrah Gneiss in this region underwent an early high-temperature, low-pressure granulite facies metamorphic event, followed by ultra-high temperature, high-pressure reworking associated with the development of the overprinting high-strain fabric. Monazite age data determined for rock samples from Ooldea 2 constrain the timing of the early metamorphic assemblage in basement rocks of that drillhole to be c. 1690-1700 Ma in age, analogous to the c. 1700 Ma high-temperature, low-pressure metamorphism recorded in Ooldea 1, and contemporaneous with the craton-wide 1730-1690 Ma Kimban Orogeny. The later ultra-high temperature reworking event, termed the Ooldean Event, occurred at c. 1660 Ma.