Mountain belts developed in an intracratonic setting during the Neoproterozoic in the center of Australia. Mesoproterozoic granulite and amphibolite facies gneisses of the Musgrave Block were overprinted during the Petermann Orogeny (~550 Ma) with zones of high strain concentrated along broadly east-west trending shear zones. These zones formed under eclogite facies (T~650 ¿C and P~12 kbars) to greenschist facies conditions and may form part of a strike-slip-related, crustal-scale flower-type structure. Granulite facies gneisses preserve ages older than 700 Ma, suggesting that these rocks did not experience temperatures greater than ~350 ¿C at ~550 Ma. For these rocks not to have been thermally equilibrated to temperatures of >350 ¿C at a depth of ~12 kbars requires either an extraordinarily low geothermal gradient (<9 ¿C km-1) or, if the geothermal gradient was more typical (~20 ¿C km-1), then transport to that depth and subsequent exhumation occurring in a short time interval (≤40 Myr). ¿ 2000 American Geophysical Union