TIMING OF THE PROGRESS GRANITE, LARSEMANN HILLS - ADDITIONAL EVIDENCEFOR EARLY PALEOZOIC OROGENESIS WITHIN THE EAST ANTARCTIC SHIELD AND IMPLICATIONS FOR GONDWANA ASSEMBLY

The Progress Granite is one of numerous S-type granitoid plutons expos ed in the Larsemann Hills region, southwest Prydz Bay, east Antarctica . The granite was emplaced into a migmatitised pelitic to felsic parag neiss sequence during a regional high-grade transpressional event (D-2 ) that pre-dates high-grade extension (D-3). SHRIMP (Ii) U-Pb dating f or two occurrences of the Progress Granite from D-2 and D-3 structural domains gives Pb-206/U-238 ages of 516.2 +/- 6.8 Ma and 514.3 +/- 6.7 Ma, respectively. These ages are interpreted as crystallisation ages for the Progress Granite and confirm Early Palaeozoic orogenesis in th e Larsemann Hills region. This orogen appears to have evolved during c ontinental convergence and is probably responsible for widespread radi ogenic isotopic resetting and the near-complete exhumation of the adja cent northern Prince Charles Mountains which evolved during a ca 1000 Ma event. The identification of a major Early Palaeozoic orogen in Pry dz Bay allows tentative correlation of other domains of Early Palaeozo ic tectonism both within the east Antarctic Shield and other, once con tiguous, Gondwana fragments and illustrates the potential complexity i nherent within intercratonic mobile belts. One such possibility, tenta tively offered here, suggests a continuous belt of Early Palaeozoic te ctonism from Prydz Bay eastward to the West Denman Glacier region and into the Leeuwin complex of Western Australia.