Process of crustal formation of the Rayner Complex, Enderby Land, East Antarctica

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The correspondence between metamorphic P-T path and geochronology is the most important issue on the discussion of the formation and evolution of continents. Enderby Land in East Antarctica is the one of the suitable areas for this study. This study aims re-examination of the geological framework in the Enderby Land and it's vicinity. The results would constrain the formation of the supercontinets in Precambrian, particularly it is expected to reveal the Grenvilian event, the world-wide orogeny in the middle to late Proterozoic. Following results have been obtained so far ; 1) The Rayner Complex and the Lutzow-Holm Complex (LHC) show similar metamorphic history of the clockwise retrograde P-T paths. 2) Tonalitic rocks in the Sor Rondane Mountains and metatrondjhemite in LHC have similar geochronological and geochemical characteristics. The petrogenesis for these p.lutonic rocks is interpreted by the melting of hot slabs which were transformed into garnet amphibolite. 3) Detailed petrographic study on the sapphirine-and osumilite-bearing paragenesis in the Napier Complex revealed that the physical condition of ultra-high temperature metamorphism reached more than 1000C and 7-8 kbar. Moreover, two-stage P-T paths were found, suggesting the intrusion of hot pluton into the middle crust as the heat source.