ADVANCES IN POLAR SCIENCE ›› 1994, Vol. 6 ›› Issue (3): 4-14.

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GEOCHEMICAL CHARACTERISTICS AND MEDIUM PRESSURE GRANULITE FACIES METAMOPHISM OF MAFIC GRANULITE ROCKS FROM THE LARSEMANN HILLS,EAST ANTARCTICA

  

  • Online:1994-09-30 Published:1994-09-30

Abstract:

Oriented distributed mafic granulite lenses,pods and boudins occur in metapelitic and leucogneiss in the Larsemann Hills,Prydz Bay,East Antarctica. The geochemical characteristic of the rocks imply that they are chemically similar to mafic cumulate.They probably represent remnants of mafic dykes. In the Mirror peninsula orthopyroxene plagioclase symplectites aroud garnet in mafic granulite is discovered ,orthopyroxene and plagioclase form by the reaction garnet+quartz→plagioclase+orthopyroxene Average pressure calculation on the assemblage indicates the prevailing conditions were 6.3±0.5kbar at 747±48°C.It is the first pressure estimate in the light of the equilibrium assemblage garnet orthopyroxene plagioclase quartz.An earlier medium pressure granulite facies event in the Larsemann Hills is confirmed.