Abstract:

Redetermination of the metamorphic age of the garnet bearing mafic granulite from the Sφstrene Island,Prydz Bay,East Antarctica,has been made and an isochron of whole rock garnet pyroxene plagioclase is obtained,giving an age of 604±28(2σ)Ma. It is pointed out that this age represents the time of peak granulite facies metamorphism of the area.As to the geological relation of the Sφstrene Island with the Bolingen Islands and Larsemann Hills to the northeast,it is deduced from the rock assemblages,metamorphic superposition and spatial changes and metamorphic age features between the above regions that the degree of the superposition of the late low pressure metamorphism is becoming stronger from west to east.While the evolution of the earlier medium pressure to late low pressure implies probably the substages of the same metamorphic cycle.