Microstructural and Chemical Study of Borosilicate Minerals in Pegmatites from the Larsemann Hills, Prydz Bay, East Antarctica

TL;DRAbstract

Pegmatites are present in many metamorphic complexes. Their distinctive mineral assemblages, especially when rich in boron, provide a distinct perspective into the pressure-temperature-chemical environment. Granulite-facies metasedimentary gneisses and associated anatectic pegmatites in Larsemann Hills, Antarctica are unusually enriched in B, and thus, provide a unique opportunity for the petrologic application of boron minerals. The seven pegmatites on which the thesis is based contain the borosilicate minerals prismatine, werdingite, boralsilite, grandidierite, dumortierite and tourmaline-group minerals. Six belong to the folded and discordant D2 and D3 generations and one belongs to the discordant and planar D4 generation. Research for the thesis included microstructural observations and chemical analyses with the electron microprobe analyses with an emphasis on tourmaline-group minerals. The first minerals to form in the D2 and D3 pegmatites were tourmaline in a graphic intergrowth

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