STAUROLITE IN A GARNET-HORNBLENDE-BIOTITE SCHIST FROM THE LANTERMAN RANGE, NORTHERN VICTORIA LAND, ANTARCTICA

Abstract

Staurolite is found as inclusions in a garnet-hornblende-biotite schist of the late Precambrian (?) Wilson group near Mt Bernstein (71o37'S, 163o07'E), Lanterman Range. It is partly replaced by a gahnite (52 mol.% ZnAl2O4)-margarite-muscovite-chlorite assemblage. The staurolite is thought to be a relict of a staurolite-hornblende-garnet-biotite-quartz assemblage that formed at an early stage in the Cambro-Ordovician Ross metamorphic event at pressures of at least 6 kbar. The staurolite (atomic Mg/(Mg + Fe) = 0.20) is relatively rich in TiO2 (0.79 wt.%) and ZnO (2.78%) and poor in divalent cations (3.444 per 46 oxygens). In comparison with a staurolite from a tourmaline-talc-phlogopite-chlori..