Abstract:
The Rocky Beach Metamorphic Melange contains metre-scale phacoids of high-P low-T metamorphic
rocks embedded in chlorite-actinolie schist. The phacoids include eclogite, glaucophane schist and
omphacitite and provide evidence for four episodes of metamorphism with mineral assemblages: M1 =
actinolite-glauccphane-titanite-apaite, M2 = almandine-ornphacite-lawsonite ± quartz, M3 = phengiteglaucophane-
K-feldspar-quartz, and M4 = chlorite-actinolie-calcite-quartz-tianite-white mica ± albite
± talc. M1-M3 occurred at a Neoproterozoic-Early Palaeozoic convergent plate boundary close to the
eastern margin of Gondwana. Peak metamorphic conditions were attained during the static phase M2,
with temperatures of -560°C and pressures in excess of 1.8 GPa, equivalent to a depth of burial of at
least 54 km.
