Compositional variation within staurolite crystals from the Ardara aureole, Co. Donegal, Ireland
نویسنده
چکیده
FEW analytical data exist for staurolite, in comparison with other metamorphic minerals such as garnet. However, using the microprobe, Hollister and Bence (1967) working with relatively inclusion-free specimens from the Kwoiek Area, British Columbia, established compositional zoning across staurolite in addition to compositional irregularities across sectoral twin boundaries. The staurolites studied from Ardara were collected from a single formation, the Gleengort (Clooney) Pelitic Schists, which occur in the thermal aureole surrounding the Ardara Pluton, Co. Donegal (fig. I). Eighteen staurolite crystals, including several that showed sector twinning, were analysed to establish the presence or absence of zoning, which might help to explain nucleation and growth.
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