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Mineral chemistries and textures are described from a suite of sapphirine-bearing granulites from the Gruf Complex of the Italian Central Alps. The granulites contain combinations of garnet, orthopyroxene, sapphirine, sillimanite, cordierite, biotite, quartz, spinel, corundum, staurolite, plagioclase, K-feldspar, ilmenite and rutile, in assemblages with low (usually negative) variance. They are outstanding in that they preserve a textural and chemical record of a protracted metamorphic evolution.Reaction textures are common and include: (i) pseudomorphs (e.g. of sillimanite after kyanite); (ii) relatively coarse-grained monomineralic reaction rims (e.g. of cordierite between sapphirine and quartz); (iii) fine-grained symplectitic coronas (e.g. of orthopyroxene + sapphirine round garnet); (iv) inclusions, in garnet cores, of minerals (e.g. staurolite) not found elsewhere in the rocks.Detailed microprobe study has revealed large chemical variations within each phase. Different textural types of each phase have different compositions, and strong zoning is preserved in garnet (Mg/(Mg + Fe) from 0-30 to 0-61) and coarse sapphirine. Inclusion populations in garnet correlate with host composition.The textural and chemical features are interpreted in terms of successive equilibrium assemblages and reactions. Metamorphic conditions operative at each stage in the evolution are calculated using published geothermometers and geobarometers as well as thermodynamically calibrated MAS and FASH equilibria. The results are used to construct a P-T-time path for the sapphirine-granulites, which can be summarized as follows:(i) Increasing Tat high P (>7 kb). Partial melting.(ii) A maximum 7"of -830 °C attained at -10 kb.(iii) Almost isothermal decompression, reaching 750 °Cat -5 kb, under conditions of low /i H ,o-(iv) Further cooling, and decompression. Localized hydration. Rocks exposed. The P-T-time path is interpreted as the product of a single metamorphic cycle (the tertiary 'Lepontine' event) and is extrapolated to the Gruf Complex as a whole. When combined with published geochronological data, the results indicate an average uplift rate in excess of 2 mm/yr for the Gruf Complex between 38 and 30 Ma ago.An in situ partial melting origin for the sapphirine-granulites is favoured. Extraction of an iron-rich granitic liquid from a normal pelitic palaeosome could generate a refractory residue with the required Mg, Al-rich composition. The change in bulk solid composition during partial melting is thought to account for the extraordinarily strong zoning in the garnets.

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The central sector of Muhlig-Hofmannfjellet (3"E/71°S) in western Dronning Maud Land (East Antarctic shield) is dominated by large intrusive bodies of predominantly orthopyroxene-bearing quartz syenites (charnockites). Metasedimentary rocks are rare; however, two distinct areas with banded gneiss-marblequartzite sequences of sedimentary origin were found during the Norwegian Antarctic Research Expedition NARE 1989/90. Cordierite-bearing metapelitic gneisses from two different localities contain the characteristic mineral assemblage: cordierite + garnet + biotite + K-feldspar + plagioclase + quartz f sillimanite f spinel. Thermobarometry indicates equilibration conditions of about 650" C and 4 kbar. Associated orthopyroxene-garnet granulites, on the other hand, revealed pressures of about 8 kbar and temperatures of 750" C. The earlier granulite facies metamorphism is not well preserved in the cordierite gneisses as a result of excess K-feldspar combined with interaction with an H,O-rich fluid phase, probably released by the cooling intrusives. These two features allowed the original high-grade K-feldspar + garnet assemblages to recrystallize as cordierite-biotite-sillimanite gneisses, completely re-equilibrating them. Phase relationships indicate that the younger metamorphic event occurred in the presence of a fluid phase that varied in composition between the lithologies.

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