Ultramafic massifs that occur in the Earth's crust are, in a complex way, samples of the mantle. They may be classified into a number of different types (Wyllie, 1970; Moores, 1973), one of which is the high-temperature peridotite massifs characterized by high-temperature contact metamorphic aureoles. One such example is the Mount Albert ultramafic intrusion in the Gaspe Peninsula of Quebec, Canada.

The high-temperature peridotites are composed of interlayered harzburgite, dunite, and lherzolite. The mineralogy is generally simple and lacks the cryptic layering generally found in comparable mineral systems in cumulate layered mafic-ultramafic intrusions (Wager and, Brown, 1967; Jackson, 1971). Compositional variations do occur, however, and the question arises as to whether they are related to the mechanism of intrusion or inherited mantle properties. Textural and structural evidence (Darot, 1973) indicate that some high-temperature peridotites have been intruded as solid material. The present study focuses on the mechanism of intrusion and the results of intrusion on the variations of chemistry hetween coexisting phases and observed textural and structural features.

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