Canadian Mineralogist

belt of Archean age in eastern Finland, there are numerous outcrops of serpentine-bearing rocks. Petrographic and mineralogical observations have led to the recognition of three stages of mineral growth during metamorphism: I) low-grade serpentinization, with dominant lizardite I cul-minating in the complete transformalion of magmatic oli-vine; II) prograde metamorphism, leading to the appear-ance of a new generation of olivine associated with acicular antigorite, which shows an interpenetrating texture, and III) a renewed episode of low-grade serpentinization, cor-responding to a partial conversion of metamorphic olivine to lizardite II. Stages I and III correspond to the develop-ment of lizardite with a mesh texture. During each stage of mineral growthn each serpentine phase shows a specific composition. Lizardite I is characterized by the presence of AI, Mn, Ca, Na, K, Cr and Ni, whereas lizardite U appears to b^e highly depleted in these elements. The varia-bility of Fea- contents in lizardite II is probably related to the compositional characteristic of the metamorphic oli-vine. Antigorite is characterized by an enrichment in Al, Cr and Mg linked to the breakdown of chromite during the main phase of prograde metamorphism