REE-patterns of some Svecofennian migmatite leucosomes

REE-patterns obtained from leucosomes of migmatites found in the southern Svecofennian Domain are of two types: one with (La/Lu)N< 7 which, together with a moderate negative Eu-anomaly defines an “upwards concave” pattern, and a “normal” light REE depleted pattern with (La/Lu)N> 10. No systematic differences can be found between migmatite leucosomes and Upper Svecofennian granites from the same area. It is concluded that the patterns are partly inherited from the migmatite protoliths and later overprinted by the process of migmatite segregation. The data do not discriminate between models for migmatite formation based on partial melting and based on metamorphic segregation.