Foliation patterns in large gneiss bodies of the Archaean Wabigoon Subprovince, southern Canadian shield

摘要: Abstract Two areas of gneissic tonalite-granodiorite are being studied in the western Wabigoon Subprovince, Rainy Lake gneiss body and southwestern Irene-Eltrut Lakes body. The is an aggregate large oval structures outlined by foliation trajectories. dominated Ash Bay dome whose leuco-gneiss core characterized highly foliated rocks surrounded a zone mafic rich greenstone relics. This seems to have distorted adjacent while growing its present size. Of various hypotheses doming considered herein, only two can be eliminated from further consideration (1) large-scale buckling gneiss-greenstone interface (2) bending thrust sheets moving over rigid ramps. Diapirism sensu lato remains attractive mechanism for growth under consideration. Whether tonality-granodiorite became rising actively or deforming passively, as wall rock magmatic diapirs, determined.