Neoarchean Gabbroids Of The Fennoscandian Shield Belomorsk Province: Geology, Composition, And Geochronology

摘要

In Belomorsk province of the Fennoscandian shield, a series of meso-leucocratic gabbroid massifs is determined, and according to isotope age dating of zircons on the SHRIMP-II ion probe, their magmatic formation stage accounts for 2711 ± 25 million years. Neoarchean gabbroids according to petrochemical peculiarities differ from basites of other Belomorsk province complexes: gabbro-anorthosites, lherzolites-gabbronorites, coronite gabbro. The gabbroids examined were formed at the collision stage of the Belomorsk orogene development and are presumably connected with the early phase of its collapse.