baltybaev further distinguishes between an "outer zone" in the northeast and an "inner zone" in the southwest. the "inner zone" is characterized by i-type calc-alkaline granitoids. in contrast the "outer zone" contains more s-type granitoids. there are differences between the metamorphosed sediments found in the two zones while the outer zone contains metagreywackes the inner zone hosts metapelites. rocks of the outer zone are estimated to have formed 1890–1860 million years ago and granitoids of the inner zone 1840–1790 million years ago. in addition to those two zones baltybaev identifies a narrow "zone of conjugation with archean complexes" between the "outer zone" and the archean craton to the north and east. nironen and mänttäri (2012) uses the terms "central svecofennian terrane" and "southern svecofennian terrane" for approximately the same areas baltybaev calls "outer" and "inner zone" respectively.