the svecofennian orogeny developed as a succession of four orogenies which by chronological order are: the lapland-savo orogeny, the fennian orogeny, the svecobaltic orogeny and the nordic orogeny. in broad terms, regardless of details, it has been proposed that the svecofennian orogeny involved more-less continuous subduction with subduction zones progressively migrating to the southwest. an alternative model postulates subduction included alternating extension and compression cycles, with the orogenic activity ceasing after the collision between the fennoscandian craton and the sarmatian craton.