The most important characteristic of the Svecofennian orogen is mainly the juvenile nature of the substances of the Proterozoic crust and the absence of geological, petrological and isotopic-geochemical evidence of the existence of rocks of the Archean complex at the base of the newly formed block of the svecofennians. All volcano-sedimentary rocks are altered up to granulite facies of metamorphism during two stages of endogenous activity. Modern configuration and the structure of the joint suture zone between Svecofennian orogeny and Karelian craton reflect the consistent development of oroclines, and not subparallel amalgamation of the island-arc complexes.