the svecofennian orogeny is a series of related orogenies that resulted in the formation of much of the continental crust in what is today sweden and finland plus some minor parts of russia. the orogenies lasted from about 2000 to 1800 million years ago during the paleoproterozoic era. the resulting orogen is known as the svecofennian orogen or svecofennides. to the west and southwest the svecofennian orogen limits with the generally younger transscandinavian igneous belt. it is assumed that the westernmost fringes of the svecofennian orogen have been reworked by the sveconorwegian orogeny just as the western parts of the transscandinavian igneous belt has. the svecofennian orogeny involved the accretion of numerous island arcs in such manner that the pre-existing craton grew with this new material from what is today northeast to the southwest. the accretion of the island arcs was also related to two other processes that occurred in the same period; the formation of magma that then cooled to form igneous rocks and the metamorphism of rocks.