Structural successions used to compare tectonic histories of Svecofennian migmatites from widely separated outcrops in southern Finland

A study has been made to test the likelihood that migmatites cropping out in the Finnish Archipelago have undergone a different, similar, or identical, tectonic history to those in small, poorly exposed inland areas of the forested region further east in the vicinity of Orijärvi. The study is based on comparison of structural associations and has used the detailed small-scale structural succession already determined from the exceptionally well-exposed Proterozoic Svecofennian migmatites on outcrops in the Jussarö-Skåldö area of the Finnish Archipelago. Preliminary results show strong similarities between the Archipelago migmatite successions and those at Orijärvi, suggesting that they shared at least part of a common tectonic history. This indicates that further detailed structural examination would be rewarding and should confirm, or otherwise, that the regions shared a comparable tectonic history.