The extension of the Transscandinavian Igneous Belt into the Baltic Sea region

Tracing the SW border of the Svecofennian Domain in the Baltic Sea region: evidence from petrology and geochronology from a granodioritic migmatite

“…1 Simplified geological map of the southern part of the Fennoscandian Shield including Precambrian units beneath the Phanerozoic cover in the Baltic Sea region. The map is modified after Koistinen et al (2001) by adding information from Sundblad et al (2003), Motuza and Motuza (2011) and Salin et al (2019). BLU Bergslagen lithotectonic unit, LLDZ Loftahammar-Linköping deformation zone, LSGM Late Svecofennian granite-migmatite zone, OJB Oskarshamn-Jönköping belt, R Riga batholith, SLU Småland lithotectonic unit, TIB Transscandinavian Igneous Belt, V Västervik quartzites, WLG West Lithuanian Granulite domain.…”

“…The Småland lithotectonic unit ( Fig. 1) mainly consists of three generations of felsic intrusive rocks belonging to the Transscandinavian Igneous Belt: TIB 0 (1855-1845 Ma), TIB 1a (1808-1794 Ma) and TIB 1b (1793-1769 Ma); (Larson and Berglund 1992;Ahl et al 2001;Salin et al 2019). The oldest generation, TIB 0, occurs mainly in the Bergslagen lithotectonic unit (Askersund-Tiveden areas, as well as the Finspång, Graversfors and Hälla intrusions), and compositionally has been assigned by Stephens et al (2009) to the 1.87-1.84 Ga intrusive suite of the Bergslagen lithotectonic unit.…”

“…The Precambrian crystalline bedrock continues beneath the Baltic Sea where it is covered by up to 2300 m thick sequences of Phanerozoic sedimentary rocks of the East European Platform ( Fig. 1; Bogdanova et al 2015;Salin et al 2019). The Precambrian bedrock beneath Gotland and adjacent offshore region has been studied through drillings (approximately 35 percussion drillings and drill cores; Sundblad et al 2003;Salin et al 2019) and geophysical investigations (EUROBRIDGE seismic working group 1999).…”

“…1; Bogdanova et al 2015;Salin et al 2019). The Precambrian bedrock beneath Gotland and adjacent offshore region has been studied through drillings (approximately 35 percussion drillings and drill cores; Sundblad et al 2003;Salin et al 2019) and geophysical investigations (EUROBRIDGE seismic working group 1999). Amphibolite is the dominant Svecofennian supracrustal rock unit beneath the sedimentary cover on southern Gotland.…”

“…In a recent contribution, Salin et al (2019) demonstrated that this geophysical feature is related to the border between two major crustal complexes in the Fennoscandian Shield; the Svecofennian Domain in the northeast and the Transscandinavian Igneous Belt in the southwest.…”