The Mesoproterozoic in the Nordic countries

During the Mesoproterozoic, central Fennoscandia and Laurentia (Greenland) were characterized by a weakly extensional stress regime, as evident from episodic rapakivi granites, dolerite dykes, continental rift intrusives, sandstone basins and continental flood basalts.Along the southwestern active margin of Fennoscandia, the 1.64-1.52Ga Gothian and 1.52-1.48Ga Telemarkian accretionary events resulted in oceanwards continental growth.The 1.47-1.42Ga Hallandian-Danopolonian event included high-grade metamorphism and granite magmatism in southern Fennoscandia.The pre-Sveconorwegian 1.34-1.14Ga period is characterized by bimodal magmatism associated with sedimentation, possibly reflecting transcurrent tectonics.The Sveconorwegian orogeny involved polyphase imbrication of terranes between 1.14 and 0.97 Ga, as a result of a collision between Baltica and another major plate, followed by relaxation and post-collisional magmatism between 0.96 and 0.90 Ga.Recent geologic data support classical models restoring the Sveconorwegian belt directly to the east of the Grenville belt of Laurentia at 1.0 Ga.Fragments of Paleo-to Mesoproterozoic crust showing late Grenvillian-Sveconorwegian (1.00-0.92Ga) magmatism and/or metamorphism are exposed in several tectonic levels in the Caledonides of Scandinavia, Svalbard and East Greenland, on both sides of the inferred Iapetus suture.Linking these fragments into a coherent late-Grenvillian tectonic model, however, require additional study. Principal Mesoproterozoic lithotectonic domainsFennoscandia (the Fennoscandian shield) represents the northwestern part of Baltica or the East European Craton.At the start of the Mesoproterozoic, it consisted of Archean core (Karelia and Murmansk cratons) surrounded by Paleoproterozoic Svecofennian domains (sensu lato) intruded by the Transcandinavian Igneous Belt (TIB, Figure 1).During the Mesoproterozoic, the centre of Fennoscandia hosted episodic continental magmatism.The Timanian margin in the northeastern was passive, while the southwestern margin was active and the location of substantial continental growth.A regional metamorphic event, the Hallandian or Danopolonian orogeny is recorded in the southern part of Fennoscandia.Greenland Episodes, Vol.31, No.