Ulf Söderlund
Professor
The Mesoproterozoic in the Nordic countries
Författare
Summary, in English
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 1.64-1.52 Ga Gothian and 1.52-1.48 Ga Tele-markian accretionary events resulted in oceanwards continental growth. The 1.47-1.42 Ga Hallandian-Danopolonian event included high-grade metamorphism and granite magmatism in southern Fennoscandia. The pre-Sveconorwegian 1.34-1.14 Ga period is characterized by bimodal magmatism associated with sedimentation, possibly reflecting transcurrent tectonics. The Sveconorwegian otogeny 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 (1.00-0.92 Ga) 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 lapetus suture. Linking these fragments into a coherent late-Grenvillian tectonic model, however, require additional study.
Avdelning/ar
- Berggrundsgeologi
Publiceringsår
2008
Språk
Engelska
Sidor
29-34
Publikation/Tidskrift/Serie
Episodes
Volym
31
Issue
1
Dokumenttyp
Artikel i tidskrift
Förlag
International Union of Geological Sciences
Ämne
- Geology
Nyckelord
- PROVENANCE
- CALEDONIDES
- EVOLUTION
- MAGMATISM
- NAPPE COMPLEX
- SW SCANDINAVIA
- U-PB GEOCHRONOLOGY
- SVECONORWEGIAN OROGEN
- GREENLAND
- SHIELD
Status
Published
ISBN/ISSN/Övrigt
- ISSN: 0705-3797