Recurrent high grade metamorphism recording a 300 Ma long Proterozoic crustal evolution in the western part of the East European Craton |
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| Institution: | 1. Institute of Geology and Geography, Nature Research Centre, Vilnius, Lithuania;2. Department of Geology, Lund University, Sweden;3. Belarussian Research Geological Exploration Institute, Minsk, Belarus;4. Faculty of Geology, Warsaw University, Poland;1. Klaipeda University, Marine Science and Technology Centre, H. Manto Str. 84, LT–92294, Klaipeda, Lithuania;2. Nature Research Centre, Institute of Botany, ?ali?j? e?er? Str. 49, LT–2021 Vilnius, Lithuania;3. Environmental Protection Agency, Marine Research Department, Taikos Str. 26, LT–91149, Klaipeda, Lithuania;4. Klaipeda University, Faculty of Natural Sciences and Mathematics, Biology Department, H. Manto Str. 84, LT–92294, Klaipeda, Lithuania;;1. Institute of Geological Sciences, Polish Academy of Sciences, Research Centre in Wroc?aw INGPAN, Podwale St. 50-449, Wroc?aw, Poland;2. Centre of Isotopic Research, All-Russian Geological Research Institute, Sredny prospect 74, 199 106 St. Petersburg, Russia;1. Department of Geosciences, Swedish Museum of Natural History, Box 50 007, SE-104 05 Stockholm, Sweden;2. Department of Geosciences and Natural Resource Management (Geology Section), University of Copenhagen, Øster Voldgade 10, 1350 Copenhagen K, Denmark;3. Department of Geosciences, University of Oslo, PO Box 1047 Blindern, N-0316 Oslo, Norway |
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| Abstract: | The Palaeoproterozoic lower crust, forming several belts and domains, is a major component of the crystalline basement within the large region to the southeast of the Baltic Sea in Belarus, Lithuania and Poland. Four stages of high grade metamorphism have been determined in the Western Lithuanian Granulite domain (WLG) and Belarus–Podlasie Granulite belt (BPG), the western East European Craton (EEC). We have carried out P–T studies, secondary ion mass-spectrometry (SIMS) zircon- and electron probe (EPMA) — monazite dating of peak metamorphism. The first stage occurred at 1.81–1.79 Ga under 800–900 °C and 8–10 kbar and was related to both accretionary and postcollisional tectonics in the South Baltic region, whereas the stages at 1.73–1.68 Ga (700–800 °C, 6–7 kbar), 1.62–1.58 Ga (700 °C, 4–5 kbar), and 1.52–1.50 Ga (900 °C, c. 10 kbar) can be attributed to extensional intracratonic regimes. The 1.81–1.79 Ga stage was connected both to the major Sarmatia–Fennoscandia collision and the eastward accretion, which led to the formation of Baltica (East-European Craton) during the assembly of the Columbia (Nuna) supercontinent. The later high grade events associated with intracratonic extensions and magmatism may be distal manifestations of accretionary processes along the long-lived common Laurentia–Baltica margin. The 1.52–1.50 Ga metamorphism was associated with extensive anorthosite–mangerite–charnockite–granite magmatism in already consolidated crust. |
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