P-T-t modelling of Proterozoic terranes in Lithuania: geodynamic implications for accretion of southwestern Fennoscandia

• Main Authors: Skridlaitė, Gražina, Willingshofer, Ernst, Stephenson, Randell
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2003
• Subjects: Palaeoproterozoic accretion; Svecofennian orogen; Lithosphere; Extension; Evolution; Flow; Eurobridge; Collapse; Granite; Fennoscandia; Fennoscandian
• Online Access: http://lmavb.lvb.lt/LMAVB:ELABAPDB5338185&prefLang=en_US

The East European Craton (EEC) consists of Archaean nucleii and accreted Proterozoic terranes. Pressure-Temperature-time (P-T-t) paths for the West Lithuanian Granulite Domain (WLG), the East Lithuanian Domain (ELD) and the Mid-Lithuanian Suture Zone (MLSZ) in the southwestern part of the EEC constrain the sequence of tectonic events and their deformational and metamorphic conditions. A kinematic and thermal model has been developed for the evolution of these terranes, given the accretion of the ELD to the Sarmatian and the WLG to the Fennoscandian continents, respectively, based on their structural and compositional differences. For initial surface heat flow values ranging from 80-90 mWm(-2), the numerical model predicts a thermal relaxation phase of at least 30-50 m.y., following very slow accretion (0.54 cm/yr) of the WLG in a subduction-type environment, prior to granulite facies metamorphism at 1.80 Ga.