40 EUROPE/East European Craton Figure The south western margin of the East European Craton in the Neoproterozoic The ruled area shows the Meso to Neoproterozoic Volyn Orsha Aulacogen, which is filled by mostly terrigenous sedimentary rocks In the vicinity of the Trans European Suture Zone, however, the approximately 550 Ma Volynian flood basalts (blue markings) form a large outcrop set in Vendian and Early Cambrian sedimentary rocks (the sand coloured areas) The basalts fill a basin that trends across the Aulacogen and runs roughly parallel to the Trans European Suture Zone This indicates that the south western margin of the craton was passive at the end of the Neoproterozoic ß Svetlana Bogdanova The Belomorian typically features extensive belts of mafic metavolcanics, continental-margin turbidites, and TTG-type granitoids, all arranged in large folded thrust sheets overriding the edge of the Karelian Protocraton Thrusting here occurred at about 2.70– 2.65 Ga, when the different terranes and crustal provinces – except possibly the western Archaean province – collided and merged to form a Neoarchaean continent Concomitantly, parts of the Karelian province underwent high-grade metamorphism and migmatite formation Along its boundary with the Belomorian Belt, 2.7 Ga eclogites are present Exhumation and cooling then followed Cratonization became complete at around 2.5 Ga Between 2.5 Ga and 2.0 Ga, Archaean Fennoscandia underwent extension, rifting, and even breakup, leading to the opening of small oceanic basins Intermittently there was strong dominantly mafic but also komatiitic igneous activity Most conspicuous are large greenstone rifts and belts, which tend to follow the boundaries between the different Archaean terranes Ophiolites with ages of about 1.96 Ga occur in places The latter half of the Palaeoproterozoic was a period of intense orogenic activity across most of Fennoscandia In the north, the Lapland–Kola collisional orogeny at about 1.96–1.85 Ga welded together the crustal units that constitute the present Archaean domain Some of these appear to have been parts of a Neoarchaean continent that was broken up in the Early Palaeoproterozoic In the case of other crustal units, an exotic provenance has been suggested Altogether, the Lapland–Kola Orogen is a tectonic collage of reworked Late Archaean terranes and intervening belts of Palaeoproterozoic juvenile crust and turbidites (Figure 10) Prominent among the latter is the Lapland Granulite Belt, made famous by Eskola’s work on the facies of metamorphism Arc magmatism has been dated at 1.96 Ga; southwards thrusting and collision occurred at 1.91–1.90 Ga, while post-collisional magmatism, exhumation, and cooling lasted until 1.85 Ga To the south-west of the Archaean domain, the Proterozoic crust of central Fennoscandia was also created around and soon after 1.90 Ga in a series of orogenic events collectively named the Svecofennian Orogeny Initial subduction between about 1.93 Ga and 1.91 Ga appears to have been towards the present south-west, creating a primitive volcanic arc, but soon its direction reversed to plunge beneath the Archaean Protocraton in the north-east In simplified outline, the Svecofennian Orogen consists of two volcanic belts and an intervening turbidite basin (the Bothnian Basin) In south central Finland there is a very large complex of granitoid plutons The northern volcanic belt follows the edge of the Archaean Protocraton in Scandinavia but then swings south-eastwards to western and southern Finland, skirting the complex of granites The southern belt extends between southernmost Finland and south central Sweden Continuations of these terranes beyond Lake Ladoga into Russia are conceivable (Figure 9) The ages of volcanism in the two belts overlap within the 1.90–1.88 Ga bracket; dominantly TTGtype plutonism lasted until about 1.87 Ga The pressure–temperature ratios of Svecofennian metamorphism were mostly low to moderate, which attests to the absence of continent–continent collision Between them, the two volcanic belts house the majority of the renowned Finnish and Swedish sulphide and iron ores By 1.85 Ga, the Svecofennian Orogen had been consolidated; however, 1.86–1.84 Ga plutons of granitoids occur locally at its south-western margin and along some major intra-orogenic province boundaries