Geological Evolution and Structure Along the Southeastern Border of the Central Finland Granitoid Complex
Development of the Paleoproterozoic Svecofennian orogeny: new constraints from the southeastern boundary of the Central Finland Granitoid Complex Edited by Perttu Mikkola, Pentti Hölttä and Asko Käpyaho Geological Survey of Finland, Bulletin 407, 5-27, 2018 GEOLOGICAL EVOLUTION AND STRUCTURE ALONG THE SOUTHEASTERN BORDER OF THE CENTRAL FINLAND GRANITOID COMPLEX by Perttu Mikkola1), Esa Heilimo1), Jouni Luukas1), Jukka Kousa1), Soile Aatos1), Hannu Makkonen1), Sami Niemi1), Maarit Nousiainen1), Marjaana Ahven1), Ilona Romu1) and Janne Hokka2) Mikkola, P., Heilimo, E., Luukas, J., Kousa, J., Aatos, S., Makkonen, H., Niemi, S., Nousiai- nen, M., Ahven, M., Romu, I. & Hokka, J. 2018. Geological evolution and structure along the southeastern border of the Central Finland Granitoid Complex. Geological Survey of Finland, Bulletin 407, 5–27, 6 figures and 1 table. The rock record present along the southeastern border of the Central Finland Granitoid Complex provides evidence for the geological evolution of the Paleoproterozoic Svecofennian orogeny from the magmatism of the Savo arc through paragneisses deposited in a passive margin setting to arc volcanism and the collisional final phases. The older Svecofennian magmatic phase (1.93–1.91 Ga) ended when the Savo arc collided with the Archean Karelia craton. After this collision, the greywacke protoliths of the paragneisses, in most cases having maximum deposition ages close to 1.92 Ga, were deposited. Most of the paragneisses have later been migmatised. The local presence of unmigmatised variants in close proximity to the migmatised ones indicates large vertical movements in the late stages of geological evolution. Mafic and ultramafic volcanic units erupted as interbeds during extensional phases of the depositional basins.
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