Palaeoproterozoic adakite- and TTG-like magmatism in the Svecofennian orogen, SW Finland
DOI:
https://doi.org/10.1344/105.000001761Keywords:
Adakite, TTG, Palaeoproterozoic, Svecofennian, U-Pb, Sm-Nd, SIMS, Diorite, Tonalite, Trondhjemite, Granodiorite, Crustal meltingAbstract
The Palaeoproterozoic Svecofennian orogen in the Fennoscandian shield is an arc accretionary orogen that was formed at c. 1.92-1.86Ga. Arc accretion, magmatism and the subsequent continent-continent collision thickened the crust up to c. 70km, forming one of the thickest Palaeoproterozic orogens. At the end stage of accretionary tectonics, voluminous synorogenic magmatism occurred in southwestern Finland leading to the intrusion of intermediate to felsic plutonic rocks. Ion microprobe single zircon dating of one diorite sample yielded an age of 1872±3Ma (εNd=+2.2) and the trondhjemite sample an age of 1867±4Ma (εNd=+2.6). Inherited 2667-1965Ma cores and 1842±5Ma metamorphic rims were also found in zircons from the trondhjemite. The dioritic magmatism is mantle-derived and is slightly enriched by subduction-related processes. The felsic magmatism shows elevated Sr/Y and La/Yb ratios, which are typical for adakite- and TTG-like magmas. Their low Mg#, Ni and Cr contents argue against slab-melting and mantle-wedge contamination. We infer that the felsic magmatism was generated through crustal melting of the lower part of the previously generated volcanic-arc type crust. Based on published melting experiments and the Sr and Y contents of the felsic rocks we suggest that the melts were generated at a minimum pressure of 10kbar, with evidence of a 15kbar pressure for the highest Sr/Y trondhjemites. It is proposed that arc accretion combined with magmatic intrusions thickened the crust so that melting of the lower crust yielded adakite- and TTG-like compositions. The mafic magmatism is considered to be the heat source.
References
Allen, R.L., Lundström, I., Ripa, M., Simeonov, A., Christofferson, H., 1996. Facies analysis of a 1.9 Ga, continental margin, back-arc, felsic caldera province with diverse Zn-Pb-Ag-(Cu-Au) sulfide and Fe oxide deposits, Bergslagen region, Sweden. Economic Geology, 91, 979-1008.
Andersen, T., Andersson, U.B., Graham, S., Åberg, G., Simonsen, S.L. 2009. Granitic magmatism by melting of juvenile continental crust: New constraints on the source of Palaeoproterozoic granitoids in Fennoscandia from Hf isotopes in zircon. London, Journal of the Geological Society, 166, 233-247.
Andersson, U.B., 1991. Granitoid episodes and mafic-felsic magma interaction in the Svecofennian of the Fennoscandian shield, with main emphasis on the ~1.8Ga plutonics. Precambrian Research, 51, 127-149.
Andersson, U.B., Neymark, L.A., Billström, K. 2002. Petrogenesis of Mesoproterozoic (Subjotnian) rapakivi complexes of central Sweden: implications from U-Pb zircon ages, Nd, Sr and Pb isotopes. Transactions of the Royal Society of Edinburgh, Earth Sciences, 92, 201-228.
Andersson, U.B., Högdahl, K., Sjöström, H., Bergman, S., 2004a. Magmatic, detrital, and metamorphic ages in metamorphic rocks from south-central Sweden. GFF, 126, 16-17.
Andersson, U.B., Sjöström, H., Högdahl, K., Eklund, O., 2004b. The Transscandinavian Igneous Belt, evolutionary models. Geological Survey of Finland, 37 (Special Paper), 104-112.
Andersson, U.B., Eklund, O., Fröjdö, S., Konopelko, D., 2006a. 1.8Ga magmatism in the Fennoscandian Shield: lateral variations in subcontinental mantle enrichment. Lithos, 86, 110-136.
Andersson, U.B., Högdahl, K., Sjöström, H., Bergman, S., 2006b. Multistage growth and reworking of the Palaeoproterozoic crust in the Bergslagen area, southern Sweden; evidence from U-Pb geochronology. Geological Magazine, 143, 679-697.
Andersson, U.B., Rutanen, H., Johansson, Å., Mansfeld, J., Rimša, A., 2007. Characterization of the Paleoproterozoic mantle beneath the Fennoscandian Shield: Geochemistry and isotope geology (Nd, Sr) of ~1.8 Ga mafic plutonic Sweden. International Geology Review, 49, 587-625.
Arth, J.G., Barker, F., Peterman, Z.E. Friedman, I., 1978. Geochemistry of the gabbro-diorite-tonalite-trondhjemite suite of southwestern Finland and its implication for the origin of tonalitic and trondhjemitic magmas. Journal of Petrology, 19, 289-316.
Baker, J.H., Hellingwerf, R.H., Oen, I.S., 1988. Structure, stratigraphy, and ore-forming processes in Bergslagen: implications for the development of the Svecofennian of the Baltic shield. Geologie en Mijnbouw, 67, 121-138.9
Barker, F., 1979. Trondhjemite: definition, environment and hypothesis of origin. In: Barker, F. (ed.). Trondhjemites, Dacites, and Related Rocks. Amsterdam, Elsevier, 1-12.
Bergman, S., Högdahl, K., Nironen, M., Ogenhall, E., Sjöström, H., Lundqvist, L., Lahtinen, R., 2008. Timing of Palaeoproterozoic intra-orogenic sedimentation in the central Fennoscandian Shield; evidence from detrital zircon in metasandstone. Precambrian Research, 161, 231-249.
Bogdanova, S.V., Bingen, B., Gorbatschev, R., Kheraskova, T.N., Kozlov, V.I., Puchkov, V.N., Volozh, Y.A., 2008. The East European Craton (Baltica) before and during the assembly of Rodinia. Precambrian Research, 160, 23-45.
Cagnard, F., Gapais, D., Barbey, P., 2007. Collision tectonics involving juvenile crust: the example of the southern Finnish Svecofennides. Precambrian Research, 154, 125-141.
Chardon, D., Gapais, D., Cagnard, F., 2009. Flow of ultrahot orogens: A view from the Precambrian, clues for the Phanerozoic. Tectonophysics, 477, 105-118.
Chung, S.-L., Liu, D., Ji, J., Chu, M.-F., Lee, H.-Y., Wen, D.-J., Lo, C.-H., Lee, T.-Y., Qian, Q., Zhang, Q., 2003. Adakites from continental collision zones: Melting of thickened lower crust beneath southern Tibet. Geology, 31, 1021-1024.
Claesson, S., 1987. Nd isotope data on 1.9-1.2 Ga old basic rocks and metasediments from the Bothnian basin, central Sweden. Precambrian Research, 35, 115-126.
Claesson, S., Lundqvist, T., 1995. Origins and ages of Proterozoic granitoids in the Bothnian basin, central Sweden: isotopic and geochemical constraints. Lithos, 36, 115-140.
Claesson, S., Huhma, H., Kinny, P.D., Williams, I.S., 1993. Svecofennian detrital zircon ages implications for the Precambrian evolution of the Baltic Shield. Precambrian Research, 64, 109-130.
Colley, H., Westra, L., 1987. The volcano-tectonic setting and mineralisation of the early Proterozoic Kemiö-Orijärvi-Lohja belt, SW Finland. Geological Society of London, 33 (Special Publications), 95-107.
Condie, K., 2005. TTGs and adakites: are they both slab melts? Lithos, 80, 33-44.
Defant, M.J., Drummond, M.S., 1990. Derivation of some modern arc magmas by melting of young subducted lithosphere. Nature, 347, 662-665.
De Paolo, D.J., 1981. Neodymium isotopes in the Colorado Front Range and crust-mantle evolution in the Proterozoic. Nature, 291, 193-196.
Ehlers, C., Lindroos, A., Jaanus-Järkkälä, M., 1986. Stratigraphy and geochemistry in the Proterozoic mafic volcanic rocks of the Nagu-Korpo area, SW Finland. Precambrian Research, 32, 307-318.
Ehlers, C., Lindroos, A., Selonen, O., 1993. The late Svecofennian granite-migmatite zone of southern Finland - a belt of transpressive deformation and granite emplacement. Precambrian Research, 64, 295-309.
Ehlers, C., Skiöld, T., Vaasjoki, M., 2004. Timing of Svecofennian crustal growth and collisional tectonics in Åland, SW Finland. Bulletin of the Geological Society of Finland, 76, 63-91.
Gaál, G., Gorbatschev, R., 1987. An outline of the Precambrian evolution of the Baltic shield. Precambrian Research, 35, 15-
Halla, J., van Hunen, J., Heilimo, E., Hölttä, P., 2009. Geochemical and numerical constraints on Neoarchean plate tectonics. Precambrian Research, 174, 155-162.
Helenius, E.-M., Eklund, O., Väisänen, M., Hölttä, P., 2004. Petrogenesis of charnockites in the Turku granulite area. Institute of Seismology, University of Helsinki, S-45 (Report), 17-20.
Hermansson, T., Stephens, M.B., Corfu, F., Andersson, J., Page, L.M., 2007. Penetrative ductile deformation and amphibolitefacies metamorphism prior to 1851 Ma in the western part of the Svecofennian orogen, Fennoscandian Shield. Precambrian Research, 153, 29-45.
Hermansson, T., Stephens, M.B., Corfu, F., Page, L.M., Andersson, J., 2008. Migratory tectonic switching, western Svecofennian orogen, central Sweden: Constraints from U/Pb zircon and titanite geochronology. Precambrian Research, 161, 250-278.
Hietanen, A., 1943. Über das Grundgebirge des Kalantigebietes im südwestlichen Finnland. Bulletin de la Commission géologique de Finlande, 130, 106pp.
Hietanen, A., 1947. Archaean geology of the Turku district in southwestern Finland. Bulletin of the Geological Society of America, 58, 1019-1084.
Hildreth, W., Moorbath, S., 1988. Crustal contributions to arc magmatism in the Andes of central Chile. Contributions to Mineralogy and Petrology, 98, 455-489.
Högdahl, K., Sjöström, H., 2001. Evidence for 1.82 Ga transpressive shearing in a 1.85 Ga granitoid in central Sweden: implications for the regional evolution. Precambrian Research, 105, 37-56.
Högdahl, K., Sjöström, H., Andersson, U.B., Ahl, M., 2008. Continental margin magmatism and migmatisation in the west-central Fennoscandian Shield. Lithos, 102, 435-459.
Högdahl, K., Sjöström, H., Bergman, S., 2009. Ductile shear zones related to crustal shortening and domain boundary evolution in the central Fennoscandian Shield. Tectonics, 28, TC1003, 18pp. doi: 10.1029/2008TC002277
Hou, Z.-Q., Gao, Y.-F., Qu, X.-M., Rui, Z.-Y., Mo, X.-X., 2004. Origin of adakitic intrusives generated during mid-Miocene east-west extension in southern Tibet. Earth and Planetary Science Letters, 220, 139-155.
Huang, X.-L., Xu, Y.-G., Lan, J.-B., Yang, Q.-J., Luo, Z.-Y., 2009. Neoproterozoic adakitic rocks from Mopanshan in the western Yangtze Craton: Partial melts of a thickened lower crust. Lithos, 112, 367-381.
Huhma, H., 1986. Sm-Nd, U-Pb and Pb-Pb isotopic evidence for the origin of the Early Proterozoic Svecokarelian crust in Finland. Geological Survey of Finland, 337 (Bulletin), 48pp.
Huhma, H., 1987. Provenance of early Proterozoic and Archean metasediments in Finland: a Sm-Nd isotopic study. Precambrian Research, 35, 127-143.
Jacobsen, S.B., Wasserburg, G.J., 1984. Sm-Nd isotopic evolution of chondrites and achondrites II. Earth and Planetary Science Letters, 6, 137-150.
Jahn, B.M., Glikson, A.Y., Peucat, J.-J., Hickman, A.H., 1981. REE geochemistry and isotope data of Archaean silicic volcanics and granitoids from the Pilbara Block, western Australia: implications for the early crustal evolution. Geochimica Cosmochimica Acta, 45, 1633-1652.
Janoušek, V., Farrow, G., Erban, V., 2006. Interpretation of wholerock geochemical data in igneous geochemistry: Introducing Geochemical Data Toolkit (GCDkit). Journal of Petrology, 47, 1255-1259.
Johannes, W., Ehlers, C., Kriegsman, L.M., Mengel, K., 2003. The link between migmatites and S-type granites in the Turku area, southern Finland. Lithos, 68, 69-90.
Johansson, Å., 2009. Baltica, Amazonia and the SAMBA connection - 1000 million years of neighbourhood during the Proterozoic? Precambrian Research, 175, 221-234.
Jurvanen, T., Eklund, O., Väisänen, M., 2005. Generation of A-type granitic melts during the late Svecofennian metamorphism in southern Finland. GFF, 127, 139-147.
Kähkönen, Y., 2005. Svecofennian supracrustal rocks. In: Lehtinen, M., Nurmi, P.A., Rämö, O.T. (eds.). Precambrian Geology of Finland - Key to the Evolution of the Fennoscandian Shield. Amsterdam, Developments in Precambrian Geology, Elsevier, 14, 343-405.
Kamber, B.S., Ewart, A., Collerson, K.D., Bruce, M.C., McDonald, G.D., 2002. Fluid-mobile trace element constraints on the role of slab melting and implications for Archean crustal growth models. Contributions to Mineralogy and Petrology, 144, 38-56.
Kirkland, C.L., Daly, J.S., Whitehouse, M.J., 2008. Basementcover relationships of the Kalak Nappe Complex, Arctic Norwegian Caledonides and constraints on Neoproterozoic terrane assembly in the North Atlantic region. Precambrian
Research, 160, 245-276.
Konopelko, D., Eklund, O., 2003. Timing and geochemistry of potassic magmatism in the eastern part of the Svecofennian domain, NW Ladoga Lake Region, Russian Karelia. Precambrian Research, 120, 37-53.
Korja, A., Korja, T., Luosto, U., Heikkinen, P., 1993. Seismic and geoelectric evidence for collisional and extensional events in the Fennoscandian Shield - implications for Precambrian crustal evolution. Tectonophysics, 219, 129-152.
Korja, A., Lahtinen, R., Nironen, M., 2006. The Svecofennian orogen: a collage of microcontinents and island arcs. London, Geological Society, 32 (Memoirs), 561-578.
Korsman, K., Hölttä, P., Hautala, T., Wasenius, P., 1984. Metamorphism as an indicator of evolution and structure of the crust in eastern Finland. Geological Survey of Finland, 328 (Bulletin), 40pp.
Korsman, K., Koistinen, T., Kohonen, J., Wennerström, M., Ekdahl, E., Honkamo, M., Edman, H., Pekkala, Y., 1997. Bedrock map of Finland 1:1 000 000. Geological Survey of Finland.
Korsman, K., Korja, T., Pajunen, M., Virransalo, P., GGT/SVEKA Working Group, 1999. The GGT/SVEKA transect: structure and evolution of the continental crust in the Paleoproterozoic Svecofennian orogen in Finland. International Geology Review, 41, 287-333.
Kurhila, M., Vaasjoki, M., Mänttäri, I., Rämö, T., Nironen, M., 2005. U-Pb ages and Nd isotope characteristics of the lateorogenic, migmatizing microcline granites in southwestern Finland. Bulletin of the Geological Society of Finland, 77, 105-128.
Kurhila, M., Andersen, T., Rämö, O.T., 2010. Diverse sources of crustal granitic magma: Lu-Hf isotope data on zircon in three Paleoproterozoic leucogranites of southern Finland. Lithos, 115, 263-271.
Lahtinen, R., 1994. Crustal evolution of the Svecofennian and Karelian domains during 2.1–1.79 Ga, with special emphasis on the geochemistry and origin of 1.93–1.91 Ga gneissic tonalites and associated supracrustal rocks in the Rautalampi area, central Finland. Geological Survey of Finland, 378 (Bulletin), 128pp.
Lahtinen, R., Huhma, H., 1997. Isotopic and geochemical constraints on the evolution of the 1.93–1.79 Ga Svecofennian crust and mantle. Precambrian Research, 82, 13-34.
Lahtinen, R., Huhma, H., Kähkönen, Y., Mänttäri, I., 2009a. Paleoproterozoic sediment recycling during multiphase orogenic evolution in Fennoscandia, the Tampere and Pirkanmaa belts, Finland. Precambrian Research, 174, 310-336.
Lahtinen, R., Korja, A., Nironen, M., 2005. Palaeoproterozoic tectonic evolution of the Fennoscandian Shield. In: Lehtinen, M., Nurmi, P.A., Rämö, O.T. (eds.). The Precambrian Bedrock of Finland – Key to the Evolution of the Fennoscandian Shield. Amsterdam, Elsevier Science B.V., 418-532.
Lahtinen, R., Korja, A., Nironen, M., Heikkinen, P., 2009b. Palaeoproterozoic accretionary processes in Fennoscandia. Geological Society of London, 318 (Special Publications), 237-256.
Ludwig, K.R., 2003. User’s Manual for Isoplot 3.00. A Geochronological Toolkit for Microsoft Excel. Berkeley Geochronology Center, 4 (Special Publications), 1-70.
Lundström, I., Allen, R.L., Persson, P.-O., Ripa, M., 1998. Stratigraphies and depositional ages of Svecofennian, Palaeoproterozoic metavolcanic rocks in E. Svealand and Bergslagen, south central Sweden. GFF, 120, 315-320.
Macpherson, C.G., Dreher, S., Thirlwall, M.F., 2006. Adakites without slab melting: high pressure differentiation of island arc magma, Mindanao, the Philippines. Earth and Planetary Science Letters, 243, 581-593.
Mansfeld, J., Beunk, F.F., Barling, J., 2005. 1.83-1.82 Ga formation of a juvenile volcanic arc – implications from U-Pb and Sm-Nd analyses of the Oskarshamn-Jönköping Belt, southeastern Sweden. GFF, 127, 149-157.
Martin, H., 1999. The adakitic magmas: modern analogues of Archaean granitoids. Lithos, 46, 411-429.
Martin, H., Smithies, R.H., Rapp, R.P., Moyen, J.-F., Champion, D.C., 2005. An overview of adakite, tonalite-trondhjemitegranodiorite (TTG) and sanukitoid: relationships and some implications for crustal evolution. Lithos, 79, 1-24.
Martins, G., Oliveira, E.P., Lafon, J.M., 2009. The Algodões amphibolite–tonalite gneiss sequence, Borborema Province, NE Brazil: Geochemical and geochronological evidence for Palaeoproterozoic accretion of oceanic plateau/back-arc basalts and adakitic plutons. Gondwana Research, 15, 71-85.
Mattila, J., 2004. Geochemical and Sm-Nd isotopic constraints on the crustal evolution of the Kitee-Lahdenpohja area, southeastern Finland and northwestern Russia. M.Sc. Thesis. University of Turku, 102pp.
Middlemost, E.A.K., 1994. Naming materials in the magma/igneous rock system. Earth-Science Reviews, 37, 215-224. Mouri, H., Väisänen, M., Huhma, H., Korsman, K., 2005. Sm-Nd garnet and U-Pb monazite dating of high-grade metamorphism and crustal melting in the West Uusimaa area, southern Finland. GFF, 127, 123-128.
Moyen, J.-F., 2009. High Sr/Y and La/Yb ratios: The meaning of the “adakitic signature”. Lithos, 112, 556-574.
Muir, R.J., Weaver, S.D., Bradshaw, J.D., Eby, G.N., Evans, J.A., 1995. Geochemistry of the Cretaceous Separation Point Batholith, New Zealand: granitoid magmas formed by melting of mafic lithosphere. Journal of the Geological Society London, 152, 689-701.
Ogenhall, E., 2007. Plate tectonic settings of the Svecofennian Palaeoproterozoic volcanic rocks at Hamrånge and Loos, south central Sweden, based on geochemical data. GFF, 129, 211-226.
Nironen, M., 1997. The Svecofennian Orogen: a tectonic model. Precambrian Research, 86, 21-44.
Nironen, M., 1999. Structural and magmatic evolution in the Loimaa area, southwestern Finland. Bulletin of the Geological Society of Finland, 71, 57-71.
Nironen, M., Elliott, B.A., Rämö, O.T., 2000. 1.88-1.87 Ga post-kinematic intrusions of the Central Finland Granitoid Complex: a shift from C-type to A-type magmatism during lithospheric convergence. Lithos, 53, 37-58.
Nironen, M., Kurhila, M., 2008. The Veikkola granite area in southern Finland: emplacement of a 1.83-1.82 Ga plutonic sequence in an extensional regime. Bulletin of the Geological Society of Finland, 80, 39-68.
Pajunen, M., Airo, M.-L., Elminen, T., Mänttäri, I., Niemelä, R., Vaarma, M., Wasenius, P., Wennerström, M., 2008. Tectonic evolution of the Svecofennian crust in southern Finland. Geological Survey of Finland, 47 (Special Paper), 15-160.
Patchett, P.J., Gorbatschev, R., Todt, W., 1987. Origin of continental crust of 1.9-1.7 Ga age. Nd isotopes in the Svecofennian orogenic terrains of Sweden. Precambrian Research, 35, 145-160.
Patchett, J., Kouvo, O., 1986. Origin of continental crust of 1.9-1.7 Ga age: Nd isotopes and U-Pb zircon ages in the Svecokarelian terrain of South Finland. Contributions to Mineralogy and Petrology, 92, 1-12.
Pearce, J.A., 1996. A user’s guide to basalt discrimination diagrams. In: Wyman, D.A. (ed.). Trace Element Geochemistry of Volcanic Rocks: Applications for Massive Sulphide Exploration. Geological Association of Canada, Short Course Notes, 12, 79-113.
Peccerillo, R., Taylor, S.R., 1976. Geochemistry of Eocene calc-alkaline volcanic rocks from the Kastamonu area, northern Turkey. Contributions to Mineralogy and Petrology, 58, 63-81.
Pin, C., Zalduegui, J.F.S., 1997. Sequential separation of light rare-earth elements, thorium and uranium by miniaturized extraction chromatography: Application to isotopic analyses of silicate rocks. Analytica Chimica Acta, 339, 79-89.
Rämö, O.T., Vaasjoki, M., Mänttäri, I., Elliott, B.A., Nironen, M., 2001. Petrogenesis of the post-kinematic magmatism of the Central Finland Granitoid Complex I; radiogenic isotope constraints and implications for crustal evolution. Journal of Petrology, 42, 1971-1993.
Richards, J.R., Kerrich, R., 2007. Adakite-like rocks: Their diverse origins and questionable role in metallogenesis. Economic Geology, 102 (Special Paper), 537-576.
Romer, R.L., Öhlander, B. 1995. Tectonic implications of an 1846±1 Ma old migmatitic granite in south-central Sweden. GFF, 117, 69-74.
Rutanen, H., Andersson, U.B., 2009. Mafic plutonic rocks in a continental-arc setting: geochemistry of 1.87-1.78 Ga rocks from south-central Sweden and models of their palaeotectonic setting. Geological Journal, 44, 241-279.
Rutanen, H., Andersson, U.B., Väisänen, M., Johansson, Å., Fröjdö, S., Lahaye, Y., Eklund, O., 2011. 1.8 Ga magmatism in southern Finland: strongly enriched mantle and juvenile crustal sources in a post-collisional setting. International Geology Review, 53, 1622-1683.
Rutland, R.W.R., Williams, I.S., Korsman, K., 2004. Pre-1. 91 Ga deformation and metamorphism in the Palaeoproterozoic Vammala Migmatite Belt, southern Finland, and implications for Svecofennian tectonics. Bulletin of the Geological Society of Finland, 76, 93-140.
Selonen, O., Ehlers, C., 1998. Structural observations on the Uusikaupunki trondhjemite sheet, SW Finland. GFF, 120, 379-382.
Sheppard, S., Griffin, T.J., Tyler, I.M., Page, R.W., 2001. Highand low-K granites and adakites at a Palaeoproterozoic plate boundary in northwestern Australia. Journal of the Geological Society, 158, 547-560.
Skjerlie, K.P., Johnston, A.D., 1996. Vapour-absent melting from 10 to 20 kbar of crustal rocks that contain multiple hydrous phases: implications for anatexis in the deep to very deep continental crust and active continental margins. Journal of Petrology, 37, 661-691.
Skyttä, P., Mänttäri, I., 2008. Structural setting of late Svecofennian granites and pegmatites in Uusimaa Belt, SW Finland: Age constraints and implications for crustal evolution. Precambrian Research, 164, 86-109.
Skyttä, P., Väisänen, M., Mänttäri, I., 2006. Preservation of Palaeoproterozoic early Svecofennian structures in the Orijärvi area, SW Finland – Evidence for polyphase strain partitioning. Precambrian Research, 150, 153-172.
Smithies, R.H., 2000. The Archaean tonalite-trondhjemitegranodiorite (TTG) series is not an analogue of Cenozoic adakite. Earth and Planetary Science Letters, 182, 115-125.
Stacey, J.S., Kramers, J.D., 1975. Approximation of terrestrial lead isotope evolution by a two-stage model. Earth and Planetary Science Letters, 26, 207-221.
Steiger, R.H., Jäger, E., 1977. Subcomission on geochronology: convention on the use of decay constants in geo- and cosmochronology. Earth and Planetary Science Letters, 36, 359-362.
Stephens, M.B., Ripa, M., Lundström, I., Persson, L., Bergman, T., Ahl, M., Wahlgren, C.-H., Persson, P.-O., Wickström, L., 2009. Synthesis of the bedrock geology in the Bergslagen region, Fennoscandian Shield, south-central Sweden. Sveriges geologiska undersökning, 58, 260pp.
Sun, S.-S., McDonough, W.F., 1989. Chemical and isotopic systematics of oceanic basalts: implications for mantle composition and processes. Geological Society of London, 42 (Special Publications), 313-345.
Suominen, V., 1991. The chronostratigraphy of southwestern Finland with special reference to Postjotnian and Subjotnian
diabases. Geological Survey of Finland, 356 (Bulletin), 100pp.
Suominen, V., Fagerström, P., Torssonen, M., 1994. Geological map of Finland 1:100 000. Pre-Quaternary rocks, Uusikaupunki. Espoo, Geological Survey of Finland, Sheet 1131.
Suominen, V., Fagerström, P., Torssonen, M., 2006. Geological Map of Finland 1:100 000, Explanation to the maps of Pre-Quaternary rocks, Uusikaupunki (in Finnish with English Summary). Espoo, Geological Survey of Finland, Sheet 1131, 89pp.
Talikka, M., Mänttäri, I., 2005. Pukala intrusion, its age and connection to hydrothermal alteration in Orivesi, southwestern Finland. Bulletin of the Geological Society of Finland, 77, 165-180.
Taylor, S.R., McLennan, S.M., 1985. The continental crust: its composition and evolution. Geoscience texts. Oxford, Blackwell, 312pp.
Torvela, T., Ehlers, C., 2010. From ductile to brittle deformation: structural development and strain distribution along a crustalscale shear zone in SW Finland. International Journal of Earth Sciences, 99, 1133-1152.
Torvela, T., Mänttäri, I., Hermansson, T., 2008. Timing of deformation phases within the South Finland shear zone, SW Finland. Precambrian Research, 160, 277-298.
Vaasjoki, M., Huhma, H., Lahtinen, R., Vestin, J., 2003. Sources of Svecofennian granitoids in the light of ion probe U-Pb measurements on their zircons. Precambrian Research, 121, 251-262.
Väisänen, M., Hölttä, P., 1999. Structural and metamorphic evolution of the Turku migmatite complex, southwestern Finland. Bulletin of the Geological Society of Finland, 71, 177-218.
Väisänen, M., Kirkland, C.L., 2008. U-Th-Pb geochronology of igneous rocks in the Toija and Salittu Formations, Orijärvi area, southwestern Finland: Constraints on the age of volcanism and metamorphism. Bulletin of the Geological Society of Finland, 80, 73-87.
Väisänen, M., Mänttäri, I., 2002. 1.90-1.88 Ga arc and backarc basin in the Orijärvi area, SW Finland. Bulletin of the Geological Society of Finland, 74, 185-214.
Väisänen, M., Mänttäri, I., Hölttä, P., 2002. Svecofennian magmatic and metamorphic evolution in southwestern Finland as revealed by U-Pb zircon SIMS geochronology. Precambrian Research, 116, 111-127.
Väisänen, M., Skyttä, P., 2007. Late Svecofennian shear zones in southwestern Finland. GFF, 129, 55-64.
Väisänen, M., Westerlund, G., 2007. Palaeoproterozoic mafic and intermediate metavolcanic rocks in the Turku area, SW Finland. Bulletin of the Geological Society of Finland, 79, 127-141.
Valbracht, J., Oen, I.S., Beunk, F.F., 1994. Sm-Nd isotope systematics of 1.9-1.8 Ga granites from western Bergslagen, Sweden: inferences on a 2.1-2.0 Ga crustal precursor. Chemical Geology, 112, 21-37.
Van Duin, J.A., 1992. The Turku Granulite Area, SW Finland: a fluid-absent Svecofennian granulite occurrence. PhD. Thesis. Amsterdam (Holland), Vrije Universiteit, 234pp.
Verma, S.P., Torres-Alvarado, I.S., Sotelo-Rodríguez, Z.T., 2002. SINCLAS: Standard igneous norm and volcanic rock classification system. Computers & Geosciences, 28, 711-715.
Weihed, P., Arndt, N., Billström, K., Duchesne, J.-C., Eilu, P., Martinsson, O., Papunen, H., Lahtinen, R., 2005. Precambrian geodynamics and ore formation: the Fennoscandian Shield. Ore Geology Reviews, 27, 273-322.
Whitehouse, M.J., Kamber, B.S., 2005. Assigning dates to thin gneissic veins in high-grade metamorphic terranes: a cautionary tale from Akilia, southwest Greenland. Journal of Petrology, 46, 291-318.
Whitehouse, M.J., Kamber, B., Moorbath, S., 1999. Age significance of U–Th–Pb zircon data from early Archaean rocks of west Greenland – a reassessment based on combined ion-microprobe and imaging studies. Chemical Geology, 160, 201-224.
Wiedenbeck, M., Allé, P., Corfu, F., Griffin, W.L., Meier, M., Oberli, F., von Quadt, A., Roddick, J.C., Spiegeln, W., 1995. Three natural zircon standards for U-Th-Pb, Lu-Hf, trace element and REE analyses. Geostandards Newsletter, 19, 1-23.
Williams, I.S., Rutland, R.W.R., Kousa, J., 2008. A regional 1.92 Ga tectonothermal episode in Ostrobothnia, Finland: implications for models of Svecofennian accretion. Precambrian Research, 165, 15-36.
Wolf, M.B., Wyllie, P.J., 1994. Dehydration-melting of amphibolite at 10 kbar: the effects of temperature and time. Contributions to Mineralogy and Petrology, 115, 369-383.
Windley, B.F., 1995. The Evolving Continents. Chichester, John Wiley & Sons, 3rd edition, 526pp.
Zhang, S.-B., Zheng, Y.-F., Zhao, Z.-F., Wu, Y.-B., Yuan, H., Wu, F.-Y., 2009. Origin of TTG-like rocks from anatexis of ancient lower crust: Geochemical evidence from Neoproterozoic granitoids in South China. Lithos, 113, 347-368.
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