Hostname: page-component-586b7cd67f-t8hqh Total loading time: 0 Render date: 2024-11-20T07:28:51.645Z Has data issue: false hasContentIssue false
  • English
  • Français

Geochronology and structural relationships of mesothermal gold mineralization in the Palaeoproterozoic Jokisivu prospect, southern Finland

Published online by Cambridge University Press:  18 January 2010

K. SAALMANN ,
I. MÄNTTÄRI ,
P. PELTONEN ,
M. J. WHITEHOUSE ,
P. GRÖNHOLM  and
M. TALIKKA
K. SAALMANN*
Affiliation:
Geological Survey of Finland, P.O. Box 96, FI-02151 Espoo, Finland
I. MÄNTTÄRI
Affiliation:
Geological Survey of Finland, P.O. Box 96, FI-02151 Espoo, Finland
P. PELTONEN
Affiliation:
Geological Survey of Finland, P.O. Box 96, FI-02151 Espoo, Finland
M. J. WHITEHOUSE
Affiliation:
Laboratory for Isotope Geology, Swedish Museum of Natural History, P.O. Box 50 007, SE-104 05 Stockholm, Sweden
P. GRÖNHOLM
Affiliation:
Polar Mining Oy, Kummunkatu 34, 83500 Outokumpu, Finland
M. TALIKKA
Affiliation:
Polar Mining Oy, Kummunkatu 34, 83500 Outokumpu, Finland
*
†Author for correspondence: [email protected]
Get access Rights & Permissions [Opens in a new window]

Abstract

The palaeoproterozoic Svecofennian orogen in southern Finland contains a number of orogenic gold occurrences. The Jokisivu gold deposit, comprising auriferous quartz veins, is hosted by syn-tectonic quartz diorites to gabbros. Mineralization occurs in approximately WNW–ESE- and WSW–ENE-trending shear zones, which probably branch from regional-scale NW–SE-trending shears. Ore zone fabrics post-date regional-scale folding and the metamorphic peak, and can be correlated with late Svecofennian regional shear tectonics (D6; 1.83–1.78 Ga), indicating that mineralization formed during the late stages of orogenic evolution. SIMS and TIMS U–Pb dating of three samples place tight constraints on the age of gold mineralization. Zircons from both unaltered and altered quartz diorites have ages of 1884±4 Ma and 1881±3 Ma, respectively. These are interpreted as the crystallization age of the rock and as providing the maximum age for mineralization. Zircon rims from an altered quartz diorite from the ore zone give ages of c. 1802±15 Ma, which overlap with the 1801±18 Ma titanite (mean Pb–Pb) age from the ore zone. The ages are similar to the age of the pegmatite dyke that cuts the ore zone and whose zircon age of 1807±3 Ma is approximately the same as the 1791±2 Ma monazite age (TIMS) giving the minimum age of the gold mineralization. The mineralization and its structural framework can be correlated with coeval late Svecofennian shear tectonics related to WNW–ESE-oriented shortening in southern Finland. Extensive c. 1.8 Ga granite magmatism, shear zone development and associated gold mineralization are of regional importance also in the northern and western Fennoscandian Shield (Finnish Lapand and Sweden). A Cordilleran-type setting can explain the widespread distribution of magmatism and gold mineralization associated with shortening, as well as the required heat source triggering hydrothermal fluid flow along shear zones.

Keywords

U–Pb geochronologyorogenic goldstructural geologySvecofennian orogenytectonic modelFinland
Type
Original Article
Information
Geological Magazine , Volume 147 , Issue 4 , July 2010 , pp. 551 - 569
Copyright
Copyright © Cambridge University Press 2010

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

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.CrossRefGoogle Scholar
Andersson, U. B., Eklund, O., Fröjjdö, S. & Konopelko, D. 2006. 1.8 Ga magmatism in the Fennoscandian Shield; lateral variations in subcontinental mantle enrichment. Lithos 86, 110–36.CrossRefGoogle Scholar
Bark, G., Broman, C. & Weihed, P. 2007. Fluid chemistry of the Palaeoproterozoic Fäboliden hypozonal orogenic gold deposit, northern Sweden: evidence from fluid inclusions. Geologiska Föreningens i Stockholm Förhandlingar (GFF) 129, 197–210.Google Scholar
Bergman-Weihed, J. 2001. Palaeoproterozoic deformation zones in the Skellefte and Arvidsjaur areas, northern Sweden. In Economic geology research, Volume 1, 1999–2000 (ed. Weihed, P.), pp. 46–68. Sveriges Geologiska Undersökning Research Paper C 833.Google Scholar
Bergman, S., Kübler, L. & Martinsson, O. 2001. Description of regional geological and geophysical maps of northern Norrbotten county (east of the Caledonian orogen). Sveriges Geologiska Undersökning Ba 56, 110 pp. Uppsala.Google Scholar
Billström, K., Bergman, S. & Martinsson, O. 2002. Post-1.9 Ga metamorphic, mineralization and hydrothermal events in northern Sweden. (Extended Abstract). Geologiska Föreningens i Stockholm Förhandlingar (GFF) 124, 228.Google Scholar
Collins, W. J. 2002. Hot orogens, tectonic switching, and creation of continental crust. Geology 30, 535–8.2.0.CO;2>CrossRefGoogle Scholar
Dragon Mining Ltd. 2007. Annual Report 2006. Perth, 86 pp. Link to source is available from the Geological Survey of Finland database: http://en.gtk.fi/ExplorationFinland/Commodities/Gold/jokisivu.htmlGoogle Scholar
Dragon Mining NL. 2005. Annual Report 2004. Perth, 80 pp. Link to source is available from the Geological Survey of Finland database: http://en.gtk.fi/ExplorationFinland/Commodities/Gold/jokisivu.htmlGoogle Scholar
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.Google Scholar
Eilu, P. 2007. FINGOLD: Brief description of all drilling-indicated gold occurrences in Finland – The 2007 data. Geological Survey of Finland Report of Investigation 166, 37 pp. Internet-link: http://en.gtk.fi/ExplorationFinland/Commodities/Gold/gtk_gold_map.htmlGoogle Scholar
Eilu, P., Hallberg, A., Bergman, T., Feoktistov, V., Korsakova, M., Krasotkin, S., Lampio, E., Litvinenko, V., Nurmi, P. A., Often, M., Philippov, N., Sandstad, J. S., Stromov, V. & Tontti, M. 2007. Fennoscandian Ore Deposit Database Explanatory remarks to the database. Geological Survey of Finland Report of Investigation 168, 17 pp. Internet-link: http://en.gtk.fi/ExplorationFinland/fodd/.Google Scholar
Eilu, P., Sorjonen-Ward, P., Nurmi, P. & Niiranen, T. 2003. A review of gold mineralization styles in Finland. Economic Geology 98, 1329–54.CrossRefGoogle Scholar
Eklund, O., Konopelko, D., Rutanen, H., Fröjdö, S. & Shebanov, A. D. 1998. 1.8 Ga Svecofennian post-collisional shoshonitic magmatism in the Fennoscandian shield. Lithos 45, 87–108.Google Scholar
Essex, R. M., Gromet, L. P., Andreasson, P. G. & Albrecht, L. 1997. Early Ordovician U–Pb metamorphic ages of the eclogite-bearing Seve Nappes, Northern Scandinavian Caledonides. Journal of Metamorphic Geology 15, 665–76.Google Scholar
Frost, B. R., Chamberlain, K. R. & Schumacher, J. C. 2000. Sphene (titanite): phase relations and role as a geochronometer. Chemical Geology 172, 131–48.CrossRefGoogle Scholar
Gascoyne, M. 1986. Evidence for the stability of potential nuclear waste host, sphene, over geological time, from uranium–lead ages and uranium series disequilibrium measurements. Applied Geochemistry 1, 199–210.CrossRefGoogle Scholar
Grönholm, P. 2006. The Jokisivu gold deposit, southwest Finland. Geological Society of Finland Bulletin 1 (Spec. Issue), 42.Google Scholar
Groves, D. I., Goldfarb, R. J., Gebre-Mariam, M., Hagemann, S. G. & Robert, F. 1998. Orogenic gold deposits: A proposed classification in the context of their crustal distribution and relationship to other gold deposit types. Ore Geology Reviews 13, 7–27.CrossRefGoogle Scholar
Haga, I. 2005. Dragon Mining's activities and strategies in Fennoscandia. FEM2005 Congress, Rovaniemi, 1–2 Dec 2005. Link to source is available from the Geological Survey of Finland FINGOLD database http://en.gtk.fi/ExplorationFinland/Commodities/Gold/jokisivu.htmlGoogle Scholar
Hakkarainen, G. 1994. Geology and geochemistry of the Hämeenlinna-Somero volcanic belt, southwestern Finland: a Paleoproterozoic island arc. In Geochemistry of Proterozoic supracrustal rocks in Finland (eds Nironen, M. & Kähkönen, Y.), pp. 85–100. Geological Survey of Finland, Special Publication no. 19.Google Scholar
Hermansson, T., Stephens, M. B., Corfu, F., Andersson, J. & Page, L. 2007. Penetrative ductile deformation and amphibolite-facies metamorphism prior to 1851 Ma in the western part of the Svecofennian orogen, Fennoscandian Shield. Precambrian Research 153, 29–45.CrossRefGoogle Scholar
Högdahl, K., Andersson, U. B. & Eklund, O. (eds) 2004. The Transscandinavian Igneous Belt (TIB) in Sweden: a review of its character and evolution. Geological Survey of Finland, Special Paper no. 37, 125 pp.Google Scholar
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.CrossRefGoogle Scholar
Hopgood, A. M., Bowes, D. R., Kouvo, O. & Halliday, A. D. 1983. U–Pb and Rb–Sr isotopic study of polyphase deformed migmatites in the Svecokarelides, southern Finland. In Migmatites, Melting and Metamorphism (eds Atherton, M. P. & Gribble, C. D.), pp. 80–92. Nantwich: Shiva.Google Scholar
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 Bulletin 337, 48 pp.Google Scholar
Kähkönen, Y., Huhma, H. & Aro, K. 1989. U–Pb zircon ages and Rb–Sr whole-rock isotope studies of early Proterozoic volcanic and plutonic rocks near Tampere, southern Finland. Precambrian Research 45, 27–43.Google Scholar
Kähkönen, Y., Lahtinen, R. & Nironen, M. 1994. Palaeoproterozoic supracrustal belts in southwestern Finland. In High temperature–low pressure metamorphism and deep crustal structures (ed. Pajunen, M.), pp. 43–7. Meeting of IGCP project 304 ‘Deep Crustal processes’ in Finland, 1994. Geological Survey of Finland Guide no. 37.Google Scholar
Kilpeläinen, T. 1998. Evolution and 3D modelling of structural and metamorphic patterns of the Palaeoproterozoic crust in the Tampere–Vammala area, southern Finland. Geological Survey of Finland Bulletin 397, 124 pp.Google Scholar
Kinny, P. D., McNaughton, N. J., Fanning, C. M. & Maas, R. 1994. 518 Ma sphene (titanite) from the Khan pegmatite, Namibia, southwest Africa: A potential ion-microprobe standard. Eighth International Conference on Geochronology, Cosmochronology and Isotope Geology Abstracts: Berkeley, US Geological Survey Circular 1107, p. 171.Google Scholar
Korja, A. & Heikkinen, P. 1995. Proterozoic extensional tectonics of the central Fennoscandian Shield: results from the Baltic and Bothnian Echoes from the Lithosphere experiment. Tectonics 14, 504–17.Google Scholar
Korsman, K., Koistinen, T., Kohonen, J., Wennerström, M., Ekdahl, E., Honkamo, M., Idman, H. & Pekkala, Y. 1997. Bedrock Map of Finland 1:1,000,000 scale. Espoo: Geological Survey of Finland.Google Scholar
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.Google Scholar
Krogh, T. E. 1973. A low-contamination method for hydrothermal decomposition of U and Pb for isotopic age determinations. Geochimica et Cosmochimica Acta 37, 485–94.Google Scholar
Krogh, T. E. 1982. Improved accuracy of U–Pb zircon ages by the creation of more concordant systems using an air abrasion technique. Geochimica et Cosmochimica Acta 46, 637–49.Google Scholar
Kurhila, M., Vaasjoki, M., Mänttäri, I., Rämö, T. & Nironen, M. 2005. U–Pb ages and Nd isotope characteristics of the late orogenic, migmatizing microcline granites in southwestern Finland. Geological Society of Finland Bulletin 77, 105–28.Google Scholar
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 tonalities and associated supracrustal rocks in the Rautalampi area, central Finland. Geological Survey of Finland Bulletin 378, 128 pp.Google Scholar
Lahtinen, R. 1996. Geochemistry of Palaeoproterozoic supracrustal and plutonic rocks in the Tampere–Hämeenlinna area, southern Finland. Geological Survey of Finland Bulletin 389, 113 pp.Google Scholar
Lahtinen, R. & Huhma, H. 1997. Isotopic and geochemical constraints on the evolution of the 1.93–1.79 Ga Svecofennian crust and mantle in Finland. Precambrian Research 82, 13–34.Google Scholar
Lahtinen, R., Korja, A. & Nironen, M. 2005. Paleoproterozoic tectonic evolution. In Precambrian Geology of Finland – Key to the Evolution of the Fennoscandian Shield (eds Lehtinen, M., Nurmi, P. A. & Rämö, O. T.), pp. 481–532. Amsterdam: Elsevier B.V.Google Scholar
Levin, T., Engström, J., Lindroos, A., Baltybaev, S. & Levchenkov, O. 2005. Late Svecofennian transpressive deformation in SW Finland – evidence from late-stage D3 structures. Geologiska Föreningens i Stockholm Förhandlingar (GFF) 127, 127–37.Google Scholar
Ludwig, K. R. 1991. PbDat 1.21 for MS-DOS: a computer program for IBM-PC compatibles for processing raw Pb–U–Th isotope dataVersion 1.07. US Geological Survey Open-File Report no. 88–542, 35 pp.Google Scholar
Ludwig, K. R. 2003. Isoplot/Ex 3. A geochronological toolkit for Microsoft Excel. Berkeley Geochronology Center, Special Publication no. 4.Google Scholar
Luukkonen, A. 1994. Main geological features, metallogeny and hydrothermal alteration phenomena of certain gold and gold-tin-tungsten prospects in southern Finland. Geological Survey of Finland Bulletin 377, 153 pp.Google Scholar
Luukkonen, A., Grönholm, P. & Hannila, T. 1992. Eräiden Etelä-Suomen kulta-ja sen seuralaismetalliesiintymien geologiset pääpiirteet. Summary: Main geological features of certain gold and tungsten-tin-gold prospects in southern Finland. Geological Survey of Finland Report of Investigation 113, 1–9.Google Scholar
Matisto, A. 1978. Huittisten kartta-alueen kallioperä. Suomen geologinen kartta 1:100 000, kallioperäkartan selitykset 2112 Huittinen (with English summary: Precambrian rocks of the Huittinen map-sheet area). Espoo: Geological Survey of Finland, 30 pp.Google Scholar
Mouri, H., Korsman, K. & Huhma, H. 1999. Tectono-metamorphic evolution and timing of the melting processes in the Svecofennian tonalite–trondhjemite migmatite belt: an example from Luopoinen, Tampere area, southern Finland. Geological Survey of Finland Bulletin 71, 31–56.CrossRefGoogle Scholar
Mouri, H., Väisänen, M., Huhma, H. & Korsman, K. 2005. Sm–Nd garnet and U–Pb monazite datig of high-grade metamorphism and crustal melting in the West Uusimaa area, southern Finland. Geologiska Föreningens i Stockholm Förhandlingar (GFF) 127, 123–8.Google Scholar
Niiranen, T., Poutiainen, M. & Mänttäri, I. 2007. Geology, geochemistry, fluid inclusion characteristics, and U–Pb age studies from iron oxide Cu–Au deposits in the Kolari region, northern Finland. Ore Geology Reviews 30, 75–105.Google Scholar
Nironen, M. 1999. Structural and magmatic evolution in the Loimaa area, southwestern Finland. Geological Society of Finland Bulletin 71, 57–71.Google Scholar
Nironen, M. & Kähkönen, Y. (eds) 1994. Geochemistry of Proterozoic Supracrustal Rocks in Finland. Geological Survey of Finland Special Paper no. 19, 184 pp.Google Scholar
Pajunen, M., Airo, M. L., Elminen, T., Mänttäri, I., Niemelä, R., Vaarma, M., Wasenius, P. & Wennerström, M. 2008. Tectonic evolution of Svecofennian crust in southern Finland. Geological Survey of Finland Special Publication 47, 15–184.Google Scholar
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.Google Scholar
Patison, N. L. 2007. Structural controls on GOLD mineralisation in the Central Lapland Greenstone Belt. In Gold in the Central Lapland Greenstone Belt, Finland (ed. Ojala, V. J.), pp. 107–22. Geological Survey of Finland, Special Paper no. 44.Google Scholar
Pidgeon, R. T., Bosch, D. & Bruguier, O. 1996. Inherited zircon and titanite U–Pb systems in an Archaean syenite from southwestern Australia: implications for U–Pb stability of titanite. Earth and Planetary Science Letters 141, 187–98.Google Scholar
Puustinen, K., Saltikoff, B. & Tontti, M. 1995. Distribution and metallogenic types of nickel deposits in Finland. Geological Survey of Finland Report of Investigation 132, 38 pp.Google Scholar
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, 1971–93.Google Scholar
Romer, R. L. & Smeds, S. A. 1997. U–Pb columbite chronology of post-kinematic Palaeoproterozoic pegmatites in Sweden. Precambrian Research 82, 85–99.CrossRefGoogle Scholar
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. Geological Society of Finland Bulletin 76, 93–140.Google Scholar
Saalmann, K. 2007. Structural control on gold mineralization in the Satulinmäki and Riukka prospects, Häme schist belt, southern Finland. Geological Society of Finland Bulletin 79, 69–93.Google Scholar
Saalmann, K., Mänttäri, I., Peltonen, P. & Whitehouse, M. J. 2008. Timing of orogenic gold mineralization in southern Finland and its relationship to the Palaeoproterozoic Svecofennian tectonic evolution. 33rd International Geological Congress, 6–14 August 2008, Oslo, Norway. Abstract CD-ROM, 1 p.Google Scholar
Saltikoff, B., Puustinen, K. & Tontti, M. 2006. Metallogenic zones and metallic mineral deposits in Finland. Explanation to the Metallogenic Map of Finland. Geological Survey of Finland Special Paper no. 35, 66 pp.Google Scholar
Schärer, U., Zhang, L. S. & Tapponnier, P. 1994. Duration of strike-slip movements in large shear zones: the Red River belt, China. Earth and Planetary Science Letters 126, 379–97.CrossRefGoogle Scholar
Scott, D. J. & St-Onge, M. R. 1995. Constraints on Pb closure temperature in titanite based on rocks from the Ungava Orogen, Canada; implications for U–Pb geochronology and P–T–t path determinations. Geology 23, 1123–6.Google Scholar
Skridlaite, G. & Motuza, G. 2001. Precambrian domains in Lithuania: evidence of terrane tectonics. Tectonophysics 339, 113–33.CrossRefGoogle Scholar
Skyttä, P. 2007. Svecofennian crustal evolution in the Uusimaa belt area, SW Finland. Espoo: Geological Survey of Finland, 17 pp.Google Scholar
Stacey, J. S. & Kramers, J. D. 1975. Approximation of terrestrial lead isotope evolution by a two-stage model. Earth and Planetary Science Letters 26, 207–21.Google Scholar
Torvela, T., Mänttäri, I. & Hermansson, T. 2008. Timing of deformation phases within the South Finland shear zone, SW Finland. Precambrian Research 160, 277–98.Google Scholar
Väisänen, M. & Hölttä, P. 1999. Structural and metamorphic evolution of the Turku migmatite complex, southwestern Finland. Geological Society of Finland Bulletin 71, 177–218.CrossRefGoogle Scholar
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, 111–27.CrossRefGoogle Scholar
Väisänen, M. & Skyttä, P. 2007. Late Svecofennian shear zones in southwestern Finland. Geologiska Föreningens i Stockholm Förhandlingar (GFF) 129, 55–64.Google Scholar
Valbracht, P. J., Oen, I. S. & Beunk, F. F. 1994. Sm–Nd isotope systematics of 1.9–1.8 Ga granites from western Bergslagn, Sweden: inferences on a 2.1–2.0 Ga crustal precursor. Chemical Geology 112, 21–37.Google Scholar
Verts, L. A., Chamberlain, K. R. & Frost, C. D. 1996. U–Pb sphene dating of metamorphism: the importance of sphene growth in the contact aureole of the Red Mountain Pluton, Laramie Mountains, Wyoming. Contributions to Mineralogy and Petrology 125, 186–99.Google Scholar
Vuori, S., Kärkkäinen, N., Huhta, P. & Valjus, T. 2005. Ritakallio gold prospect, Huittinen, SW Finland. Geological Survey of Finland Report of Investigation CM06/2112/2005/1/10, 53 pp.Google Scholar
Weihed, P., Billström, K., Persson, P.-O. & Bergman Weihed, J. 2002. Relationship between 1.90–1.85 Ga accretionary processes and 1.82–1.80 Ga oblique subduction at the Karelian craton margin, Fennoscandian Shield. Geologiska Föreningens i Stockholm Förhandlingar (GFF) 124, 163–80.Google Scholar
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.Google Scholar
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, 201–24.Google Scholar
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 analysis. Geostandards Newsletter 19, 1–23.CrossRefGoogle Scholar
Wiszniewska, J., Krzeminska, E. & Dörr, W. 2007. Evidence of arc-related Svecofennian magmatic activity in the southwestern margin of the East European Craton in Poland. Gondwana Research 12, 268–78.Google Scholar