Skip to main content
SpringerLink
Log in

Genesis of Palaeoproterozoic iron skarns in the Misi region, northern Finland

  • Article
  • Published:
Mineralium Deposita Aims and scope Submit manuscript

Abstract

Sodic alteration is widespread in Palaeoproterozoic greenstone and schist belts of the northern Fennoscandian shield. In the Misi region that forms the easternmost part of the Peräpohja schist belt, several small magnetite deposits show intimate spatial relationships with intensely albitised gabbros, raising the possibility that regional sodic alteration released iron, which was subsequently accumulated into deposits. Two of these magnetite deposits, Raajärvi and Puro display a typical paragenesis as follows (from oldest to youngest): (1) diopside, (2) actinolite/tremolite-magnetite ± chlorite, biotite, and (3) serpentine ± hematite, chlorite. Mass balance calculations suggest that significant amounts of Fe, Ca, Mg, K, Cu, V, and Ba were lost, and Na and Si gained during the albitisation of the gabbro, at near-constant Al, Ga, Ti, and Zr. Significant amounts of Si, Ca, Fe, and Na were enriched in the formation of skarn related to magnetite deposits. Fe and V leached from country rocks deposited during the skarn-alteration and formed the vanadium rich iron deposits while Cu passed through the system without significant precipitation due to low sulphur fugasity. Variations in Na, Ca, Mg, K, and Ba contents reflect the composition of the infiltrating fluid during alteration. Conventional heating-freezing measurements and proton-induced X-ray emission (PIXE) analyses of the fluid inclusions related to actinolite/tremolite-magnetite stage alteration indicate that the fluids that caused the alteration and the Fe-mineralisation were complex, oxidised, highly saline H2O ± CO2 fluids that contained high amounts of Na, Ca, K, Fe, and Ba as well as elevated concentrations of Cu, Zn, and Pb. The oxygen isotope thermometry suggest that temperature during the Fe-mineralisation stage was between 390 and 490°C. Calculated δ18Ofluid values of 6.1–9.8‰ SMOW and δ13C values of calcites in the ores and skarns were between −7.7 and 10.9‰ PDB and most likely reflect admixture of 13C depleted, possibly magmatic fluids with the marble wall rocks that show δ13Ccalcite values of 13‰ PDB. The SIMS U–Pb data on the zircons in the albitised gabbro next to the Raajärvi and Puro deposits suggest that intrusion of the gabbro took place at 2123±7 Ma and was accompanied by the formation of diopside skarn. The TIMS data on the metasomatic titanites related to sodic alteration yielded ages of 2062±3 and 2017±3 Ma. Iron was probably stripped from the mafic country rocks by sodic alteration between 2123 and 2017 Ma, driven by repeated brine influxes. Subsequently, the metal-rich brine was focused by a fault system and the iron was precipitated from this fluid by a combination of wall rock reaction, fluid mixing, and a drop in the temperature.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Log in via an institution

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Fig. 1a
Fig. 2
Fig. 3
Fig. 4
Fig. 5
Fig. 6
Fig. 7
Fig. 8
Fig. 9a
Fig. 10
Fig. 11
Fig. 12
Fig. 13a
Fig. 14
Fig. 15

Similar content being viewed by others

References

  • Adshead ND, Voulgaris P, Muscio VN (1998) Osborne copper-gold deposit. In: Berkman DA, Mackenzie DH (eds) Geology of Australian and Papua New Guinean mineral deposits. The Australian institute of mining and metallurgy, Melbourne, pp 793–799

    Google Scholar 

  • Baker T (1998) Alteration, mineralization and fluid evolution at the Eloise Cu–Au deposit, Cloncurry district, Northwestern Queensland, Australia. Econ Geol 93:1213–1236

    Google Scholar 

  • Barton MD, Johnson DA (1996) Evaporitic-source model for igneous-related Fe oxide-(REE-Cu–Au–U) mineralization. Geology (Boulder) 24:259–262

    Article  Google Scholar 

  • Bodnar RJ (1993) Revised equation and table for determining the freezing point depression of H2O–NaCl solutions. Geochim Cosmochim Acta 57:683–684

    Article  Google Scholar 

  • Bohlke JK, Irwin JJ (1992) Laser microprobe analyses of Cl, Br, I, and K in fluid inclusions: Implications for sources of salinity insome ancient hydrothermal fluids. Geochim Cosmochim Acta 56:81–95

    Article  Google Scholar 

  • Bowman JR (1998) Stable-isotope systematics of skarns. In: Lentz DR (ed) Mineralized intrusion-related skarn systems. Mineralogical Assoc Canada Short Course Ser 26:99–145

    Google Scholar 

  • Brothwick J, Harmon RS (1982) A note regarding CIF3 as an alternative to BrF5 for oxygen isotope analysis. Geochim Cosmochim Acta 46:1665–1668

    Article  Google Scholar 

  • Brown PE (1989) A microcomputer program for the reduction and investigation of fluid inclusion data. Am Mineralogist 74:1390–1393

    Google Scholar 

  • Clayton RN, Mayeda TK (1963) The use of bromine pentafluoride in the extraction of oxygen from oxides and silicates for isotopic analysis. Geochim Cosmochim Acta 27:43–52

    Article  Google Scholar 

  • Coplen TB, Kendall C, Hopple J (1983) Comparison of stable isotope reference samples. Nature 302:236–238

    Article  Google Scholar 

  • Davidson GJ, Large RR (1994) Gold metallogeny and the copper–gold association of the Australian Proterozoic. Mineralium Deposita 29:208–223

    Google Scholar 

  • Eilu P (1994) Hydrothermal alteration in volcano-sedimentary rocks in the central Lapland greenstone belt, Finland. Geological Survey of Finland, Bull 374:145

    Google Scholar 

  • Eilu P, Sorjonen-Ward P, Nurmi P, Niiranen T (2003) A review of gold mineralization styles in Finland. Econ Geol 98:1329–1353

    Article  Google Scholar 

  • Einaudi M, Burt DM (1982) Introduction; terminology, classification, and composition of skarn deposits. Econ Geol 77:745–754

    Article  Google Scholar 

  • Eugster HP, Chou I-M (1979) A model for deposition of Cornwall-type magnetite deposits. Econ Geol 74:763–774

    Google Scholar 

  • Frietsch R, Tuisku P, Martinsson O, Perdahl J-A (1997) Early Proterozoic Cu–(Au) and Fe ore deposits associated with regional Na–Cl metasomatism in northern Fennoscandia. Ore Geol Rev 12:1–34

    Article  Google Scholar 

  • Grant JA (1986) The isocon diagram—a simple solution to Gresens’ equation for metasomatic alteration. Econ Geol 81:1976–1982

    Article  Google Scholar 

  • Hanski E (2002) Vikajärvi. Geological map of Finland 1:100 000. Pre-Quaternary rocks, Sheet 3614. Geological Survey of Finland

    Google Scholar 

  • Hanski E, Perttunen V, Sorjonen-Ward P (1997) Overview of the geology of northern Finland. Geological Survey of Finland, Guide 43:7–9

    Google Scholar 

  • Hanski E, Huhma H, Vaasjoki M (2001) Geochronology of northern Finland: a summary and discussion. In: Vaasjoki M (ed) Radiometric age determinations from Finnish Lapland and their bearing on timing of Precambrian volcano-sedimentary sequences. Geological Survey of Finland, Special Paper 33:255–279

  • Helgeson HC, Delaney JM, Nesbit HW, Bird DK (1978). Summary and critique of the thermodynamic properties of rock-forming minerals. Am J Sci 278A:229

    Google Scholar 

  • Hemley JJ, Hunt JP (1992) Hydrothermal ore-forming processes in the light of studies in rock-buffered systems: II Some general geologic applications. Econ Geol 87:23–43

    Google Scholar 

  • Hemley JJ, Cygan GL, Fein JB, Robinson GR, D’Angelo WM (1992) Hydrothermal ore-forming processes in the light of studies in rock-buffered systems: I Iron–copper–zinc–lead sulfide solubility relations. Econ Geol 87:1–22

    Google Scholar 

  • Karhu JA (1993) Palaeoproterozoic evolution of the carbon isotope rations of sedimentary carbonates in the Fennoscandian Shield. Geological Survey of Finland, Bull 371:87

    Google Scholar 

  • Karhu JA, Holland HD (1996) Carbon isotopes and the rise of atmospheric oxygen. Geology 24:867–870

    Article  Google Scholar 

  • Kendrick MA, Burgess R, Pattrick RAD, Turner G (2001) Fluid inclusion noble gas and halogen evidence on the origin of Cu–Porphyry mineralising fluids. Geochim Cosmochim Acta 65:2651–2668

    Article  Google Scholar 

  • Krogh TE (1973) A low-contamination method for hydrothermal decomposition of U and Pb for isotopic age determinations. Geochim Cosmochim Acta 37:485–494

    Article  Google Scholar 

  • Lauerma R (1985) On the ages of some granitoid and schist complexes in northern Finland. Bull Geol Soc Finland 54:85–100

    Google Scholar 

  • Ludwig KR (1991) PbDat 1.21 for MS-dos: a computer program for IBM-PC compatibles for processing raw Pb–U–Th isotope data. Version 1.07. US. Geological Survey Open-File Report 35:88–542

    Google Scholar 

  • Ludwig KR (1998) Using Isoplot/Ex Version 1.00. Berkeley Geochronological Center. Special Publ 1:43

    Google Scholar 

  • Mänttäri I (1995) Lead isotope characteristics of epigenetic gold mineralization in the Palaeoproterozoic Lapland greenstone belt, northern Finland. Geological Survey of Finland, Bull 381:70

    Google Scholar 

  • Marschik R, Fontbote L (2001) The Candelaria-Punta del Cobre iron oxide Cu–Au(–Zn–Ag) deposits, Chile. Econ Geol 96:1799–1826

    Article  Google Scholar 

  • Mutanen T, Huhma H (2001) U–Pb geochronology of the Koitelainen, Akanvaara and Keivitsa mafic layered intrusion and realated rocks. In: Vaasjoki M (ed) Radiometric age determinations from Finnish Lapland and their bearing on the timing of Precambrian volcano-sedimentary sequences. Geological Survey of Finland, Special Paper 33:229–246

  • Niiranen T, Hanski E, Eilu P (2003) General geology, alteration, and iron deposits in Palaeoproterozoic Misi region, northern Finland. Geological Society of Finland, Bull 75:69–92

    Google Scholar 

  • Nuutilainen J (1968) On the geology of the Misi iron ore Province, northern Finland. Annales Academiae Scientiarum Fennicae Series A III. Geologica–Geographica 98

  • Oliver NHS, Cleverley JS, Mark G, Pollard PJ, Fu B, Marshall LJ, Rubenach MJ, Williams PJ, Baker T (2004) Modeling the role of sodic alteration in the genesis of iron oxide–copper–gold deposits; eastern Mt. Isa Block, Australia. Econ Geol 99:1145–1176

    Article  Google Scholar 

  • Pankka HS, Vanhanen EJ (1992) Early Proterozoic Au–Co–U mineralization in the Kuusamo district, northeastern Finland. Precambrian Res 58:387–400

    Article  Google Scholar 

  • Perring CS, Pollard PJ, Dong G, Nunn AJ, Blake KL (2000) The Lightning Creek Sill Complex, Cloncurry District, Northwestern Queensland: a source of fluids for the Fe oxide Cu–Au mineralization and sodic-calcic alteration. Econ Geol 95:1067–1089

    Article  Google Scholar 

  • Perttunen V (1985) On the Proterozoic stratigraphy and exogenic evolution of the Peräpohja area, Finland. In: Laajoki K, Paakkola J (eds) Proterozoic exogenic processes and related metallogeny. In: Proceedings of the symposium held in Oulu, Finland, August 15–16 1983. Geological Survey of Finland, Bull 331:131–141

  • Perttunen V, Vaasjoki M (2001) U–Pb geochronology of the Peräpohja Schist Belt, northwestern Finland. In: Vaasjoki M (ed) Radiometric age determinations from Finnish Lapland and their bearing on the timing of Precambrian volcano-sedimentary sequences. Geological Survey of Finland, Special Paper 33:45–84

  • Perttunen V, Hanski E, Väänänen J (1995) Stratigraphical map of the Peräpohja Schist Belt. 22nd Nordic Geological Winter Meeting, January 8–11 1996 Turku, Abstracts, p 152

  • Pollard PJ (2001) Sodic(-calcic) alteration in Fe–oxide–Cu–Au districts: an origin via unmixing of magmatic H2O–CO2–NaCl±CaCl2–KCl fluids. Mineralium Deposita 36:93–100

    Article  Google Scholar 

  • Ryan CG, Cousens DR, Heinrich CA, Griffin WL, Sie SH, Mernagh TP (1991) Quantitative PIXE microanalysis of fluid inclusions based on a layered yield model. Nucl Instr Meth Phys Res Section B 54:292–297

    Article  Google Scholar 

  • Ryan CG, Heinrich CA, Achterberg E, Van Ballhaus C, Mernagh TP (1995) Microanalyses of ore-forming fluids using the scanning proton microprobe. Nucl Instr Meth Phys Res Sect B 104:182–190

    Article  Google Scholar 

  • Ryan CG, McInnes BM, Williams PJ, Dong G, Win TT, Yeats CJ (2001) Imaging Fluid Inclusion Content using the New CSIRO-GEMOC. Nucl Instr Meth Phys Res Sect B 181:570–577

    Article  Google Scholar 

  • Shepherd TJ, Rankin, AH, Alderton DHM (1985) A practical guide to fluid inclusion studies. Blackie, London, p 239

    Google Scholar 

  • Sorjonen-Ward P, Nurmi P (1997) An overview of the tectonix setting and characteristics of gold mineralization in Finlland. In: Papunen H (ed) Research and exploration—where do they meet? Biennal Society for Geology Applied for Mineral Deposits Meeting, 4th, Turku, Finland, August 11–13, 1997, Proceedings, pp309–312

  • Sorjonen-Ward P, Nurmi P, Härkönen I, Pankka H (1992) Epigenetic gold mineralization and tectonic evolution of a lower Proterozoic greenstone terrain in the northern Fennoscandian (Baltic) Shield. In: Sarkar SC (ed) Metallogeny Related to Tectonics of the Proterozoic Mobile Belts. Oxford& IBH Publishing, New Delhi, pp 37–52

    Google Scholar 

  • Sorjonen-Ward P, Ojala VJ, Airo M-L (2003) Structural modelling and magmatic expression of hydrothermal alteration in the Paleoproterozoic Lapland greenstone belt, northern Fennoscandian Shield. In: Eliopoulos DG et al (eds) Mineral exploration and sustainable development. Proceedings of the Seventh Biennial SGA Meeting, Athens, Greece, 24–28. August 2003. Millpress, Rotterdam, pp 1107–1110

  • Sun S-S, McDonough WF (1989) Chemical and isotopic systematics of oceanic basalts: implications for mantle composition and processes In Magmatism in the ocean basins. Geol Soc Special Publ 42:313–345

    Google Scholar 

  • Sourirajan S, Kennedy GC (1962) The system H20–NaCl at elevated temperature pressures. Am J Sci 260:115–141

    Article  Google Scholar 

  • Vanhanen E (2001) Geology, mineralogy and geochemistry of the FeCo–Au–(U) deposits in the Paleoproterozoic Kuusamo Schist Belt, northeastern Finland. Geol Survey Finland, Bull 399:299

    Google Scholar 

  • Ward P (1987) Early Proterozoic deposition and deformation at the Karelian craton margin in southeastern Finland. Precambrian Res 35:71–93

    Article  Google Scholar 

  • Ward P, Härkönen I, Pankka HS (1989) Structural studies in the Lapland greenstone belt, northern Finland and their application to gold mineralization. Geol Survey Finland, Special Paper 10:71–78

    Google Scholar 

  • Whitehouse MJ, Claesson S, Sunde T, Vestin J (1997) Ion microprobe U–Pb zircon geochronology and correlation of Archaean gneisses from the Lewisian complex of Gruinard Bay, northwestern Scotland. Geochim Cosmochim Acta 61:4429–4438

    Article  Google Scholar 

  • Whitehouse MJ, 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. Chem Geol 160:201–224

    Article  Google Scholar 

  • Whitney JA, Hemley JJ, Simon FO (1985) The concentration of iron in chloride solutions equilibrated with synthetic granitic compositions; the sulfur-free system. Econ Geol 80:444–460

    Google Scholar 

  • Williams PJ (1994) Iron mobility during synmetamorphic alteration in Selwyn Range area, NW Queensland: implications for the origin of ironstone hosted Au–Cu deposits. Mineralium Deposita 29:250–260

    Article  Google Scholar 

  • Williams PJ, Skirrow RG (2000) Overview of Iron oxide–copper–gold deposits in Curnamona province and Cloncurry district (Eastern Mont Isa block), Australia. In: Porter TM (ed) Hydrothermal iron oxide copper–gold and related deposits: A global perspective. Australian Mineral Foundation, Adelaide, pp 105–122

    Google Scholar 

  • Williams PJ, Dong G, Ryan CG, Pollard PJ, Rotherham JF, Mernagh TP, Chapman LH (2001) Geochemistry of hypersaline fluid includions from the Starra (Fe oxide)-Au–Cu deposit Cloncurry district, Queensland. Econ Geol 96:875–883

    Article  Google Scholar 

  • Yardley BWD, Banks DA, Bottrell SH (1993) Post-metamorphic gold-quartz veins from N W Italy; the composition and origin of the ore fluid. Miner Mag 57:407–422

    Article  Google Scholar 

  • Yardley BWD, Banks DA, Barnicoat AC (2000) The chemistry of crustal brines: tracking their origins. In: Porter TM (ed) Hydrothermal iron oxide copper-gold and related deposits: a global perspective. Australian Mineral Foundation, Adelaide, pp 61–70

    Google Scholar 

  • Zheng Y-F (1993a) Calculation of oxygen isotope fractionation in anhydrous silicate minerals. Geochim Cosmochim Acta 57:1079–1091

    Article  Google Scholar 

  • Zheng Y-F (1993b) Calculation of oxygen isotope fractionation in hydroxyl-bearing silicates. Earth Planet Sci Lett 120:247–263

    Article  Google Scholar 

  • Zheng Y-F (1999) Oxygen isotope fractionation in carbonate and sulfate minerals. Geochem J 33:109–126

    Google Scholar 

  • Zheng Y-F, Simon K (1991) Oxygen isotope fractionation in hematite and magnetite: a theoretical calculation and application to geothermometry of metamorphic iron-formation. Eur J Mineral 3:877–886

    Google Scholar 

Download references

Acknowledgements

The authors wish to acknowledge the efforts of following persons: Dr Chris Ryan, Mrs Esme van Achterberg, Mr Akseli Torppa, Dr Pasi Eilu, Dr Bo Johanson, Dr Martin Whitehouse, Mr Lev Ilyinsky, and Ms Kerstin Lindèn. Reviews by Dr Robert Moritz and an anonymous reviewer are highly appreciated. The ion microprobe facility in Stockholm (Nordsims) is operated under an agreement between the joint Nordic research councils (NOS-N), the Geological Survey of Finland and the Swedish Museum of Natural History. This paper is Nordsims publication 119. Outokumpu Oyj foundation, Academy of Finland (Grant No. 202628), and an Australian Research Council Discovery Grant provided the financial support for this work.

Author information

Authors and Affiliations

  1. Department of Geology, University of Helsinki, P.O. Box 64, 00014, Helsinki, Finland

    Tero Niiranen & Matti Poutiainen

  2. Geological Survey of Finland, P.O. Box 96, 02151, Espoo, Finland

    Irmeli Mänttäri

  3. School of Earth Sciences, Economic Geology Research Unit, James Cook University, Townsville, 4811, Australia

    Nicholas H. S. Oliver

  4. Department of Geosciences, University of Cape Town, Rondebosch, 7700, Republic of South Africa

    Jodie A. Miller

  5. Department of Geology, University of Stellenbosch, Private Bag X1, Matieland, 7602, Republic of South Africa

    Jodie A. Miller

Authors
  1. Tero Niiranen
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Irmeli Mänttäri
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. Matti Poutiainen
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. Nicholas H. S. Oliver
    View author publications

    You can also search for this author in PubMed Google Scholar

  5. Jodie A. Miller
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to Tero Niiranen.

Additional information

Communicated by R. Moritz

Electronic Supplementary Material

Ion microprobe U-Pb age data on zircons from samples A1158 Matkavaara gabbro and A1695 Kielivaara felsic dyke, Misi.

(PDF 25 KB)

Rights and permissions

Reprints and permissions

About this article

Cite this article

Niiranen, T., Mänttäri, I., Poutiainen, M. et al. Genesis of Palaeoproterozoic iron skarns in the Misi region, northern Finland. Miner Deposita 40, 192–217 (2005). https://doi.org/10.1007/s00126-005-0481-0

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s00126-005-0481-0

Keywords

Search

Navigation