Genesis of Palaeoproterozoic iron skarns in the Misi region, northern Finland
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...
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ftjamescook:oai:researchonline.jcu.edu.au:4566 2024-02-11T10:03:47+01:00 Genesis of Palaeoproterozoic iron skarns in the Misi region, northern Finland Niiranen, Tero Mänttäri, Irmeli Poutiainen, Matti Oliver, Nicholas H.S. Miller, Jodie A. 2005-03 application/pdf https://researchonline.jcu.edu.au/4566/1/13320_Niiranen_et_al_2005.pdf unknown Springer http://dx.doi.org/10.1007/s00126-005-0481-0 https://researchonline.jcu.edu.au/4566/ https://researchonline.jcu.edu.au/4566/1/13320_Niiranen_et_al_2005.pdf Niiranen, Tero, Mänttäri, Irmeli, Poutiainen, Matti, Oliver, Nicholas H.S., and Miller, Jodie A. (2005) Genesis of Palaeoproterozoic iron skarns in the Misi region, northern Finland. Mineralium Deposita, 40 (2). pp. 192-217. restricted Article PeerReviewed 2005 ftjamescook https://doi.org/10.1007/s00126-005-0481-0 2024-01-22T23:22:39Z 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 ... Article in Journal/Newspaper Fennoscandian Northern Finland James Cook University, Australia: ResearchOnline@JCU Misi ENVELOPE(26.683,26.683,66.617,66.617) Raajärvi ENVELOPE(27.067,27.067,66.683,66.683) Mineralium Deposita 40 2 192 217 |
institution |
Open Polar |
collection |
James Cook University, Australia: ResearchOnline@JCU |
op_collection_id |
ftjamescook |
language |
unknown |
description |
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 ... |
format |
Article in Journal/Newspaper |
author |
Niiranen, Tero Mänttäri, Irmeli Poutiainen, Matti Oliver, Nicholas H.S. Miller, Jodie A. |
spellingShingle |
Niiranen, Tero Mänttäri, Irmeli Poutiainen, Matti Oliver, Nicholas H.S. Miller, Jodie A. Genesis of Palaeoproterozoic iron skarns in the Misi region, northern Finland |
author_facet |
Niiranen, Tero Mänttäri, Irmeli Poutiainen, Matti Oliver, Nicholas H.S. Miller, Jodie A. |
author_sort |
Niiranen, Tero |
title |
Genesis of Palaeoproterozoic iron skarns in the Misi region, northern Finland |
title_short |
Genesis of Palaeoproterozoic iron skarns in the Misi region, northern Finland |
title_full |
Genesis of Palaeoproterozoic iron skarns in the Misi region, northern Finland |
title_fullStr |
Genesis of Palaeoproterozoic iron skarns in the Misi region, northern Finland |
title_full_unstemmed |
Genesis of Palaeoproterozoic iron skarns in the Misi region, northern Finland |
title_sort |
genesis of palaeoproterozoic iron skarns in the misi region, northern finland |
publisher |
Springer |
publishDate |
2005 |
url |
https://researchonline.jcu.edu.au/4566/1/13320_Niiranen_et_al_2005.pdf |
long_lat |
ENVELOPE(26.683,26.683,66.617,66.617) ENVELOPE(27.067,27.067,66.683,66.683) |
geographic |
Misi Raajärvi |
geographic_facet |
Misi Raajärvi |
genre |
Fennoscandian Northern Finland |
genre_facet |
Fennoscandian Northern Finland |
op_relation |
http://dx.doi.org/10.1007/s00126-005-0481-0 https://researchonline.jcu.edu.au/4566/ https://researchonline.jcu.edu.au/4566/1/13320_Niiranen_et_al_2005.pdf Niiranen, Tero, Mänttäri, Irmeli, Poutiainen, Matti, Oliver, Nicholas H.S., and Miller, Jodie A. (2005) Genesis of Palaeoproterozoic iron skarns in the Misi region, northern Finland. Mineralium Deposita, 40 (2). pp. 192-217. |
op_rights |
restricted |
op_doi |
https://doi.org/10.1007/s00126-005-0481-0 |
container_title |
Mineralium Deposita |
container_volume |
40 |
container_issue |
2 |
container_start_page |
192 |
op_container_end_page |
217 |
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1790600117783363584 |