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  • 1.
    Alakangas, Lena
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Bark, Glenn
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Ericsson, Magnus
    Luleå University of Technology, Department of Business Administration, Technology and Social Sciences, Social Sciences.
    Martinsson, Olof
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Söderholm, Patrik
    Luleå University of Technology, Department of Business Administration, Technology and Social Sciences, Social Sciences.
    Wanhainen, Christina
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Weihed, Pär
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Widerlund, Anders
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Öhlander, Björn
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Norrbottens malm- och mineralresurs och dess potentiella betydelse för innovation, samhälle och miljö2014Report (Other academic)
    Abstract [sv]

    Gruvindustrins betydelse för samhällsutveckling och infrastruktur i Sverige och inte minst i Norrbottens län är mycket stor. De geologiska förutsättningarna att hitta nya brytvärda förekomster i Norrbotten är goda. Länet är tillsammans med Västerbotten en av Europas viktigaste regioner för utvinning av metaller. Det syns också i den nyligen framtagna regionala mineralstrategin för Norrbotten och Västerbotten. Visionen för den regionala mineralstrategin: ”Genom långsiktigt hållbart nyttjande av Norrbottens och Västerbottens läns mineralresurser har ytterligare tillväxt skapats i regionen och hela Sverige. Vi har utvecklat och stärkt vår ställning som ledande gruv- och mineralnation.”Eftersom framtidspotentialen för gruvnäringen är mycket god men okunnigheten hos både allmänhet och beslutsfattare om näringens betydelse för innovation och samhällsutveckling är stor, kopplat med en utbredd oro för miljöpåverkan, måste dessa viktiga framtidsfrågor belysas. Med finansiering från Länsstyrelsen i Norrbotten bedrevs därför under första hälften av 2014 en förstudie som syftade till att sammanfatta kunskapsläget om framtidens gruvindustri i Norrbotten. Resultaten av förstudien redovisas i den här rapporten. En viktig slutsats är att det under nästa strukturfondsperiod (med start 2015) behövs ett framtidsinriktat forskningsprogram för att belysa de möjligheter som finns. Denna förstudie utgör grund för en kommande ansökan till strukturfonderna. Kompetensen som finns vid Luleå tekniska universitet, Sveriges centrum för gruvrelaterad forskning och utbildning, bör användas för att studera troliga framtidsmöjligheter och hur de ska kunna användas för att få en så positiv utveckling som möjligt för länet. Projektet bör innehålla följande tre huvudinriktningar, som naturligtvis hör ihop:Vilka malm- och mineralresurser finns det potential för i Norrbotten, och vilka kommer sannolikt att exploateras i framtiden?Vad kommer den exploateringen att ha för betydelse för innovation och samhällsutveckling?Vad kommer den exploateringen att få för miljöeffekter och hur ska man göra för att minska miljöbelastningen?En annan slutsats är att nedlagda gruvområden inte måste ses som förstörd natur. Betydande mervärden som gruvturism skulle kunna skapas om vilja, kreativitet och beslutsamhet finns. Detta är ett givet utvecklingsområde där småföretag och entreprenörer kan göra stor insats om de politiska och myndighetsmässiga förutsättningarna finns. Dessa aspekter skulle också kunna belysas i det föreslagna forskningsprogrammet eller i ett eget projekt.

  • 2.
    Alakangas, Lena
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Sandström, Åke
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Rosenkranz, Jan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Martinsson, Olof
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Hällström, Lina
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Project: Improve Resource Efficiency and Minimize Environmental Footprint2016Other (Other (popular science, discussion, etc.))
    Abstract [en]

    The REMinE project is organized in five work packages that comprise: detailedcharacterization and risk assessment of the mine wastes selected (WP2), identification of new processing methods for mine waste (WP3), characterization and risk assessment of the remaining residuals (WP4), outlining business opportunities and environmental impact in a conceptual model for sustainable mining (WP5). The project comprises case studies of historical mine wastes from three different European countries, namely Portugal, Romania and Sweden. The interdisciplinary research collaboration in this project is innovative in the sense that separation of minerals and extraction of metals not only are basedon technical and economic gain but also considers the environmental perspective.

  • 3.
    Allen, Rodney
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Martinsson, OlofWeihed, Pär
    Svecofennian Ore-Forming Environments Field Trip Volcanic-associated Zn-Cu-Au-Ag and magnetite-apatite, sediment-hosted Pb-Zn, and intrusion-associated Cu-Au deposits in northern Sweden2004Collection (editor) (Other academic)
  • 4.
    Andersson, Joel B.H.
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Bauer, Tobias E.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Martinsson, Olof
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Wanhainen, Christina
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    The tectonic overprint on the Per Geijer apatite iron ores in Kiruna, northern Sweden2017In: Mineral Resources to Discover / [ed] Mercier Langevin, P; Dube, B; Bardoux, M; Ross, PS; Dion, C, Society for Geology Applied to Mineral Deposits , 2017, p. 903-906Conference paper (Refereed)
    Abstract [en]

    This ongoing project focusses on the structural evolution of the Per Geijer apatite iron ores in Kiruna, northern Sweden. The Per Geijer iron ores are situated in a NNE-SSW trending shear zone. This study indicate that the shear zone was active during D2 E-W compression giving rise to dip-slip and oblique slip components. The ductile fabric is overprinted by brittle structures carrying Cu, possibly representing traces of a separate Iron Oxide Copper Gold event in northern Norrbotten.

  • 5.
    Bergman, Stefan
    et al.
    Sveriges Geologiska Undersökning.
    Kubler, Lutz
    Sveriges Geologiska Undersökning.
    Martinsson, Olof
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Synthesis bedrock maps of northern Norrbotten, Sweden1998In: Abstracts volume: 23. Nordiske Geologiske Vintermøde, 13-16 January, Århus, 1998 / [ed] J. Richard Wilson, Århus: Århus university , 1998, p. 31-Conference paper (Other academic)
  • 6.
    Bergman, Stefan
    et al.
    Geological Survey of Sweden.
    Weihed, Pär
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Martinsson, Olof
    Eilu, Pasi
    Geological Survey of Finland.
    Geological and tectonic evolution of the northernpart of the Fennoscandian Shield2007In: Metallogeny and tectonic evolution of the Northern Fennoscandian Shield: field trip guidebook, Espoo: Geological Survey of Finland , 2007, p. 6-15Chapter in book (Other academic)
  • 7.
    Billström, K.
    et al.
    Dep. of Geological Sciences, Swedish Museum of Natural History, Stockholm, Sweden.
    Evins, P.
    WPS Consulting Group, Stockholm, Sweden.
    Martinsson, Olof
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Jeon, H.
    Dep. of Geological Sciences, Swedish Museum of Natural History, Stockholm, Sweden.
    Weihed, Pär
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Conflicting zircon vs. titanite U-Pb age systematics and the deposition of the host volcanic sequence to Kiruna-type and IOCG deposits in northern Sweden, Fennoscandian shield2019In: Precambrian Research, ISSN 0301-9268, E-ISSN 1872-7433, Vol. 321, p. 123-133Article in journal (Refereed)
    Abstract [en]

    The Northern Norrbotten region, and in particular the Kiruna area, hosts a number of large apatite iron oxide deposits (e.g. the huge Kiirunavaara ore) of significant economic importance. Age data from rock lithologies hosting these ores, represented by metamorphosed rocks of the Porphyrite and Kiirunavaara Groups, are complex to interpret. This is illustrated by (LA-ICP-MS) data for titanite, and to some extent for rutile, which scatter considerably yielding ages within a span from ca. 2.1 Ga to 1.7 Ga. These analysed hydrothermal minerals, characterized by complex BSE images revealing darker and brighter zones, are located in ore zones and associated with e.g. strong scapolitisation, albitisation and actinolitisation. Previous (TIMS) zircon ages of host rocks, on the other hand, define a more narrower age interval between ca. 1900 and 1870 Ma, and this is supported by new U-Pb zircon results presented here. Furthermore, one coherent set of SIMS data for titanite from the Luossavaara ore favour that crystallization took place at ca 1.88 Ga, although laser ICP data from the same locality are much more complex. An implication arising from published pre-1.9 Ga laser ablation ages for titanites is that the emplacement of host rocks started already at around 2.1 Ga. As the depositional time of these rocks is crucial for the understanding of the overall crustal formation in northern Norrbotten, additional rocks were selected for age dating. New zircon age data (LA-ICP-MS and SIMS) give support to a scenario where host rocks to ores started to develop at around 1900 Ma and this calls for a re-evaluation of published LA-ICP-MS data of hydrothermal mineral phases.

    Here, we present four models that aim to explain how pre-1.9 Ga titanite ages, believed to have a questionable geological significance, may develop. The principal idea is that ≤2.1 Ga alteration events were not responsible for the crystallization of the hydrothermal minerals, instead it is believed that apparent old age domains carry excess radiogenic lead due to the effect of ≤1.9 Ga hydrothermal processes. Currently, the interpretation of U-Pb isotope data in the study area remains enigmatic, and further radiometric analyses are required.

  • 8.
    Billström, Kjell
    et al.
    Swedish Museum of Natural History.
    Bergman, Stefan
    Geological Survey of Sweden.
    Martinsson, Olof
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Post-1.9 Ga metamorphic, mineralization and hydrothermal events in northern Sweden2002In: GFF, ISSN 1103-5897, E-ISSN 2000-0863, Vol. 124, no 4, p. 228-228Article in journal (Refereed)
  • 9.
    Billström, Kjell
    et al.
    Museum of Natural History.
    Eilu, Pasi
    Geological Survey of Finland.
    Martinsson, Olof
    Niiranen, Tero
    Geological Survey of Finland.
    Broman, Curt
    Stockholm University.
    Weihed, Pär
    Wanhainen, Christina
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Ojala, Juhani
    Geological Survey of Finland.
    IOCG and related mineral deposits of the northern Fennoscandian Shield2011In: Hydrothermal iron oxide copper-gold & related topics: a global perspective, Adelaide: PGC Publishing , 2011, p. 381-414Chapter in book (Other academic)
    Abstract [en]

    The northernmost Fennoscandian shield comprises Archaean and Palaeoproterozoic rocks. Unlike most other shield areas, economic mineral deposits are largely restricted to its Palaeoproterozoic parts. The latter are characterised by intracratonic basin evolution between ca. 2.5 and 2.0 Ga, involving recurrent mantle hotspot activity with numerous layered intrusions, komatiite and picrite eruptions, but no signs of accretionary phases or formation of major new felsic crust. Accretion and continent-continent collision followed from ca. 1.9 to 1.8 Ga, during the Svecofennian orogeny. A range of mineralisation styles are hosted by extensive ca. 2.5 to 2.0 Ga greenstone belts and younger, subduction-related 1.9 to 1.8 Ga Svecofennian intrusive and extrusive settings. These mineralisation styles partially overlap, and individual deposits may not readily be placed into genetic classification schemes. A provisional grouping of observed mineralisation styles comprises (1) stratiform-stratabound sulphide, (2) apatite-iron, (3) skarn-related iron and BIF, and (4) epigenetic(±syngenetic?) Au and Cu-Au deposits. The descriptive section of this paper also highlights features that may relate to orogenic-gold, IOCG and 'atypical metal association' categories of mineralisation. The assumption made is that the deposition of a diverse range of ore deposits was made possible by a long and complex geological evolution. This involved an initial (sowing) stage where iron, and to some extent copper and gold, were concentrated during 2.3 to 2.1 Ga (Karelian) rock-forming processes. Following this, ore elements were mobilised during two younger (Svecofennian) stages at 1.92 to 1.87 and 1.85 to 1.79 Ga, respectively. The latter were triggered by metamorphic and magmatic episodes, and fluids liberated during these stages precipitated IOCG and related deposits when fluids met structural and chemical traps in suitable host rocks. Ore fluids are generally saline, and their development probably involved incorporation of evaporates and, at least locally, also felsic magmatism may have played a role. Skarn-related mineralisation, hosted by ca. 2.1 Ga greenstones, occurs both as a BIF type in Sweden (formed at around 2.1 Ga), and as a gold-copper enriched variety (the result of Svecofennian epigenetic processes) in the Kolari region of Finland. The huge Kiirunavaara deposit is the type example of apatite iron ores, and is here considered to have formed from a magma at ca. 1.88 Ga, although it also has features best explained by a magmatic-hydrothermal overprint. A younger, less prominent, stage of apatite iron ore formation took place at approximately 1.78 Ga. Epigenetic gold and copper-gold deposits are particularly hard to classify as these show mixed ore characteristics, and to some extent this is likely to be due to multiple mineralisation stages (cf. the huge, low grade Aitik deposit in Sweden which is interpreted to be a hybrid porphyry-IOCG-type of ore). Structurally controlled, orogenic-gold mineralisation is common in the Central Lapland greenstone belt, although there are also gold deposits with enhanced contents of e.g., copper, cobalt and uranium (e.g., at Saatopoora). The latter, sometimes referred to as being of an 'atypical metal association' type, could potentially also include syngenetic mineralisation (e.g., at Juomasou). The range of epigenetic (±syngenetic) gold and copper-gold deposits could possibly be related to a vague east-west trend defined by gold-rich deposits in the east (Finland), followed by IOCG (copper±gold) and more iron-dominant ore types near the Finnish-Swedish border and further west into Sweden.

  • 10.
    Broman, Curt
    et al.
    Stockholms Universitet.
    Martinsson, Olof
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Fluid inclusions in epigenetic Fe-Cu-Au ores in northern Norrbotten2000In: Abstract volume & Field trip guidebook / [ed] Pär Weihed; Olof Martinsson, Luleå: Luleå tekniska universitet, 2000, p. 7-Conference paper (Other academic)
  • 11. Denisova, Nikola
    et al.
    Allan, Åsa
    Martinsson, Olof
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Sulfide distribution and its relation to different types of skarn alteration at the Tapuli deposit, northern Sweden2013In: Mineral deposit research for a high-tech world: proceedings / [ed] Erik Jonsson, Uppsala: Sveriges Geologiska Undersökning , 2013, p. 1539-1542Conference paper (Refereed)
    Abstract [en]

    The Tapuli deposit is a skarn iron ore located in the Pajala municipality in Northern Sweden. It is situated at the margin of the Karelian craton, at the stratigraphic contact between Karelian and Svecofennian rocks. The ore forms stratabound lenses concordant with the metasedinnentary sequences and dips 45 - 60 degrees towards NW. Footwall rocks are dolomitic marbles, phyllites and graphitic phyllites; the hanging wall comprises phyllites and quartzites. Mafic dykes and sills crosscut the stratigraphic succession. Magnetite is the only ore mineral. The skarn minerals are serpentine, diopside, tremolite and actinolite. The skarn altered rocks show a zonation with serpentine skarn closest to or as part of the ore, thereafter, tremolite-diopside skarn and, finally, actinolite skarn closest to the phyllites and quartzites in the hanging wall. Sulfides occur in minor amounts, but their content generally increases with proximity to the footwall rocks. The dolomitic marble was the precursor of the serpentine and tremolite-diopside skarn. Immobile element data suggests that mafic dykes and sills were the precursors of the actinolite skarn. Possible controls of the sulfide distribution are the presence of sulfide-bearing source rocks (dolomitic marble, graphitic phyllite) and rennobilization of sulfides during the intrusion of mafic dykes.

  • 12. Edfelt, Åsa
    et al.
    Armstrong, Robin N.
    Natural History Museum, London.
    Smith, Martin
    University of Brighton.
    Martinsson, Olof
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Alteration paragenesis and mineral chemistry of the Tjårrojåkka apatite-iron and Cu (-Au) occurrences, Kiruna area, northern Sweden2005In: Mineralium Deposita, ISSN 0026-4598, E-ISSN 1432-1866, Vol. 40, no 4, p. 409-434Article in journal (Refereed)
    Abstract [en]

    The northern Norrbotten area in northern Sweden, is an important mining district and hosts several deposits of Fe-oxide Cu-Au-type. One of the best examples of spatially, and possibly genetically, related apatite-iron and copper-gold deposits in the region is at Tjårrojåkka, 50 km WSW of Kiruna. The deposits are hosted by strongly sheared and metamorphosed intermediate volcanic rocks and dolerites and show a structural control. The Tjårrojåkka iron deposit is a typical apatite-iron ore of Kiruna-type and the Tjårrojåkka copper occurrence shows the same characteristics as most other epigenetic deposits in Norrbotten. The host rock has been affected by strong albite and K-feldspar alteration related to mineralisation, resulting in an enrichment of Na, K, and Ba. Fe and V were depleted in the altered zones and added in mineralised samples. REE were enriched in the system, with the greatest addition related to mineralisation. Y was also mobile associated with albite alteration and copper mineralisation. The Tjårrojåkka iron and copper deposits show comparable hydrothermal alteration minerals and paragenesis, which might be a product of common host rock and similarities in ore fluid composition, or overprinting by successive alteration stages. Mineralogy and mineral chemistry of the alteration minerals (apatite, scapolite, feldspars, amphiboles, and biotite) indicate a higher salinity and Ba/K ratio in the fluid related to the alterations in the apatite-iron occurrence than in the copper deposit, where the minerals are enriched in F and S. The presence of hematite, barite, and in SO4 in scapolite suggests more oxidising-rich conditions during the emplacement of the Tjårrojåkka-Cu deposit. From existing data it might be suggested that one evolving system created the two occurrences, with the copper mineralisation representing a slightly later product.

  • 13. Edfelt, Åsa
    et al.
    Broman, C.
    Martinsson, Olof
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    A preliminary fluid inclusion study of the Tjårrojåkka IOCG-occurrence, Kiruna Area, northern Sweden2004In: The 26th Nordic Geological Winter Meeting: abstract volume / [ed] Joakim Mansfeld, Uppsala: Geological Society of Sweden , 2004, p. 148-Conference paper (Refereed)
  • 14. Edfelt, Åsa
    et al.
    Martinsson, Olof
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Fennoscandian Shield: iron oxide-copper-gold deposits. Tjårrojåkka, northern Sweden: Lat 67° 40′ N, Long. 19° 10′ E2005In: Ore Geology Reviews, ISSN 0169-1368, E-ISSN 1872-7360, Vol. 27, no 1-4, p. 328-329Article in journal (Refereed)
  • 15. Edfelt, Åsa
    et al.
    Martinsson, Olof
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    The Tjårrojåkka Fe-oxide and Cu-Au occurrences northern Sweden: products of one ore forming event?2004Conference paper (Other academic)
  • 16. Edfelt, Åsa
    et al.
    Martinsson, Olof
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    The Tjårrojåkka Fe-oxide Cu(-Au) occurrence, Kiruna area, northern Sweden2003In: Mineral Exploration and Sustainable Development: proceedings of the Seventh Biennial SGA Meeting, Athens, Greece, 24-28 August 2003 / [ed] D.G. Eliopoulos, Rotterdam: Millpress , 2003, p. 1069-1071Conference paper (Refereed)
  • 17. Edfelt, Åsa
    et al.
    Sandrin, Alessandro
    Luleå tekniska universitet.
    Evins, Paul
    EGRU, School of Earth Sciences, James Cook University.
    Jeffries, Teresa
    Natural History Museum, London.
    Storey, Craig
    Open University, Walton Hall, Milton Keynes.
    Elming, Sten-åke
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Martinsson, Olof
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Stratigraphy and tectonic setting of the host rocks to the Tjårrojåkka Fe-oxide Cu-Au deposits, Kiruna area, northern Sweden2006In: GFF, ISSN 1103-5897, E-ISSN 2000-0863, Vol. 128, no 3, p. 221-232Article in journal (Refereed)
    Abstract [en]

    The Tjårrojåkka area is located about 50 km WSW of Kiruna, northern Sweden, and hosts one of the best examples of spatially and possibly genetically related Fe-oxide and Cu-Au occurrences in the area. The bedrock is dominated by intermediate and basic extrusive and intrusive rocks. An andesite constrains the ages of these rocks with a U-Pb LA-ICPMS age of 1878±7 Ma. They are cut by dolerites, which acted as feeder dykes for the overlying basalts. Based on geochemistry and the obtained age the andesites and basaltic andesites can be correlated with the 1.9 Ga intermediate volcanic rocks of the Svecofennian Porphyrite Group in northern Sweden. They formed during subduction-related magmatism in a volcanic arc environment on the Archaean continental margin above the Kiruna Greenstone Group. Chemically the basalts and associated dolerites have the same signature, but cannot directly be related to any known basaltic unit in northern Sweden. The basalts show only minor contamination of continental crust and may represent a local extensional event in a subaquatic back arc setting with extrusion of mantle derived magma. The intrusive rocks range from gabbro to quartz-monzodiorite in composition. The area is metamorphosed at epidote-amphibolite facies and has been affected by scapolite, K-feldspar, epidote, and albite alteration that is more intense in the vicinity of deformation zones and mineral deposits. Three events of deformation have been distinguished in the area. D1 brittle-ductile deformation created NE-SW-striking steep foliation corresponding with the strike of the Tjårrojåkka-Fe and Cu deposits and was followed by the development of an E-W deformation zone (D2). A compressional event (D3), possible involving thrusting from the SW, produced folds in the central part of the area and a NNW-SSE striking deformation zone in NE.

  • 18. Edfelt, Åsa
    et al.
    Smith, M.
    University of Brighton.
    Armstrong, R.N.
    Natural History Museum, London.
    Martinsson, Olof
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Apatite chemistry - a potential tool for IOCG exploration2006In: The 27th Nordic Geological Winter Meeting, January 9-12, 2006, Oulu, Finland: abstract volume / [ed] Petri Peltonen ; Antti Pasanen, Helsinki: Geological Society of Finland , 2006, p. 29-Conference paper (Other academic)
    Abstract [en]

    Northern Norrbotten is an important mining region of Sweden and is regarded as an iron-oxide copper-gold (IOCG) district hosting several apatite-iron oxide and copper-gold sulphide ores (e.g. Hitzman et. al., 1992). The IOCG group of deposits is diverse with respect to age, host rock, ore and alteration mineralogy as well as ore-forming processes and there is still an ongoing debate regarding a possible genetic link between "classical" Kiruna type ores and copper dominated end-members within this class of deposits. Apatites from Kiruna-type apatite-iron deposits (Kiirunavaara, Rektorn, Nukutus, Ekströmsberg, Tjårrojåkka-Fe), IOCG copper occurrences (Tjårrojåkka-Cu and Nautanen), a 1.89 Ga andesite and a Perthite-monzonite group intrusion were collected and analysed for their mineral chemistry and rare earth elements using electron microprobe and LA-ICPMS analysis. The apatite chemistry can subsequently be used as an indicator of the composition of fluids involved in the formation of the deposits (Korzhinskiy, 1982). Different trends with regard to F-Cl content as well as REE pattern in the apatites were observed for apatite-iron ores with no spatial relation to copper mineralisation compared to the apatite-iron ore spatially related to a copper occurrence. The apatites from the former were almost pure F-apatites with steep REE patterns, while the apatites from the latter and the copper mineralisations themselves contained a large Cl-component and showed depletion in LREE.It can be concluded that apatite chemistry could be a potential tool for distinguishing copper mineralising apatite-iron systems from barren ones. However, so far only one apatite-iron deposit spatially related to a copper occurrence has been studied and more studies are needed to confirm the results.

  • 19.
    Eilu, Pasi
    et al.
    Geological Survey of Finland.
    Martinsson, Olof
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Epigenetic au and cu-au deposits2007In: Metallogeny and tectonic evolution of the Northern Fennoscandian Shield: field trip guidebook, Espoo: Geological Survey of Finland , 2007, p. 22-25Chapter in book (Other academic)
  • 20.
    Elming, Sten-åke
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Moakhar, Mohsen Oveisy
    Razi University, Kermanshah.
    Martinsson, Olof
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    A palaeomagnetic and geochemical study of basic intrusions in northern Sweden2004In: GFF, ISSN 1103-5897, E-ISSN 2000-0863, Vol. 126, no 2, p. 243-252Article in journal (Refereed)
    Abstract [en]

    A palaeomagnetic and geochemical study has been performed on basic dykes in northern Sweden. The dykes and a gabbro formation were sampled in 28 sites and characteristic magnetizations could be defined in 23 of them. The dykes form a part of a swarm that trends in NE-SW to E-W. From differences in palaeomagnetic signatures and composition it is concluded that this swarm is composed of two generations of dykes, group A and B, trending in similar directions. The dykes of group A have compositions that are similar to rapakivi related dykes, while those of group B are different from most rapakivi dykes in Fennoscandia. The calculated pole positions may suggest that the group B dykes are older than those of group A and both groups intruded within the time span 1.77 Ga to 1.50 Ga. The trend of the dykes is more or less parallell to a palaeo-compressional stress field that may be expected from the collisional tectonics related to the Gothian orogeny. The intrusion of the rapakivi formations in Fennoscandia has been suggested to be related with the Gothian orogeny and the intrusion of the dykes may thus be guided by the stress field generated by the collisional tectonics.

  • 21.
    Frietsch, Rudyard
    et al.
    Luleå tekniska universitet.
    Tuisku, Pekka
    Martinsson, Olof
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Perdahl, Jan-Anders
    Luleå tekniska universitet.
    Early Proterozoic Cu-(Au) and Fe ore deposits associated with regional Na-Cl metasomatism in northern Fennoscandia1997In: Ore Geology Reviews, ISSN 0169-1368, E-ISSN 1872-7360, Vol. 12, no 1, p. 1-34Article in journal (Refereed)
    Abstract [en]

    Scapolite is widely distributed in 1.9-2.5 Ga volcano-sedimentary rocks and 1.77-2.2 Ga igneous rocks over several hundred square kilometres in northern Fennoscandia, comprising northern Sweden, northern Finland and adjacent parts of Norway and Russia. This region is one of the largest scapolite-bearing Precambrian terranes in the world. Albitization, and to a lesser extent carbonatization, phyllic and tourmaline alteration, are spatially associated with scapolite. A number of epigenetic Cu-(Au) sulphide and Fe oxide deposits in northern Fennoscandia show a spatial and genetic relationship to this type of alteration, mainly scapolitization and albitization. The main metal occurrences are in 2.0-2.5 Ga mafic volcanics and sediments of the Lapponian Greenstone group and in 1.9 Ga intermediate-composition volcanic and volcaniclastic rocks of the Svecofennian Porphyry group. The scapolite is mainly a dipyre-mizzonite with Cl and CO3 and small amounts of SO4 and F, indicating high Na and Cl activity at the time of crystallization. Fluid inclusion data of the Lapponian Pahtohavare and similar Cu-Au deposits indicate formation temperatures of about 300°C and ore deposition from highly saline aqueous solutions. The deposition of copper and gold was in places regulated by a redox barrier; graphite in associated schists controlled the reduction reactions of the ore fluids and metals were precipitated. The Lapponian and Svecofennian sulphide deposits contain tourmaline of the schorl-dravite series. Aitik-Nautanen Cu-(Au) style deposits and in particular some deposits with vein-style iron ore, contain dravite-schorl deficient in Al and enriched in Fe3+, which is due to Fe-Al substitution in an oxidizing, relatively iron-rich environment. Scapolite and, probably also tourmaline, formed by a complex, multistage process. The source of the components in scapolite may have been evaporitic sequences or high salinity brines in Lapponian rift basins that contain 2.0-2.5 Ga mafic volcanics. During low to medium-grade (low P) regional metamorphism, the components that formed scapolite and tourmaline were mobilized and transported to their present positions in several metasomatic phases. Fault zones with fractures and breccias channeled the fluids, resulting in locally developed intense alteration. Gold and copper was transported by saline, high fO2, high temperature solutions as metal-chloride complexes. The ultimate source of fluids and heat sources is uncertain, but deep-seated crustal magmatic processes seem prerequisite. The alteration occurred mainly around 1.9 Ga at the peak of the main regional metamorphism and the intrusion of granitoids through to around 1.8 Ga. Cu-(Au) sulphide and Fe oxide ore deposits associated with large-scale scapolite-forming metasomatic processes are found elsewhere in the world (e.g., Australia, Kazakhstan, Russia) and show similarities with the Cu-(Au) deposits in northern Fennoscandia. However, the close genetic connection between scapolite-albite and ore formation of Fennoscandian deposits is not a common feature in other belts

  • 22.
    Hällström, Lina
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Alakangas, Lena
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Martinsson, Olof
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Geochemical characterization of W, Cu and F skarn tailings at Yxsjöberg, Sweden2018In: Journal of Geochemical Exploration, ISSN 0375-6742, E-ISSN 1879-1689, Vol. 194, p. 266-279Article in journal (Refereed)
    Abstract [en]

    Little attention has been paid to tailings from skarn ore deposits and their environmental impact, even though they can contain elevated concentrations of elements of potential concern together with sulfides and fluorite. Historical skarn tailings at Yxsjöberg, Sweden, containing e.g. Be, Bi, Cu, F, Sn, S, W, and Zn were geochemically characterized as a first step to evaluate the environmental impact and the potential to re-mine the tailings. The tailings were deposited between 1897 and 1963 in the Smaltjärnen Repository without dams or a complete cover, and have been in contact with the atmosphere for >30 years. Four vertical cores throughout the tailings were taken and divided into 134 subsamples, which were analyzed for total concentrations and paste pH. Selected samples from different depths were mineralogically characterized using optical microscopy, scanning electron microscopy (SEM) with energy dispersive X-ray spectroscopy (EDS), Raman vibrational spectroscopy, and X-ray diffraction (XRD). Minerals, hand-picked from drilled rock cores, were analyzed for the element content, and a modified Element to Mineral Conversion (EMC) that pinpoints the quantitative distribution of elements between the minerals in the tailings was carried out. The average concentrations of Be, Bi, Cu, Sn, Zn, W, F and S in the tailings were 284, 495, 946, 559, 301, and 960 ppm, and 1.9 and 1.2 wt%, respectively. The tailings has reached a late stage development due to pyrrhotite oxidation resulting in low pH (<4) in the uppermost tailings, and formations of secondary minerals such as gypsum, hydrous ferric oxides (HFO) and orthogonal calcite. Secondary pyrite and magnetite, formed from monoclinic pyrrhotite was detected, and different weathering rates of secondary pyrite, hexagonal and monoclinic pyrrhotite was indicated, with secondary pyrite as the most stable and monoclinic pyrrhotite as the least. The rare and easily-weathered mineral danalite (Fe4Be3(SiO4)3S) was found in the drilled rock cores and by XRD in the tailings. However, the mineral could not be found by optical microscopy or SEM-EDS. This suggests that the mineral has been weathered to a great extent, which poses a high risk of releasing elements of potential concern to the groundwater since danalite contains approximately 40% of the total Be and Zn concentrations in the tailings. Fluorine was mainly found in fluorite, Cu in chalcopyrite, and Bi in bismuthinite; which all showed signs of weathering in acidic condition in the uppermost part, subsequent with decreased concentrations, followed by accumulation peaks deeper down in the tailings correlated with Al. Tungsten was mainly found in scheelite; most grains were unweathered, but a few grains had altered rims or HFO on the mineral surfaces. Tin was mainly found in ferrohornblende, hedenbergite and grossular. Beryllium, Cu, F, and Zn has high potential to be released to the surrounding environment from the Smaltjärnen Repository, while W, Bi and Sn are relatively stable in the tailings. Most of the scheelite is intact and re-mining could, therefore, be a suitable remediation method that would both reduce the environmental impact and simultaneously support the supply of critical raw materials in the EU.

  • 23.
    Hällström, Lina
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Alakangas, Lena
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Martinsson, Olof
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Metal Release from Acidic and Near-Neutral pH-Conditions in Historical W, Cu and F Skarn Tailings at Yxsjöberg, Sweden2018In: 11th ICARD | IMWA | WISA MWD 2018 Conference: Risk to Opportunity / [ed] Wolkersdorfer, Ch.; Sartz, L.; Weber, A.; Burgess, J.; Tremblay, G., 2018, Vol. 1, p. 351-356Conference paper (Refereed)
    Abstract [en]

    Weathering products stored in the pore water and/or as easily soluble salts in historical skarn tailings containing Be, Bi, Cu, W, and Zn, were released in water soluble fraction in the upper-most acidic tailings, at the visual oxidation front (1.5m), and/or below 2.5m (pH>7). Thus, there is a risk that these metals can pollute receiving waters by neutral mine drainage. Re-mining the tailings could be a suitable remediation method that would both reduce the environmental impact and simultaneously support the supply of metals.

  • 24.
    Hällström, Lina, P.B
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Alakangas, Lena
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Martinsson, Olof
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Scheelite Weathering and Tungsten (W) Mobility in Historical Oxidic-Sulfidic Skarn Tailings at Yxsjöberg, SwedenManuscript (preprint) (Other academic)
  • 25.
    Kontturi, Monika
    et al.
    Boliden AB.
    Martinsson, Olof
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Gold in the Aitik Cu-Au deposit, Gellivare area, Northern Sweden2000In: Abstract volume & Field trip guidebook / [ed] Pär Weihed; Olof Martinsson, Luleå: Luleå tekniska universitet, 2000, p. 22-Conference paper (Other academic)
  • 26.
    Lindblom, S.
    et al.
    Department of Geology and Geochemistry, Stockholm University.
    Broman, C.
    Department of Geology and Geochemistry, Stockholm University.
    Martinsson, Olof
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Magmatic-hydrothermal fluids in the Pahtohavare Cu-Au deposit in greenstone at Kiruna, Sweden1996In: Mineralium Deposita, ISSN 0026-4598, E-ISSN 1432-1866, Vol. 31, no 4, p. 307-318Article in journal (Refereed)
    Abstract [en]

    The Proterozoic Pahtohavare Cu-Au deposit is located in the greenstone belt near Kiruna, northern Sweden. The greenstone consists of mafic volcanic rocks with pillow lavas, mafic sills and albitized rocks, including tuffites, black schists and mafic sills, together with carbonates and mineralized zones. Mineralization occurs as impregnations, epigenetic quartz-rich breccias and fracture fillings with pyrite, chalcopyrite, pyrrhotite and gold in a complex tectonic environment. Fluid inclusions indicate an early formation of quartz and pyrite at temperatures initially near 500°C and a pressure of 2-2.4 kbar from a supersaturated aqueous solution of magmatic origin. In addition to halite cubes, daughter minerals of sylvite, calcite, hematite, graphite and two unknown phases are found. The main stage of chalcopyrite and gold deposition is characterized by aqueous fluids of variable salinity (up to 30 eq. wt.% NaCl including CaCl2), at temperatures below 350°C and pressures between 1 and 2 kbar. A minor CO2 phase with some N2 accompanies this stage. Gold was transported as a chloride complex which destabilized due to an increase in pH (as a consequence of the CO2 loss) as well as cooling and dilution of the solution. The ore deposition occurred as a result of mixing with a low salinity aqueous solution during tectonic fracturing with pressure fluctuations and CO2 unmixing. Late oxidation of ores was caused by low to moderately saline (3 to 13 eq. wt.% NaCl) low temperature aqueous solutions.

  • 27.
    Lindblom, S.
    et al.
    University of Stockholm, Department of Geological Sciences Ore Research Group.
    Martinsson, Olof
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Fluids associated with Cu-Au mineralization in the Kiruna greenstone belt at Viscaria and Pahtohavare, northern Sweden1991In: Greenstone gold and crustal evolution: NUNA conference volume : Proceedings of a workshop held at Val d'Or, Québec, May 24-27, 1990 / [ed] Francois Robert; Patricia A. Sheahan; Stephen B. Green, St. Johns, Nfld: Geological and Mineralogical Association of Canada, 1991Conference paper (Refereed)
  • 28.
    Lund, Cecilia
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Martinsson, Olof
    A characterising of the ore minerals due to mineralogical, chemical and textural properties in Malmberget2008In: Conference in Minerals Engineering 2008, Luleå: Luleå tekniska universitet, 2008, p. 71-80Conference paper (Other academic)
    Abstract [en]

    This study was an attempt to find a way of characterising an iron ore body both mineralogical and textural in a quantitative manner by using analytical methods like optical microscopy, microprobe (EMPA) and an automatic SEM based system, Particle Texture Analysis (PTA). The source of this study is an iron ore body, called Fabian, located in Malmberget, Sweden. Two types of ores were identified and analysed in this study named "orebreccia" and "ore". The Particle Texture Analysis was made on two fractions of crushed ore. The mineralogy was evaluated and characterized as mineral liberation and mineral association. Magnetite has a simple outline and straight grain boundaries and the gangue minerals have a finer particle size with a more complicated texture. The liberation of magnetite in "ore" and "ore breccia" is high. The ore quality for both "ore" and "ore breccia" does have similarities in a process technique perspective.

  • 29.
    Lund, Cecilia
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Martinsson, Olof
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Oxide mineralogy and magnetite chemistry of the Malmberget apatite iron ore, Northern Norr2013In: 12th Biennial SGA Meeting: Mineral deposit research for a high-tech world, Uppsala: Geological Society of Sweden , 2013, p. 273-276Conference paper (Refereed)
    Abstract [en]

    The Malmberget deposit has produced morethan 600 Mt of ore and comprises several ore bodies thatexhibit different mineralogical, chemical and structuralfeatures. In the eastern part, the ore bodies occur asmassive lenses of magnetite surrounded by ore breccia,while the western part is characterized by hematitedominated ores. In contrast to most other apatite iron oresin Northern Norrbotten, the Malmberget deposit have beenstrongly affected by deformation, metamorphicrecrystallization and felsic intrusions.Variations in whole rock chemistry of the ores aremainly reflecting primary features with different signaturesfor massive ore and ore breccia, but also indicatingdifferent types of massive ore. Magnetite from ore brecciahave low content of trace elements similar to magnetitefrom IOCG deposits and may have formed byhydrothermal processes while magnetite in massive oreshow chemical characteristics typical for apatite iron ores.The chemistry of magnetite has in various extentsbeen modified due to element redistribution duringmetamorphic recrystallization and oxidation. Mostsignificant is the preferential partition of Ti and to someextent V into porphyroblasts of hematite. The formation ofilmenite and rutile affects the chemistry of magnetite andgives it a lower content of Ti and V and a signatureresembling magnetite from IOCG deposits.

  • 30.
    Lund, Cecilia
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Martinsson, Olof
    Trace-element chemistry of magnetite from the Malmberget apatite-iron deposit2008Conference paper (Other academic)
    Abstract [en]

    Iron is the most used metal and it is mined from several different types of deposits. Those of a chemical-sedimentary origin dominate, but also deposits of hydrothermal or magmatic origin are important in some parts of the world. Due to an expanding market of iron ore and increased customer demands on product quality the producers has to meet this with a more detailed knowledge of their resources, including trace element composition of the iron oxides.Sweden is Europe's most important producer of iron ore with two large underground mines in Kiruna and Malmberget operated by LKAB. Both deposits are apatite iron ores, an ore type that is common in northern Sweden but rare in other parts of the world. These two world class deposits have a similar origin and were formed by magmatic-hydrothermal process at 1.89-1.88 Ga. However, the Malmberget ore is more strongly affected by later metamorphose, deformation and intrusion of granitic rocks.More than 20 different tabular to stock shaped ore bodies are known at Malmberget, occupying an area of 2.5 x 5km. The Malmberget deposit was probably from the beginning a more or less continuous ore lens which were exposed for at least two phases of folding and metamorphism. By strong ductile deformation it was torn into several lenses that today occupy a large-scale fold structure were the individual ore bodies stretches parallel to the fold axis, which plunge 40º-50º towards SSW. Due to the strong metamorphic overprinting of the area, the ore minerals are recrystallised, coarse grained, and elongated in the direction of the lineation of the rocks.The iron ore minerals are both magnetite (Fe3O4) and hematite (Fe2O3) with magnetite as the only iron oxide in most major ore bodies. Hematite dominates some minor ore bodies and is mixed with magnetite in others. The main gangue minerals are apatite, amphibole, pyroxene, feldspars, quartz and biotite. Among the accessory minerals are pyrite, chalcopyrite, titanite, zircons and calcite most common. Each ore body is characterised by its own mineral, chemical and textural properties. Magnetite belongs to the spinel group of minerals and besides the ferrides it may also contain Al and Mg substituting for Fe. Apatite iron ores, including the Malmberget deposit, are characterized by magnetite chemistry different to most other iron deposits. They typically have high vanadium content similar to magmatic segregations of magnetite in mafic rocks but a Ti content that is between magmatic and sedimentary iron deposits. Microprobe analyses of magnetite of different textures and from different ore types indicate that magnetite is not uniform in composition and the content of e.g. Al and Mg seem to be largely controlled by local chemical conditions with Al most enriched in ore of breccia style while Mg is highest in magnetite from massive ore.

  • 31.
    Lund, Cecilia
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Martinsson, Olof
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Lindberg, Therese
    LKAB, Research & Development, 983 81 Malmberget.
    Mineralogical-textural characterisation of different apatite-iron ore bodies, Malmberget deposit, Sweden, treated in a sorting process in laboratory scale2010Conference paper (Other academic)
    Abstract [en]

    The Malmberget apatite iron ore deposit encloses more than twenty ore bodies which are mined separately but are blended in the mine before it is hoisted up to the sorting plant. The geology of the deposit shows metamorphic overprints and strong alteration which makes each individual ore body heterogeneous in its composition. In this study the aim is to be able to identify and quantify important mineralogical and textural characters of each ore body which will be part and impact the upgrading process. Two different ores bodies were processed in order to simulate a dry sorting process by bench scale measurements. The analytical methods for quantitative characterisation were optical microscopy and QEMSCAN®. Preliminary results show both differences and similarities between the ore bodies. The mineralogy composition differs between the ore bodies but the most important mineral associations for both ore bodies are binary magnetite/feldspar and magnetite/FeTi-oxides. The magnetite liberation is high for both ore bodies.

  • 32. Malinovskiy, Dmitry
    et al.
    Hammarlund, Dan
    Lunds universitet.
    Ilyashuk, Boris
    Kola Science Centre, Russian Academy of Sciences, Apatity.
    Martinsson, Olof
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Gelting, Johan
    Variations in the isotopic composition of molybdenum in freshwater lake systems2007In: Chemical Geology, ISSN 0009-2541, E-ISSN 1872-6836, Vol. 236, no 3-4, p. 181-198Article in journal (Refereed)
    Abstract [en]

    Variations in molybdenum isotopic composition, spanning the range of ≈ 2.3‰ in the terms of 97Mo/95Mo ratio, have been measured in sediment cores from three lakes in northern Sweden and north-western Russia. These variations have been produced by both isotopically variable input of Mo into the lakes due to Mo isotopic heterogeneity of bedrock in the drainage basins and fractionation in the lake systems due to temporal variations in limnological conditions. Mo isotope abundances of bedrock in the lake drainage basins have been documented by analysis of Mo isotope ratios of a suite of molybdenite occurrences collected in the studied area and of detrital fractions of the lake sediment cores. The median δ97Mo value of the investigated molybdenites is 0.26‰ with standard deviation of 0.43‰ (n = 19), whereas the median δ97Mo value of detrital sediment fractions from two lakes is - 0.40‰ with standard deviation of 0.36‰ (n = 15). The isotopic composition of Mo in the sediment cores has been found to be dependent on redox conditions of the water columns and the dominant type of scavenging phases. Hydrous Fe oxides have been shown to be an efficient scavenger of Mo from porewater under oxic conditions. Oxidative precipitation of Fe(II) in the sediments resulted in co-precipitation of Mo and significant authigenic enrichment at the redox boundary. In spite of a pronounced increase in Mo concentration associated with Fe oxides at the redox boundary the isotopic composition of Mo in this zone varies insignificantly, suggesting little or no isotope fractionation during scavenging of Mo by hydrous Fe oxides. In a lake with anoxic bottom water a chironomid-inferred reconstruction of O2 conditions in the bottom water through the Holocene indicates that increased O2 concentrations are generally associated with low δ97Mo/95Mo values of the sediments, whereas lowered O2 contents of the bottom water are accompanied by relatively high δ97Mo/95Mo values, thus confirming the potential of Mo isotope data to be a proxy for redox conditions of overlying waters. However, it is pointed out that other processes including input of isotopically heterogeneous Mo and Mn cycling in the redox-stratified water column can be a primary cause of variations in Mo isotopic compositions of lake sediments.

  • 33.
    Martinsson, Olof
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Apatite-iron deposits2007In: Metallogeny and tectonic evolution of the Northern Fennoscandian Shield: field trip guidebook, Espoo: Geological Survey of Finland , 2007, p. 20-21Chapter in book (Other academic)
  • 34.
    Martinsson, Olof
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Bispbergs järnmalmsfält: En geologisk och geokemisk studie1987Licentiate thesis, monograph (Other academic)
  • 35.
    Martinsson, Olof
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Diversity and character of apatite iron ores and their relation to epigenetic Cu-Au deposits in the Norrbotten Fe-Cu-Au province, northern Sweden2001In: Abstracts with programs (Geological Society of America), ISSN 0016-7592, Vol. 33, no 6, p. 2-Article in journal (Other academic)
    Abstract [en]

    Norrbotten is an important mining province in northern Sweden, which is dominated by Fe- and Cu-Au deposits. Economically most important for the region are the apatite iron ores with an annual production of c. 31 M ton of Fe-ore and a total production of about 1600 M ton of ore the last 100 years. A Paleoproterozoic succession of greenstones, porphyries and clastic sediments that rests unconformably on a 2.7-2.8 Ga old Archean basement is geologically important in this area. Stratigraphically lowest are 2.5-2.0 Ga old rift-related greenstones. They are followed by c. 1.9 Ga Svecofennian volcanic and sedimentary rocks. Synorogenic 1.89-1.87 Ga plutons range in composition from gabbro to granite, while late orogenic intrusions are dominated by c. 1.79 Ga minimum melt granites and pegmatites. The apatite iron ores in Norrbotten shows a considerable variation in host rock relations, P-content, host rock lithology, associated minor components and host rock alterations. Most occurrences are dominated by either magnetite or hematite. Apatite, actinolite, carbonate and quartz are the main gangue minerals. Sulfides are mostly rare within the ores but may occur in the altered wall rocks. The content of Fe and P varies between 30-70% and 0.05-5%, respectively. A typical geochemical feature is the strong enrichment of REE. Epigenetic Cu-Au occurrences are common in Norrbotten. They are of at least two generations (c. 1.88 and 1.77 Ga) and have formed from highly saline fluids. Limited chronological data indicate a similar c. 1.88 Ga age for the older generation of Cu-Au occurrences and some of the apatite iron ores suggesting a possible genetic relation between Fe-oxide and Cu-Au mineralization. A combination of magmatic processes, deep crustal structures and evaporitic units in the lower part of the Paleoproterozoic succession might be genetically important for both types of occurrences.

  • 36.
    Martinsson, Olof
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Exhaliter vid Skelleftefältets malmer: delprojekt Långdal1987Report (Other academic)
  • 37.
    Martinsson, Olof
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Genesis of the Per Geijer Apatite Iron Ores, Kiruna Area, Northern Sweden2015In: Mineral Resources in a Sustainable World / [ed] A.S. Andre-Mayer; M. Cathelineau; P. Muchez; E. Pirard; S. Sindern, 2015, p. 1107-1110Conference paper (Refereed)
    Abstract [en]

    Apatite iron ores are rather uncommon and the genesis of these deposits has been debated for more than a century. In the Kiruna area in northern Sweden the Per Geijer deposits shows a large variation in mineral composition, structures and textures. Apatite, carbonate and quartz are gangue minerals occurring disseminated in varying amounts in the ore as well as segregations in the form of blebs. Larger accumulations of apatite carbonate-quartz exhibit cutting contacts or mingling structures to the ore. The Per Geijer deposits are interpreted as having formed from iron oxide melts with high content of volatiles. During cooling these iron oxide melts underwent unmixing of volatile rich and iron-poor magma that generated apatite-carbonate-quartz rocks. The volatile components expelled during formation of the apatite iron ores also generated extensive hydrothermal brecciation and alteration in the wall rocks. The alteration is mainly developed in the hanging wall and includes K-feldspar, quartz, sericite, chlorite and carbonates

  • 38.
    Martinsson, Olof
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Geokemi och faciesuppbyggnad hos Långdalmalmen, en massiv sulfidmalm i Skelleftefältet1986In: Abstracts: 17e Nordiska geologmötet, Helsingfors universitet, 12-15.5. 1986, 1986Conference paper (Other academic)
  • 39.
    Martinsson, Olof
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Geological and geochemical evidence for the genesis of the Viscaria Cu-deposit1989In: New ore types in Northern Fennoscandia: September 26-28, 1989, Luleå University of Technology, Luleå, Sweden, Luleå: Högskolan i Luleå , 1989, p. 25-Conference paper (Other academic)
  • 40.
    Martinsson, Olof
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Geology and Metallogeny of the Northern Norrbotten Fe-Cu-Au Province2004In: Svecofennian Ore-Forming Environments Field Trip Volcanic-associated Zn-Cu-Au-Ag and magnetite-apatite, sediment-hosted Pb-Zn, and intrusion-associated Cu-Au deposits in northern Sweden, Society of Economic Geologists, 2004Chapter in book (Other academic)
  • 41.
    Martinsson, Olof
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Geotectonic evolution of Paleoproterozoic greenstones in northern Sweden indicated by lithostratigraphic and geochemical data1999In: Geodynamic evolution and metallogeny of the Central Lapland, Kuhmo and Suomussalmi greenstone belts, Finland, Turku: University of Turku , 1999, p. 78-82Chapter in book (Other academic)
  • 42.
    Martinsson, Olof
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Kiskamavaara: a shear zone hosted IOCG-style of Cu-Co-Au deposit in Northern Norrbotten, Sweden2011Conference paper (Refereed)
  • 43.
    Martinsson, Olof
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Mesothermal Cu-Au deposits and hydrothermal alterations in Paleoproterozoic greenstones in northern Sweden1999In: Geodynamic evolution and metallogeny of the Central Lapland, Kuhmo and Suomussalmi greenstone belts, Finland, Turku: University of Turku , 1999, p. 107-111Chapter in book (Other academic)
  • 44.
    Martinsson, Olof
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Metallogeny of the northern Norrbotten Fe-Cu-Au-ore province2000In: Abstract volume & Field trip guidebook / [ed] Pär Weihed; Olof Martinsson, Luleå tekniska universitet, 2000, p. 26-28Conference paper (Other academic)
  • 45.
    Martinsson, Olof
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Skarn-like iron deposits2007In: Metallogeny and tectonic evolution of the Northern Fennoscandian Shield: field trip guidebook, Espoo: Geological Survey of Finland , 2007, p. 19-Chapter in book (Other academic)
  • 46.
    Martinsson, Olof
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Tectonic setting and metallogeny of the Kiruna greenstones1997Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The Paleoproterozoic Kiruna Greenstones belong to a large c. 2.1 Ga tholeiitic province in the north-eastern part of the Baltic Shield. The mainly basaltic volcanism was related to an event of continental rifting, which ended up with continental rupture. The occurrence of komattites, picrites and thick piles of tholeiites in the northern parts of Sweden, Norway and Finland is in contrast to the sedimentary dominated areas in central-eastern Finland. This suggests the location of a mantle plume to the northern area, which generated the large volumes of mantle melts. The stratigraphical record of the well preserved Kiruna Greenstone Group demonstrates a change from initial clastic sedimentation, evaporate deposition and WPB-type volcanism to later extensive volcanism of flood basalt character. Subsequent crustal thinning generated MORB-type magmas by decompressional mantle melting. The later development of a subaqueous basin was accompanied by a change to explosive volcanism, and large amounts of volcaniclastic material was formed by Surtseyan eruptions. During ocean opening along a line from Ladoga to Lofoten a NNE-directed failed rift-arm was formed. This is expressed by rapid basin subsidence and voluminous eruption of MORB-type pillowlava, which created an anomalous environment of local extent within the greenstone domain. Basin shoaling and subsequent uplift and erosion of the rifted margin marks an end of the rift event. Two different types of economic sulfide deposits occur in the Kiruna Greenstones, syngenetic Cu-(Zn) ores of exhalative origin (Viscaria-type), and epigenetic Cu-Au ores (Pahtohavare-type). Both types are formed from highly saline hydrothermal fluids, but they are clearly different in metal association, ore related alteration and ore character. Conspicuous for the Viscaria-type is the occurrence of stacked blanket-shaped mineralizations of magnetite and sulfides, and the layered structure of high-grade Cu-ore, which is explained by repeated exhalative activity and deposition of the ores in brinepools. The most productive ore was formed in association with the main stage of basin subsidence and MORB-type volcanism in the failed rift. Faults parallel with the rift axis acted as channels for the ore fluids, and controlled the shape and location of brine-pool in which the ore was precipitated. Ores of the Pahtohavare-type have formed in zones of active ductile to brittle shearing. In detail the location of ores are mainly lithologically controlled by black schists, which has acted as chemical traps. The ores are hosted by albite felsites, and surrounded by characteristic zones of scapolite-biotite alteration. Calcopyrite and pyrite are the main ore minerals and they occur mainly as veinlets, veins and matrix to brecciated albite felsite. Ferro-dolomite is a characteristic ore related mineral formed in several generations from early dissemination in albite felsite, gangue to ore minerals and late barren veins. The Viscaria and Pahtohavare deposits are different in many respects to typical massive sulfide deposits and Au-ores in most other greenstone terrains. This is mainly due to their formation from highly saline solution, which is a common feature of both exhalative and epigenetic sulfide deposits formed in continental rift environments. Thus, the existence of evaporitic sediments at the base of the Kiruna Greenstones may be of major metallogenetic importance for this region, serving as a source for saline hydrothermal fluids.

  • 47.
    Martinsson, Olof
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    The Narken iron oxide-(Cu) deposits: a link between Kiruna-type iron ore and IOCG-style of mineralization2009In: Smart science for exploration and mining: proceedings of the 10th Biennial SGA Meeting, Townsville, Australia 17th-20th August / [ed] Patrick Williams, James Cook University of North Queensland , 2009Conference paper (Refereed)
    Abstract [en]

    The Northern Norrbotten Ore Province is the type area for iron deposits of Kiruna-type (apatite iron ores). These deposits are mainly hosted by 1.9 Ga Svecofennian porphyries and occur as massive lenses or as breccia style of mineralisation in the Kiruna and Malmberget regions. Just outside this area an unusual type of apatite iron ore occur at Narken. Euhedral crystals of hematite altered magnetite, apatite, and pyrite occur as breccia infill together with tabular hematite, epidote, chlorite and some quartz. The occurrences of iron oxide mineralization are enriched in REE, and contain up to 0.5% Cu but are low in Au. The wall rocks and clasts of these rocks within the breccia bodies are strongly altered by silicification, epidotization and chloritization. Sulphur isotope data and mineral paragenesis indicate increasingly oxidizing conditions during development of the mineralization. Magnetite, apatite and pyrite are early formed minerals, transported to higher levels in the crust by a fluidized hydrothermal system and deposited in breccia bodies where they occur in a xenocrystic manner in a breccia infill of flaky hematite, epidote, chlorite, quartz and minor chalcopyrite. In many respects the Narken deposits are transitional in character to apatite iron ores and IOCG-style mineralization.

  • 48.
    Martinsson, Olof
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    The northern Norrbotten ore province, northern Sweden1997In: Research and exploration - where do they meet?: excursion guidebook - B1 - Ore deposits of Lapland in Northern Finland and Sweden / [ed] Esko A. Korkiakoski; Peter Sorjonen-Ward, Espoo: Geological Survey of Finland , 1997, p. 33-36Conference paper (Refereed)
  • 49.
    Martinsson, Olof
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    The Pahtohavare Cu-Au deposit and related geological excursion stops in the Kiruna area1997In: Research and exploration - where do they meet?: excursion guidebook : B1 : Ore deposits of Lapland in Northern Finland and Sweden / [ed] Esko A. Korkiakoski; Peter Sorjonen-Ward, Espoo: Geological Survey of Finland , 1997, p. 37-39Conference paper (Refereed)
  • 50.
    Martinsson, Olof
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Allan, Åsa
    Envipro Miljöteknik AB, Linköping.
    Niiranen, Tero
    Northland Exploration Finland.
    Wanhainen, Christina
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Eilu, Pasi
    GTK.
    Ojala, Juhani
    GTK.
    Nykänen, Vesa
    GTK.
    Weihed, Pär
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Iron oxide-Cu-Au deposits in the northern part of the Fennoscandian shield2008Conference paper (Other academic)
    Abstract [en]

    The northern part of the Fennoscandian Shield, which formed during repeated extensional and compressional events at 3.1-1.8 Ga, is an ore province characterized by regionally developed albite and scapolite alteration and the occurrence of world class Fe-oxide (Kiirunavaara) and Cu-Au deposits (Aitik). It host several styles of Fe-oxide-Cu-Au deposits, including skarn and apatite-iron style deposits, many of them with features that also warrant classification as iron oxide-copper-gold (IOCG) deposits.The apatite-iron ores are economically most important with a total production of c. 1900 Mt from 10 mines during the last 100 years and with a total pre-mining resource of c. 4100 Mt. In these deposits, the Fe and P content vary between 30-70 % and 0.05-5 %, respectively. The ore minerals magnetite and hematite occur in lenses or as breccia infill. The ores are usually enriched in LREE, sulphides are rare but subeconomic amounts of Cu may occur.Skarn-like iron occurrences consisting of magnetite and Mg and Ca-Mg silicates have been less important with c. 20 Mt mined from 6 deposits and a pre-mining resource of 760 Mt. Most of them occur as conformable lenses with a banded internal structure. Pyrite, pyrrhotite and minor chalcopyrite are commonly present disseminated or as veinlets. Typical grades are 30-55% Fe, 0.2-3.5 % S, 0.05-0.3% Cu, 0.005-1g/t Au and 0.02-0.2% P. A few of the deposits are also enriched in LREE. Epigenetic Cu±Au occurrences include the porphyry-style giant Aitik deposit with a pre-mining resource of 2000 Mt at 0.3% Cu and 0.2 g/t Au and a total production of 465 Mt. Other deposits vary in style from disseminated to breccia infill or veins. Chalcopyrite is the most important ore mineral but bornite, pyrite, pyrrhotite, magnetite, molybdenite and native gold may occur in varying amounts. The skarn-like ores occur in 2.1Ga Karelian greenstones in association to carbonate rocks, BIF and graphite schist. The apatite iron ores are hosted by 1.9 Ga Svecofennian intermediate to felsic porphyries. The epigenetic Cu±Au deposits occur in both Karelian and Svecofennian volcanic and sedimentary rocks and 1.9 Ga intrusive rocks. The two last type of deposits show similar alteration styles including albite, K-feldspar, biotite, scapolite, carbonate, amphibole and tourmaline, whereas the skarn-like deposits are associated with diopside, amphibole, scapolite and biotite alteration.Deposit studies and geochronological data reveal a multiphase origin of the Fe oxide and Cu±Au occurrences with multiple sources of the ore fluids and peaks of mineralization at c. 1.88 and 1.77 Ga. These events are temporally related to major orogenic stages in the evolution of the Fennoscandian Shield. This implies that mineralization formed in different tectonic settings, and with different magmatic associations. Thus, the IOCG deposits are not uniform in origin, which may well explain their diverse features and also makes a simple genetic model for them dubious.

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