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  • 1.
    Abdelnasser, Amr
    et al.
    Geological Engineering Department, Faculty of Mines, Istanbul Technical University. Geology Department, Faculty of Science, Benha University, Benha.
    Kumral, Mustafa
    Geological Engineering Department, Faculty of Mines, Istanbul Technical University.
    Zoheir, Basem
    Geology Department, Faculty of Science, Benha University, Benaha.
    Karaman, Muhittin
    Geological Engineering Department, Faculty of Mines, Istanbul Technical University.
    Weihed, Pär
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    REE geochemical characteristics and satellite-based mapping of hydrothermal alteration in Atud gold deposit, Egypt2018In: Journal of African Earth Sciences, ISSN 0899-5362, Vol. 145, p. 317-330Article in journal (Refereed)
    Abstract [en]

    New geochemical data of the hydrothermal alteration zones associated with gold-bearing quartz veins at Atud mine are used for better understanding the ore evolution and exploration vectoring. ASTER and Landsat 8 OLI data are used to elucidate the distribution of gold-associated alteration zones. Three alteration zones are defined; zone 1 (sericite-kaolinite-quartz-pyrite), zone 2 (quartz-sericite-albite-pyrite), and zone 3 (chlorite-carbonate-epidote ± pyrite). Sericite and hydrothermal quartz are confined to the mineralized quartz veins. Fe-OH and OH-bearing minerals are observed along NW- and NE-trending shear zones in the Main Atud mine. The association of gold-bearing quartz veins and sericite alteration is constrained by processing ASTER- and OLI-imagery data. The geochemical data of the ore-enveloping hydrothermally altered rocks are used to assess the behavior of the REEs during the mineralization process. Mild enrichment in LREE and significant enrichment in the HREE are associated with sericite in zones (1) and (2) alterations. Carbonate alteration (zone 3) is enriched in LREE and in immobile HREE. Moreover, LREE and Eu anomalies have negative correlated with the Alteration Index (A.I.) and K2O index (K.I.) in zones 1 and 2, suggesting high mobility of LREE in K-rich hydrothermal fluids. On the other hand, HREE anomalies with increasing MgO index (M.I.) in alteration zone 3 may imply low solubility of these elements in alkaline solutions. Au anomalies linked to sericite/silica alteration is a rather meaningful vector for further exploration in the area.

  • 2. Ahl, Martin
    et al.
    Bergman, Stefan
    Bergström, Ulf
    Eliasson, Thomas
    Ripa, Magnus
    Weihed, Pär
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Geochemical classification of plutonic rocks in central and northern Sweden2001Report (Other academic)
  • 3.
    Aiglsperger, Thomas
    et al.
    Department of Crystallography, Mineralogy, and Ore Deposits, University of Barcelona.
    Proenza, Joaquín A.
    Departament de Cristal·lografia, Mineralogia i Dipòsits Minerals, Universitat de Barcelona.
    Font-Bardia, Mercé
    Departament de Mineralogia, Petrologia i Geologia Aplicada, Universitat de Barcelona .
    Baurier-Aymat, Sandra
    Departament de Mineralogia, Petrologia i Geologia Aplicada, Universitat de Barcelona .
    Galí, Salvador
    Departament de Mineralogia, Petrologia i Geologia Aplicada, Universitat de Barcelona .
    Lewis, John F.
    Department of Earth and Environmental Sciences, George Washington University, .
    Longo, Francisco
    Faculty of Engineering, Universidad Católica Tecnológica del Cibao (UCATECI), La Vega.
    Supergene neoformation of Pt-Ir-Fe-Ni alloys: multistage grains explain nugget formation in Ni-laterites2016In: Mineralium Deposita, ISSN 0026-4598, E-ISSN 1432-1866, p. 1-15Article in journal (Refereed)
    Abstract [en]

    Ni-laterites from the Dominican Republic host rare but extremely platinum-group element (PGE)-rich chromitites (up to 17.5 ppm) without economic significance. These chromitites occur either included in saprolite (beneath the Mg discontinuity) or as ‘floating chromitites’ within limonite (above the Mg discontinuity). Both chromitite types have similar iridium-group PGE (IPGE)-enriched chondrite normalized patterns; however, chromitites included in limonite show a pronounced positive Pt anomaly. Investigation of heavy mineral concentrates, obtained via hydroseparation techniques, led to the discovery of multistage PGE grains: (i) Os-Ru-Fe-(Ir) grains of porous appearance are overgrown by (ii) Ni-Fe-Ir and Ir-Fe-Ni-(Pt) phases which are overgrown by (iii) Pt-Ir-Fe-Ni mineral phases. Whereas Ir-dominated overgrowths prevail in chromitites from the saprolite, Pt-dominated overgrowths are observed within floating chromitites. The following formation model for multistage PGE grains is discussed: (i) hypogene platinum-group minerals (PGM) (e.g. laurite) are transformed to secondary PGM by desulphurization during serpentinization; (ii) at the stages of serpentinization and/or at the early stages of lateritization, Ir is mobilized and recrystallizes on porous surfaces of secondary PGM (serving as a natural catalyst) and (iii) at the late stages of lateritization, biogenic mediated neoformation (and accumulation) of Pt-Ir-Fe-Ni nanoparticles occurs. The evidence presented in this work demonstrates that in situ growth of Pt-Ir-Fe-Ni alloy nuggets of isometric symmetry is possible within Ni-laterites from the Dominican Republic.

  • 4.
    Aiglsperger, Thomas
    et al.
    Department of Crystallography, Mineralogy, and Ore Deposits, University of Barcelona.
    Proenza, Joaquín A.
    Departament de Cristal·lografia, Mineralogia i Dipòsits Minerals, Universitat de Barcelona.
    Galí, Salvador
    Departament de Mineralogia, Petrologia i Geologia Aplicada, Universitat de Barcelona .
    Rius, Jordi
    Institut de Ciència de Materials de Barcelona, CSIC, Campus de la Universitat Autònoma de Barcelona.
    Longo, Francisco
    Falcondo Glencore, Santo Domingo .
    Domènech, Cristina
    Departament de Mineralogia, Petrologia i Geologia Aplicada, Facultat de Ciències de la Terra, Universitat de Barcelona (UB).
    The supergene origin of ruthenian hexaferrum in Ni-laterites2017In: Terra Nova, ISSN 0954-4879, E-ISSN 1365-3121, Vol. 29, no 2, p. 106-116Article in journal (Refereed)
    Abstract [en]

    For two decades, the nature of Fe‐rich, oxygen‐bearing, Ru–Os compounds found in the supergene environment has been debated. Ru–Os–Fe‐oxides and nano‐intergrowths of ruthenium with magnetite have been proposed. We applied FE‐SEM, EMPA, μ‐Raman spectroscopy and synchrotron tts‐μXRD to Ru–Os–Fe compounds recovered from Ni‐laterites from the Dominican Republic. The results demonstrate that a significant portion of Fe exists in a common structure with the Ru–Os alloy, that is, ruthenian hexaferrum. This mineral occurs both as nanoparticles and as micrometric patches within a matrix of Fe‐oxide(s). Our data suggest that supergene ruthenian hexaferrum with a (Ru0.4(Os,Ir)0.1Fe0.5)Ʃ1.0 stoichiometry represents the most advanced weathering product of primary laurite within Ni‐laterites from the Dominican Republic.

  • 5.
    Aiglsperger, Thomas
    et al.
    Departament de Cristal·lografia, Mineralogia i Dipòsits Minerals, Universitat de Barcelona .
    Proenza, Joaquín A.
    Departament de Cristal·lografia, Mineralogia i Dipòsits Minerals, Universitat de Barcelona .
    Lewis, John F.
    Department of Earth and Environmental Sciences, George Washington University, .
    Labrador, Manuel
    Departament de Cristal·lografia, Mineralogia i Dipòsits Minerals, Universitat de Barcelona.
    Svojtka, Martin
    Institute of Geology, Academy of Sciences.
    Rojas-Purón, Arturo
    Departamento de Geología, Instituto Superior Minero Metalúrgico de Moa.
    Longo, Francisco
    Falcondo Glencore Nickel.
    Ďurišová, Jana
    Institute of Geology, Academy of Sciences.
    Critical metals (REE, Sc, PGE) in Ni laterites from Cuba and the Dominican Republic2016In: Ore Geology Reviews, ISSN 0169-1368, E-ISSN 1872-7360, Vol. 73, p. 127-147Article in journal (Refereed)
    Abstract [en]

    Ni laterites are considered worthy targets for critical metals (CM) exploration as Rare Earth Elements (REE), Sc and platinum group elements (PGE) can be concentrated during weathering as a result of residual and secondary enrichment. In this contribution geochemical and mineralogical data of CM from two different nickel laterite types (i) from the Moa Bay mining area in Cuba (oxide type) and (ii) from the Falcondo mining area in the Dominican Republic (hydrous Mg silicate type) are presented. Emphasis is given on examining their potential to accumulate CM and on processes involved. Results show that CM are concentrated towards the surface in specific zones: (i) REE in clay minerals rich horizons and within zones composed of secondary Mn oxide(s), (ii) Sc within zones rich in secondary Fe and Mn bearing oxide(s) and (iii) PGE in zones with high concentrations of residual chromian spinel and secondary Fe and Mn bearing oxide(s) at upper levels of the Ni laterite profiles. Concentration factors involve (i) residual enrichment by intense weathering, (ii) mobilization of CM during changing Eh and pH conditions with subsequent reprecipitation at favourable geochemical barriers and (iii) interactions between biosphere and limonitic soils at highest levels of the profile (critical zone) with involved neoformation processes. Total contents of CM in both Ni laterite types are low when compared with conventional CM ore deposits but are of economic significance as CM have to be seen as cost inexpensive by-products during the Ni (+ Co) production. Innovative extraction methods currently under development are believed to boost the significance of Ni laterites as future unconventional CM ore deposits.

  • 6.
    Aiglsperger, Thomas
    et al.
    Department of Crystallography, Mineralogy, and Ore Deposits, University of Barcelona.
    Proenza, Joaquín A.
    Departament de Cristal·lografia, Mineralogia i Dipòsits Minerals, Universitat de Barcelona.
    Longo, Francisco
    Falcondo Glencore, Santo Domingo .
    Font-Bardia, Mercé
    Departament de Mineralogia, Petrologia i Geologia Aplicada, Universitat de Barcelona .
    Galí, Salvador
    Departament de Mineralogia, Petrologia i Geologia Aplicada, Universitat de Barcelona .
    Roqué, Josep
    Departament de Mineralogia, Petrologia i Geologia Aplicada, Facultat de Ciències de la Terra, Universitat de Barcelona.
    Baurier-Aymat, Sandra
    Departament de Mineralogia, Petrologia i Geologia Aplicada, Universitat de Barcelona .
    Fibrous Platinum-Group Minerals in “Floating Chromitites” from the Loma Larga Ni-Laterite Deposit, Dominican Republic2016In: Minerals, E-ISSN 2075-163X, Vol. 6, no 4, article id 126Article in journal (Refereed)
    Abstract [en]

    This contribution reports on the observation of enigmatic fibrous platinum-group minerals (PGM) found within a chromitite body included in limonite (“floating chromitite”) from Ni-laterites in the Dominican Republic. Fibrous PGM have a Ru-Os-Ir-Fe dominated composition and are characterized by fibrous textures explained by grain-forming fibers which are significantly longer (1–5 _m) than they are wide (~100 nm). Back-scattered electron (BSE) images suggest that these nanofibers are platinum-group elements (PGE)-bearing and form <5 _m thick layers of bundles which are oriented orthogonal to grains’ surfaces. Trace amounts of Si are most likely associated with PGE-bearing nanofibers. One characteristic fibrous PGM was studied in detail: XRD analyses point to ruthenian hexaferrum. However, the unpolished fibrous PGM shows numerous complex textures on its surface which are suggestive for neoformation processes: (i) features suggesting growth of PGE-bearing nanofibers; (ii) occurrence of PGM nanoparticles within film material (biofilm?) associated with PGE-bearing nanofibers; (iii) a Si-rich and crater-like texture hosting PGM nanoparticles and an Ir-rich accumulation of irregular shape; (iv) complex PGM nanoparticles with ragged morphologies, resembling sponge spicules and (v) oval forms (<1 _m in diameter) with included PGM nanoparticles, similar to those observed in experiments with PGE-reducing bacteria. Fibrous PGM found in the limonite may have formed due to supergene (bio-)weathering of fibrous Mg-silicates which were incorporated into desulphurized laurite during stages of serpentinization.

  • 7.
    Aiglsperger, Thomas
    et al.
    Departament de Cristal·lografia, Mineralogia i Dipòsits Minerals, Universitat de Barcelona, .
    Proenza, Joaquín A.
    Departament de Cristal·lografia, Mineralogia i Dipòsits Minerals, Universitat de Barcelona.
    Zaccarini, Frederica
    Department of Applied Geological Sciences and Geophysics, University of Leoben.
    Lewis, John F.
    Department of Earth and Environmental Sciences, George Washington University, .
    Garuti, Giorgio
    Department of Applied Geosciences and Geophysics, University of Leoben.
    Labrador, Manuel
    Departament de Cristal·lografia, Mineralogia i Dipòsits Minerals, Universitat de Barcelona, .
    Longo, Francisco
    Falcondo Glencore, Santo Domingo .
    Platinum group minerals (PGM) in the Falcondo Ni-laterite deposit, Loma Caribe peridotite (Dominican Republic)2015In: Mineralium Deposita, ISSN 0026-4598, E-ISSN 1432-1866, Vol. 50, no 1, p. 105-123Article in journal (Refereed)
    Abstract [en]

    Two Ni-laterite profiles from the Loma Caribe peridotite (Dominican Republic) have been investigated for their platinum group element (PGE) geochemistry and mineralogy. One profile (Loma Peguera) is characterized by PGE-enriched (up to 3.5 ppm total PGE) chromitite bodies incorporated within the saprolite, whereas the second profile is chromitite-free (Loma Caribe). Total PGE contents of both profiles slightly increase from parent rocks (36 and 30 ppb, respectively) to saprolite (∼50 ppb) and reach highest levels within the limonite zone (640 and 264 ppb, respectively). Chondrite-normalized PGE patterns of saprolite and limonite reveal rather flat shapes with positive peaks of Ru and Pd. Three types of platinum group minerals (PGM) were found by using an innovative hydroseparation technique: (i) primary PGM inclusions in fresh Cr-spinel (laurite and bowieite), (ii) secondary PGM (e.g., Ru-Fe-Os-Ir compounds) from weathering of preexisting PGM (e.g., serpentinization and/or laterization), and (iii) PGM precipitated after PGE mobilization within the laterite (neoformation). Our results provide evidence that (i) PGM occurrence and PGE enrichment in the laterite profiles is independent of chromitite incorporation; (ii) PGE enrichment is residual on the profile scale; and (iii) PGE are mobile on a local scale leading to in situ growth of PGM within limonite, probably by bioreduction and/or electrochemical metal accretion.

  • 8.
    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.

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  • 9.
    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.

  • 10.
    Allen, Ann
    et al.
    Boliden Mineral, Garpenberg.
    Allen, Rodney
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Kaiser, Majka C.
    Boliden Mineral, Garpenberg.
    Geochemistry as a Tool for Exploration at the Renstrom Zn-Pb-Cu-Au-Ag VMS Camp, Skellefte District, Sweden2015In: Mineral Resources in a Sustainable World / [ed] A.S. Andre-Mayer; M. Cathelineau; P. Muchez; E. Pirard; s. Sindern, 2015, p. 2047-2050Conference paper (Refereed)
    Abstract [en]

    The Skellefte mining district in northern Sweden contains over 85 pyritic Zn-Cu-Au-Ag massive sulphide deposits. The Renstrom area, one of the most intensely mineralized parts of the Skellefte district, contains five zinc-and gold-rich deposits, three of which are confined to a specific continuous stratigraphic unit, the "Renstrom ore host unit". The great structural complexity of the area made it difficult to locate and follow the ore horizon to generate new exploration targets. A new study in the Kyrkvagen area, based on stratigraphic correlations, structural interpretations and lithogeochemical and geophysical data interpretation, revealed several NW-trending faults which separate five structural blocks. The rocks of the area could be characterized in terms of geochemistry, stratigraphy and their position in the hanging or footwall with respect to the ore horizon. Moreover, alteration patterns allowed predictions of possible extensions of the ore horizon. This increased knowledge of the Kyrkvagen area led to the identification of five new drilling targets for further exploration in one of Boliden's most important mining areas.

  • 11.
    Allen, Rodney
    et al.
    Volcanic Resources AB.
    Bauer, Tobias E.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Persson, Mac Fjellerad
    Boliden Mineral AB.
    Jansson, Nils F.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Mercier-Langevin, Patrick
    Natural Resources Canada.
    Base, Precious, and Critical Metal Deposits of the Paleoproterozoic Skellefte District, Sweden: September 25 –30, 20222023Book (Other academic)
    Download (pdf)
    table of contents
  • 12. Allen, Rodney
    et al.
    Cas, R.A.F.
    Yamagishi, H.
    Ishikawa, Y.
    Ohguchi, T.
    Submarine silicic volcanoes associated with Miocene Kuroko mineralization, northern Japan1989Conference paper (Other academic)
  • 13.
    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)
  • 14.
    Allen, Rodney
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Montelius, Cecilia
    Schlatter, Denis
    Imana, Marcello
    Barrett, T.
    Svenson, Sven-Åke
    Boliden Mineral AB.
    Application of volcanology to understanding massive sulphide deposits in the 1.9 Ga Skell2004In: The 26th Nordic Geological Winter Meeting: abstract volume / [ed] Joakim Mansfeld, Uppsala: Geological Society of Sweden , 2004, p. 45-Conference paper (Refereed)
  • 15.
    Allen, Rodney
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Montelius, Cecilia
    Svenson, Sven-Åke
    Geology of the Maurliden Area, Central Skellefte District, and Visit to the West Maurliden Zn-Cu-Au Massive Sulfide Deposit: Day three field guide2004In: 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, Littleton, Colorado: Society of Economic Geologists, 2004, p. 111-Chapter in book (Other academic)
  • 16.
    Allen, Rodney
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Ohguchi, Takeshi
    Volcanic setting of kuroko massive sulphide deposits, Hokuroku Basin, Japan2006In: 12th Quadrennial IAGOD Symposium, Taylor and Francis Group , 2006Conference paper (Other academic)
  • 17.
    Allen, Rodney
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Svenson, Sven-Åke
    1.9 Ga Volcanic Stratigraphy, Structure, and Zn-Pb-Cu-Au-Ag Massive Sulfide Deposits of the Renström area, Skellefte District, Sweden2004In: 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)
  • 18.
    Allen, Rodney
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Svenson, Sven-Åke
    Day one field guide: Overview of the Stratigraphy, Structure, and Volcanology of the Skellefte Mining District2004In: 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)
  • 19.
    Allen, Rodney
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Svenson, Sven-Åke
    Boliden Mineral AB.
    Jonsson, Rolf
    Day two field guide: Volcanic Stratigraphy and Structure of the Renström Area and Mine Tour of the Petiknäs South Zn-Pb-Cu-Au-Ag Massive Sulfide Deposit2004In: 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)
  • 20.
    Allen, Rodney
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Tornos, F.
    Peter, J.
    Cagatay, N.
    Links between volcanism and massive sulphide deposits: a global perspective2005In: GAC-MAC-CSPG-CSSS [joint Meeting], Halifax, 2005: building bridges - across science, through time, around the world : abstracts, St. John's: Geological and Mineralogical Association of Canada, 2005, p. 3-Conference paper (Other academic)
  • 21.
    Allen, Rodney
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Tornos, F.
    Instituto Geológico y Minero de España.
    Peter, J. M.
    Geological Survey of Canada.
    A thematic issue on the geological setting and genesis of volcanogenic massive sulfide (VMS) deposits2011In: Mineralium Deposita, ISSN 0026-4598, E-ISSN 1432-1866, Vol. 46, no 5, p. 429-430Article in journal (Other academic)
  • 22.
    Allen, Rodney
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Tornos, F.
    Instituto Geológico y Minero de España.
    Peter, J.
    Geological Survey of Canada.
    Çagatay, N.
    Istanbul Technical University.
    Links between volcanism and the distribution and timing of massive sulphide (VMS) deposits2006In: The 27th Nordic Geological Winter Meeting, January 9-12, 2006, Oulu, Finland: abstract volume / [ed] Petri Peltonen; Annti Pasanen, Helsinki: Geological Society of Finland , 2006, p. 7-Conference paper (Other academic)
    Abstract [en]

    The links between volcanism and massive sulphide deposits are being studied as part of the "Global Volcanic-hosted Massive Sulphide (VMS) Project", which is IGCP project 502. Different types and settings of VMS deposit show different degrees of influence from volcanic or magmatic processes, with the most distinct genetic connection shown by some felsic-hosted deposits. These influences include:(1) Basin-wide volcano-tectonic events cause deposition of VMS on specific time-stratigraphic horizons. (2) With the exception of mid-ocean ridge settings, major VMS deposits are mainly associated with felsic volcanic rocks, even where felsic rocks form a minor component of the region. (3) Most VMS deposits form in proximal volcanic settings. (4) Most VMS deposits form at a particular stage in the evolution of their host volcanoes, typically late in the magmatic-hydrothermal cycle following a significant felsic eruptive event. The specific relationship in time and place implied by these last two points indicate that either the magmatic-hydrothermal cycle creates an important part of the ore solution, or controls when and where a metal-bearing geothermal solution can be focused and expelled to the sea floor, or both.(5) VMS deposits occur preferentially at times and places where both felsic and mafic magmas were erupted. In felsic-dominated regions, eruption of the mafic rocks commonly closely followed deposition of the ore-host felsic package. (6) Volcanic host rocks influence the morphology and stratigraphic position of VMS. Volcaniclastic and especially pumiceous strata promote deposition of VMS below the sea floor via replacement, whereas coherent lava flows and intrusions promote deposition of VMS on the sea floor. (7) Volcanic rocks and/or magmas are probably the source of metals in most VMS deposits.

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  • 23. Allen, Rodney
    et al.
    Weihed, Pär
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Global comparisons of volcanic-associated massive sulphide districts2002In: The timing and location of major ore deposits in an evolving Orogen, London: Geological Society of London, 2002, p. 13-37Chapter in book (Other academic)
    Abstract [en]

    Although volcanic-associated massive sulphide (VMS) deposits have been studied extensively, the geodynamic processes that control their genesis, location and timing remain poorly understood. Comparisons among major VMS districts, based on the same criteria, have been commenced in order to ascertain which are the key geological events that result in high-value deposits. The initial phase of this global project elicited information in a common format and brought together research teams to assess the critical factors and identify questions requiring further research. Some general conclusions have emerged. (1) All major VMS districts relate to major crustal extension resulting in graben subsidence, local or widespread deep marine conditions, and injection of mantle-derived mafic magma into the crust, commonly near convergent plate margins in a general back-arc setting. (2) Most of the world-class VMS districts have significant volumes of felsic volcanic rocks and are attributed to extension associated with evolved island arcs, island arcs with continental basement, continental margins, or thickened oceanic crust. (3) They occur in a part of the extensional province where peak extension was dramatic but short-lived (failed rifts). In almost all VMS districts, the time span for development of the major ore deposits is less than a few million years, regardless of the time span of the enclosing volcanic succession. (4) All of the major VMS districts show a coincidence of felsic and mafic volcanic rocks in the stratigraphic intervals that host the major ore deposits. However, it is not possible to generalize that specific magma compositions or affinities are preferentially related to major VMS deposits world-wide. (5) The main VMS ores are concentrated near the top of the major syn-rift felsic volcanic unit. They are commonly followed by a significant change in the pattern, composition and intensity of volcanism and sedimentation. (6) Most major VMS deposits are associated with proximal (near-vent) rhyolitic facies associations. In each district, deposits are often preferentially associated with a late stage in the evolution of a particular style of rhyolite volcano. (7) The chemistry of the footwall rocks appears to be the biggest control on the mineralogy of the ore deposits, although there may be some contribution from magmatic fluids. (8) Exhalites mark the ore horizon in some districts, but there is uncertainty about how to distinguish exhalites related to VMS from other exhalites and altered, bedded, fine grained tuffaceous rocks. (9) Most VMS districts have suffered fold-thrust belt type deformation, because they formed in short-lived extensional basins near plate margins, which become inverted and deformed during inevitable basin closure. (10) The specific timing and volcanic setting of many VMS deposits, suggest that either the felsic magmatic-hydrothermal cycle creates and focuses an important part of the ore solution, or that specific types of volcanism control when and where a metal-bearing geothermal solution can be focused and expelled to the sea floor, or both. This and other questions remain to be addressed in the next phase of the project. This will include in-depth accounts of VMS deposits and their regional setting and will focus on an integrated multi-disciplinary approach to determine how mineralisation, volcanic evolution and extensional tectonic evolution are interrelated in a number of world-class VMS districts.

  • 24.
    Allen, Rodney
    et al.
    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.
    Gold deposit types in Palaeoproterozoic greenstone belts and accretionary complexes in northern Sweden1999In: Gold '99 Trondheim: Precambrian gold in the Fennoscandian and Ukrainian shields and related areas : abstract volume / [ed] Nigel J. Cook; Krister Sundblad, Trondheim: American Speech-Language-Hearing Association, 1999, p. 115-118Conference paper (Other academic)
  • 25. Allen, Rodney
    et al.
    Weihed, Pär
    Geological Survey of Sweden.
    Svenson, S. A.
    Jonsson, Rolf
    Evolution of the Skellefte massive sulphide district, Sweden, and facies analysis of mineralized silicic submarine intrusive dome-hyaloclastite-tuff cone volcanoes1993In: IAVCEI abstracts: ancient volcanism & modern analogues, Australian Geological Survey Organisation , 1993Conference paper (Other academic)
  • 26.
    Allen, Rodney
    et al.
    Volcanic Resources Ltd, Stavanger.
    Weihed, Pär
    Geological Survey of Sweden.
    Svensson, S. Å.
    Boliden AB.
    Setting of Zn-Cu-Au-Ag massive sulfide deposits in the evolution and facies architecture of a 1.9 Ga marine volcanic arc: Skellefte district, Sweden1996In: Economic geology and the bulletin of the Society of Economic Geologists, ISSN 0361-0128, E-ISSN 1554-0774, Vol. 91, no 6, p. 1022-1053Article in journal (Refereed)
    Abstract [en]

    Skellefte mining district occurs in an Early Proterozoic, mainly 1.90-1.87 Ga (Svecofennian) magmatic province of low to medium metamorphic grade in the Baltic Shield in northern Sweden. The district contains over 85 pyritic Zn-Cu-Au-Ag massive sulfide deposits and a few vein Au deposits and subeconomic porphyry Cu-Au-Mo deposits, The massive sulfide deposits mainly occur within, and especially along the top of: a regional felsic-dominant volcanic unit attributed to a stage of intense, extensional, continental margin are volcanism. From facies analysis we interpret the paleogeography of this stage to have comprised many scattered islands and shallow-water areas. surrounded by deeper seas. All the major massive sulfide ores occur in below-wave base facies associations: however, some ores occur close to stratigraphic intervals of above-wave base facies associations, and the summits of some volcanoes that host massive sulfides emerged above sea level. Intense marine volcanism was superceded at different times in different parts of tile district by a stage of reduced volcanism, uplift resulting in subregional disconformities, and then differential uplift and subsidence resulting in a complex horst and graben paleogeography. Uplift of the are is attributed to the relaxation of crustal extension and the emplacement of granitoids to shallow crustal levels. A few massive sulfide ores formed within the basal strata of this second stage. The horst and graben system was filled by prograding fluvial-deltaic sediments and mainly mafic lavas, and during this stage the Skellefte district was a transitional area between renewed are volcanism of more continental character to the north, and subsidence and basinal mudstone-turbidite sedimentation to the south. This whole volcanotectonic cycle occurred within 10 to 15 m.y. We define 26 main volcanic, sedimentary, and intrusive facies in the Skellefte district. The most abundant facies are (1) normal-graded pumiceous breccias, which are interpreted as syneruptive subaqueous mass flow units of pyroclastic debris, (2) porphyritic intrusions, and (3) mudstone and sandstone turbidites. Facies associations define seven main volcano types, which range from basaltic shields to andesite cones and rhyolite calderas. Despite this diversity of volcano types, most massive sulfide ol es are associated with one volcano type: subaqueous rhyolite cryptodome-tuff volcanoes. These rhyolite volcanoes are 2 to 10 km in diameter, 250 to 1,200 m thick at the center, and are characterized by a small to moderate volume rhyolitic pyroclastic unit, intruded by rhyolite cryptodomes, sills, and dikes. Massive sulfide ores occur near the top of the proximal (near vent) facies association The remarkable coincidence in space and time between the ores and this volcano type indicates an intimate, genetic relationship between the ores and the magmatic evolution of the volcanoes.Many of the massive sulfide ores occur within rapidly emplaced volcaniclastic facies and are interpreted to have formed by infiltration and replacement of these facies. Some of the ore deposits have characteristics of both marine massive sulfides and subaerial epithelial deposits. We suggest that massive sulfides in the Skellefte district span a range in ore deposit style from deep-water sea floor ores, to subsea-floor replacements, to shallow-water and possible subaerial synvolcanic replacements. Facies models are provided for the mineralized rhyolite volcanoes and volcanological guides are provided for exploration for blind ores within these volcanoes.

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  • 27.
    Alvarenga, Rodrigo A.F.
    et al.
    Ghent University, Belgium.
    Dewulf, Jo
    Ghent University, Belgium.
    Guinée, Jeroen
    Leiden University, the Netherlands.
    Schulze, Rita
    Leiden University, the Netherlands.
    Weihed, Pär
    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.
    Drielsma, Johannes
    Euromines, Belgium.
    Towards product-oriented sustainability in the (primary) metal supply sector2019In: Resources, Conservation and Recycling, ISSN 0921-3449, E-ISSN 1879-0658, Vol. 145, p. 40-48Article in journal (Refereed)
    Abstract [en]

    Consideration of sustainable supply of (primary) metals is increasingly influencing the policy agenda of western societies. Environmental sustainability can be managed from different perspectives, including a site-oriented one (strongly used by the mining sector) and a product-oriented one (as with life cycle assessment). The objectives of this article are to analyse and discuss the differences in these perspectives; to discuss potential benefits to the metal/mining sector of also considering the product-oriented perspective; and to propose ways for a smooth implementation. We made use of literature and expert knowledge, on top of interviews with different stakeholders, to identify why and how these perspectives are (not) used in the metal/mining sector. Moreover, we identified three key concerns related to the implementation of a product-oriented perspective in the sector (e.g., use of unrepresentative life cycle inventory (LCI) datasets for metal-based products) and proposed three corrective actions for all of them (e.g., increase the quantity and quality of LCI). Finally, we discuss how the corrective actions could be implemented in the sector in a smooth way and some potential benefits from its implementation.

  • 28.
    Amjad, Muhammad Raiees
    et al.
    Department of Earth and Environmental Sciences, Bahria School of Engineering and Applied Sciences, Bahria University, Islamabad44000, Pakistan.
    Ehsan, Muhsan
    Institute of Geophysics and Geomatics, China University of Geosciences, Wuhan430074, P. R. China.
    Hussain, Muyyassar
    Advance Reservoir Characterization, LMK Resources, Islamabad44000, Pakistan.
    Al-Ansari, Nadhir
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Rehman, Abdul
    Department of Earth and Environmental Sciences, Bahria School of Engineering and Applied Sciences, Bahria University, Islamabad44000, Pakistan.
    Naseer, Zohaib
    Department of Earth and Environmental Sciences, Bahria School of Engineering and Applied Sciences, Bahria University, Islamabad44000, Pakistan.
    Ejaz, Muhammad Nauman
    Department of Earth and Environmental Sciences, Bahria School of Engineering and Applied Sciences, Bahria University, Islamabad44000, Pakistan.
    Baouche, Rafik
    Department of Geophysics, Laboratory of Resources Minérals at Energétiques, Faculty of Sciences, M’Hamed Bougara University of Boumerdes, Boumerdès35000, Algeria.
    Elbeltagi, Ahmed
    Agricultural Engineering Dept., Faculty of Agriculture, Mansoura University, Mansoura35516, Egypt.
    Carbonate Reservoir Quality Variations in Basins with a Variable Sediment Influx: A Case Study from the Balkassar Oil Field, Potwar, Pakistan2023In: ACS Omega, E-ISSN 2470-1343, Vol. 8, no 4, p. 4127-4145Article in journal (Refereed)
    Abstract [en]

    The carbonate reservoir quality is strongly reliant on the compaction process during sediment burial and other processes such as cementation and dissolution. Porosity and pore pressure are the two main factors directly affected by mechanical and chemical compactions. Porosity reduction in these carbonates is critically dependent on the overburden stress and subsidence rate. A variable sediment influx in younger basins may lead to changes in the reservoir quality in response to increasing lithostatic pressure. Deposition of molasse sediments as a result of the Himalayan orogeny caused variations in the sedimentation influx in the Potwar Basin of Pakistan throughout the Neogene times. The basic idea of this study is to analyze the carbonate reservoir quality variations induced by the compaction and variable sediment influx. The Sakesar Limestone of the Eocene age, one of the proven carbonate reservoirs in the Potwar Basin, shows significant changes in the reservoir quality, specifically in terms of porosity and pressure. A 3D seismic cube (10 km2) and three wells of the Balkassar field are used for this analysis. To determine the vertical and lateral changes of porosity in the Balkassar area, porosity is computed from both the log and seismic data. The results of both the data sets indicate 2–4% porosities in the Sakesar Limestone. The porosity reduction rate with respect to the lithostatic pressure computed with the help of geohistory analysis represents a sharp decrease in porosity values during the Miocene times. Pore pressure predictions in the Balkassar OXY 01 well indicate underpressure conditions in the Sakesar Limestone. The Eocene limestones deposited before the collision of the Indian plate had enough time for fluid expulsion and show underpressure conditions with high porosities. 

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  • 29.
    Amoorizi Varnamkhasti, Kianoosh
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering.
    Competitive Business framework design toward the circular economy2021Independent thesis Advanced level (degree of Master (Two Years)), 80 credits / 120 HE creditsStudent thesis
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  • 30.
    Andersson, Joel
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Paleoproterozoic deformation in the Kiruna‑Gällivare area in northern Norrbotten, Sweden: Setting, character, age, and control of iron oxide-apatite deposits2021Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis covers the structural evolution of the Kiruna‑Gällivare area in the northern Norrbotten ore province, Sweden. The study area hosts several economically significant iron oxide-apatite (IOA) deposits and includes the type locality for this ore type. Despite the abundant work on the genesis of IOA-systems, their structural setting and control is poorly constrained. This highlights the need for multi-scale structural studies that can help to unravel structural controls on the genesis and overprinting deformation histories. Four IOA-hosting key study areas were under investigation covering multi-scale structural controls from regional to deposit scale. Extensive geological mapping focused on structures, stratigraphy, and hydrothermal alteration, combined with multi-scale structural analysis and U-Pb geochronology was conducted. Results are synthesized in a time-constrained tectonothermal model for IOA deposits and host rocks of the Kiruna‑Gällivare area.

    The results indicate that the IOA deposits in Norrbotten formed in an overall extensional regime coeval with basin development in a backarc setting. The onset of basin development is indicated by a U-Pb age in zircon from a volcanic intercalation in a stratigraphically basal alluvial conglomerate of the ore-bearing sequence. A titanite age indicates that an ore-proximal cataclastic fault has syn-volcanic origin and formed coeval with basin development and ore formation. A similar origin is postulated for ore-proximal biotite-bearing structures at the Malmberget IOA deposit. In comparison with Kiruna, the Malmberget area experienced higher metamorphic conditions and records a more complex deformation history. 

    Following backarc extension, subsequent crustal shortening resulted in basin inversion and re-activation of structures. Crustal scale, reverse shear zones developed in favourable lithologies and inferred pre-existing structures during D1. The timing of D1 crustal shortening coincides with peak metamorphism (M1) and is bracketed by crosscutting relationships. In contrast, the timing of an overprinting D2 crustal shortening is directly constrained by U-Pb geochronology in titanite indicating an age of approx. 1.8 Ga during an event tentatively interpreted to have lasted up to 20 m.y. This time span is coeval with the exhumation of the Kiruna mining district as recorded by an U‑Pb reset age in apatite in association to an IOA deposit. The D2 deformation is characterized by reactivation of older structures and responsible for juxtaposition of blocks from different crustal levels and tectonic exhumation into upper crustal domains. Transposition of fabrics and ore bodies into re-activated listric faults during basin inversion explains sub-parallel relationships between the ore-proximal structures, bedding, and stratiform/stratabound orebodies.

    Sodic-calcic + Fe ± Cl alteration is widespread and generally sits in early structural positions and interpreted as pre‑ to syn‑D1. However, U-Pb titanite results indicate that sodic-calcic alteration was developed also during the younger D2 event and shows that the alteration style is temporally and spatially widely distributed. Commonly, the alteration styles associated with D2 deformation are potassic in character and associated to Fe- and Cu-sulphide minerals. These potassic alteration assemblages sit in structurally late positions, often brittle in character. Sulphides were remobilized into D2-structures and the entrapment style is mainly controlled by rock competency.

    A least two additional overprinting deformation phases are identified (D3 and D4). Clockwise rotation of the overall crustal shortening direction resulted in a gentle refolding of the inverted basin and influences the shape of some IOA deposits in the Kiruna mining district. Dominant joint structures at the Malmberget IOA deposit are indicated as relatively early features and their development is controlled by pre-existing foliation and crosscut by hydrothermally altered structures, that may be coeval with hydraulic fracturing in the Kiruna mining district that crosscut all other fabrics.

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  • 31.
    Andersson, Joel
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Structural evolution of two ore-bearing Palaeoproterozoic metasupracrustal belts in the Kiruna area, Northwestern Fennoscandian Shield2019Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    In this project, two key study areas in the northwestern Fennoscandian Shield are under investigation. The “Western supracrustal belt” and “Central Kiruna area” are both located along lithotectonically comparable Rhyacian-Orosirian metasupracrustal belts and both areas are characterized by iron oxide-apatite (IOA) and iron oxide-copper-gold (IOCG)-style mineralizations and related hydrothermal alterations. The area is in general well studied but the structural evolution remains unresolved. In order to build a structural framework for the Kiruna area, the number of deformation events, kinematics, geometries, mineralogy and interrelationships of the dominant structures are under focus in this study. The paired structural-alteration configuration is targeted in order to constrain the relative timing of dominant structures and mineral alteration parageneses in order to use these systems as structural vectors of mineralized systems. Furthermore, the Orosirian stratigraphy is re-evaluated in order to constrain the pre-compressional geological history of the study areas. This is important as it controls the character of the structural development during subsequent compression forming the sub-surface architecture as we see today.

    The Orosirian stratigraphy suggests the development of a syn-extensional basin in Kiruna where iron oxide-apatite deposits were emplaced. This basin was subsequently inverted accompanied by shearing, folding, and faulting during D1 and D2, refolded during D3, and further fractured during D4. The shortening directions inferred during the deformation events suggest a clockwise rotation of the stress field from NE-SW (D1) to E-W (D2) and finally NNW-SSE (D3). Regional scapolite ± albite alteration is interpreted to be coeval with regional amphibole + magnetite alteration during D1. Mineral alteration parageneses linked to D2 is more potassic in character and often structurally controlled by shear zones. As a regional generalization, the potassic dominated D2-alteration is characterized by sericite ± epidote ± biotite ± chlorite ± magnetite ± sulphide ± K-feldspar. Fe- and Cu-sulphides are concentrated into brittle D2-structures suggesting that a IOCG-style of mineralization can be linked to the potassic D2 event. This implies that iron oxide-apatite emplacement can be linked to the basin development phase, whereas epigenetic Fe- and Cu-sulphides are linked to the basin inversion-phase of the geological evolution, and hence, separated in time and probably not directly genetically linked in Kiruna.

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  • 32.
    Andersson, Joel B. H.
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Warlo, Mathis
    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.
    Bergqvist, Mikael
    Orexplore AB, Kista, Sweden.
    Hansson, Alexander
    Orexplore AB, Kista, Sweden.
    Structural controls on sulphide (re)-distribution in Kiruna2019In: Proceedings of the 15th SGA Biennial Meeting, 27-30 August, University of Glasgow Publicity Services , 2019, Vol. 1, p. 115-118Conference paper (Refereed)
    Abstract [en]

    In this study, we investigate a potential structural control on sulphide distribution in phyllite from the Kiruna area, northern Norrbotten, Sweden. We use X-ray tomography and X-ray fluorescence analyzed in tandem on a 40 cm section of oriented drill core. Scanning Electron Microscopy and Energy Dispersive Spectrometry are used in combination with optical microscopy to analyze mineralogy and microstructures. The results show that sulphides are distributed along So bedding planes, re-distributed along S-2 axial planar cleavage planes, and trapped by F-2-hinge zones and shear bands visible as elevated sulphide concentrations. The results of this study underlines the strength of X-ray tomography to image 3D geological structures and their relation to mineral distributions.

  • 33.
    Andersson, Joel
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Bauer, Tobias
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Lynch, Edward P.
    Department of Mineral Resources, Geological Survey of Sweden, Uppsala, Sweden.
    Evolution of structures and hydrothermal alteration in a Palaeoproterozoic supracrustal belt: Constraining paired deformation–fluid flow events in an Fe and Cu–Au prospective terrain in northern Sweden2020In: Solid Earth, ISSN 1869-9510, E-ISSN 1869-9529, Vol. 11, no 2, p. 547-578Article in journal (Refereed)
    Abstract [en]

    An approximately 90 km long Palaeoproterozoic supracrustal belt in the northwestern Norrbotten ore province (northernmost Sweden) was investigated to characterize its structural components, assess hydrothermal alteration–structural geology correlations, and constrain a paired deformation–fluid flow evolution for the belt. New geological mapping of five key areas (Eustiljåkk, Ekströmsberg, Tjårrojåkka, Kaitum West, and Fjällåsen–Allavaara) indicates two major compressional events (D1 and D2) have affected the belt, with each associated with hydrothermal alteration types typical for iron oxide–apatite and iron oxide Cu–Au systems in the region. Early D1 generated a regionally distributed, penetrative S1 foliation and oblique reverse shear zones that show a southwest-block-up sense of shear that formed in response to NE–SW crustal shortening. Peak regional metamorphism at epidote–amphibolite facies broadly overlaps with this D1 event. Based on overprinting relationships, D1 is associated with regional scapolite ± albite, magnetite + amphibole, and late calcite alteration of mafic rock types. These hydrothermal mineral associations linked to D1 structures may form part of a regionally pervasive evolving fluid flow event but are separated in this study by crosscutting relationships.

    During D2 deformation, folding of S0–S1 structures generated F2 folds with steeply plunging fold axes in low-strain areas. NNW-trending D1 shear zones experienced reverse dip-slip reactivation and strike-slip-dominated movements along steep, E–W-trending D2 shear zones, producing brittle-plastic structures. Hydrothermal alteration linked to D2 structures is a predominantly potassic–ferroan association comprising K-feldspar ± epidote ± quartz ± biotite ± magnetite ± sericite ± sulfides. Locally, syn- or post-tectonic calcite is the main alteration mineral in D2 shear zones that intersect mafic rocks. Our results highlight the importance of combining structural geology with the study of hydrothermal alterations at regional to belt scales to understand the temporal–spatial relationship between mineralized systems. Based on the mapping results and microstructural investigations as well as a review of earlier tectonic models presented for adjacent areas, we suggest a new structural model for this part of the northern Fennoscandian Shield. The new model emphasizes the importance of reactivation of early structures, and the model harmonizes with tectonic models presented by earlier workers based mainly on petrology of the northern Norrbotten area.

  • 34.
    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.

  • 35.
    Andersson, Joel B.H.
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Bauer, Tobias
    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. Division of Geosciences and Environmental Engineering, Luleå University of Technology, SE-971 87 Luleå, Sweden.
    Structural Evolution of the Central Kiruna Area, Northern Norrbotten, Sweden: Implications on the Geologic Setting Generating Iron Oxide-Apatite and Epigenetic Iron and Copper Sulfides2021In: Economic geology and the bulletin of the Society of Economic Geologists, ISSN 0361-0128, E-ISSN 1554-0774, Vol. 116, no 8, p. 1981-2009Article in journal (Refereed)
    Abstract [en]

    To guide future exploration, this predominantly field based study has investigated the structural evolution of the central Kiruna area, the type locality for iron oxide-apatite deposits that stands for a significant amount of the European iron ore production. Using a combination of geologic mapping focusing on structures and stratigraphy, petrography with focus on microstructures, X-ray computed tomography imaging of sulfide-structure relationships, and structural 2D-forward modeling, a structural framework is provided including spatial-temporal relationships between iron oxide-apatite emplacement, subeconomic Fe and Cu sulfide mineralization, and deformation. These relationships are important to constrain as a guidance for exploration in iron oxide-apatite and iron oxide copper-gold prospective terrains and may help to understand the genesis of these deposit types. Results suggest that the iron oxide-apatite deposits were emplaced in an intracontinental back-arc basin, and they formed precrustal shortening under shallow crustal conditions. Subsequent east-west crustal shortening under greenschist facies metamorphism inverted the basin along steep to moderately steep E-dipping structures, often subparallel with bedding and lithological contacts, with reverse, oblique to dip-slip, east-block-up sense of shears. Fe and Cu sulfides associated with Fe oxides are hosted by structures formed during the basin inversion and are spatially related to the iron oxide-apatite deposits but formed in fundamentally different structural settings and are separated in time. The inverted basin was gently refolded and later affected by hydraulic fracturing, which represent the last recorded deformation-hydrothermal events affecting the crustal architecture of central Kiruna.

  • 36.
    Andersson, Joel B.H.
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Logan, Leslie
    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.
    Chew, David
    Department of Geology, School of Natural Sciences, Trinity College Dublin, Ireland.
    Kooijman, Ellen
    Department of Geosciences, Swedish Museum of Natural History, 10405 Stockholm, Sweden.
    Kielman-Schmitt, Melanie
    Department of Geosciences, Swedish Museum of Natural History, 10405 Stockholm, Sweden.
    Kampmann, Tobias C.
    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.
    U-Pb zircon-titanite-apatite age constraints on basin development and basin inversion in the Kiruna mining district, Sweden2022In: Precambrian Research, ISSN 0301-9268, E-ISSN 1872-7433, Vol. 372, article id 106613Article in journal (Refereed)
    Abstract [en]

    To constrain the tectonothermal evolution of the type locality for iron oxide-apatite deposits, we have obtained U-Pb zircon, titanite, and apatite age data for the Kiruna mining district in northernmost Sweden. The results indicate that the host basin initiated in an overall extensional regime as indicated by the deposition of alluvial conglomerates and greywackes. A volcanic intercalation in a conglomerate unit northwest of the Luossavaara iron oxide-apatite deposit yields a U-Pb zircon age of 1887 ± 3 Ma representing the timing of the earliest Orosirian volcanism in the central Kiruna mining district coinciding with the onset of basin development. In-situ analysis of titanite on hydrothermally altered fracture planes within a cataclastic fault damage zone (c. 270 m from the fault core system associated to the Luossavaara iron oxide-apatite deposit) yields complex U-Pb data. Applying a strict discordance filter yields a 207Pb/206Pb age of 1889 ± 26 Ma. The age implies that the fault probably has a syn-volcanic origin and that syn-volcanic faults may have played an important role during iron ore emplacement. The mineralized basin was subsequently buried and metamorphosed under upper greenschist-facies conditions and later tectonically exhumed and cooled below the apatite closure temperature at 1805 ± 26 Ma indicated by apatite from the Nukutus iron oxide-apatite deposit. Basin inversion is temporally constrained by syn-tectonic titanite as part of sodic-calcic + Fe + Cl hydrothermal alteration along a brittle-ductile reverse shear zone to the east of the study area. Titanite grains that show sector and oscillatory zoning yield an age of 1812 ± 3 Ma, which we interpret as the onset of basin inversion. Homogeneous (relatively unzoned) titanite in the same sample yields an age of 1802 ± 8 Ma, tentatively indicating that the tectonothermal activity lasted up to c. 20 m.y.

  • 37.
    Andersson, L. Christer
    Luleå University of Technology.
    The application of landsat data on geological structure interpretation1981In: Geoexploration, ISSN 0016-7142, Vol. 19, no 2, p. 143-144Article in journal (Other academic)
  • 38.
    Andersson, Ulf Bertil
    et al.
    Committee for Geological Nomenclature, Swedish National Committee for Geology, Royal Swedish Academy of Sciences, Stockholm, Sweden.
    Jansson, Nils
    Committee for Geological Nomenclature, Swedish National Committee for Geology, Royal Swedish Academy of Sciences, Stockholm, Sweden.
    Wickström, Linda
    Committee for Geological Nomenclature, Swedish National Committee for Geology, Royal Swedish Academy of Sciences, Stockholm, Sweden.
    Bergman, Stefan
    Committee for Geological Nomenclature, Swedish National Committee for Geology, Royal Swedish Academy of Sciences, Stockholm, Sweden.
    Kumpulainen, Risto
    Committee for Geological Nomenclature, Swedish National Committee for Geology, Royal Swedish Academy of Sciences, Stockholm, Sweden.
    Johnson, Mark
    Committee for Geological Nomenclature, Swedish National Committee for Geology, Royal Swedish Academy of Sciences, Stockholm, Sweden.
    Olvmo, Mats
    Committee for Geological Nomenclature, Swedish National Committee for Geology, Royal Swedish Academy of Sciences, Stockholm, Sweden.
    McLoughlin, Stephen
    Committee for Geological Nomenclature, Swedish National Committee for Geology, Royal Swedish Academy of Sciences, Stockholm, Sweden.
    Calner, Mikael
    Committee for Geological Nomenclature, Swedish National Committee for Geology, Royal Swedish Academy of Sciences, Stockholm, Sweden.
    Emendment to the term complex in: “Guide for geological nomenclature in Sweden” (Kumpulainen 2016)2022In: GFF, ISSN 1103-5897, E-ISSN 2000-0863, Vol. 144, no 3-4, p. 151-151Article in journal (Other academic)
  • 39.
    Antal, Ildiko
    et al.
    Sveriges Geologiska Undersökning.
    Bergström, Ulf
    Sveriges Geologiska Undersökning.
    Kathol, Benno
    Sveriges Geologiska Undersökning.
    Lundström, Ingmar
    Sveriges Geologiska Undersökning.
    Weihed, Pär
    Kartbladen 23J Norsjö2000In: Regional berggrundsgeologisk undersökning: sammanfattning av pågående undersökningar 2000, Uppsala: Sveriges Geologiska Undersökning , 2000, p. 38-47Chapter in book (Other academic)
  • 40.
    Anthony, Niklas
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Frostevarg, Jan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Product and Production Development.
    Suhonen, Heikki
    Department of Physics, P.O. Box 64, 00014 University of Helsinki, Finland.
    Wanhainen, Christina
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Granvik, Mikael
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology. Department of Physics, P.O. Box 64, 00014 University of Helsinki, Finland.
    Laser-induced spallation of minerals common on asteroids2021In: Acta Astronautica, ISSN 0094-5765, E-ISSN 1879-2030, Vol. 182, p. 325-331Article in journal (Refereed)
    Abstract [en]

    The ability to deflect dangerous small bodies in the Solar System or redirect profitable ones is a necessary and worthwhile challenge. One well-studied method to accomplish this is laser ablation, where solid surface material sublimates, and the escaping gas creates a momentum exchange. Alternatively, laser-induced spallation and sputtering could be a more efficient means of deflection, yet little research has studied these processes in detail. We used a 15-kW Ytterbium fiber laser on samples of olivine, pyroxene, and serpentine (minerals commonly found on asteroids) to induce spallation. We observed the process with a high-speed camera and illumination laser, and used X-ray micro-tomography to measure the size of the holes produced by the laser to determine material removal efficiency. We found that pyroxene will spallate at power densities between 1.5 and 6.0 kW cm−2, serpentine will also spallate at 13.7 kW cm−2, but olivine does not spallate at 1.5 kW cm−2 and higher power densities melt the sample. Laser-induced spallation of pyroxene and serpentine can be two- to three-times more energy efficient (volume removed per unit of absorbed energy) than laser-induced spattering, and over 40x more efficient than laser ablation.

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  • 41.
    Anthony, Niklas
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Frostevarg, Jan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Product and Production Development.
    Suhonen, Heikki
    Department of Physics, P.O. Box 64, 00014 University of Helsinki, Finland.
    Wanhainen, Christina
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Penttilä, Antti
    Department of Physics, P.O. Box 64, 00014 University of Helsinki, Finland.
    Granvik, Mikael
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology. Department of Physics, P.O. Box 64, 00014 University of Helsinki, Finland.
    Laser processing of minerals common on asteroids2021In: Optics and Laser Technology, ISSN 0030-3992, E-ISSN 1879-2545, Vol. 135, article id 106724Article in journal (Refereed)
    Abstract [en]

    Asteroid mining and redirection are two trends that both can utilize lasers, one to drill and cut, the other to ablate and move. Yet little is known about what happens when a laser is used to process the types of materials we typically expect to find on most asteroids. To shed light on laser processing of asteroid material, we used a 300-W, pulsed Ytterbium fiber laser on samples of olivine, pyroxene, and serpentine, and studied the process with a high-speed camera and illumination laser at 10 000 frames per second. We also measure the sizes of the resulting holes using X-ray micro-tomography to find the pulse parameters which remove the largest amount of material using the least amount of energy. We find that at these power densities, all three minerals will melt and chaotically throw off spatter. Short, low-power pulses can efficiently produce thin, deep holes, and long, high-power pulses are more energy efficient at removing the most amount of material.

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  • 42.
    Arvanitidis, N
    et al.
    Institute of Geology and Mineral Exploration (IGME).
    Michael, C
    Institute of Geology and Mineral Exploration (IGME).
    Christidis, C
    National and Kapodistrian University of Athens.
    Weihed, Pär
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Gaal, Gabor
    Geological Survey of Finland, P.O.Box 96, 02151 Espoo.
    Royer, J.J.
    Université de Lorraine, CNRS, Nancy.
    Perantonis, G
    Hellas Gold S.A..
    Bakalis, V
    Hellas Gold S.A..
    Ballas, D
    Hellas Gold S.A..
    Using 3D/4D modelling tools in exploration for epithermal gold potential areas in Eastern Rhodope zone (Western Thrace, NE Greece)2013In: Mineral deposit research for a high-tech world: Proceedings of the 12th Biennial SGA Meeting, 12–15 August 2013, Uppsala, Sweden, Uppsala: Sveriges Geologiska Undersökning , 2013, Vol. 1, p. 58-61Conference paper (Refereed)
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  • 43.
    Arvanitidis, N
    et al.
    Institute of Geology and Mineral Exploration (IGME).
    Michael, C
    Institute of Geology and Mineral Exploration (IGME).
    Christidis, C
    National and Kapodistrian University of Athens.
    Weihed, Pär
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Gaal, Gabor
    Geological Survey of Finland.
    Royer, J.J.
    Université de Lorraine, CNRS, Nancy.
    Perantonis, G
    Hellas Gold S.A..
    Bakalis, V
    Hellas Gold S.A..
    Ballas, D
    Hellas Gold S.A..
    Using 3D/4D modelling tools in exploration for porphyry and manto-polymetallic potential areas in Eastern Chalkidiki peninsula2013In: Mineral deposit research for a high-tech world: Proceedings of the 12th SGA Biennial Meeting 2013, 12-15 August 2013, Uppsala, Sweden, Uppsala: Sveriges Geologiska Undersökning , 2013, Vol. 1, p. 54-57Conference paper (Refereed)
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  • 44.
    Asani, Besnik
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Investigation of bedrock quality for use as aggregates in Umeå municipality2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
  • 45.
    Ask, Maria
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Ask, Daniel
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering. FracSinus Rock Stress Measurement AB, Luleå.
    Cornet, Francois
    University of Strasbourg, School and Observatory of Earth Sciences, Strasbour.
    Nilsson, Tommy
    University of Strasbourg, School and Observatory of Earth Sciences, Strasbourg.
    A hydraulic stress measurement system for deep borehole investigations2017In: Geophysical Research Abstracts, ISSN 1029-7006, E-ISSN 1607-7962, Vol. 19Article in journal (Other academic)
    Abstract [en]

    Lulea University of Technology (LTU) is developing and building a wire-line system for hydraulic rock stress measurements, with funding from the Swedish Research Council and Lulea University of Technology. In this project, LTU is collaborating with University of Strasbourg and Geosigma AB. The stress state influences drilling and drillability, as well as rock mass stability and permeability. Therefore, knowledge about the state of in-situ stress (stress magnitudes, and orientations) and its spatial variation with depth is essential for many underground rock engineering projects, for example for underground storage of hazardous material (e.g. nuclear waste, carbon dioxide), deep geothermal exploration, and underground infrastructure (e.g. tunneling, hydropower dams). The system is designed to conduct hydraulic stress testing in slim boreholes. There are three types of test methods: (1) hydraulic fracturing, (2) sleeve fracturing and (3) hydraulic testing of pre-existing fractures. These are robust methods for determining in situ stresses from boreholes. Integration of the three methods allows determination of the three-dimensional stress tensor and its spatial variation with depth in a scientific unambiguously way. The stress system is composed of a downhole and a surface unit. The downhole unit consists of hydraulic fracturing equipment (straddle packers and downhole imaging tool) and their associated data acquisition systems. The testing system is state of the art in several aspects including: (1) Large depth range (3 km), (2) Ability to test three borehole dimensions (N=76 mm, H=96 mm, and P=122 mm), (3) Resistivity imager maps the orientation of tested fracture; (4) Highly stiff and resistive to corrosion downhole testing equipment; and (5) Very detailed control on the injection flow rate and cumulative volume is obtained by a hydraulic injection pump with variable piston rate, and a highly sensitive flow-meter. At EGU General Assembly 2017, we would like to present this new and unique stress measurement system and some initial test results from a 1200 m long borehole in crystalline rock

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  • 46.
    Autio, U.A.
    et al.
    Oulu Mining School, University of Oulu, P.O. Box 3000, FI-90014 Oulu, Finland.
    Smirnov, Maxim Yu.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Smirnova, M.
    Institute of Geophysics and Meteorology, University of Cologne, Pohligstrasse 3, 50969 Cologne, Germany.
    Bauer, Tobias E.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Korja, T.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Magnetotelluric array in the central Finnish Lapland II: 3-D inversion and tectonic implications2020In: Tectonophysics, ISSN 0040-1951, E-ISSN 1879-3266, Vol. 794, article id 228574Article in journal (Refereed)
    Abstract [en]

    The northern part of the Fennoscandian shield records several Palaeoproterozoic phases of rifting, crustal shortening, metamorphism and structural reactivation. The geologic history has left behind a complex crustal geoelectric structure as evidenced by magnetotelluric (MT) data from the central Finnish Lapland acquired in the context of the MaSca-project in 2014. The data are characterized by strong 3-D effects such as high phase tensor skew values and anomalous induction vectors. Interestingly, however, at the same time a dominant E-W principal direction from the phase tensor data can be inferred. 3-D conductivity models derived using the ModEM code display, high crustal conductance (> 10,000 S) in the vicinity of the Central Lapland Greenstone Belt, the Peräpohja Belt and the Kuusamo Belt. Conductors in the northern and southern part of the study area are separated by a resistor coinciding with the Central Lapland Granitoid Complex. A remarkable feature is an arc-shaped conductor inside the northern part of the Central Lapland Granitoid Complex, which continues into the Central Lapland Greenstone Belt in the north. The conductor is associated with a major induction vector anomaly and also coincides with extreme responses (negative phase tensor principal values), which are discussed in an accompanying paper. The conductive structures in the models are interpreted as deeply buried graphite and sulphide bearing metasedimentary rocks or as reactivated Archaean shear zones. The revealed geoelectric structures also partly correlate with seismic reflection and other geophysical data from the area. A possible explanation for the observed pervasive E-W principal direction of the phase tensor data could be the aulacogen (failed rift) suggested in recent tectonic evolution models.

  • 47.
    Backer, Sumina Namboorimadathil
    et al.
    Research Institute of Sciences and Engineering, University of Sharjah, Sharjah P.O. Box 27272, United Arab Emirates.
    Bouaziz, Ines
    Research Institute of Sciences and Engineering, University of Sharjah, Sharjah P.O. Box 27272, United Arab Emirates.
    Kallayi, Nabeela
    Department of Chemistry, India Institute of Technology Indore, Indore 453552, India.
    Thomas, Reny Thankam
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Preethikumar, Gopika
    Functional Materials, Materials Science and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology (NIIST), Thiruvananthapuram 695019, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India.
    Takriff, Mohd Sobri
    Research Institute of Sciences and Engineering, University of Sharjah, Sharjah P.O. Box 27272, United Arab Emirates; Chemical and Water Desalination Engineering Program, College of Engineering, University of Sharjah, Sharjah P.O. Box 27272, United Arab Emirates; Department of Chemical and Processing Engineering, Universiti Kebangsaan Malaysia, Bangi 43600, Malaysia; Department of Mechanical and Nuclear Engineering, College of Engineering, University of Sharjah, Sharjah P.O. Box 27272, United Arab Emirates.
    Laoui, Tahar
    Research Institute of Sciences and Engineering, University of Sharjah, Sharjah P.O. Box 27272, United Arab Emirates; Department of Mechanical and Nuclear Engineering, College of Engineering, University of Sharjah, Sharjah P.O. Box 27272, United Arab Emirates.
    Atieh, Muataz Ali
    Research Institute of Sciences and Engineering, University of Sharjah, Sharjah P.O. Box 27272, United Arab Emirates; Chemical and Water Desalination Engineering Program, College of Engineering, University of Sharjah, Sharjah P.O. Box 27272, United Arab Emirates.
    Review: Brine Solution: Current Status, Future Management and Technology Development2022In: Sustainability, E-ISSN 2071-1050, Vol. 14, no 11, article id 6752Article, review/survey (Refereed)
    Abstract [en]

    Desalination brine is extremely concentrated saline water; it contains various salts, nutrients, heavy metals, organic contaminants, and microbial contaminants. Conventional disposal of desalination brine has negative impacts on natural and marine ecosystems that increase the levels of toxicity and salinity. These issues demand the development of brine management technologies that can lead to zero liquid discharge. Brine management can be productive by adopting economically feasible methodologies, which enables the recovery of valuable resources like freshwater, minerals, and energy. This review focuses on the recent advances in brine management using various membrane/thermal-based technologies and their applicability in water, mineral, and energy recoveries, considering their pros and cons. This review also exemplifies the hybrid processes for metal recovery and zero liquid discharge that may be adopted, so far, as an appropriate futuristic strategy. The data analyzed and outlook presented in this review could definitely contribute to the development of economically achievable future strategies for sustainable brine management.

  • 48.
    Bahrami, Ataallah
    et al.
    Department of Mining Engineering, Faculty of Engineering – Urmia University, Urmia, Iran.
    Kazemi, Fatemeh
    Mineral Processing, Faculty of Engineering – University of Kashan, Kashan, Iran.
    Abdollahi, Morteza
    Mineral Processing, Faculty of Mining Engineering – Isfahan University of Technology, Isfahan, Iran.
    Mirmohammadi, MirSaleh
    School of Mining Engineering, University of Tehran, Tehran, Tehran, Iran.
    Danesh, Abolfazl
    PhD student of Mineral processing, Faculty of Mining Engineering, Sahand University of Technology, Tabriz, Iran.
    Ghorbani, Yousef
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    The effect of grinding circuit efficiency on the grade and recovery of copper and molybdenum concentrates2022In: Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, ISSN 1556-7036, E-ISSN 1556-7230, Vol. 44, no 3, p. 8121-8134Article in journal (Refereed)
    Abstract [en]

    The efficiency of grinding and flotation process in copper-molybdenum processing circuit, largely affected by performance of thickeners and hydrocyclones devices. The goal of this paper is to investigate the effect of the rate-limiting factors on the performance of these devices and consequently on grinding and separation efficiency of the molybdenum processing circuit. So, a full process mineralogical study have been carried out on outputs of thickeners and hydrocyclone of the molybdenite flotation circuit. According to the results, coarse-grained fractions (>50 μm) of the planar molybdenite will not necessarily be recovered by thickener and hydrocyclones. This is especially true for hydrocyclones when the inlet-load rate is high, i.e., the erroneous discharge of planar molybdenite particles from the overflow of hydrocyclone, as well as their floatability in the thickener overflow, can be attributed to the effect of particle shape and size. This issue harms the grade and recovery of flotation due to the increase in the amount of circulating load (regrinding) and consequently the generation of fine particles (<10 μm) in the hydrocyclone-milling circuit. On the other hand, the almost spherical particles of copper minerals, as well as the nonplanar molybdenite fine-grained particles, are easily removed from the hydrocyclone underflow or settled in thickeners. The introduction of copper mineral particles into molybdenum concentrate and vice versa has reduced the quality of the produced concentrate and undesirable flotation performance.

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  • 49.
    Ballivián Justiniano, Carlos A.
    et al.
    Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET). Instituto de Recursos Minerales (INREMI), Universidad Nacional de La Plata–Comisión de Investigaciones Científicas de la Provincia de Buenos Aires, La Plata, Argentina.
    Lajoinie, María F.
    Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET). Instituto de Recursos Minerales (INREMI), Universidad Nacional de La Plata–Comisión de Investigaciones Científicas de la Provincia de Buenos Aires, La Plata, Argentina.
    Recio, Clemente
    Departamento de Geología, Facultad de Ciencias, Universidad de Salamanca (USAL), Salamanca, Spain.
    Sato, Ana M.
    Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET). Centro de Investigaciones Geológicas (CIG), CONICET–Universidad Nacional de La Plata, La Plata, Argentina.
    Basei, Miguel A.S.
    Centro de Pesquisas Geocronológicas (CPGeo), Instituto de Geociências, Universidade de São Paulo, Cidade Universitária, São Paulo (SP), Brazil.
    Proenza, Joaquín A.
    Departament de Mineralogia, Petrologia i Geologia Aplicada, Facultat de Ciències de la Terra, Universitat de Barcelona (UB), Barcelona, Spain.
    Aiglsperger, Thomas
    Departament de Mineralogia, Petrologia i Geologia Aplicada, Facultat de Ciències de la Terra, Universitat de Barcelona (UB), Barcelona, Spain.
    de Barrio, Raúl E.
    Instituto de Recursos Minerales (INREMI), Universidad Nacional de La Plata–Comisión de Investigaciones Científicas de la Provincia de Buenos Aires, La Plata, Argentina.
    Curci, Marcela V.
    Instituto de Recursos Minerales (INREMI), Universidad Nacional de La Plata–Comisión de Investigaciones Científicas de la Provincia de Buenos Aires, La Plata, Argentina.
    Lanfranchini, Mabel E.
    Comisión de Investigaciones Científicas de la Provincia de Buenos Aires (CIC). Instituto de Recursos Minerales (INREMI), Universidad Nacional de La Plata–CIC, La Plata, Argentina.
    Metamorphic evolution of the Loma Marcelo skarn within the geotectonic context of the crystalline basement of the Ventania System (Argentina)2019In: Journal of South American Earth Sciences, ISSN 0895-9811, E-ISSN 1873-0647, Vol. 92, p. 56-76Article in journal (Refereed)
    Abstract [en]

    This study describes the mineralogical and isotopic changes that carbonate xenoliths experienced under multiple metamorphic events and hydrothermal fluid circulation during the evolution of the Ventania System basement. The high reactivity of carbonate xenoliths allowed the preservation of mineral assemblages corresponding to at least three metamorphic events in the resulting Loma Marcelo skarn. The Ventania System basement is composed of Neoproterozoic granites and ignimbrites, Early Cambrian granites, and Middle Cambrian rhyolites. Carbonate xenoliths were incorporated during the intrusion of a calc-alkaline granite with an LA-ICP-MS U-Pb crystallization age of 621.6 Å} 2.2 Ma. The intrusion induced pyroxene–hornfels facies metamorphism in the carbonate xenoliths and the associated metasomatism generated calcic and magnesian skarns depending on the protolith composition. Garnet, clinopyroxene, wollastonite, bytownite, and meionite were formed in the calcic skarn (CaS), whereas forsterite and spinel were formed in the magnesian skarn (MgS). Crystallization of Early Cambrian alkaline granites was accompanied by intense hydrothermal activity that was responsible for low temperature (≤300 ÅãC) F-metasomatism in the skarn, as evidenced by the presence of F-rich vesuvianite (CaS) and chondrodite (MgS), among other minerals. Vesuvianite was formed from calc-silicate mineral assemblages of the previous metamorphic event, whereas chondrodite was formed by replacement of forsterite. The low temperature formation of these typical high-grade minerals could be an evidence of mineral formation under disequilibrium conditions favoured by the high reactivity of hydrothermal fluids. Neopalaeozoic basement mylonitization under greenschist facies metamorphism was accompanied by hydrothermal fluid circulation. This event promoted extreme mobility of chemical elements in the basement rocks and epidotization (CaS) and serpentinization (MgS) in the Loma Marcelo skarn. The elongated and boudinaged shape of the skarn bodies, parallel to the mylonitic foliation, is a consequence of dextral shearing that affected the basement rocks. Additionally, almost pure grossular crystallized post-tectonically in the CaS. Carbonates of the Loma Marcelo skarn are depleted in 13C and 18O (δ13CV PDB=−2.5/−10.1‰; δ18OV-SMOW = +7.3/+14.0‰) relative to carbonate sedimentary rocks. The δ13C and δ18O variations can be attributed to the interaction between large amounts of hydrothermal fluids (W/R=30–50) and Neoproterozoic carbonate sedimentary rocks.

  • 50.
    Barbosa, Leo
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering.
    EXAMINATION OF MICRO-SCALE SULFIDE DISTRIBUTION FOR THE GOLD MINERALIZATION IN THE LAPPBERGET DEPOSIT, GARPENBERG MINE, SWEDEN: TOWARDS A GEOMETALLURGICAL APPROACH2021Independent thesis Advanced level (degree of Master (Two Years)), 80 credits / 120 HE creditsStudent thesis
    Abstract [en]

    Ore characterization studies are of great importance to the mining industry, especially when dealing with precious metals by-products. It is a way towards increasing mining efficiency. The Swedish Boliden’s Zn–Pb–Ag–(Cu–Au) Lappberget Deposit is the main ore body at the Garpenberg Mine producing concentrates of zinc, lead, copper, and a gravity concentrate of silver and gold, which accounts for a significant revenue for the mine. Garpenberg Mine is an ancient and traditional mining site in Sweden, nonetheless the Lappberget deposit is a relatively recent discovery and there are still on-going studies on this ore body. More recently detailed ore investigations have been carried out on the sulfides and silver mineralization in different geological domains within the Lappberget deposit. In this context, the present work is focused on investigating the gold mineralization of the deposit, aiming to study the occurrence and distribution of gold minerals, characterize the gold in the ore and how its characteristics affect gold recoveries during its processing. To achieve these goals, different investigative methods were applied on drill core samples of the footwall disseminated to semi-massive mineralization (FWD), and on samples from the gravity concentrator at Boliden’s processing plant. The techniques applied were optical microscopy, scanning electron microscopy, energy dispersive x-ray spectrometry, electron probe microanalysis, laser ablation inductively couple plasma mass spectrometry, and bulk chemical analysis. The main findings pointed electrum as the main gold mineral, occurring with a strong sulfide association, in a variety of textures and grain sizes. The study also identified the occurrence of Au-Bi alloy, not previously described in literature of the Garpenberg region. The potential of invisible gold in the sulfide carriers was also a subject of investigation, as well as the evaluation of the characteristics of the samples from the gravity concentrator.

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    Barbosa.Leo_Master.Thesis
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