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  • 1.
    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
  • 2.
    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.

  • 3.
    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.

  • 4.
    Andersson, Joel B.H.
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Bauer, Tobias E.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Martinsson, Olof
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Wanhainen, Christina
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    The tectonic overprint on the Per Geijer apatite iron ores in Kiruna, northern Sweden2017In: Mineral Resources to Discover / [ed] Mercier Langevin, P; Dube, B; Bardoux, M; Ross, PS; Dion, C, Society for Geology Applied to Mineral Deposits , 2017, p. 903-906Conference paper (Refereed)
    Abstract [en]

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

  • 5.
    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.
    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.

  • 6.
    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.

  • 7.
    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.

  • 8.
    Bauer, Tobias
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Structural and sedimentological reconstruction of the inverted Vargfors basin: a base for 4D-modelling2010Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    The Palaeoproterozoic Skellefte mining district in northern Sweden covers an area of 120 by 30 km and is one of the most important mining districts in Europe, producing mainly Zn, Cu, Pb, As and Au from volcanogenic massive sulfide (VMS) and orogenic gold deposits.Detailed mapping of structures and stratigraphy within the sedimentary Vargfors Group combined with a structural analysis revealed a syn-extensional fault pattern of NW-SE-trending normal faults and associated NE-SW-trending transfer faults, creating the segmented sedimentary Vargfors basin. It comprises distinct fault-bound compartments, which incluence the sedimentary stratigraphy in each of these compartments.Syn-rift subsidence affected the sedimentary conditions from near-shore to shallow submarine environment.Intensive fault movements associated with mafic volcanic activity along these faults resulted in the rapid uplift of the oldest phase of the Jörn intrusive complex and/or subsidence of its surrounding areas. Subsequent erosion of the intrusive rocks led to the formation of a tonalite to granodiorite bearing conglomeratic sequence, representing an alluvial fan. Further uplift to the north of the district resulted in the erosion of Arvidsjaur volcanic rocks and the formation of a braided river system. Subsidence of the intrusive complex and/or a sedimentary coverage on top of the same caused a break in sedimentation of tonalite to granodiorite clasts. Stratigraphical evolution of the sedimentary rocks and the Vargfors Group - Skellefte Group contact relationships show that rifting started in the centre and proceeded with time towards SE and NW. Subsequent basin inversion resulted in the reactivation of the existing normal faults along a carbonate-rich basal layer forming asymmetric synclines. Primary geometries of sedimentary strata within each fault-bound compartment controlled their deformation styles. Furthermore, strain was partitioned into the faults, forming high strain zones along the basin margins, where foliations parallel the main faults, and low strain domains in the core of the basin, where foliation is oblique to the main structural grain of the basin. This oblique foliation is either a result of a rotating stress field or a transpressional regime. This case study on basin inversion gives implications for accretion processes along the Svecokarelian Craton margin as well as forthe formation of VMS-deposits and their possible transposition. Basic modelling of the main geological boundaries in the central Skellefte district was performed by integrating data from regional to outcrop scale using the GoCAD (Paradigm) software platform. Available data included geographical and geological data, which were imported from ArcGIS (ESRI) as well as drill-hole data, seismic profiles, resistivity and gravimetry profiles and EM-profiles. Creation of the main geological boundaries utilized GoCAD and SPARSE (Mirageoscience) algorithms, whereas structural geological data was exclusively modelled with SPARSE. Furthermore, this study provides a base for refining the 3-dimensional model and developing a 4-dimensional model, showing the geological evolution of the Skellefte district.

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  • 9.
    Bauer, Tobias
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    VISUAL3D: an EIT network on visualization of geomodels2017In: Geophysical Research Abstracts, ISSN 1029-7006, E-ISSN 1607-7962, Vol. 19Article in journal (Other academic)
    Abstract [en]

    When it comes to interpretation of data and understanding of deep geological structures and bodies at different scales then modelling tools and modelling experience is vital for deep exploration. Geomodelling provides a platform for integration of different types of data, including new kinds of information (e.g., new improved measuring methods). EIT Raw Materials, initiated by the EIT (European Institute of Innovation and Technology) and funded by the European Commission, is the largest and strongest consortium in the raw materials sector worldwide. The VI-SUAL3D network of infrastructure is an initiative by EIT Raw Materials and aims at bringing together partners with 3D-4D-visualisation infrastructure and 3D-4D-modelling experience. The recently formed network collaboration interlinks hardware, software and expert knowledge in modelling visualization and output. A special focus will be the linking of research, education and industry and integrating multi-disciplinary data and to visualize the data in three and four dimensions. By aiding network collaborations we aim at improving the combination of geomodels with differing file formats and data characteristics. This will create an increased competency in modelling visualization and the ability to interchange and communicate models more easily. By combining knowledge and experience in geomodelling with expertise in Virtual Reality visualization partners of EIT Raw Materials but also external parties will have the possibility to visualize, analyze and validate their geomodels in immersive VR-environments. The current network combines partners from universities, research institutes, geological surveys and industry with a strong background in geological 3D-modelling and 3D visualization and comprises: Lulea University of Technology, Geological Survey of Finland, Geological Survey of Denmark and Greenland, TUBA Freiberg, Uppsala University, Geological Survey of France, RWTH Aachen, DMT, KGHM Cuprum, Boliden, Montan Universitat Leoben, Slovenian National Building and Civil Engineering Institute, Tallinn University of Technology and Turku University. The infrastructure within the network comprises different types of capturing and visualization hardware, ranging from high resolution cubes, VR walls, VR goggle solutions, high resolution photogrammetry, UAVs, lidar-scanners, and many more.

  • 10.
    Bauer, Tobias
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Andersson, Joel B.H.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Regional structural setting of late-orogenic IOCG mineralization along the northern Nautanen deformation zone, Norrbotten, Sweden2023In: Ore Geology Reviews, ISSN 0169-1368, E-ISSN 1872-7360, Vol. 163, article id 105814Article in journal (Refereed)
    Abstract [en]

    The northern Norrbotten ore province in Sweden is one of the most mineralized areas in Europe. Iron, gold and/or copper deposits occur as iron oxide-apatite-style mineralization (IOA, Kiruna-type) as well as iron oxide-copper–gold (IOCG) style. Regardless of mineralization style, most deposits appear to be spatially controlled by a set of crustal-scale Palaeoproterozoic shear zones which share similar structural characteristics and deformation histories.

    Reappraisal of regional geological and geophysical data, coupled with structural mapping, suggests crustal-scale shear zones form continuous c. N-S-trending zones extending from the Skellefte district in the south into the northern Norrbotten ore province. One example from Norrbotten is a zone that extends SSW from Karesuando in the north towards Svappavaara. While this structure has traditionally been inferred to continue SW towards Arjeplog (i.e. the Karesuando – Arjeplog Deformation Zone; KADZ), we favour its deflection SSE into the Nautanen-Aitik trend, making it a continuous, IOCG-bearing, crustal-scale deformation zone. Similar shear zone geometries can be observed in analogous zones to the west. Most of these crustal scale structures record at least two time-separated deformation events of regional significance. IOA and IOCG deposits form in different tectonic environments, separated in time and overprinting each other.

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  • 11.
    Bauer, Tobias
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Andersson, Joel
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering. LKAB, Malmberget.
    Sarlus, Zimer
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Lund, Cecilia
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Kearney, Thomas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Structural controls on the setting, shape and hydrothermal alteration of the Malmberget IOA deposit, northern Sweden2018In: Economic geology and the bulletin of the Society of Economic Geologists, ISSN 0361-0128, E-ISSN 1554-0774, Vol. 113, no 2, p. 377-395Article in journal (Refereed)
    Abstract [en]

    The Malmberget iron oxide-apatite (IOA) deposit in northern Sweden is one of the largest underground iron ore mine operations in the world with estimated ore reserves in 2015 of 346 million metric tons (Mt) at 42.5% Fe. The underground operation is concentrated in 10 orebodies of 5 to 245 Mt each, which currently produce 17.4 Mt of apatite iron ore per year. Structural investigations were combined with data on hydrothermal mineral assemblages in order to reconstruct the relative timing of ore-forming, deformation, and overprinting hydrothermal events. The results improve the understanding of structural geometries, relationships, and control on orebody transposition in the deposit. A first compressional event (D1) around 1.88 Ga represents the main metamorphic event (M1) in the area and was responsible for a strong transposition of potential primary layering and the orebodies and led to the formation of a composite S0/1 fabric. A subsequent F2 folding event around 1.80 Ga resulted in the formation of an open, slightly asymmetric synform with a steeper southeast limb and a roughly SW-plunging fold axis. The result of structural modeling implies that the ore formed at two separate horizons. The folding was accompanied by stretching, resulting in boudinage of the iron orebodies. D2-related high-strain zones and syntectonic granites triggered the remobilization of amphibole, biotite, magnetite, and hematite and controlled the formation of iron oxide-copper-gold (IOCG)-type hydrothermal alteration, including an extensive K-feldspar alteration accompanied with sulfides, scapolite, and epidote. This shows a distinct time gap of at least 80 m.y. between the formation of iron oxides and sulfides. Brittle structures and the lack of an axial planar parallel fabric in conjunction with previous results suggest upper crustal, low-pressure, and high-temperature conditions during this D2 deformation phase, indicating a hydrothermal event rather than a purely regional metamorphic compression. It is proposed in the present study that the Malmberget IOA deposit was deformed and metamorphosed during a 1.88 Ga crustal shortening event. Moreover, the Malmberget IOA deposit was affected by a 1.8 Ga folding and hydrothermal event that is related to a regional IOCG overprint.

  • 12.
    Bauer, Tobias E.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    The crustal architecture of the central Skellefte district, Sweden: Structural analysis, setting of VMS deposits and 3D-modelling2013Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The Skellefte district in northern Sweden is a Palaeoproterozoic volcanic arc hosting abundant volcanogenic massive sulphide (VMS) deposits. The dominating rocks in the district are submarine volcanic and volcaniclastic rocks of the Skellefte Group deposited in an extensional regime at 1.89–1.88 Ga. Structural analysis and facies analysis combined with reflection seismic investigations in the central part of the Skellefte district revealed a pronounced pattern of WNW–ESE-striking normal faults and NE–SW-striking transfer faults that developed synchronously with volcanic activity. Dextral strike-slip movement along regional-scale NE-SW-striking faults favoured the opening of a pull-apart system. VMS deposits formed as sub-seafloor replacement and partly exhalative deposits mainly in the uppermost parts of Skellefte Group but also in the lowermost parts of the overlying Vargfors Group. Furthermore, the VMS deposits show a close spatial relationship to faults indicating that the ore-forming hydrothermal fluids utilized the synextensional faults as fluid conduits. The Vargfors Group sedimentary rocks form a distinct sub-basin in the central Skellefte district, the so called Vargfors basin or Vargfors syncline. Syn-extensional faulting created fault-bound compartments within the Vargfors basin. Syn-tectonic sedimentation of the Vargfors Group within the sub-basin is responsible for changes in stratigraphy between the individual compartments. Progressive opening of the sub-basin from the centre towards north-west and south-east is evident from the change of sedimentary facies associations. The onset of Vargfors Group deposition is characterized by turbiditic sedimentation with intercalated sandstones and monomict conglomerates derived from eroded and/or reworked Skellefte Group volcanic rocks. These facies associations are unconformably overlain by polymict conglomerates of alluvial fan and braided systems caused by the uplift of the Jörn intrusive complex and the subsequent formation of the Arvidsjaur volcanic arc, respectively. It is unclear if the polymict series formed during the latest stages of crustal extension or at the onset of subsequent crustal shortening. Crustal shortening at around 1.87 Ga is attributed to basin inversion and accretionary processes at the Svecokarelian craton margin and is assumed to result in inversion of normal and transfer faults and the formation of upright, fault-bound syn- and anticlines. A rheologically weak carbonate-rich layer at the base of the sedimentary sequence is suggested to favour the fault inversion over more distributed shortening as the controlling deformation mechanism in the Vargfors syncline. Furthermore, VMS deposits were transposed along the faults, and the deformation style of the ore bodies generally mimics the deformation styles of the hosting high-strain zones. Moreover, the size of the VMS deposits is coupled to the size of the associated high-strain zone with large-tonnage deposits associated with regional-scale high-strain zones and their splays. Progressive crustal shortening led to the formation of N-dipping break-back and shortcut faults. Mafic volcanic rocks are commonly observed along early, inverted faults and later break-back and short-cut faults indicating a long history of mafic volcanic activity both during extension and crustal shortening in the central Skellefte district.Three-dimensional geological multi-scale modelling combined results from geological and geophysical investigations in order to visualise the crustal architecture in the Skellefte district. Modelling was carried out in different scales ranging from detailed deposit-scale models of 21 VMS ore bodies to a semi-regional scale model of the Vargfors syncline and a simplified regional scale model of the central Skellefte district.

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  • 13.
    Bauer, Tobias E.
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Andersson, Joel B.H.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Kampmann, Tobias Christoph
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Analysis of data from Unmanned Aerial Systems (UAS) in a Virtual Reality environment2019In: Proceedings of the Visual3D conference 2019, 1–2 October 2019, Uppsala, Sweden: Visualization of 3D/4D models in geosciences, exploration and mining / [ed] Tobias C. Kampmann, Luleå University of Technology, 2019, p. 19-19Conference paper (Refereed)
    Abstract [en]

    The use of Unmanned Aerial Systems (UAS) is getting increasingly popular for many different types of applications. The field of geology is slowly catching up resulting in new and innovative UAS solutions for various kinds of airborne measurement techniques. These techniques comprise a wide range of geophysical and remote sensing methods used to investigate the sub-surface. At Luleå University of Technology two different types of UAS are used in combination with a Virtual Reality environment in order to analyze geological structures and related ore deposits and mineralizations. The two UAS comprise a) a custom made quadrocopter (HUGIN) with a pay load of approx. 3.5 kg and an operational time of 5 times (batteries) maximum 35 minutes depending on payload, ambient temperatures and wind speed; and b) a foldable DJI Mavic Pro with an operational time of 3 times 30 minutes. The HUGIN system can be operated with a high-resolution optical camera for photogrammetry surveys and a 3-axial fluxgate magnetometer for measuring magnetic anomalies within bedrock and ultimately delineating geological structures. The system is highly flexible and a thermal camera is currently added to the system in order detect water fluxes in relation to geological structures or exothermal mineral processes. The DJI system is equipped with an optical camera for photogrammetric surveying and is a highly valuable tool in remote areas due to its lightweight and compact construction.Data acquired from both UAS is subsequently analysed in a Virtual Reality lab utilizing a 6m wide screen with active stereo functions. Photogrammetry data is first processed using the Aigsoft software package following a Structure for Motion (SfM) workflow where dense point cloud models and subsequently meshed and textured 3D surface models are produced. These models are then converted and transferred to the GeoVisionary software package that allows visualization of models in stereo 3D view. This allows digitizing geological structures such as foliation, fractures, and faults among others in an immersive 3D environment and provides an efficient tool complimentary to traditional field mapping. In particular, this makes it possible to capture and analyse data from hardly accessible and dangerous areas such as rock faces in open pits. Another complimentary method of data analysis comprises SCAT analysis of the meshed surfaces using the MOVE software package.

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  • 14.
    Bauer, Tobias E.
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Imana, Marcello
    Agnico Eagle Sweden AB, Storuman, Sweden.
    Hoglund, Kare
    Agnico Eagle Sweden AB, Storuman, Sweden.
    Thomas, Helen
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    The structural setting of the Barsele Au deposit, Sweden2019In: Proceedings of the 15th SGA Biennial Meeting, 27-30 August, University of Glasgow Publicity Services , 2019, p. 627-630Conference paper (Refereed)
    Abstract [en]

    The Barsele Au deposit is hosted in Paleoproterozoic rocks that were subject to multiple deformation events during the Svecofennian orogeny 1.9-1.8 Ga ago. Rocks have been subjected to an approx. N-S-directed extensional event (1.89 Ga) potentially responsible for the formation of VMS deposits. The crustal extension was followed by a compressional event under ductile conditions and related basin inversion (D-2; 1.87 Ga) and overprinted by a brittle event at 1.8 Ga (D-3). The distribution of alteration minerals and veins suggests multiple phases of fluid flow and remobilisation. The latest phase of enrichment appears to be coupled to low-angle thrusting from ESE and brittle reactivation of earlier structures with emplacement of quartz veins along fault planes and tensile structures in an oblique Riedel system.

  • 15.
    Bauer, Tobias
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Lynch, Edward
    Department of Mineral Resources, Geological Survey of Sweden, SE-75236 Uppsala, Sweden.
    Sarlus, Zimer
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Drejing-Carrol, David
    Boliden Mines Exploration AB, SE-936 31 Boliden, Sweden; Irish Centre for Research in Applied Geosciences, University College Dublin, Belfield, Dublin, Ireland.
    Martinsson, Olof
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Metzger, Nicolai
    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.
    Structural Controls on Iron Oxide Copper-Gold Mineralization and Related Alteration in a Paleoproterozoic Supracrustal Belt: Insights from the Nautanen Deformation Zone and Surroundings, Northern Sweden2022In: Economic geology and the bulletin of the Society of Economic Geologists, ISSN 0361-0128, E-ISSN 1554-0774, Vol. 117, no 2, p. 327-359Article in journal (Refereed)
    Abstract [en]

    The Nautanen deformation zone in the Gällivare area of northern Sweden is a highly Cu-mineralized, magnetite-rich, large-scale shear zone with a long-lived (~100 m.y.) deformation, hydrothermal alteration, and mineralization history. This composite structure hosts the Aitik porphyry Cu-Au-Ag ± Mo deposit and several Cu-Au ± Fe ± Ag ± Mo occurrences assigned to the iron oxide copper-gold (IOCG) deposit class. The Nautanen deformation zone was a locus for polyphase deformation and intermittent metasomatic-hydrothermal activity that overprinted middle Orosirian (ca. 1.90–1.88 Ga) continental arc-related volcanic-plutonic rocks. The deformation zone is characterized by intense shearing fabrics that form a series of subvertical to moderately W-dipping, NNW-SSE–trending, first-order shear zones with oblique reverse kinematics and related NNE-SSW–oriented second-order shear zones that control hydrothermal alteration patterns and Cu-Au mineralization.

    Hydrothermal alteration in the study area formed during several phases. Volcanic-volcaniclastic rocks to the east and west of the Nautanen deformation zone display low to moderately intense, pervasive to selectively pervasive (i.e., patchy zones or bands, disseminations) sericite ± feldspar, amphibole + biotite + magnetite ± tourmaline, and K-feldspar + hematite alteration. Both the amphibole + biotite and K-feldspar + hematite associations occur adjacent to NNW- and NE-oriented deformation zones and are locally associated with minor sulfide. Within the deformation zone, a moderate to intense biotite + amphibole + garnet + magnetite + tourmaline + sericite alteration assemblage is typically associated with chalcopyrite + pyrrhotite + pyrite and forms linear and subparallel, mainly NNW-oriented seams, bands, and zones that locally appear to overprint possibly earlier scapolite + sericite ± feldspar alteration. Late-stage epidote ± quartz ± feldspar alteration (retrograde saussuritization) forms selectively pervasive zones and epidote veinlets across the area and is partly related to brittle faulting.

    A magnetite-amphibole-biotite–rich, penetrative S1 foliation records shortening during early Svecokarelian-related deformation (D1) and can be related to ca. 1.88 to 1.87 Ga arc accretion processes and basin inversion that overlaps with regional peak metamorphism to near mid-amphibolite facies conditions and a potential initial Cu mineralization event. Folding and repeated shearing along the Nautanen deformation zone can be assigned to a second, late-Svecokarelian deformation event (D2 stage, ca. 1.82–1.79 Ga) taking place at a higher crustal level. This D2 deformation phase is related to late-stage accretionary processes active during a transition to a stage of postorogenic collapse, and it was accompanied by abundant, syntectonic intrusions. D2-related magmatism produced high-temperature and low-pressure conditions and represents a regional magmatic-hydrothermal event that controlled the recrystallization/remobilization of magnetite, biotite, and amphibole. Associated shear zone reactivation during D2 favors the utilization of the Nautanen deformation zone as a fluid conduit, which preferentially controlled the siting and formation of epigenetic Cu-Au mineralization with distinctive IOCG characteristics within second-order shear zones.

  • 16.
    Bauer, Tobias
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Sarlus, Zimer
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Project: Multi-scale 4-dimensional geological modelling of the Gällivare area2013Other (Other (popular science, discussion, etc.))
    Abstract [en]

    Due to an increasing demand on metals the production of iron and copper will rise during the next years. While the Gällivare area is one of the most active exploration areas in Europe, hosting two of Europe’s most important metal mines, the Aitik Cu-Au-Ag-(Mo) deposit and the Malmberget Fe-deposit, the northern Norrbotten ore province is still underexplored. In a multi-disciplinary project we intend to unravel the structural setting of ore deposits in the Gällivare area in close cooperation with both active mining companies LKAB and New Boliden AB. By reconstructing the geological history and especially the structural evolution of the region we aim at understanding the history of the ore deposits from their formation to their deformation and transposition into their present day position. Structural geological studies will be combined with geochemical and geochronological studies in order to reconstruct the structural evolution through time. These geological investigations will be furthermore accomplished by geophysical studies for constraining the 3D-geometries of the subsurface. Based on these results geological multi-scale 3D- and 4D-models will be produced aiding the prospecting and exploration of unknown ore deposits.

  • 17.
    Bauer, Tobias
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Sarlus, Zimer
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Nordin, Roger
    Boliden Mineral AB.
    Andersson, Joel
    LKAB.
    The three dimensional crustal architecture of the Aitik Cu-Au-Ag-(Mo)-deposit and the Malmberget Fe-deposit2014Conference paper (Other academic)
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  • 18.
    Bauer, Tobias
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Skyttä, Pietari
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Allen, Rodney
    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.
    Fault-controlled sedimentation in a progressively opening extensional basin: the Palaeoproterozoic Vargfors basin, Skellefte mining district, Sweden.2013In: International journal of earth sciences, ISSN 1437-3254, E-ISSN 1437-3262, Vol. 102, no 2, p. 385-400Article in journal (Refereed)
    Abstract [en]

    The Vargfors basin in the central part of the Skellefte mining district is an inverted sedimentary basin within a Palaeoproterozoic (1. 89 Ga) marine volcanic arc. The fault-segmented basin formed from upper-crustal extension and subsequent compression, following a period of intense sub-marine volcanism and VMS ore formation. New detailed mapping reveals variations in stratigraphy attributed to syn-extensional sedimentation, as well as provenance of conglomerate clasts associated with tectonic activity at the transition from extension to compression. The onset of fan delta to alluvial fan sedimentation associated with basin subsidence indicates that significant dip-slip displacement accommodating rapid uplift of the intrusive complex and/or subsidence of the adjacent volcano-sedimentary domain took place along a major fault zone at the southern margin of the intrusive complex. Subsidence of the Jörn intrusive complex and/or its burial by sedimentary units caused a break in erosion of the intrusion and favoured the deposition of a tonalite clast-barren conglomerate. Clast compositions of conglomerates show that the syn-extensional deposits become younger in the south-eastern parts of the basin, indicating that opening of the basin progressed from north-west to south-east. Subsequent basin inversion, associated with the accretion to the Karelian margin, involved reverse activation of the normal faults and development of related upright synclines. Progressive crustal shortening caused the formation of break-back faults accompanied by mafic volcanic activity that particularly affected the southern contact of the Jörn intrusive complex and the northern contact of the Vargfors basin

  • 19.
    Bauer, Tobias
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Skyttä, Pietari
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Allen, Rodney
    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.
    Syn-extensional faulting controlling structural inversion: Insights from the Palaeoproterozoic Vargfors syncline, Skellefte mining district, Sweden2011In: Precambrian Research, ISSN 0301-9268, E-ISSN 1872-7433, Vol. 191, no 3-4, p. 166-183Article in journal (Refereed)
    Abstract [en]

    The Vargfors basin in the central Skellefte district, Sweden, is an inverted sedimentary sub-basin within a Palaeoproterozoic (1.89 Ga) marine volcanic arc. The sub-basin formed from upper-crustal extension and subsequent compression, following a period of intense marine volcanism and VMS ore formation. Detailed mapping and structural analysis reveals a pattern of SE–NW-striking normal faults and interlinked NE–SW-striking transfer faults, which define distinct fault-bound compartments, each with an individual structural geometry and stratigraphy. Constraints on the deformation style and mechanisms achieved by 2D forward modelling are in agreement with the previously inferred inversion of the early normal faults during a regional crustal shortening event. A rheologically weak carbonate-rich layer at the base of the sedimentary sequence favoured the fault inversion over more distributed shortening as the controlling deformation mechanism. Transposition of sedimentary strata into the approximately SE–NW faults led to formation of asymmetric synclines that were tightened during progressive shortening. Structural analysis infers a progressive opening of the basin towards SE and NW with time. Furthermore, it is inferred that a displacement gradient was developed along the main structural grain, with decreasing dip-slip displacements towards SE and NW, both during the extension and the structural inversion.VMS deposits in the vicinity of the contact between the volcanic and the overlying sedimentary rocks were formed along early normal faults, which reacted as fluid conduits. Subsequently, the deposits were transposed into the inverted faults during crustal shortening. Consequently, the inverted faults provide a useful tool for mineral exploration in the district.

  • 20.
    Bauer, Tobias
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Skyttä, Pietari
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Dehghannejad, Mahdieh
    Uppsala University.
    Tavakoli, Saman
    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.
    Geological multi-scale modelling as a tool for modern ore exploration in the Skellefte mining district, Sweden2011In: Proceedings IAMG 2011 Salzburg: Mathematical Geosciences at the crossroads of theory and practice, 2011, p. 759-Conference paper (Other academic)
    Abstract [en]

    The Palaeoproterozoic Skellefte Mining District is host to abundant ore deposits. Geological 3Dmodelling was performed using the gOcad software platform. Geological methods such as field mapping, structural analysis and facies analysis combined with geophysical techniques such as reflection seismic investigations, resistivity, magnetic, electromagnetic and gravimetric studies and analysis of potential field data provide a framework for the reconstruction of the crustal geometry and geological history of the district as a tool for modern ore exploration. Results will be furthermore utilized for kinematic 4-dimensional modelling

  • 21.
    Bauer, Tobias
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Skyttä, Pietari
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Hermansson, Tobias
    Boliden Mineral AB.
    Allen, Rodney
    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.
    Correlation between distribution and shape of VMS deposits, and regional deformation patterns, Skellefte district, northern Sweden2014In: Mineralium Deposita, ISSN 0026-4598, E-ISSN 1432-1866, Vol. 49, no 5, p. 555-573Article in journal (Refereed)
    Abstract [en]

    The Skellefte district in northern Sweden is host to abundant volcanogenic massive sulphide (VMS) deposits comprising pyritic, massive, semi-massive and disseminated Zn–Cu–Au ± Pb ores surrounded by disseminated pyrite and with or without stockwork mineralisation. The VMS deposits are associated with Palaeoproterozoic upper crustal extension (D1) that resulted in the development of normal faults and related transfer faults. The VMS ores formed as sub-seafloor replacement in both felsic volcaniclastic and sedimentary rocks and partly as exhalative deposits within the uppermost part of the volcanic stratigraphy. Subsequently, the district was subjected to deformation (D2) during crustal shortening. Comparing the distribution of VMS deposits with the regional fault pattern reveals a close spatial relationship of VMS deposits to the faults that formed during crustal extension (D1) utilising the syn-extensional faults as fluid conduits. Analysing the shape and orientation of VMS ore bodies shows how their deformation pattern mimics those of the hosting structures and results from the overprinting D2 deformation. Furthermore, regional structural transitions are imitated in the deformation patterns of the ore bodies. Plotting the aspect ratios of VMS ore bodies and the comparison with undeformed equivalents in the Hokuroko district, Japan allow an estimation of apparent strain and show correlation with the D2 deformation intensity of the certain structural domains. A comparison of the size of VMS deposits with their location shows that the smallest deposits are not related to known high-strain zones and the largest deposits are associated with regional-scale high-strain zones. The comparison of distribution and size with the pattern of high-strain zones provides an important tool for regional-scale mineral exploration in the Skellefte district, whereas the analysis of ore body shape and orientation can aid near-mine exploration activities.

  • 22.
    Bauer, Tobias
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Skyttä, Pietari
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Hermansson, Tobias
    Boliden Mines, Boliden, Sweden.
    Dehghannejad, Mahdieh
    Department of Earth Sciences, Uppsala University, Uppsala, Sweden.
    Tavakoli, Saman
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    The Skellefte District2015In: 3D, 4D and Predictive Modelling of Major Mineral Belts in Europe, Encyclopedia of Global Archaeology/Springer Verlag, 2015, p. 93-121Chapter in book (Refereed)
    Abstract [en]

    Four-dimensional geological modelling has been conducted in the Palaeoproterozoic Skellefte mining district. 3D-modelling of volcanic-hosted massive sulphide deposits and associated host-rocks has been carried out in multiple scales from deposit to regional scale and is based on a combination of geological and geophysical investigations. A conceptual model founded on unravelling the structural control on sedimentation, volcanism and mineralization and the subsequent deformation patterns, acts as a base for geological modelling. The final 3D-model provides a structural framework in which the mineralizations can be studied by improved understanding of the structural evolution in the mine areas, and by comparing the regional structural patterns versus the form and attitude of ore deposits. Additionally, uncertainty and prospectivity models were constructed showing the distribution of data and the potential of discovering new ore deposits. Subsequent 4D-modelling adds the time aspect to the 3D-models and aims at visualizing and understanding the geological history in the district and as a support for ore targeting. Moreover, adding geological time to the modelling helps gaining confidence about both the conceptual models and the 3D-models. The final 3D- and 4D-models provide a regional three-dimensional context for both industrial and academic activities in the Skellefte district, and aid the understanding of large-scale tectonic processes.

  • 23.
    Bauer, Tobias
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Skyttä, Pietari
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Hermansson, Tobias
    Boliden Mineral AB.
    Weihed, Pär
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Ore body shapes versus regional deformation patterns as a base for 3D prospectivity mapping in the Skellefte Mining District, Sweden2012Conference paper (Refereed)
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  • 24.
    Bauer, Tobias
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Skyttä, Pietari
    Hermansson, Tobias
    Boliden Mineral AB, Sweden.
    Weihed, Pär
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    The comparison of ore body shapes and regional deformat patterns as a base for prospectivity mapping in the Skellefte mining district, Sweden2012Conference paper (Refereed)
  • 25.
    Bauer, Tobias
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Skyttä, Pietari
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Tavakoli, Saman
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Dehghannejad, Mahdieh
    Uppsala University, Uppsala universitet, Department of Earth Sciences, Uppsala University.
    Weihed, Pär
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    From deposit to regional scale: 4-dimensional geological modelling in the Skellefte Mining District, Sweden2011Conference paper (Refereed)
  • 26.
    Bauer, Tobias
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Skyttä, Pietari
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Tavakoli, Saman
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Hermansson, Tobias
    Boliden Mineral AB.
    Dehghannejad, Mahdieh
    Uppsala University.
    Juanatey, Maria Garcia
    Uppsala University.
    Weihed, Pär
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Allen, Rodney
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Juhlin, Christopher
    Uppsala University.
    A regional scale 3D-model of the Skellefte mining district, northern Sweden2013In: Mineral depostits 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. 62-65Conference paper (Refereed)
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  • 27.
    Bauer, Tobias
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Skyttä, Pietari
    Weihed, Pär
    Allen, Rodney
    3D-modelling of the Central Skellefte District, Sweden2009In: Smart science for exploration and mining: proceedings of the 10th Biennial SGA Meeting, Townsville, Australia 17th-20th August 2009 / [ed] Patrick Williams, James Cook University of North Queensland , 2009Conference paper (Refereed)
    Abstract [en]

    The central part of the Palaeoproterozoic Skellefte District in northern Sweden is host to several VMS deposits. This area is dominated by upright folds with axial surfaces trending WNW - ESE. Northeast - SW trending faults crosscut WNW - ESE trending faults and impart a distinct fault pattern. Subvertical stretching as expressed by subvertical mineral lineations as well as gently W-plunging mineral lineations parallel to the F2 fold axes indicate not only significant vertical movement, but also pronounced lateral movement. The faults formed in an extensional stage and were reactivated during a compressional stage oblique to the earlier phase. This crustal shortening caused folding and development of the main foliation. Overturned, tight to isoclinal folds within the Vargfors meta-sediments coincide with 1st and 2nd order faults and are considered to be related to reactivation of the early normal and transfer faults. A three dimensional model taking into account the structures was constructed using the GoCAD 3D-modelling software.

  • 28.
    Bauer, Tobias
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Tavakoli, Saman
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Dehghannejad, Mahdieh
    Uppsala University, Department of Earth Sciences, Villavägen 16, 752 36 Uppsala, Sweden.
    Garcia, Maria
    Uppsala University, Department of Earth Sciences, Villavägen 16, 752 36 Uppsala, Sweden.
    Weihed, Pär
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering.
    4-dimensional geological modelling of the Skellefte district, Sweden2010In: The international archives of the photogrammetry, remote sensing and spatial information sciences, ISPRS Commission IV - Working Group 8 , 2010, Vol. XXXVIII-4, p. 93-96Conference paper (Other academic)
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    fulltext
  • 29.
    Bauer, Tobias
    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.
    Crustal Scale Shear Zones Controlling Grade and Tonnage of VMS Deposits in the Skellefte District, Northern Sweden2015In: Mineral Resources in a Sustainable World / [ed] A.S. Andre-Mayer; M. Cathelineau; P. Muchez; E. Pirard; S. Sindern, 2015, p. 45-48Conference paper (Refereed)
    Abstract [en]

    The Skellefte district in northern Sweden hosts abundant Paleoproterozoic, volcanic-hosted massive sulfide (VMS) deposits. The deposits formed due to pull apart basin formation in a volcanic arc setting and utilized the syn-extensional faults as fluid conduits. By comparing the structural setting in distinct structural domains with the tonnage and Cu, Au, and Ag grades a clear coupling between VMS deposits and the size of structures becomes evident. This shows how major crustal fault zones acted as fluid conduits for the ore forming hydrothermal fluids during an extensional phase. The same structures were subsequently re-activated as shear zones and possibly enhanced secondary enrichment processes.

  • 30.
    Brethes, Anais
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering. Geological Survey of Denmark and Greenland (GEUS), Department of Petrology and Economic Geology, Denmark.
    Guarnieri, Pierpaolo
    Geological Survey of Denmark and Greenland (GEUS), Department of Petrology and Economic Geology.
    Rasmussen, Thorkild Maack
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Bauer, Tobias Erich
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Interpretation of aeromagnetic data in the Jameson Land Basin, central East Greenland: Structures and related mineralized systems2018In: Tectonophysics, ISSN 0040-1951, E-ISSN 1879-3266, Vol. 724-725, p. 116-136Article in journal (Refereed)
    Abstract [en]

    This paper provides a detailed interpretation of several aeromagnetic datasets over the Jameson Land Basin in central East Greenland. The interpretation is based on texture and lineament analysis of magnetic data and derivatives of these, in combination with geological field observations. Numerous faults and Cenozoic intrusions were identified and a chronological interpretation of the events responsible for the magnetic features is proposed built on crosscutting relationships and correlated with absolute ages. Lineaments identified in enhanced magnetic data are compared with structures controlling the mineralized systems occurring in the area and form the basis for the interpretations presented in this paper. Several structures associated with base metal mineralization systems that were known at a local scale are here delineated at a larger scale; allowing the identification of areas displaying favorable geological settings for mineralization. This study demonstrates the usefulness of high-resolution airborne magnetic data for detailed structural interpretation and mineral exploration in geological contexts such as the Jameson Land Basin.

  • 31.
    Brethes, Anais
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering. GEUS (Geological Survey of Denmark and Greenland).
    Rasmussen, Thorkild Maack
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Guarnieri, Pierpolo
    GEUS (Geological Survey of Denmark and Greenland).
    Bauer, Tobias
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    3D modelling of the base-metal mineralized Jameson Land Basin (central East Greenland) using geologically constrained inversion of magnetic data2015Conference paper (Other academic)
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    fulltext
  • 32.
    Brethes, Anaïs
    et al.
    Geological Survey of Denmark and Greenland.
    Guarnieri, Pierpaolo
    Geological Survey of Denmark and Greenland.
    Rasmussen, Thorkild Maack
    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.
    3D-Modelling of the Early Triassic Base-Metal Mineralized Syn-Rift Sequence in the Jameson Land Basin (East Greenland)2015In: Mineral Resources in a Sustainable World / [ed] A.S. Andre-Mayer; M. Cathelineau; P. Muchez; E. Pirard; S. Sindern, 2015, p. 1701-1704Conference paper (Refereed)
    Abstract [en]

    The Jameson Land Basin in central East Greenland is mineralized in Pb, Zn and Cu. Mineralization occurs in several stratigraphic horizons and along structures in Upper Permian and Triassic sediments. A good understanding of the basin architecture and evolution is therefore essential for mineral exploration in this area. 3D-Photomapping from high resolution aerial photos along with a structural interpretation of aeromagnetic data, electromagnetic data, and results from fieldwork and drilling were integrated into a 3D-structural model. This data integration allowed modelling the rift architecture in the eastern margin of the Jameson Land Basin.

  • 33.
    Brethes, Anaïs
    et al.
    Geological Survey of Denmark and Greenland, Denmark.
    Guarnieri, Pierpaolo
    Geological Survey of Denmark and Greenland, Denmark.
    Rasmussen, Thorkild Maack
    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.
    Geological Analysis of Aeromagnetic Data over the Blyklippen Lead-zinc Mine at Mesters Vig, Central East Greenland2016In: First Conference on Geophysics for Mineral Exploration and Mining: Near Surface Geoscience 2016, Barcelona, Spain, 4-8 September 2016, European Association of Geoscientists and Engineers, 2016, article id Mo MIN 05Conference paper (Refereed)
    Abstract [en]

    In the Mesters Vig area epithermal Pb-Zn sulphide-bearing quartz veins are associated with the border faults of a NNW-SSE elongated graben down-faulting Carboniferous to Lower Triassic sediments. The analysis of the total magnetic field, tilt derivative, vertical derivative and analytic signal allowed to define subcropping magnetic domains and identify structural trends. Doleritic dykes, sills and faults were mapped and structural relationships were established between them. Finally, aeromagnetic data allowed here to delineate structural trends along and in the vicinity of which mineralized quartz veins are mapped.

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  • 34.
    Brethes, Anaïs
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Rasmussen, Thorkild Maack
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Guarnieri, Pierpaolo
    GEUS.
    Bauer, Tobias
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Mapping and characterization of Induced Polarization in airborne TEM data from central East Greenland: application of a Self-Organizing Map procedure2016Conference paper (Refereed)
    Abstract [en]

    nduced Polarization (IP) effects were observed in airborne Time Domain EM (TEM) data acquired in central East Greenland in the context of exploration for disseminated sulphides in a sedimentary basin. Some of the IP anomalies were targeted by drilling which revealed the absence of mineralization. In order to understand the possible causes of the IP effects we first identified them in the TEM data. IP indicators were extracted from the shape of the transient curves at every measurement location and were analysed by using a Self-Organizing Map (SOM) procedure. Results from K-mean clustering of the SOM are visualized on a geographical map showing the transient curves’ characteristics. Some of the clusters are clearly correlated with the geology whereas others merely reflect recordings below the noise level. In order to interpret the cause of the IP anomalies the airborne TEM data were inverted for the Cole-Cole parameters.

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  • 35.
    Dehghannejad, Mahdieh
    et al.
    Department of Earth Sciences, Uppsala University.
    Bauer, Tobias
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Malehmir, Alireza
    Department of Earth Sciences, Uppsala University.
    Juhlin, Christopher
    Department of Earth Sciences, Uppsala University.
    Weihed, Pär
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Crustal geometry of the central Skellefte district, northern Sweden: constraints from reflection seismic investigations2012In: Tectonophysics, ISSN 0040-1951, E-ISSN 1879-3266, Vol. 524-525, p. 87-99Article in journal (Refereed)
    Abstract [en]

    The Palaeoproterozoic Skellefte mining district in Sweden is one of the most important mining districts in Europe. As a part of a 4D geologic modeling project, three new sub-parallel reflection seismic profiles, with a total length of about 95 km, were acquired in the central part of the district. Processed seismic data reveal a series of gentle- to steeply- dipping reflections and a series of diffraction packages. The majority of reflections that extend to the surface can be correlated with geological features either observed in the field or interpreted from the aeromagnetic map. A set of south-dipping reflections represent inferred syn-extensional listric extensional faults that were inverted during subsequent crustal-shortening. Cross-cutting north-dipping reflections are correlated to late-compressional break-back faults. Flat-lying reflections in the central parts of the study area could represent lithological contacts within the Skellefte Group, or the contact between Skellefte Group rocks and their unknown basement. Flat-lying reflections occurring further north are inferred to originate from the top of the Jörn intrusive complex or an intrusive contact within it. So far unknown south- and north-dipping faults have been identified in the vicinity of the Maurliden deposit. Based on the seismic results, a preliminary 3D-model has been created in order to visualize the fault pattern and to provide a base for future 3D/4D modeling in the Skellefte district.

  • 36.
    Dehghannejad,, Mahdieh
    et al.
    Department of Earth Sciences, Uppsala University.
    Juhlin,, Christopher
    Department of Earth Sciences, Uppsala University.
    Malehmir, Alireza
    Department of Earth Sciences, Uppsala University.
    Juanatey, Maria A. Garcia
    Department of Earth Sciences, Uppsala University.
    Skyttä, Pietari
    Department of Geosciences and Geography, University of Helsinki, FI-00014 Helsinki.
    Weihed, Pär
    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.
    Reflection seismic imaging in the Skellefte ore district, northern Sweden2013In: Mineral depostits 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. 126-129Conference paper (Refereed)
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  • 37.
    Gaal, Gabor
    et al.
    Geological Survey of Finland, P.O.Box 96, 02151 Espoo.
    Cassard, D.
    Bureau de Recherches Géologiques et Minières, Orléans.
    Bertrand, G.
    Bureau de Recherches Géologiques et Minières, Orléans.
    Schaeben, H.
    TU Bergakademie Freiberg.
    Royer, J.J.
    Université de Lorraine, CNRS, Nancy.
    Weihed, Pär
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Skyttä, Pietari
    Bauer, Tobias
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Pan-European mineral resource assessment2012Conference paper (Refereed)
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  • 38.
    Juanatey, Maria Garcia
    et al.
    Uppsala University.
    Hübert, Juliane
    Uppsala University.
    Tryggvason, Ari
    Uppsala University.
    Juhlin, Christopher
    Uppsala University.
    Pedersen, Laust
    Uppsala University.
    Dehghannejad, Mahdieh
    Uppsala University.
    Bauer, Tobias
    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.
    Skyttä, Pietari
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Magnetotelluric measurements in the Skellefte ore district, northern Sweden2013In: Mineral depostits for a high-tech world: Proceedings of the 12th SGA Biennial Meeting 2013, 12-15 August 2013, Uppsala, Sweden, Uppsala, 2013, Vol. 1, p. 138-141Conference paper (Refereed)
  • 39.
    Juanatey, María A. García
    et al.
    Uppsala University, Sweden.
    Hübert, Juliane
    Uppsala University, Sweden.
    Tryggvason, Ari
    Uppsala University, Sweden.
    Juhlin, Christopher
    Uppsala University, Sweden.
    Pedersen, Laust B.
    Uppsala University, Sweden.
    Bauer, Tobias E.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Dehghannejad, Mahdieh
    Uppsala University, Sweden.
    2D and 3D MT in the central Skellefte Ore District, northern Sweden2019In: Tectonophysics, ISSN 0040-1951, E-ISSN 1879-3266, Vol. 764, p. 124-138Article in journal (Refereed)
    Abstract [en]

    New broadband magnetotelluric (MT) data have been acquired along two parallel profiles in the central part of the metallogenic Skellefte district in northern Sweden. The data were recorded as part of the Swedish 4D modelling of mineral belts project and cover an area with several economical and sub-economical deposits. The dimensionality and quality of the data were carefully analyzed and new error floors were systematically determined prior to inverse modelling in 2D and 3D. The algorithms used were EMILIA and WSINV3DMT. For the 2D inversion, only the determinant of the impedance tensor was used, while for the 3D inversion all elements were considered. The obtained models fit the inverted data, and image the main regional features. A detailed comparison reveals the superiority of the 3D model, both in model structures and data fit. After assessing the main features in the model, an interpretation is proposed and refined with the support of previous geophysical studies. The most interesting features are large and medium-sized conductors associated with crustal-scale shear zones and faults within the Skellefte Group rocks. These may be depicting a network of fossil pathways for hydrothermal fluid transport and as such, provide new insight into past processes in the area.

  • 40.
    Kampmann, Tobias Christoph
    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.
    The benefits of organized networking and matchmaking for the development of 3D/4D geomodel visualization2019In: Proceedings of the Visual3D conference 2019, 1–2 October 2019, Uppsala, Sweden: Visualization of 3D/4D models in geosciences, exploration and mining / [ed] Tobias C. Kampmann, Luleå, Sweden: Luleå University of Technology, 2019, p. 43-43Conference paper (Refereed)
    Abstract [en]

    While huge territory of the EU shows a very high exploration potential and many EU countries remain attractive to investors (e.g. Fraser Institute, 2015), a mere 4% of global exploration expenditure is currently invested within European countries. One tool to trigger a higher degree of investment in exploration and to secure the domestic supply of both main commodities and critical raw materials (CRM) is to enhance our three-dimensional geometric understanding of the Earth’s crust.For these reasons, EIT Raw Materials decided to fund the Visual3D network of infrastructure (NoI) for three years (2017–2019). Visual3D involves to-date 14 partner organisations from nine EU countries. The NoI aims to integrate expertise within exploration and 3D modelling from industry, academia and research institutes, with the ambition to increase the understanding of geological bodies in 3D and 4D through improved visualisation techniques. The network believes firmly that the integration of novel visualization technologies (e.g. virtual and augmented reality) into workflows of exploration, mining and geoscientific research will bring a much-needed innovation boost to the European raw materials sector and increase its competitiveness.During its first year, Visual3D has compiled the network expertise and infrastructure regarding visualization tools available at the partner facilities. An overview of this infrastructure, as well as projects conducted by network partners is available on the Visual3D homepage (www.visual3d.info). The network also managed to identify common issues in the field of geomodelling, the solutions to which may be facilitated by a pan-European network approach, such as data compatibility, communication of geomodels, as well as complexity and variety of software. Subsequent years have been dedicated to the conceptualization of possible projects in order to solve the issues name above, as well as matchmaking to find expert consortia for these projects.So far, four workshops including project partners and invited external stakeholders have been held. Networking and matchmaking during these workshops has resulted in successful project proposals in the EIT RawMaterials KAVA calls for educational (MireBooks), as well as upscaling projects (FARMIN). Both these projects are presented at the Visual3D conference 2019. Further project ideas have been discussed within Visual3D and will be developed further.The benefits of organized networking in novel research and developments fields, such as visualization of 3D/4D models for exploration and geosciences, has become apparent during the lifetime of the Visual3D network. The network partners would encourage pan-European funding institutions such as EIT RawMaterials to provide continuous funding to similar networking initiatives, especially in highly innovative and novel research fields. Well-organized communication between different stakeholders is the basis of technological innovation and has the potential to give the European raw materials sector the leading edge in this highly competitive global market.

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  • 41.
    Kampmann, Tobias Christoph
    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.
    Visual3D: A European network of infrastructure with focus on 3D/4D geomodelling2018Conference paper (Refereed)
    Abstract [en]

    While the territory of the EU in many parts shows a very high exploration potential and many EU countries remain attractive to investors (e.g. Fraser Institute, 2015), a mere 4% of global exploration expenditure is currently invested within European countries. One tool to trigger a higher degree of investment in exploration and to secure the domestic supply of both main commodities and critical raw materials (CRM) is to enhance our three-dimensional geometric understanding of the Earth’s crust.

    For these reasons, EIT Raw Materials decided to fund a network of infrastructure (NoI) –Visual3D – for three years (2017–2019). Visual3D involves to-date 14 partner organisations from nine EU countries. The NoI aims to integrate expertise within exploration and 3D modelling from industry, academia and research institutes, with the ambition to increase the understanding of geological bodies in 3D and 4D through improved visualisation techniques.

    During its first year, Visual3D has worked to identify common issues in the field of geomodelling, the solutions to which may be facilitated by a Pan-European network approach:

    1. Data compatibility. The vast majority of European mining companies are currently working with 3D solutions for mine planning, resource estimation and production, utilizing a vast variety of expert programs (e.g. Leapfrog, Vulcan, Surpac, gOcad, MOVE). This leads to a wide range in character of 3D-models, as well as various types of data and file formats. Especially the combination of models on different scales, such as the incorporation of deposit scale models into regional-scale models, often necessitates simplifications and may lead to a loss of data. Therefore, a NoI that improves the interchangeability of models and furthermore enables full data integration will increase the usability of geomodels in exploration and research.
    2. Communication of geomodels. Commonly, specific expert software in order to make different data formats readable and communicate geomodels between collaborators, clients, stakeholders and decision makers. This limits the group of possible co-workers in a modelling project and the group of people that can utilize such models to the amount of available and often expensive licenses. A network of 3D-modelling users can substantially widen the possibilities to make geomodels accessible to a wider audience.
    3. Complexity and variety of CAM software. Software packages for computer-aided modelling (CAM) for geology and for industry standard mineral resource and reserve models are rather complex. Furthermore, there is a wide variety of available CAM software, each yielding individual functions, advantages and disadvantages. Changing a software or personnel within an organisation necessitates investment in additional training and causes downtimes. Implementing work flows for data interoperability may minimize expenditures on software and training for mining and exploration companies. Hence the NoI aims to work on solutions in order to optimize the generation, interpretation and application of geomodels, and improve the time and cost efficiency of these processes.

    Integration and improved outward communication of the available visualisation tools at the NoI partners will support better targeting of new mineral resources at depth, and eventually reduce environmental impacts and costs by enhancing the efficiency of exploration workflows. The distribution and possible commercialization of the NoI´s outcomes among stakeholders of the extractive industry will improve the competitiveness of European exploration and mining.

  • 42.
    Kampmann, Tobias Christoph
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Skyttä, Pietari
    University of Turku.
    Bauer, Tobias E.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Lynch, Edward P.
    Geological Survey of Sweden.
    Ore Deposits and 3D/4D modelling in Northern Fennoscandia: Fruitful knowledge exchange about one of Europe’s most prospective regions for metal exploration2016In: SGA News, no 39, p. 26-27Article in journal (Other (popular science, discussion, etc.))
  • 43.
    Lishchuk, Viktor
    et al.
    Västerås, Sweden.
    Haller, Elena
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Mathematical Science.
    Martinsson, Olof
    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.
    Analytical Modeling of a Synthetic VMS Deposit Data: a Proxy Tool for Education and Initial Research2021In: Mining, Metallurgy & Exploration, ISSN 2524-3462, Vol. 38, no 2, p. 863-874Article in journal (Refereed)
    Abstract [en]

    Freely accessible and non-confidential real-life geological data sets from mineral deposits are desirable for the wide range of applications in research and education. However, publicly available statistical data are limited in their number and quality-they contain reduced information about geological, geophysical, geotechnical, chemical, mineralogical, and other relevant properties of deposits. This makes such data insufficient for scientific purposes. However, the amount of geological knowledge obtained for a variety of deposits in the past allows the construction of an idealized synthetic ore body model using analytical approach. Such a model could be used for education purposes and testing basic scientific theories, e.g., visualization of deposit structure; teaching sampling strategies; testing new algorithms for mine planning; or comparing geostatistical modeling methods. This paper presents an analytical approach to simulate volcanic massive sulfide (VMS) deposits and shows how synthetic deposit model can be constructed and further used for studying sampling with drilling and simulating folding and faulting.

  • 44.
    Logan, Leslie
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Andersson, Joel B. H.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Whitehouse, Martin J.
    Department of Geosciences, Swedish Museum of Natural History, SE-104 05 Stockholm, Sweden.
    Martinsson, Olof
    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.
    Energy Drive for the Kiruna Mining District Mineral System(s): Insights from U-Pb Zircon Geochronology2022In: Minerals, E-ISSN 2075-163X, Vol. 12, no 7, article id 875Article in journal (Refereed)
    Abstract [en]

    The Kiruna mining district, Sweden, known for the type locality of Kiruna-type iron oxide-apatite (IOA) deposits, also hosts several Cu-mineralized deposits including iron oxide-copper-gold (IOCG), exhalative stratiform Cu-(Fe-Zn), and structurally controlled to stratabound Cu +/- Au. However the relationship between the IOA and Cu-systems has not been contextualized within the regional tectonic evolution. A broader mineral systems approach is taken to assess the timing of energy drive(s) within a regional tectonic framework by conducting U-Pb zircon geochronology on intrusions from areas where Cu-mineralization is spatially proximal. Results unanimously yield U-Pb ages from the early Svecokarelian orogeny (ca. 1923-1867 Ma including age uncertainties), except one sample from the Archean basement (2698 +/- 3 Ma), indicating that a distinct thermal drive from magmatic activity was prominent for the early orogenic phase. A weighted average Pb-207/Pb-206 age of 1877 +/- 10 Ma of an iron-oxide-enriched gabbroic pluton overlaps in age with the Kiirunavaara IOA deposit and is suggested as a candidate for contributing mafic signatures to the IOA ore. The results leave the role of a late energy drive (and subsequent late Cu-mineralization and/or remobilization) ambiguous, despite evidence showing a late regional magmatic-style hydrothermal alteration is present in the district.

  • 45.
    Logan, Leslie
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Veress, Ervin Csaba
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Andersson, Joel B. H.
    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.
    Bauer, Tobias E.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Structural framework and timing of the Pahtohavare Cu ± Au deposits, Kiruna mining district, Sweden2023In: Solid Earth, ISSN 1869-9510, E-ISSN 1869-9529, Vol. 14, no 7, p. 763-784Article in journal (Refereed)
    Abstract [en]

    As part of the larger mineral systems approach to Cu-bearing mineralization in northern Norrbotten, this study utilizes structural geology to set the classic Pahtohavare Cu ± Au deposits into an up-to-date tectonic framework. The Pahtohavare Cu ± Au deposits, situated only 5 km southwest of the Kiirunavaara world-class iron oxide–apatite (IOA) deposit, have a dubious timing, and their link to IOA formation is not constrained. The study area contains both epigenic Cu ± Au (Pahtohavare) and iron oxide–copper–gold (IOCG; Rakkurijärvi) mineral occurrences which are hosted in bedrock that has been folded and bound by two shear zones trending northeast to southwest and northwest to southeast to the east and southwest, respectively. Structural mapping and petrographic investigation of the area reveal a noncylindrical, SE-plunging anticline. The cleavage measurements mirror the fold geometry, which characterizes the fold as F2 associated with the late phase of the Svecokarelian orogeny. Porphyroclasts with pressure shadows, mylonitic fabrics, and foliation trails in porphyroblasts indicate S0/S1  is a tectonic fabric. The epigenetic Pahtohavare Cu ± Au mineralization sits in brittle–ductile structures that cross-cut an earlier foliation and the F2 fold, indicating that the timing of the deposits occurred syn- to post-F2 folding, at least ca. 80 Myr after the Kiirunavaara IOA formation. A 3D model and cross-sections of the Pahtohavare–Rakkurijärvi area and a new structural framework of the district are presented and used to suggest that the shear zones bounding the area are likely reactivated early structures that have played a critical role in ore formation in the Kiruna mining district.

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  • 46.
    Lynch, Edward P.
    et al.
    Geological Survey of Sweden, Uppsala, Sweden.
    Andersson, Joel B.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Sadeghi, Martiya
    Geological Survey of Sweden, Uppsala, Sweden.
    Bečelytė, Irma
    Lund University, Lund, Sweden.
    Hedin, Peter
    Geological Survey of Sweden, Uppsala, Sweden.
    Bauer, Tobias E.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Geology of the Paleoproterozoic Järkvissle Li-Sn-Ta Pegmatite System, Central Sweden2023Conference paper (Other academic)
  • 47.
    Marschik, Robert
    et al.
    Department of Earth and Environmental Sciences, Ludwig-Maximilians Universität, München.
    Bauer, Tobias
    Hensler, Anna-Sophie
    Department of Earth and Environmental Sciences, Ludwig-Maximilians Universität, München.
    Skarpelis, Nikos
    Department of Geology and Geoenvironment, University of Athens.
    Hölzl, Stefan
    Department of Earth and Environmental Sciences, Ludwig-Maximilians Universität, München; Bayerische Staatssammlung für Paläontologie und Geologie, München.
    Isotope geochemistry of the Pb-Zn-Ba(-Ag-Au) mineralization at Triades-Galana, Milos Island, Greece2010In: Resource geology (Tokyo. 1998), ISSN 1344-1698, E-ISSN 1751-3928, Vol. 60, no 4, p. 335-347Article in journal (Refereed)
    Abstract [en]

    The Pb-Zn-Ba(-Ag-Au) mineralization in the Triades and Galana mine areas is hosted in 2.5-1.4 Ma pyroclastic rocks, and structurally controlled mostly by NE-SW or N-S trending brittle faults. Proximal pervasive silica and distal pervasive sericite-illite alteration are the two main alteration types present at the surface. The distribution of mineralization-alteration in the district suggests at least two hydrothermal events or that hydrothermal activity lasted longer at Galana. The Sr isotope signature of sphalerite and barite (87Sr/86Sr = 0.709162 to 0.710214) and calculated oxygen isotope composition of a fluid in equilibrium with barite and associated quartz at temperatures of around 230°C are suggestive of a seawater hydrothermal system and fluid/rock interaction. Lead isotope ratios of galena and sphalerite (206Pb/204Pb from 18.8384 to 18.8711; 207Pb/204Pb from 15.6695 to 15.6976; 208Pb/204Pb from 38.9158 to 39.0161) are similar to those of South Aegean Arc volcanic and Aegean Miocene plutonic rocks, and compatible with Pb derived from an igneous source. Galena and sphalerite from Triades-Galana have δ34SVCDT values ranging from +1 to +3.6‰, whereas barite sulfate shows δ34SVCDT values from +22.8 to +24.4‰. The sulfur isotope signatures of these minerals are explained by seawater sulfate reduction processes. The new analytical data are consistent with a seawater-dominated hydrothermal system and interaction of the hydrothermal fluid with the country rocks, which are the source of the ore metals.

  • 48.
    Palmu, Jukka-Pekka
    et al.
    Geological Survey of Finland, Espoo, Finland.
    Ojala, Antti E. K.
    Geological Survey of Finland, Espoo, Finland; Department of Geography and Geology, University of Turku, Finland.
    Mattila, Jussi
    Rock Mechanics Consulting Finland Oy, Vantaa, Finland.
    Markovaara-Koivisto, Mira
    Geological Survey of Finland, Espoo, Finland.
    Ruskeeniemi, Timo
    Geological Survey of Finland, Espoo, Finland.
    Sutinen, Raimo
    Geological Survey of Finland, Rovaniemi, Finland.
    Bauer, Tobias
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Keiding, Marie
    Department of Geophysics, Geological Survey of Denmark and Greenland, København K, Denmark.
    Glacially Induced Fault Identification with LiDAR, Based on Examples from Finland2021In: Glacially-Triggered Faulting / [ed] Holger Steffen; Odleiv Olesen; Raimo Sutinen, Cambridge University Press , 2021, p. 89-99Chapter in book (Other academic)
  • 49.
    Riegler,, Thomas
    et al.
    Trinity Coll Dublin, Dept Geol, Sch Nat Sci, Museum Bldg, Coll Green, Ireland.
    McClenaghan, Sean H.
    Trinity Coll Dublin, Dept Geol, Sch Nat Sci, Museum Bldg, Coll Green, Ireland.
    Drakou, Foteini
    Trinity Coll Dublin, Dept Geol, Sch Nat Sci, Museum Bldg, Coll Green, Ireland.
    Thomas, Helen
    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.
    Bark, Glenn
    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.
    Petrographic and mineralogical study of the Kilmacoo gold occurrence, Avoca District, Southeast Ireland2019In: Proceedings of the 15th SGA Biennial Meeting, 27-30 August, University of Glasgow Publicity Services , 2019, p. 323-326Conference paper (Refereed)
    Abstract [en]

    Petrographic investigation of the quartz vein hosted Kilmacoo gold occurrence spatially associated with the copper rich Avoca massive sulphide ore body evidenced a close association between gold and sulphides. Visible electrum grains are frequently observed within chalcopyrite, and more rarely as minute inclusions in both arsenopyrite and pyrite. Mineralogical investigations also revealed complex sulphide paragenetic succession from framboidal pyrite to colloform and idiomorphic cements with overall a low arsenopyrite content. We also documented the presence of hydrothermal phosphates (apatite and monazite) subsequently altered in aluminum phosphate sulphate minerals, as well as a broad diversity of phyllosilicates. These observations as well as the cross cutting relationships tend to indicate a brittle deformation event involving possible remobilization of some of the copper mineralization from the main VMS ore body. At the present time the source of gold is still under investigation to determine the possible contribution from both local and distal sources.

  • 50. Rydman, Oskar
    et al.
    Smirnov, Maxim
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Rasmussen, Thorkild Maack
    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.
    Juhojuntti, Niklas
    LKAB.
    3-D conductivity structure of Malmberget iron oxide apatitedeposit from Magnetotelluric dataManuscript (preprint) (Other academic)
12 1 - 50 of 77
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