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  • 1.
    Andersson, Joel B.H.
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Bauer, Tobias E.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Martinsson, Olof
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Wanhainen, Christina
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    The tectonic overprint on the Per Geijer apatite iron ores in Kiruna, northern Sweden2017Ingår i: Mineral Resources to Discover / [ed] Mercier Langevin, P; Dube, B; Bardoux, M; Ross, PS; Dion, C, Society for Geology Applied to Mineral Deposits , 2017, s. 903-906Konferensbidrag (Refereegranskat)
    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.

  • 2.
    Bauer, Tobias
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Structural and sedimentological reconstruction of the inverted Vargfors basin: a base for 4D-modelling2010Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
    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.

  • 3.
    Bauer, Tobias
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    VISUAL3D: an EIT network on visualization of geomodels2017Ingår i: Geophysical Research Abstracts, ISSN 1029-7006, E-ISSN 1607-7962, Vol. 19Artikel i tidskrift (Refereegranskat)
    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.

  • 4.
    Bauer, Tobias
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Andersson, Joel
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik. LKAB, Malmberget.
    Sarlus, Zimer
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Lund, Cecilia
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Kearney, Thomas
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Structural controls on the setting, shape and hydrothermal alteration of the Malmberget IOA deposit, northern Sweden2018Ingår i: Economic geology and the bulletin of the Society of Economic Geologists, ISSN 0361-0128, E-ISSN 1554-0774, Vol. 113, nr 2, s. 377-395Artikel i tidskrift (Refereegranskat)
    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.

  • 5.
    Bauer, Tobias E.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    The crustal architecture of the central Skellefte district, Sweden: Structural analysis, setting of VMS deposits and 3D-modelling2013Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    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.

  • 6.
    Bauer, Tobias
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Sarlus, Zimer
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Project: Multi-scale 4-dimensional geological modelling of the Gällivare area2013Övrigt (Övrig (populärvetenskap, debatt, mm))
    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.

  • 7.
    Bauer, Tobias
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Sarlus, Zimer
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    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-deposit2014Konferensbidrag (Övrigt vetenskapligt)
  • 8.
    Bauer, Tobias
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Skyttä, Pietari
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Allen, Rodney
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Weihed, Pär
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Fault-controlled sedimentation in a progressively opening extensional basin: the Palaeoproterozoic Vargfors basin, Skellefte mining district, Sweden.2013Ingår i: International journal of earth sciences, ISSN 1437-3254, E-ISSN 1437-3262, Vol. 102, nr 2, s. 385-400Artikel i tidskrift (Refereegranskat)
    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

  • 9.
    Bauer, Tobias
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Skyttä, Pietari
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Allen, Rodney
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Weihed, Pär
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Syn-extensional faulting controlling structural inversion: Insights from the Palaeoproterozoic Vargfors syncline, Skellefte mining district, Sweden2011Ingår i: Precambrian Research, ISSN 0301-9268, E-ISSN 1872-7433, Vol. 191, nr 3-4, s. 166-183Artikel i tidskrift (Refereegranskat)
    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.

  • 10.
    Bauer, Tobias
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Skyttä, Pietari
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Dehghannejad, Mahdieh
    Uppsala University.
    Tavakoli, Saman
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Weihed, Pär
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Geological multi-scale modelling as a tool for modern ore exploration in the Skellefte mining district, Sweden2011Ingår i: Proceedings IAMG 2011 Salzburg: Mathematical Geosciences at the crossroads of theory and practice, 2011, s. 759-Konferensbidrag (Övrigt vetenskapligt)
    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

  • 11.
    Bauer, Tobias
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Skyttä, Pietari
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Hermansson, Tobias
    Boliden Mineral AB.
    Allen, Rodney
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Weihed, Pär
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Correlation between distribution and shape of VMS deposits, and regional deformation patterns, Skellefte district, northern Sweden2014Ingår i: Mineralium Deposita, ISSN 0026-4598, E-ISSN 1432-1866, Vol. 49, nr 5, s. 555-573Artikel i tidskrift (Refereegranskat)
    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.

  • 12.
    Bauer, Tobias
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Skyttä, Pietari
    Hermansson, Tobias
    Boliden Mineral AB, Luleå tekniska universitet.
    Dehghannejad, Mahdieh
    Uppsala University, Uppsala universitet, Department of Earth Sciences, Uppsala University.
    Tavakoli, Saman
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    The Skellefte District2015Ingår i: 3D, 4D and Predictive Modelling of Major Mineral Belts in Europe, Encyclopedia of Global Archaeology/Springer Verlag, 2015, s. 93-121Kapitel i bok, del av antologi (Refereegranskat)
    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.

  • 13.
    Bauer, Tobias
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Skyttä, Pietari
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Hermansson, Tobias
    Boliden Mineral AB.
    Weihed, Pär
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Ore body shapes versus regional deformation patterns as a base for 3D prospectivity mapping in the Skellefte Mining District, Sweden2012Konferensbidrag (Refereegranskat)
  • 14.
    Bauer, Tobias
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Skyttä, Pietari
    Hermansson, Tobias
    Boliden Mineral AB, Luleå tekniska universitet.
    Weihed, Pär
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    The comparison of ore body shapes and regional deformat patterns as a base for prospectivity mapping in the Skellefte mining district, Sweden2012Konferensbidrag (Refereegranskat)
  • 15.
    Bauer, Tobias
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Skyttä, Pietari
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Tavakoli, Saman
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Dehghannejad, Mahdieh
    Uppsala University, Uppsala universitet, Department of Earth Sciences, Uppsala University.
    Weihed, Pär
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    From deposit to regional scale: 4-dimensional geological modelling in the Skellefte Mining District, Sweden2011Konferensbidrag (Refereegranskat)
  • 16.
    Bauer, Tobias
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Skyttä, Pietari
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Tavakoli, Saman
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Hermansson, Tobias
    Boliden Mineral AB.
    Dehghannejad, Mahdieh
    Uppsala University.
    Juanatey, Maria Garcia
    Uppsala University.
    Weihed, Pär
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Allen, Rodney
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Juhlin, Christopher
    Uppsala University.
    A regional scale 3D-model of the Skellefte mining district, northern Sweden2013Ingår i: 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, s. 62-65Konferensbidrag (Refereegranskat)
  • 17.
    Bauer, Tobias
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Skyttä, Pietari
    Weihed, Pär
    Allen, Rodney
    3D-modelling of the Central Skellefte District, Sweden2009Ingår i: 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 , 2009Konferensbidrag (Refereegranskat)
    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.

  • 18.
    Bauer, Tobias
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Tavakoli, Saman
    Dehghannejad, Mahdieh
    Department of Earth Sciences, Uppsala University.
    Garcia, Maria
    Department of Earth Sciences, Uppsala University.
    Weihed, Pär
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser.
    4-dimensional geological modelling of the Skellefte district, Sweden2010Ingår i: The international archives of the photogrammetry, remote sensing and spatial information sciences, ISPRS Commission IV - Working Group 8 , 2010, Vol. XXXVIII-4, s. 93-96Konferensbidrag (Övrigt vetenskapligt)
  • 19.
    Bauer, Tobias
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Weihed, Pär
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Crustal Scale Shear Zones Controlling Grade and Tonnage of VMS Deposits in the Skellefte District, Northern Sweden2015Ingår i: Mineral Resources in a Sustainable World / [ed] A.S. Andre-Mayer; M. Cathelineau; P. Muchez; E. Pirard; S. Sindern, 2015, s. 45-48Konferensbidrag (Refereegranskat)
    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.

  • 20.
    Brethes, Anais
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik. 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 tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Bauer, Tobias Erich
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Interpretation of aeromagnetic data in the Jameson Land Basin, central East Greenland: Structures and related mineralized systems2018Ingår i: Tectonophysics, ISSN 0040-1951, E-ISSN 1879-3266, Vol. 724-725, s. 116-136Artikel i tidskrift (Refereegranskat)
    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.

  • 21.
    Brethes, Anais
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Rasmussen, Thorkild Maack
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Guarnieri, Pierpolo
    GEUS.
    Bauer, Tobias
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    3D modelling of the base-metal mineralized Jameson Land Basin (central East Greenland) using geologically constrained inversion of magnetic data2015Konferensbidrag (Övrigt vetenskapligt)
  • 22.
    Brethes, Anaïs
    et al.
    Geological Survey of Denmark and Greenland.
    Guarnieri, Pierpaolo
    Geological Survey of Denmark and Greenland.
    Rasmussen, Thorkild Maack
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Bauer, Tobias
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    3D-Modelling of the Early Triassic Base-Metal Mineralized Syn-Rift Sequence in the Jameson Land Basin (East Greenland)2015Ingår i: Mineral Resources in a Sustainable World / [ed] A.S. Andre-Mayer; M. Cathelineau; P. Muchez; E. Pirard; S. Sindern, 2015, s. 1701-1704Konferensbidrag (Refereegranskat)
    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.

  • 23.
    Brethes, Anaïs
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Guarnieri, Pierpaolo
    GEUS.
    Rasmussen, Thorkild Maack
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Bauer, Tobias
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Geological Analysis of Aeromagnetic Data over the Blyklippen Lead-zinc Mine at Mesters Vig, Central East Greenland2016Ingår i: First Conference on Geophysics for Mineral Exploration and Mining: Near Surface Geoscience 2016, Barcelona, Spain, 4-8 September 2016, Houten, 2016, artikel-id Mo MIN 05Konferensbidrag (Refereegranskat)
    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.

  • 24.
    Brethes, Anaïs
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Rasmussen, Thorkild Maack
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Guarnieri, Pierpaolo
    GEUS.
    Bauer, Tobias
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Mapping and characterization of Induced Polarization in airborne TEM data from central East Greenland: application of a Self-Organizing Map procedure2016Konferensbidrag (Refereegranskat)
    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.

  • 25.
    Dehghannejad, Mahdieh
    et al.
    Department of Earth Sciences, Uppsala University.
    Bauer, Tobias
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Malehmir, Alireza
    Department of Earth Sciences, Uppsala University.
    Juhlin, Christopher
    Department of Earth Sciences, Uppsala University.
    Weihed, Pär
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Crustal geometry of the central Skellefte district, northern Sweden: constraints from reflection seismic investigations2012Ingår i: Tectonophysics, ISSN 0040-1951, E-ISSN 1879-3266, Vol. 524-525, s. 87-99Artikel i tidskrift (Refereegranskat)
    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.

  • 26.
    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 tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Bauer, Tobias
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Reflection seismic imaging in the Skellefte ore district, northern Sweden2013Ingår i: 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, s. 126-129Konferensbidrag (Refereegranskat)
  • 27.
    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 tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Skyttä, Pietari
    Bauer, Tobias
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Pan-European mineral resource assessment2012Konferensbidrag (Refereegranskat)
  • 28.
    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 tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Weihed, Pär
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Skyttä, Pietari
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Magnetotelluric measurements in the Skellefte ore district, northern Sweden2013Ingår i: 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, s. 138-141Konferensbidrag (Refereegranskat)
  • 29.
    Kampmann, Tobias Christoph
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Bauer, Tobias
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Project: Enhanced Exploration (EnEx)2017Övrigt (Övrig (populärvetenskap, debatt, mm))
  • 30.
    Kampmann, Tobias Christoph
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Bauer, Tobias
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Project: Visualisation of 3D–4D models in exploration and geosciences (Visual3D)2017Övrigt (Övrig (populärvetenskap, debatt, mm))
    Abstract [en]

    While the territory of the EU in many parts shows a very high exploration potential and many EU countries obtain high rankings in the Fraser Institute annual reports on attractiveness (Fraser Institute, 2015) it is still a fact that a mere 4% of global expenditure in exploration is invested within European countries. One tool to trigger a higher degree of investment in exploration and to secure ultimately the domestic supply of both main commodities and critical raw materials (CRM) is to enhance our understanding of the Earth’s crust below the surface—and the major aspect is here to optimised our understanding about the 3rd dimension in geology. By integrating industry, academia and research institutes with expertise and excellence in exploration and 3D modelling it is the ambition of the network of infrastructure to increase the understanding of geological bodies in 3D and 4D through improved visualisation techniques. The vast majority of European mining companies are working in 3D for mine planning, re-source estimations and production. For this purpose a wide range of expert programs is uti-lized such as Leapfrog, Vulcan, Surpac, gOcad, MOVE and many others. This leads to a wide range of 3D-models with very differing character as well as various types of data and file for-mats. Especially the combination of models on different scales, such as the incorporation of deposit scale models into regional scales models, often includes over-simplifications and may lead to the loss of data, respectively. Therefore, a network that improves the interchangeability of models and furthermore enables full data integration will decrease the need for over-simplifications and consequently increase the usability of geomodels in exploration and research. One further benefit of some of the software packages is the possibility to dynamically generate alternative solutions to the geological problems, which are evident in cases where the data coverage is sparse, and the model uncertainties are con-sequently high to start with. The alternative solutions should be based on geologically valid hypotheses, and testing their applicability should at the least rule out geologically unreasona-ble alternatives.One other major problem is output and communication of the produced geomodels. The cur-rent communication of geomodels often requires specific expert software in order to make different data formats readable. 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 up the possibilities to make geomodels accessible to a wider audience.Software packages for computer aided modelling (CAM) for geology and for industry standard mineral resource and reserve models are very complex. Furthermore there is a wide bunch of CAM software available. Each package has its individual functions, advantages and disadvantages. Often a person is skilled in application one or two different software packages. Hence software and applicant can be seen as a unit. Changing software or personnel needs investment in additional training and causes downtimes. To set up work flows for data interoperability could minimize expenditures on software and training for M&E; companies. Hence the results of such a network could maximize the benefit of the work related to modelling, interpretation and engineering and improve the time and cost efficiency of these processes.The visualisation tools available at the partners will support better targeting of new mineral resources at depth, and new technologies optimized for deep exploration in diverse terrains will enhance the efficiency of exploration by reducing environmental impacts and costs. This expected outcome will also re-shape exploration practices on low-grade and deep-seated mineral resources. The distribution and commercialization of the project´s outcomes among stakeholders of the extractive industry will improve competitiveness of European exploration and mining. Testing the results of the project in mineral belts with different geological, environmental and societal challenges of exploration will also support the generalization of know-how and technologies and their potential transfer outside of Europe.A large number of partners at all CLCs in EIT Raw Materials have decided to promote activities related to exploration for primary raw materials under the umbrella Lighthouse Exploration. The intention is to explore synergies and integration between different types of KAVAs related to the theme and in this way to maximize the outcome and KPIs for this important theme. The concept will be developed further during the construction phase of EIT Raw Materials.

  • 31.
    Kampmann, Tobias Christoph
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Skyttä, Pietari
    University of Turku.
    Bauer, Tobias E.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    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 exploration2016Ingår i: SGA News, nr 39, s. 26-27Artikel i tidskrift (Övrig (populärvetenskap, debatt, mm))
  • 32.
    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, Greece2010Ingår i: Resource geology (Tokyo. 1998), ISSN 1344-1698, E-ISSN 1751-3928, Vol. 60, nr 4, s. 335-347Artikel i tidskrift (Refereegranskat)
    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.

  • 33.
    Sarlus, Zimer
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Bauer, Tobias
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Tavakoli, Saman
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Wanhainen, Christina
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Nordin, Roger
    Boliden Mineral AB, Boliden AB, Boliden Mineral, Exploration Department, Boliden.
    Andersson, Joel
    LKAB, Exploration Department, Malmberget.
    Geochemistry of Ultramafic-Mafic Units Related to Fe-, Cu-, and Au Deposits in the Gallivare Region, Northern Norrbotten, Sweden2015Ingår i: Mineral Resources in a Sustainable World / [ed] A.S. Andre-Mayer; M. Cathelineau; P. Muchez; E. Pirard; S. Sindern, 2015, s. 1123-1126Konferensbidrag (Refereegranskat)
    Abstract [en]

    Geochemical investigations were carried out in the Gallivare area as a part of a larger project aiming to understand the crustal architecture of the region in 3D. Major igneous suites such as the Dundret and Vassaravaara intrusions with additional smaller mafic intrusions have been identified as key localities and investigated. Results indicate two distinct rock units. The first suite is assigned to ultramafic-mafic layered intrusions with a calc-alkaline to a more tholeiitic composition belonging to the Dundret and Vassaravaara intrusions. The second suite is mainly of mafic to intermediate composition with a clear ophitic texture. This paper investigate the source and origin of the key rock suites, playing a major role on the evolution of the Gallivare region, a region which is characterized by porphyry Cu, IOCG, and Al0 deposits including some of Europe's top producing Fe and Cu-Au-Ag (-Mo) mines.

  • 34.
    Sarlus, Zimer
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Bauer, Tobias
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Tavakoli, Saman
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Wanhainen, Christina
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Nordin, Roger
    Boliden Mineral, Exploration Department, Boliden.
    Andersson, Joel
    LKAB.
    Geochemistry of Ultramafic-mafic Units Related to Fe-, Cu-, and Au Deposits in the Gällivare Region, Northern Norrbotten, Sweden2015Konferensbidrag (Refereegranskat)
  • 35.
    Sarlus, Zimer
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Martinsson, Olof
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Bauer, Tobias E.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Wanhainen, Christina
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Timing and tectonic setting of host rocks to the Malmberget AlO deposit, Sweden2017Ingår i: Mineral Resources to Discover / [ed] Mercier Langevin, P; Dube, B; Bardoux, M; Ross, PS; Dion, C, Society for Geology Applied to Mineral Deposits , 2017, s. 959-962Konferensbidrag (Refereegranskat)
    Abstract [en]

    Host felsic and intermediate meta-volcanic rocks to the Malmberget apatite iron ore (AlO) deposit have been investigated geochemically and geochronologically, the latter using the U-Pb method on a set of zircons. Results indicate emplacement age of 1.9 Ga for the felsic and intermediate volcanic rocks, potentially in an extensional environment. The zircon U-Pb radiometric ages are among the first conclusive ages with implicit constraint on the geological evolution of the northern Norrbotten ore district and Malmberget deposit.

  • 36.
    Sarlus, Zmar
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Andersson, Ulf B.
    Luossavaara-Kiirunavaara AB, SE-981 86 Kiruna.
    Bauer, Tobias E.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Wanhainen, Christina
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Martinsson, Olof
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Nordin, Roger
    Boliden Mineral AB.
    Andersson, Joel B.H.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Timing of plutonism in the Gällivare area: mplications for Proterozoic crustal development in the northern Norrbotten ore district, Sweden2018Ingår i: Geological Magazine, ISSN 0016-7568, E-ISSN 1469-5081, Vol. 155, nr 6, s. 1351-1376Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Zircon ion probe (secondary-ion mass spectrometry or SIMS) data from a set of intrusive rocks emplaced in the vicinity of major ore bodies, as well as from large igneous intrusions in the Gällivare area, gave the following results: (1) the Dundret ultramafic–mafic layered complex (1883±5 Ma), the Aitik granite (1883±5 Ma), the Nautanen diorite (1870±12 Ma), the Vassaravaara ultramafic–mafic layered complex (1798±4 Ma), the Aitik dolerite (1813±9 Ma), the Bergmästergruvan and Sikträsk syenites (1795±4 Ma and 1801±3 Ma, respectively) and the Naalojärvi granite (1782±5 Ma). These data broadly fall within the ranges 1.89–1.87 Ga (early Svecofennian) and 1.80–1.78 Ga (late Svecofennian), but geochronologically allow further subdivision into pulses at 1885–1880, 1875–1870, 1800 and 1780 Ma. During these events, large layered ultramafic–mafic and felsic plutonic rocks were generated with distinct overlap in time suggesting coeval felsic–mafic magmatism. Results also indicate the presence of inherited c. 1.87 Ga zircon crystals in the plutonic rocks at 1.78 Ga, supporting reworking of the previous crust. These data indicate the importance of mantle-derived mafic underplating in the process of crustal magma generation in the region. The c. 1.88 Ga event that generated ultramafic–mafic layered complexes is tentatively suggested to have played an important role in the formation of the Aitik Cu–Au porphyry system. The later event at c. 1.80 Ga, generating voluminous mafic–felsic units, is suggested to be coupled to the regional iron-oxide-copper-gold (IOCG) overprint.

  • 37.
    Skyttä, Pietari
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Bauer, Tobias
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Hermansson, Tobias
    Boliden Mineral AB.
    Dehghannejad, Mahdieh
    Uppsala University.
    Juhlin, Christopher
    Uppsala University.
    Hübert, Juliane
    Uppsala University.
    Weihed, Pär
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Crustal 3-D geometry of the Kristineberg area (Sweden) with implications on VMS deposits2013Ingår i: Solid Earth, ISSN 1869-9510, E-ISSN 1869-9529, Vol. 4, s. 387-404Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Structural analysis of the Palaeoproterozoic volcanogenic massive sulfide (VMS) hosting Kristineberg area, Sweden, constrained by existing magnetotelluric (MT) and seismic reflection data, reveals that the complex geometry characterized by non-cylindrical antiformal structures is due to transpression along the termination of a major high-strain zone. Similar orientations of the host rock deformation fabrics and the VMS ore lenses indicate that the present-day geometry of the complex VMS deposits in the Kristineberg area may be attributed to tectonic transposition. The tectonic transposition was dominantly controlled by reverse shearing and related upright to overturned folding, with increasing contribution of strike-slip shearing and sub-horizontal flow towards greater crustal depths. Furthermore, the northerly dip of the previously recognized subsurface crustal reflector within the Kristineberg area is attributed to formation of crustal compartments with opposite polarities within the scale of the whole Skellefte district. The resulting structural framework of the main geological units is visualized in a 3-D model which is available as a 3-D PDF document through the publication website.

  • 38.
    Skyttä, Pietari
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Bauer, Tobias
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Tavakoli, Saman
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Hermansson, Tobias
    Boliden Mineral AB.
    Andersson, Jenny
    Geological Survey of Sweden.
    Weihed, Pär
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Pre-1.87 Ga development of crustal domains overprinted by 1.87 Ga transpression in the Palaeoproterozoic Skellefte district, Sweden2012Ingår i: Precambrian Research, ISSN 0301-9268, E-ISSN 1872-7433, Vol. 206–207, s. 109-136Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The complex structural evolution within the VMS-hosting Skellefte district, Sweden, has been investigated to provide a solid structural framework for the known mineral deposits in the area. The area occurs in a transition zone between dominantly N-S to NNE-WSW striking structures in the north and approximately WNW-ESE oriented structural trends in the south. The presence of high-strain zones with both the above orientations in the Skellefte district allows constraining their mutual relationship, as well as their significance for the build-up of the Svecokarelian orogen at around 1.89 Ga and for the following tectonic overprint between 1.87-1.80 Ga. The methods used in this study include structural analysis complemented by potential field modelling and SIMS U-Pb geochronology on zircon. Based on the results of this study, the earliest deformation (D1) is constrained at 1.89–1.88 (1.87) Ga and tentatively attributed to crustal extension occurring synchronously with volcanism. Deposition of the Skellefte Group metavolcanic rocks is inferred to have occurred in a pull-apart basin developed due to dextral strike-slip shearing along approximately N-S striking regional-scale shear zones. Variations in the development of deformation fabric across the district indicate that the crust was divided into an upper, un-metamorphosed domain and a lower, strongly metamorphosed domain during D1. We further infer that the transition from the upper to lower crust was locally coupled with development of low-angle crustal-scale detachment zones during D1. The heterogenous crust was subsequently overprinted by transpressional deformation which may be explained by two alternative models. According to the first model, one single SSE-NNW transpressional event with distinct strain partitioning between the coaxially deformed upper crust and the non-coaxially deformed lower crust is largely responsible for the present-day structural geometry. A post-folding rhyolite dyke, here dated at 1871 ± 4 Ma, constrains the minimum age of this event (D2). The alternative model includes two separate transpressional events: a SW-NE one at (1.88-) 1.87 Ga, followed by SSE-NNW transpression at 1.86 Ga. Recognition of the early-orogenic detachment zones allow us to suggest that many of the major crustal-scale shear zones in the central Fennoscandian Shield have originated as 1.89-1.87 Ga crustal detachment zones, i.e. earlier than typically considered.

  • 39.
    Skyttä, Pietari
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Bauer, Tobias
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Tavakoli, Saman
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Hermansson, Tobias
    Boliden Mineral AB.
    Andersson, Jenny
    Sveriges Geologiska Undersökning, Geological Survey of Sweden.
    Weihed, Pär
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Evolution of early-orogenic deformation zones and their significance for the development of contrasting structural domains within the Palaeoproterozoic Skellefte District, Sweden2012Konferensbidrag (Refereegranskat)
  • 40.
    Skyttä, Pietari
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Bauer, Tobias
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Tavakoli, Saman
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Weihed, Pär
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Allen, Rodney
    Boliden Mineral AB.
    Dehghannejad, Mahdieh
    Uppsala University, Uppsala universitet, Department of Earth Sciences, Uppsala University.
    Juanatey, Maria A. Garcia
    Department of Earth Sciences, Uppsala University, Uppsala University.
    Hübert, Juliane
    Uppsala University, Department of Earth Sciences, Uppsala University.
    Multiscale 3/4D-modelling of mineral belts: examples from the Skellefte Mining District, Sweden2011Konferensbidrag (Refereegranskat)
  • 41.
    Skyttä, Pietari
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Bauer, Tobias
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Tavakoli, Saman
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Weihed, Pär
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Allen, Rodney
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Dehghannejad, Mahdieh
    Juanatey, Maria Garcia
    Hübert, Juliane
    4-dimensional geological modelling of mineral belts2011Konferensbidrag (Övrigt vetenskapligt)
  • 42.
    Skyttä, Pietari
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Hermansson, T.
    Luleå tekniska universitet.
    Bauer, Tobias
    Three dimensional structure of the VMS-hosting Palaeoproterozoic Kristineberg area, northern Sweden2009Ingår i: 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 , 2009Konferensbidrag (Refereegranskat)
    Abstract [en]

    The Palaeoproterozoic Kristineberg area in northern Sweden comprises five sulphide mineralizations occurring within a regional-scale, fault-controlled antiformal structure. The ~E-W faults show reverse shear senses with the largest dip-slip displacements in the east. However, based on both the steep orientations of the faults, as well as their close relationship with intense folding on the above metavolcanic rocks, the faults are considered to have their origin in a phase of crustal extension pre-dating compressional deformation. The SW-NE crustal shortening was regionally partitioned into both ~E-W and ~N-S trending high-strain structural domains, whereas the Kristineberg mine vicinity shows a pattern of sub-horizontal stretching with top-to-the-E kinematics and S-block-up reverse faulting. The above features together formed the Kristineberg deposit into its present shape with steep planar bodies close to the surface and elongate, gently W-plunging bodies indicating intense stretching at depth.

  • 43.
    Skyttä, Pietari
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser.
    Hermansson, Tobias
    Boliden Mineral AB.
    Bauer, Tobias
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Elming, Sten-åke
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Magnetic fabrics as constraints on the kinematic history of a pre-tectonic granitoid intrusion, Kristineberg, northern Sweden2010Ingår i: Journal of Structural Geology, ISSN 0191-8141, E-ISSN 1873-1201, Vol. 32, nr 8, s. 1125-1136Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Outcrop-scale correlations of deformation fabrics with low-field anisotropy of magnetic susceptibility (AMS) measurements revealed a two-stage structural evolution of the pre-tectonic, Palaeoproterozoic Viterliden intrusion in the Skellefte District, Sweden. The first deformation event reflected ˜N-S compression during basin inversion, and comprised reverse dip-slip shearing along major ˜E-W faults, whereas the low-strain lenses in between experienced penetrative deformation with a component of NE-SW elongation along the main foliation. This event is largely responsible for the present structural geometry regionally and locally, and also for the magnetic fabric of the rocks. In particular, the sub-vertical maximum principal susceptibility axes (Kmax) within the high-strain zones are related to early dip-slip deformation, and were virtually unaffected by subsequent dextral strike-slip reactivation, which is recorded by sub-horizontal rock lineations. The strike-slip deformation reflects ˜E-W bulk shortening and may regionally be correlated with reverse faulting along a ˜N-S trending major shear zone east of the study area.

  • 44.
    Tavakoli, Saman
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Bauer, Tobias
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Elming, Sten-åke
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Thunehed, Hans
    Geovista AB.
    Weihed, Pär
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Regional-scale geometry of the central Skellefte district, northern Sweden: results from 2.5D potential field modeling along three previously acquired seismic profiles2012Ingår i: Journal of Applied Geophysics, ISSN 0926-9851, E-ISSN 1879-1859, Vol. 85, s. 43-58Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The Skellefte district in northern Sweden is one of the most important mining districts in Europe hosting approximately 80 volcanic massive sulfide (VMS) deposits. Due to its economical importance, geological and geophysical studies were carried out in order to create an image of the geometry of the upper crustal structure and integral geological elements and to evaluate their relationship to mineral deposits. Consequently, seismic reflection data along three sub-parallel profiles were acquired during 2009–2010 to map the spatial relationships between the geological structures down to a depth of ~4.5 km. Although these seismic studies helped researchers understand the regional relationship between geologic units in the central Skellefte district (CSD), the seismic reflection data did not succeed entirely in mapping the lithological contacts in the area. In this study, themodel derived fromthe seismic reflection datawas examined by using 2.5D modeling of potential field data (down to a 5 km depth) constrained by physical properties of the rocks and surface geology.Moreover, we modeled gravity and magnetic data along the non-reflective or poorly reflective parts of the seismic profiles to identify major lithological contacts and shear zones in the CSD, which could not be modeled on the basis of the seismic reflection data. Gravity and magnetic data helped reveal the spatial relationship between the Skellefte volcanic rocks, Vargfors groupmeta-sedimentary rocks and two metaintrusive complexes.Results suggest amaximum depth extent of 2.1 kmfor the tectonic contact at the southern border of the Jörn granitoid. Furthermore, this north-dipping Skellefte–Jörn contact coincides closely with magnetic lows and gravity highs, which implies that the Jörn intrusive rocks have a greater thickness than the underlying basalt. Further to the NW, gravity and magnetic data suggest a depth extent of 2 km for the Gallejaur complex, which coincides with a set of gently dipping reflectors. In addition, this study supports previous concepts of fault geometries and fault patterns as a result of upper-crustal extension and subsequent inversion during crustal shortening. In the final model interpretations of the IP data were included, thus relating indications of mineralization to the geological structures.

  • 45.
    Tavakoli, Saman
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Bauer, Tobias
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Rasmussen, Thorkild Maack
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Weihed, Pär
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Elming, Sten-åke
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Deep massive sulphide exploration using 2D and 3D geoelectrical and induced polarization data in Skellefte mining district, northern Sweden2016Ingår i: Geophysical Prospecting, ISSN 0016-8025, E-ISSN 1365-2478, Vol. 64, nr 6, s. 1602-1619Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Geoelectrical and induced polarization data from measurements along three profiles and from one 3D survey are acquired and processed in the central Skellefte District, northern Sweden. The data were collected during two field campaigns in 2009 and 2010 in order to delineate the structures related to volcanogenic massive sulphide deposits and to model lithological contacts down to a maximum depth of 1.5 km. The 2009 data were inverted previously, and their joint interpretation with potential field data indicated several anomalous zones. The 2010 data not only provide additional information from greater depths compared with the 2009 data but also cover a larger surface area. Several high-chargeability low-resistivity zones, interpreted as possible massive sulphide mineralization and associated hydrothermal alteration, are revealed. The 3D survey data provide a detailed high-resolution image of the top ∼450 m of the upper crust around the Maurliden East, North, and Central deposits. Several anomalies are interpreted as new potential prospects in the Maurliden area, which are mainly concentrated in the central conductive zone. In addition, the contact relationship between the major geological units, e.g., the contact between the Skellefte Group and the Jörn Intrusive Complex, is better understood with the help of 2010 deep-resistivity/chargeability data. The bottommost part of the Vargfors basin is imaged using the 2010 geoelectrical and induced polarization data down to ∼1-km depth.

  • 46.
    Tavakoli, Saman
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Bauer, Tobias
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Skyttä, Pietari
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Elming, Sten-åke
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Thunehed, Hans
    Geovista AB.
    Weihed, Pär
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Skellefte mining district in 3D: results from integrated interpretation of potential field, resistivity/IP and reflection-seismic data2012Konferensbidrag (Refereegranskat)
    Abstract [en]

    Located in northern Sweden, the Skellefte mining district has been subject to several geological and geophysical investigations, as it is hosting abundant volcanic-hosted massive sulfide deposits. The importance of mineral exploration at greater depths in the Skellefte District has been increased since most of mineralization at shallow depths are already discovered and exploited. Therefore, geophysical methods become particularly important as they can improve our knowledge about spatial relationship between geological features at the depth. In the first part (local-scale) of this study, we used resistivity/IP data to map the subsurface geometry down to 430m. Furthermore, the results of the resistivity/IP studies were constrained with potential field data down to 1.5 km depth. In the second part (Regional-scale), potential field data were used to constrain the interpretation of the reflection-seismic data down to 5 km depth. The result from the first part indicated a good correlation between the initial resistivity model and the magnetic and gravity field calculated from that model. In Part II, the gravity and magnetic data were investigated to better understand the contact between the Skellefte Group,volcanic rocks and the Bothnian Basin sedimentary rocks. Furthermore the method was used to constrain the geometry of late-orogenic gabbro-diorite and granite intrusions which occur along inferred shear zones that are only poorly indicated, or not visible at all on the reflection-seismic profiles. As the main outcome, the proposed integrated 3D model of the central Skellefte District (CSD) revealed crucial information about the spatial relationship between key lithologies which will be further used to understand the evolution of CSD in the 4th dimension, time.

  • 47.
    Tavakoli, Saman
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Dehghannejad, Mahdieh
    Department of Earth Sciences, Division of Geophysics, Uppsala University .
    de los Ángeles García Juanatey, María
    Department of Earth Sciences, Division of Geophysics, Uppsala University .
    Bauer, Tobias
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Weihed, Pär
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Elming, Sten-Åke
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Potential Field, Geoelectrical and Reflection Seismic Investigations for Massive Sulphide Exploration in the Skellefte Mining District, Northern Sweden2016Ingår i: Acta Geophysica, ISSN 1895-6572, E-ISSN 1895-7455, Vol. 64, nr 6, s. 2171-2199Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Multi-scale geophysical studies were conducted in the central Skellefte district (CSD) in order to delineate the geometry of the upper crust (down to maximum ∼ 4.5 km depth) for prospecting volcanic massive sulphide (VMS) mineralization. These geophysical investigations include potential field, resistivity/induced polarization (IP), reflection seismic and magnetotelluric (MT) data which were collected between 2009 and 2010. The interpretations were divided in two scales: (i) shallow (∼ 1.5 km) and (ii) deep (∼4.5 km). Physical properties of the rocks, including density, magnetic susceptibility, resistivity and chargeability, were also used to improve interpretations. The study result delineates the geometry of the upper crust in the CSD and new models were suggested based on new and joint geophysical interpretation which can benefit VMS prospecting in the area. The result also indicates that a strongly conductive zone detected by resistivity/IP data may have been missed using other geophysical data.

  • 48.
    Zainy, Maher T.
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Al-Ansari, Nadhir
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Bauer, Tobias
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Ask, Maria
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    The Tectonic and Structural Classifications of the Western Part of the Zagros Fold and Thrust Belt, North Iraq, Review and Discussion2017Ingår i: Journal of Earth Sciences and Geotechnical Engineering, ISSN 1792-9040, E-ISSN 1792-9660, Vol. 7, nr 2, s. 71-89Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The Zagros fold and thrust belt represents a tectonically significant area, and one of the richest areas in oil and gas reservoirs in the world. The Zagros fold and thrust belt is the deformational product of the Cretaceous-present day convergence of the Arabian and Iranian (Eurasian) plates (subduction and collision). The belt extends more than 2000 km from southern Turkey through the north and northeastern Iraq to the Strait of Hormuz in southwestern Iran. The Zagros fold and thrust belt is divided into two parts which are; Western part within Iraqi region and Eastern part within Iranian region. The western part of the Zagros fold and thrust belt has been traditionally subdivided into several structural zones that are generally striking parallel to the plate boundary. This is characterized by exposure of Late Ordovician to Pliocene - Pliestocene formations with different types of Quaternary Sediments. This research will concentrate on Western part of Zagros fold and thrust belt and the styles of structural classifications, which will aid to clarify and better understand the tectonic and structural history and evolution of the region. We have considered the last version of structural classification as the most relevant one to the reality, especially within outer platform (Unstable shelf). Where it divides the region into four structural zones, which are: Low Folded zone, High Folded Zone, Imbricate Zone, and Zagros Suture Zone and these zones were further divided to several subzones. This classification is based on the structural style and intensity of deformation, stratigraphy, mechanicalstratigraphy and tectono-stratigraphy of the deformed sequences, Age of deformation, surface physiography and morphology. The data used in the classification is more reliable, up to date and relevant.

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