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  • 51.
    Warlo, Mathis
    et al.
    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.
    Karlsson, Peter
    Boliden AB, Exploration Department.
    Höglund, Sofia
    Boliden AB, Exploration Department.
    Mineralisation paragenesis of the Liikavaara Cu-(W-Au) deposit, 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. 971-974Conference paper (Refereed)
    Abstract [en]

    The Liikavaara Cu-(W-Au) deposit is located in the Gallivare ore district in northern Sweden, a few kilometres east of the renowned Aitik Cu-(Au) deposit. Its enrichment in Critical Raw Materials and its scheduled production for the near future make the Liikavaara deposit ideal as the subject of a case study on improved ore characterisation using various micro-analytical techniques. Here we present a general overview of the mineralogy in Liikavaara to provide a base for future micro-analytical studies. The deposit lies within Palaeoproterozoic volcanosedimentary rocks of andesitic composition. A unit of biotite schist hosts the ore. Mineralisation in Liikavaara is mainly controlled by quartz-(calcite)-(tourmaline) veins. Aplitic dykes and calcite veinlets also cut the deposit. Ore minerals are chalcopyrite, pyrrhotite, pyrite, sphalerite, galena, and molybdenite. Non-sulfide sources include scheelite and minor magnetite. The deposit is affected by alteration such as sericitisation, calcification, tourmalinisation, epidotisation, and chloritisation. The genesis of the deposit is up to today not determined and studies are few. However, the deposit's spatial proximity to a mineralised granodiorite dated at ca. 1.87 Ga offer some similarities to the Aitik deposit and its 1.89 Ga quartz monzodiorite. A primary magmatic origin with later IOCG overprint could therefore be a possibility.

  • 52.
    Warlo, Mathis
    et al.
    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.
    Butcher, Alan
    Geological Survey of Finland/Geologian tutkimuskeskus, Espoo, Finland.
    McElroy, Iris
    Boliden AB.
    Brising, Dominique
    Boliden AB.
    Rollinson, Gavyn
    Camborne School of Mines, University of Exeter.
    Automated quantitative mineralogy optimized for simultaneous detection of (precious/critical) rare metals and base metals in a production-focused environment2019In: Minerals, ISSN 2075-163X, E-ISSN 2075-163X, Vol. 9, no 7, article id 440Article in journal (Refereed)
    Abstract [en]

    Automated Scanning Electron Microscopy (ASEM) systems are applied in the mining industry to quantify the mineralogy of the ore feed and products. With society pushing towards sustainable mining, this quantification should be comprehensive and include trace minerals since they are often either deleterious or potential by-products. Systems like QEMSCAN® offer a mode for trace mineral analysis (TMS mode); However, it is unsuitable when all phases require analysis. Here, we investigate the potential of detecting micron-sized trace minerals in fieldscan mode using the QEMSCAN® system with analytical settings in line with the mining industry. For quality comparison, analysis was performed at a mining company and a research institution. This novel approach was done in full collaboration with both parties. Results show that the resolution of trace minerals at or below the scan resolution is difficult and not always reliable due to mixed X-ray signals. However, by modification of the species identification protocol (SIP), quantification is achievable, although verification by SEM-EDS is recommended. As an add-on to routine quantitative analysis focused on major ore minerals, this method can produce quantitative data and information on mineral association for trace minerals of precious and critical metals which may be potential by-products in a mining operation

  • 53.
    Warlo, Mathis
    et al.
    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.
    Martinsson, Olof
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Karlsson, Peter
    Boliden AB.
    Mineralogy and origin of the intrusion-related Liikavaara Cu-(W-Au) deposit, northern Sweden2019In: GFF, ISSN 1103-5897, E-ISSN 2000-0863Article in journal (Refereed)
    Abstract [en]

    The Liikavaara Cu-(W-Au) deposit is situated proximal to the Aitik Cu-Au deposit in northern Sweden. It shows occurrence of scheelite and enrichment in trace metals including Au, Ag and Bi. In this study, petrological, mineralogical and geochemical investigations of the host rocks and ore, and geochronological analysis of a footwall intrusion were carried out. The ore is hosted by a metadiabase partly metamorphosed to biotite schist. The wall rocks are composed of metavolcaniclastic rocks of andesitic to basaltic composition. A granodiorite intrusion occurs in the footwall and related aplite dikes cut the deposit. Veins of quartz (±tourmaline) and calcite are numerous. Mineralisation is bound to these veins and their distribution is controlled by the aplite dikes. Chalcopyrite, pyrrhotite and pyrite are major in abundance. Sphalerite, galena, scheelite, molybdenite and magnetite are minor. Gold occurs native and as electrum and Ag is mostly bound in hessite and acanthite. The bismuth mineralogy is diverse but native Bi, pilsenite, bismuthinite, and tetradymite are common. A single grain of Sb (breithauptite) was observed. The major and minor minerals show intergrowth and replacement textures. The trace minerals are found as inclusions, along the borders and in cracks in the major sulphides, sphalerite, molybdenite and quartz. The footwall intrusion is dated at 1.87 Ga and suggested to be the source for ore genesis. The dikes may have acted as pathways for the magmatic hydrothermal fluids that carried the ore from the intrusion to the host rock.

  • 54. Williams, P.
    et al.
    Guoyi, D.
    Pollard, P.
    Broman, C.
    Martinsson, Olof
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Wanhainen, Christina
    Mark, G.
    Ryan, C.
    Mernagh, T.
    The nature of iron oxide-copper-gold ore fluids: fluid inclusion evidence from Norrbotten (Sweden) and the Cloncurry district (Australia)2003In: Mineral Exploration and Sustainable Development: Proceedings of the Seventh Biennial SGA Meeting on Mineral Exploration and Sustainable Development / [ed] D.G. Eliopoulos, Rotterdam: Millpress , 2003, p. 1127-1130Conference paper (Other academic)
  • 55.
    Yousefi, Fazilat
    et al.
    Department of Petrology and Economic Geology, Faculty of Earth Sciences, Shahrood University of Technology.
    Sadeghian, Mahmoud
    Department of Petrology and Economic Geology, Faculty of Earth Sciences, Shahrood University of Technology.
    Wanhainen, Christina
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Ghasemi, Habibollah
    Department of Petrology and Economic Geology, Faculty of Earth Sciences, Shahrood University of Technology.
    Frei, Dirk
    Department of Earth Science, Faculty of Natural Science, University of the Western Cape.
    Geochemistry, petrogenesis and tectonic setting of middle Eocene hypabyssal rocks of the Torud–Ahmad Abad magmatic belt: An implication for evolution of the northern branch of Neo-Tethys Ocean in Iran2017In: Journal of Geochemical Exploration, ISSN 0375-6742, E-ISSN 1879-1689, Vol. 178, p. 1-15Article in journal (Refereed)
    Abstract [en]

    The Torud–Ahmad Abad magmatic belt is located in the south-southeast of Shahrood (East of Semnan Province, NE Iran) and lies in the northern part of the Central Iran Structural Zone (CISZ), where a thick sequence of Paleocene to middle Eocene volcanic and volcanosedimentary rocks cropped out. This sequence was intruded by numerous dikes, hypabyssal igneous domes and one small gabbrodioritic intrusion, with compositions ranging from trachybasaltic andesite, trachyandesite, dacite, trachyte, gabbro, diorite and syenite. Various enclaves (cogentic and noncogenetic) with different composition, size and shape have been found in these domes and dikes. These enclaves are evidence of magma mixing and crustal contamination. Geochemically, the studied rocks exhibit a calc-alkaline to high potassium calc-alkaline affinity, and are enriched in LREE and LILE and depleted in HREE and HSFE. Other geochemical characteristics, such as a silica content varying between 59–63 wt% and 51–59 wt%, a Na2O content > 3 wt%, Al2O3 content > 16 wt%, Yb < 1.8 ppm, and Y < 18 ppm, make it possible to classify these rocks as high silica adakite in the Ahmad Abad region and low silica adakite in the Sahl-Razzeh region or at least, adakitic like rocks. Also, depletion of Nb and Ti, and high enrichment in Rb, Ba, K and Th, imply crustal contamination of the mentioned adakitic domes. The petrographical and geochemical evidence show that the magma forming of the high silica adakites has been originated from partial melting of the subducted oceanic slab of Neo-Tethys (Sabzevar–Darouneh branch) in amphibolite to eclogite facies and the low silica adakites formed by partial melting of the metasomatized or modified mantle wedge, above the subduction zone. Gabbroic to syenitic rocks are the products of fractional crystallization of basic magma which originated from a nearly non-modified mantle wedge above the subducted oceanic slab. U-Pb dating of the dacitic and andesitic rocks belong to hypabyssal rocks yielded age of 41.4 ± 0.3 Ma, and 35.5 ± 0.2 Ma respectively and consistent to Middle to Late Eocene.

  • 56.
    Yousefi, Fazilat
    et al.
    Faculty of Earth Sciences, Shahrood University of Technology.
    Sadeghian, Mahmoud
    Faculty of Earth Sciences, Shahrood University of Technology.
    Wanhainen, Christina
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Ghasemi, Habibollah
    Department of Petrology and Economic Geology, Faculty of Earth Sciences, Shahrood University of Technology.
    Lambrini, Papadopoulou
    Department of Mineralogy-Petrology-Economic Geology, Aristotle University of Thessaloniki.
    Bark, Glenn
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Rezaei-Kahkhaei, Mehdi
    Department of Petrology and Economic Geology, Faculty of Earth Sciences, Shahrood University of Technology.
    Koroneos, Antonis
    Department of Mineralogy-Petrology-Economic Geology, Aristotle University of Thessaloniki.
    Mineral chemistry and P-T conditions of the adakitic rocks from Torud–Ahmad Abad magmatic belt, S-SE Shahrood, NE Iran2017In: Journal of Geochemical Exploration, ISSN 0375-6742, E-ISSN 1879-1689, Vol. 182, no A, p. 110-120Article in journal (Refereed)
    Abstract [en]

    Torud-Ahmad Abad magmatic belt is located 175 km east and southeast of Shahrood in the northern part of the Central Iran Structural Zone and includes a thick sequence of Paleocene to middle Eocene volcanic and volcanosedimentary rocks. This magmatic belt was formed by numerous hypabyssal igneous adakitic domes constituting basaltic andesite, andesite, trachyandesite, dacite, trachydacite, and dacite. The investigated rocks are mainly composed of pyroxene, amphibole, and plagioclase, with minor biotite and opaque minerals. Mineral chemical analysis reveals that plagioclase composition varies from albite to labradorite, clinopyroxene varies from diopside to augite, and amphibole varies from Mg-hastingsite to Mg-hornblende.

    Amphibole geothermobarometry suggests crystallization temperatures of 850–1050 °C, at 2–6 kbar and the temperature of 920–970 °C, at a pressure of 3–4.5 kbar, which are conditions in agreement with andesite and dacite formation. Clinopyroxene crystallized at temperatures of 1020–1170 °C, at 2–10 kbar, indicating crystallization at crustal depths of maximum 30 km for the studied intrusive rocks in the Torud-Ahmad Abad magmatic belt.

12 51 - 56 of 56
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