| 1. |
- Andersson, Joel B.H., et al.
(författare)
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The tectonic overprint on the Per Geijer apatite iron ores in Kiruna, northern Sweden
- 2017
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Ingår i: Mineral Resources to Discover. - : Society for Geology Applied to Mineral Deposits. - 9782981689801 ; , s. 903-906
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Konferensbidrag (refereegranskat)abstract
- 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.
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| 2. |
- Holsti, Mari, 1963-, et al.
(författare)
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Circulating Vascular Basement Membrane Fragments are Associated with the Diameter of the Abdominal Aorta and Their Expression Pattern is Altered in AAA Tissue
- 2018
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Ingår i: European Journal of Vascular and Endovascular Surgery. - : Saunders Elsevier. - 1078-5884 .- 1532-2165. ; 56:1, s. 110-118
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Tidskriftsartikel (refereegranskat)abstract
- Objective: Abdominal aortic aneurysm (AAA) is characterised by enhanced proteolytic activity, and extracellular matrix (ECM) remodelling in the vascular wall. Type IV and XVIII collagen/endostatin are structural proteins in vascular basement membrane (VBM), a specialised ECM structure. Here the association between plasma levels of these collagens with the aortic diameter and expansion rate is studied, and their expression in aortic tissue characterised. Methods: This was a retrospective population based cohort study. Type IV and XVIII collagen/endostatin were analysed in plasma by ELISA assay in 615 men, divided into three groups based on the aortic diameter: 1) normal aorta <= 25 mm, 2) sub-aneurysmal aorta (SAA) 26-29 mm, and 3) AAA >= 30 mm. Follow up data were available for 159 men. The association between collagen levels and aortic diameter at baseline, and with the expansion rate at follow up were analysed in ordinal logistic regression and linear regression models, controlling for common confounding factors. Tissue expression of the collagens was analysed in normal aorta (n = 6) and AAA (n = 6) by immunofluorescence. Results: Plasma levels of type XVIII collagen/endostatin (136 ng/mL [SD 29] in individuals with a normal aorta diameter, 154 ng/ml [SD 45] in SAA, and 162 ng/ml [SD 46] in AAA; p = .001) and type IV collagen (105 ng/mL [SD 42] normal aorta, 124 ng/ml [SD 46] SAA, and 127 ng/ml [SD 47] AAA; p = .037) were associated with a larger aortic diameter. A significant association was found between the baseline levels of type XVIII/endostatin and the aortic expansion rate (p = .035), but in the multivariable model, only the initial aortic diameter remained significantly associated with expansion (p = .005). Altered expression patterns of both collagens were observed in AAA tissue. Conclusion: Plasma levels of circulating type IV and XVIII collagen/endostatin increase with AAA diameter. The expression pattern of VBM proteins is altered in the aneurysm wall.
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| 3. |
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| 4. |
- Kampmann, Tobias Christoph, 1987-, et al.
(författare)
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Syn-tectonic sulphide remobilization and trace element redistribution at the Falun pyritic Zn-Pb-Cu-(Au-Ag) sulphide deposit, Bergslagen, Sweden
- 2018
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Ingår i: Ore Geology Reviews. - : Elsevier. - 0169-1368 .- 1872-7360. ; 96, s. 48-71
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Tidskriftsartikel (refereegranskat)abstract
- Mineralization types at the Palaeoproterozoic Falun base metal sulphide deposit are predominantly pyritic Zn-Pb-Cu-rich massive sulphide mineralization, disseminated to semi-massive Cu-Au mineralization, auriferous quartz veins, and mineralized shear zones of talc-chlorite-dominated schist. The massive and disseminated to semi-massive sulphide mineralization types were subject to polyphase ductile deformation (D1 and D2) and metamorphism under low-P, lower-amphibolite facies conditions, which led to the development of ore textures and paragenetic relationships indicating both mechanical and chemical remobilization of sulphides. In the massive sulphide mineralization, rare inclusion-rich pyrite occurs as relic cores inside inclusion-poor metamorphosed pyrite. Imaging and spot analysis using multielement laser ablation inductively-coupled plasma mass spectrometry (LA-ICP-MS) reveal that inclusion-poor pyrite was depleted in trace elements, which were originally present as non-stoichiometric lattice substitutions or in mineral inclusions. The inclusion-rich pyrite was shielded from depletion and, at least partly, retained its initially higher trace element concentrations, including Au.Gold is also associated with chalcopyrite in the disseminated to semi-massive Cu-Au mineralization and in the system of auriferous quartz veins hosted therein, the latter being also affected by the D2 ductile strain. It is inferred that emplacement of the vein system took place after the peak of metamorphism, which occurred between D1 and D2, but prior to and possibly even shortly after completion of the D2 deformational event. Similarities in trace element signatures in chalcopyrite are compatible with the interpretation that the quartz veins formed by local chemical remobilization of components from the Cu-Au mineralization. Transport of liberated Au from pyrite during grain growth in the massive sulphide mineralization may have upgraded the Au endowment in the quartz veins, leading to the additional formation of native gold in the veins. A strong correspondence between elements liberated from pyrite (e.g. Pb, Bi, Se and Au) and those forming discrete and characteristic mineral phases in the quartz veins (Pb-Bi sulphosalts, native gold) supports this hypothesis.Trace element signatures for the main sulphide minerals pyrite, chalcopyrite, sphalerite and galena are similar to previously published data from other metamorphosed massive sulphide deposits. The association of the Falun mineralization with elevated Bi is reflected by its occurrence in sulphide minerals (e.g. galena) and in abundant mineral inclusions of Pb-Bi sulphosalts (e.g. weibullite), especially in the disseminated to semi-massive Cu-Au mineralization. Elevated Sn concentrations in the lattice and/or as cassiterite inclusions in chalcopyrite, sphalerite and galena are compatible with a hot, acidic and reducing fluid during formation of the syn-volcanic, base metal sulphide mineralization and associated host-rock alteration.
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| 5. |
- Lundberg, Christina, 1972-
(författare)
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Screening for Atherosclerosis with Magnetic Resonance Imaging and Ultrasound
- 2015
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Atherosclerosis is a major cause of death and disability worldwide. Although traditional risk factors can identify the healthy or severely affected individuals, sudden lethal outcome is still frequent in those suggested as intermediate in risk for cardiovascular events (CVE). Adding imaging to the traditional scoring systems might improve risk stratification.This thesis investigates whether the addition of magnetic resonance imaging (MRI) and ultrasound (US) to traditional risk factors might render atherosclerosis suitable for mass screening, selective screening or screening in research settings.In paper I the carotid arteries were assessed in six different manners (carotid intima media thickness (CIMT) in two different locations, presence of plaque, number of plaques, plaque size and plaque composition) using US. More than 800 Caucasian subjects were assessed at ages 70 and 75, and outcome examined at 80 years of age. Plaques with an area exceeding 10mm2 in the bulb were found to be most closely related to CVE.Paper II established that carotid plaque volume measured with MRI did not correlate with carotid plaque area assessed with US. MRI reached the highest levels of reproducibility of the two methods.Paper III used the previously created total atherosclerotic score (TAS), a scoring system based on whole body magnetic resonance angiography (WBMRA) that assesses global atherosclerosis. TAS was found to predict CVE in 305 PIVUS-subjects at age 70 years during 5 years of follow-up. The risk for CVE was found to be eightfold with TAS>0.In paper IV CIMT was assessed with US at ages 70 and 75 years. CIMT at baseline, but not the change in CIMT over five years, was significantly related to TAS, thus suggesting carotid changes to correlate with atherosclerosis throughout the body.In conclusion, in research settings WBMRA and MRI, as well as US, can be used for screening and following up of atherosclerotic changes, as their predictive values and reproducibility are good. US might be feasible in selective screening but none of these methods are as of now suitable for mass screening.
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| 6. |
- Lundberg, Jan, et al.
(författare)
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Measurements of friction coefficients between rails lubricated with a friction modifier and the wheels of an IORE locomotive during real working conditions
- 2015
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Ingår i: Wear. - : Elsevier BV. - 0043-1648 .- 1873-2577. ; 324-325, s. 109-117
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Tidskriftsartikel (refereegranskat)abstract
- The real friction coefficients between the rails and the wheels on a 360. t and 10,800. kW IORE locomotive were measured using the locomotive׳s in-built traction force measurement system. The locomotive consisted of two pair-connected locomotives had a CoCo+CoCo bogie configuration, and hauled a fully loaded set of 68 ore wagons (120. t/wagon). The measurements were performed both on rails in a dry condition and on rails lubricated with a water-based top-of-rail (ToR) friction modifier on the Iron Ore Line between the cities of Kiruna and Narvik in Northern Sweden and Norway, respectively. Since full-scale measurements like these are costly, the friction coefficients were also measured at the same time and place using a conventional hand-operated tribometer, with and without the ToR friction modifier. The most important results are that the real friction coefficient is definitely not constant and is surprisingly low (0.10-0.25) when the ToR friction modifier is used, and that it is also significantly dependent on the amount of ToR friction modifier. A large amount will reduce the friction coefficient. Furthermore, it is concluded that the real friction coefficients are in general lower than the friction coefficients measured with the hand-operated tribometer. A final remark is thus that the use of a water-based ToR friction modifier can give excessively low friction, which can result in unacceptably long braking distances.
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| 7. |
- Martinsson, Olof, et al.
(författare)
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Metallogeny of the Northern Norrbotten Ore Province, northern Fennoscandian Shield with emphasis on IOCG and apatite-iron ore deposits
- 2016
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Ingår i: Ore Geology Reviews. - : Elsevier BV. - 0169-1368 .- 1872-7360. ; 78, s. 447-492
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Forskningsöversikt (refereegranskat)abstract
- The Northern Norrbotten Ore Province in northernmost Sweden includes the type localities for Kiruna-type apatite iron deposits and has been the focus for intense exploration and research related to Fe oxide-Cu-Au mineralisation during the last decades. Several different types of Fe-oxide and Cu-Au +/- Fe oxide mineralisation occur in the region and include: stratiform Cu +/- Zn +/- Pb +/- Fe oxide type, iron formations (including BIF's), Kiruna-type apatite iron ore, and epigenetic Cu +/- Au +/- Fe oxide type which may be further subdivided into different styles of mineralisation, some of them with typical IOCG (Iron Oxide-Copper-Gold) characteristics. Generally, the formation of Fe oxide +/- Cu +/- Au mineralisation is directly or indirectly dated'between-2.1 and 1.75 Ga, thus spanning about 350 m.y. of geological evolution. The current paper will present in more detail the characteristics of certain key deposits, and aims to put the global concepts of Fe-oxide Cu-Au mineralisation into a regional context. The focus will be on iron deposits and various types of deposits containing Fe-oxides and Cu-sulphides in different proportions which generally have some characteristics in common with the IOCG style. In particular, ore fluid characteristics (magmatic versus non magmatic) and new geochronological data are used to link the ore-forming processes with the overall crustal evolution to generate a metallogenetic model. Rift bounded shallow marine basins developed at similar to 2.1-2.0 Ga following a long period of extensional tectonics within the Greenstone-dominated, 2.5-2.0 Ga Karelian craton. The similar to 1.9-1.8 Ga Svecofennian Orogen is characterised by subduction and accretion from the southwest. An initial emplacement of calc-alkaline magmas into similar to 1.9 Ga continental arcs led to the formation of the Haparanda Suite and the Porphyrite Group volcanic rocks. Following this early stage of magmatic activity, and separated from it by the earliest deformation and metamorphism, more alkali-rich magmas of the Perthite Monzonite Suite and the Kiirunavaara Group volcanic rocks were formed at similar to 1.88 Ga. Subsequently, partial melting of the middle crust produced large volumes of similar to 1.85 and 1.8 Ga S-type granites in conjunction with subduction related A-/I-type magmatism and associated deformation and metamorphism. In our metallogenetic model the ore formation is considered to relate to the geological evolution as follows. Iron formations and a few stratiform sulphide deposits were deposited in relation to exhalative processes in rift bounded marine basins. The iron formations may be sub-divided into BIF-(banded iron formations) and Mg rich types, and at several locations these types grade into each other. There is no direct age evidence to constrain the deposition of iron formations, but stable isotope data and stratigraphic correlations suggest a formation within the 2.1-2.0 Ga age range. The major Kiruna-type ores formed from an iron-rich magma (generally with a hydrothermal over-print) and are restricted to areas occupied by volcanic rocks of the Kiirunavaara Group. It is suggested here that 1.89-1.88 Ga tholeiitic magmas underwent magma liquid immiscibility reactions during fractionation and interaction with crustal rocks, including metaevaporites, generating more felsic magmatic rocks and Kiruna-type iron deposits. A second generation of this ore type, with a minor economic importance, appears to have been formed about 100 Ma later. The epigenetic Cu-Au +/- Fe oxide mineralisation formed during two stages of the Svecofennian evolution in association with magmatic and metamorphic events and crustal scale shear zones. During the first stage of mineralisation, from 1.89-1.88 Ga, intrusion-related (porphyry style) mineralisation and Cu-Au deposits of IOCG affinity formed from magmatic-hydrothermal systems, whereas vein-style and shear zone deposits largely formed at c. 1.78 Ga. The large range of different Fe oxide and Cu-Au +/- Fe oxide deposits in Northern Norrbotten is associated with various alteration systems, involving e.g. scapolite, albite, K feldspar, biotite, carbonates, tourmaline and sericite. However, among the apatite iron ores and the epigenetic Cu-Au +/- Fe oxide deposits the character of mineralisation, type of ore- and alteration minerals and metal associations are partly controlled by stratigraphic position (i.e. depth of emplacement). Highly saline, NaCl + CaCl2 dominated fluids, commonly also including a CO2-rich population, appear to be a common characteristic feature irrespective of type and age of deposits. Thus, fluids with similar characteristics appear to have been active during quite different stages of the geological evolution. Ore fluids related to epigenetic Cu-Au Fe oxides display a trend with decreasing salinity, which probably was caused by mixing with meteoric water. Tentatively, this can be linked to different Cu-Au ore paragenesis, including an initial (magnetite)-pyrite-chalcopyrite stage, a main chalcopyrite stage, and a late bornite stage. Based on the anion composition and the Br/Cl ratio of ore related fluids bittern brines and metaevaporites (including scapolite) seem to be important sources to the high salinity hydrothermal systems generating most of the deposits in Norrbotten. Depending on local conditions and position in the crust these fluids generated a variety of Cu-Au deposits. These include typical IOCG-deposits (Fe-oxides and Cu-Au are part of the same process), IOCG of iron stone type (pre-existing Fe-oxide deposit with later addition of Cu-Au), IOCG of reduced type (lacking Fe-oxides due to local reducing conditions) and vein-style Cu-Au deposits. From a strict genetic point of view, IOCG deposits that formed from fluids of a mainly magmatic origin should be considered to be a different type than those deposits associated with mainly non-magmatic fluids. The former tend to overlap with porphyry systems, whereas those of a mainly non-magmatic origin overlap with sediment hosted Cu-deposits with respect to their origin and character of the ore fluids.
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| 8. |
- Minz, Friederike, et al.
(författare)
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Distribution of Sb minerals in the Cu and Zn flotation of Rockliden massive sulphide ore in north-central Sweden
- 2015
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Ingår i: Minerals Engineering. - : Elsevier BV. - 0892-6875 .- 1872-9444. ; 82, s. 125-135
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Tidskriftsartikel (refereegranskat)abstract
- The Rockliden massive sulphide Zn–Cu deposit contains minor amounts of Sb minerals. The Sb mineralogy is complex in terms of composition, micro textures and mineral associations. The main Sb minerals comprise tetrahedrite, bournonite, gudmundite and Sb–Pb sulphides such as meneghinite. The presence of these minerals is especially critical to the quality of the Cu–Pb concentrate. To study how they are distributed in a simplified flotation circuit and what controls their process behaviour Sb-rich drill core samples were selected from the Rockliden deposit and a standard laboratory flotation test was run on the composite samples. Scanning electron microscope-based automated mineralogy was used to measure the Sb mineralogy of the test products, and the particle tracking technique was applied to mass balance the different liberation classes to finally trace the distribution of liberated and locked Sb minerals. The mineralogical factors controlling the distribution of Sb minerals are mineral grain size, the degree of liberation, and associated minerals. Similarities in the distribution of specific particle types from the tested composites point towards systematics in the behaviour of particles and predictability of their distribution which is suggested to be used in a geometallurgical model of the deposit.
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| 9. |
- Minz, Friederike, et al.
(författare)
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Mineralogical controls on the distribution of antimony in a base-metal flotation test at the Rockliden massive sulphide deposit, north-central Sweden
- 2015
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Ingår i: Mineral resources in a sustainable world. ; , s. 1439-1442
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Konferensbidrag (refereegranskat)abstract
- The Rockliden Zn-Cu massive sulphide mineralisation shows elevated concentrations of critical elements. In particularly the presence of Sb in the Cu–Pb concentrate causes metallurgical challenges in the treatment of this flotation product. The Sb mineralogy at Rockliden is complex, comprising of four main Sb minerals. For this study one mafic dyke and three Sb-rich massive sulphide samples with different base-metal and Sb mineralogy were collected and subjected to a simplified flotation test. The Sb mineralogy of the flotation products was analysed using scanning electron microscope-based image analysis. The distribution of liberated and locked Sb minerals between the flotation products was studied using a particle tracking technique. A comparison of results from the different mineralisation types indicates systematic behaviour of specific particle types, pointing towards the predictability of distribution of the Sb minerals during base-metal flotation.
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| 10. |
- Minz, Friederike, et al.
(författare)
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Particle-based Sb distribution model for Cu–Pb flotation as part of geometallurgical modelling at the polymetallic Rockliden deposit, north-central Sweden
- 2017
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Ingår i: Mineral Processing and Extractive Metallurgy. - : Taylor & Francis. - 0371-9553 .- 1743-2855. ; 126:4, s. 212-223
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Tidskriftsartikel (refereegranskat)abstract
- The polymetallic Cu–Zn ore of the Rockliden massive sulphide deposit in the Skellefte District in north-central Sweden contains a number of deleterious elements in relevant concentrations. Of particular concern is the amount of antimony (Sb) reporting to the Cu–Pb concentrate. The aim of this study was to compare different model options to simulate the distribution of Sb minerals in a laboratory flotation test based on different degrees of details in the mineralogical information of the flotation feed. Experimental data obtained from four composites were used for the modelling and simulation. The following different simulation levels were run (sorted from least to highest level of detail of their mineralogical information): chemical assays, unsized bulk mineralogy, sized bulk mineralogy and particle information. It was shown that recoveries simulated based on bulk mineralogy are mostly within the error margin acceptable in the exploration stage of the Rockliden deposit. Unexpected high deviation in the simulation using particle information from the original recovery has been partly attributed to the fact that recovery of non-liberated particles cannot be modelled appropriately in the present version of the modelling and simulation software. It is expected that the implementation of full particle information in simulation will improve the Sb distribution model for the mineralogically complex Rockliden deposit.
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| 11. |
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| 12. |
- Riegler, Thomas, et al.
(författare)
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Petrographic and mineralogical study of the Kilmacoo gold occurrence, Avoca District, Southeast Ireland
- 2019
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Ingår i: Proceedings of the 15th SGA Biennial Meeting, 27-30 August. - : University of Glasgow Publicity Services. ; , s. 323-326
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Konferensbidrag (refereegranskat)abstract
- Petrographic investigation of the quartz vein hosted Kilmacoo gold occurrence spatially associated with the copper rich Avoca massive sulphide ore body evidenced a close association between gold and sulphides. Visible electrum grains are frequently observed within chalcopyrite, and more rarely as minute inclusions in both arsenopyrite and pyrite. Mineralogical investigations also revealed complex sulphide paragenetic succession from framboidal pyrite to colloform and idiomorphic cements with overall a low arsenopyrite content. We also documented the presence of hydrothermal phosphates (apatite and monazite) subsequently altered in aluminum phosphate sulphate minerals, as well as a broad diversity of phyllosilicates. These observations as well as the cross cutting relationships tend to indicate a brittle deformation event involving possible remobilization of some of the copper mineralization from the main VMS ore body. At the present time the source of gold is still under investigation to determine the possible contribution from both local and distal sources.
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| 13. |
- Sarlus, Zimer, 1984-, et al.
(författare)
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Character and tectonic setting of plutonic rocks in the Gällivare area, northern Norrbotten, Sweden
- 2019
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Ingår i: GFF. - : Taylor & Francis. - 1103-5897 .- 2000-0863. ; 141:1, s. 1-20
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Tidskriftsartikel (refereegranskat)abstract
- Petrographical and lithogeochemical investigations in combination with mapping in the Gällivare area, northern Norrbotten, Sweden, have led to the identification of several igneous intrusive rock types. These include: (1) ultramafic-mafic complexes, (2) mafic-intermediate rocks, (3) dolerites and (4) felsic plutons. The ultramafic-mafic rocks include the ca. 1.88 Ga Dundret complex and ca. 1.80 Ga Vassaravaara complex. The Dundret complex has tholeiitic to calc-alkaline affinity, shows a primitive mineral content and was formed in an extensional tectonic setting. The Vassaravaara complex has a similar chemical signature as the Dundret complex. The mafic-intermediate plutons vary in composition from gabbro to diorite. The chemical signature of the dioritic rocks indicate formation in a volcanic arc setting. Dolerites occur as solitary dikes and have calc-alkaline affinity. The felsic plutons include granite and syenite of ca. 1.88, 1.80 and 1.78 Ga age. The felsic plutons have calc-alkaline to shoshonitic affinity and mostly show a metaluminous I-type character. Results indicate subduction at 1.90 Ga resulting in a volcanic arc system, and including extensional events generating back-arc environments leading to mafic, intermediate and felsic magmatism in the Gällivare area. Subduction at 1.80 Ga is suggested to have caused a similar process generating mafic and felsic magmatic rocks in the same area. A subsequent collision event finally generated 1.78 Ga granitic rocks.
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| 14. |
- Sarlus, Zimer, et al.
(författare)
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Geochemistry of Ultramafic-Mafic Units Related to Fe-, Cu-, and Au Deposits in the Gallivare Region, Northern Norrbotten, Sweden
- 2015
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Ingår i: Mineral Resources in a Sustainable World. - 9782855550664 ; , s. 1123-1126
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Konferensbidrag (refereegranskat)abstract
- 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.
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| 15. |
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| 16. |
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| 17. |
- Sarlus, Zimer, 1984-
(författare)
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Timing and Origin of Igneous Rocks in the Gällivare area, Northern Sweden
- 2018
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The Gällivare area is one of Europe’s top mining regions. The area is located in the northern Norrbotten ore district which hosts ore deposits such as the Malmberget underground iron ore mine, the Aitik open pit Cu-Au mine and the currently explored Nautanen Cu-Au deposit. In addition, several small, mineralized bodies are found. These deposits are hosted by volcanic and volcanosedimentary rocks intruded by intrusive rocks. Previous studies of intrusive and volcanic rocks have often been of local scale and restricted to the major deposits, or of regional scale including entire northern Norrbotten. Minor attention has been paid to rocks of the Gällivare area on a semi-regional scale, especially the intrusive rocks. Very few studies have presented radiometric data of the intrusive and volcanic rocks. In addition, the choice of radiometric method or the re-sults have been lacking confidence. A multidisciplinary approach combining structural geology, geochemistry, geochronology and geophysics is commenced to understand the geological history, crustal geometries and geological evolution of the Gällivare area. This forms basis for future exploration of ore deposits. This study presents geochemical, geochronological and Hf-isotope results with the purpose to characterize and classify major intrusive and volcanic rocks, their timing, source magmas and tectonic environment.Petrographical and geochemical investigations reveal that the intrusive rocks range in composition from ultramafic-mafic to felsic. The ultramafic-mafic rocks comprise dominantly gabbroic layered complexes with peridotitic sequences and have tholeiitic to calc-alkaline affinity. The intermediate and felsic intrusive rocks show calc-alkaline to shoshonitic affinity. Volcanic rocks of the Malmberget deposit show alkali to alkali-calcic character. The geochemical character of the intrusive and volcanic rocks favors a continental arc, transitional to extensional setting (late- to post-collisional).Radiometric in situ U-Pb zircon analyses indicate that mafic and felsic intrusive rocks were generated during magmatic episodes at 1.88, 1.80 Ga and 1.78 Ga. Volcanic rocks hosting the Malmberget deposit belong to the 1.88 Ga magmatic episode. Hydrothermal overgrowth rims from the analyzed zircon crystals indicate extensive reworking and high-T metamorphism of the area around 1.81-1.78 Ga.The mafic-intermediate rocks show minor internal variations in Hf-isotopic signature as well as minor variations inbetween the samples indicative of relatively homogenous source regions beneath the Archean basement. The felsic rocks show a wider range in their Hf-isotopic signature suggesting multiple sources with contribution from old Archean crust.It is here suggested that a subduction process active at 1.9 Ga resulted in a volcanic arc system and ex-tensional environments (back-arc environments) leading to mafic, intermediate and felsic magmatism in the Gällivare area at 1.88 Ga. The mafic-intermediate rocks were extracted from a rather homogenous source reservoir. The c. 1.80 Ga and 1.78 Ga intrusive rocks indicate a complex tectonic evolution of the area at that time. The early 1.80 Ga mafic rocks are suggested to have been generated as a result of extensional magmatism related to an east-directed 1.80 Ga subduction system. Subsequent compression followed by uplift, resulted in the generation of 1.78 Ga felsic rocks.
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| 18. |
- Sarlus, Zimer, 1984-, et al.
(författare)
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Timing and tectonic setting of host rocks to the Malmberget AlO deposit, Sweden
- 2017
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Ingår i: Mineral Resources to Discover. - : Society for Geology Applied to Mineral Deposits. - 9782981689801 ; , s. 959-962
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Konferensbidrag (refereegranskat)abstract
- 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.
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| 19. |
- Sarlus, Zmar, et al.
(författare)
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Timing of plutonism in the Gällivare area : mplications for Proterozoic crustal development in the northern Norrbotten ore district, Sweden
- 2018
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Ingår i: Geological Magazine. - : Cambridge University Press. - 0016-7568 .- 1469-5081. ; 155:6, s. 1351-1376
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 20. |
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| 21. |
- Tiu, Glacialle, et al.
(författare)
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Sulfide chemistry and trace element deportment at the metamorphosed Lappberget Zn-Pb-Ag-(Cu-Au) ore body, Sweden : Implications for Mineral Processing
- 2019
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Ingår i: Life with Ore Deposits on Earth. - Glasgow, Scotland. ; , s. 1486-1489
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Konferensbidrag (refereegranskat)abstract
- The 58 Mt Lappberget Zn-Pb-Ag-(Cu-Au) ore body represents one of the largest and most significant polymetallic base metal sulfide deposits in Sweden. The complex mineralogical characteristics of the ore body pose particularly tough challenges for successful production forecast because of the mixed Zn-Pb-Cu base metals, the complex association of the beneficial Ag and Au, and the presence of influential elements such as Sb, Mn and Mg. Thus, a detailed mineralogical characterization study was conducted, focusing on the deportment of trace and minor elements (including credit and penalty elements). Mineral chemistry data derived from electron microprobe and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) analyses reveal the complexity in the composition and associations of the ore minerals, consisting of textural and chemical varieties of sphalerite, galena, chalcopyrite, iron sulfides, antimonides and sulfosalts. Recrystallization, re-mobilization and re-concentration of sulfide minerals, compositional banding, and ductile and brittle deformation textures (i.e. deformation twins on sphalerite, brecciation, bent cleavage planes, etc.) are observed throughout the deposit. The mineralogical and textural complexity and heterogeneity of the sulfide ore are reflected in the variability in grades and recovery from the processing plant.
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| 22. |
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| 23. |
- Wanhainen, Christina, et al.
(författare)
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Rare earth mineralogy in tailings from Kiirunavaara iron ore, northern Sweden : Implications for mineral processing
- 2017
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Ingår i: Minerals & metallurgical processing. - : Society for Mining, Metallurgy and Exploration. - 0747-9182. ; 34:4, s. 189-200
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Tidskriftsartikel (refereegranskat)abstract
- Four main and three minor rare-earth-element (REE)-bearing minerals were identified and quantified in the Kiirunavaara apatite iron ore tailings using optical microscopy, an electron probe microanalyzer (EPMA) and a mineral liberation analyzer, and their chemical compositions were analyzed by the EPMA and laser ablation inductively coupled plasmamass spectrometry. REEs are shown to be contained in the minerals apatite, monazite, allanite, titanite, zircon, thorite and synchysite. In zircon, thorite and synchysite, they occurred in only trace amounts and contributed limited amounts to the total REE budget, and these are consequently of minor importance. Monazite occurred as inclusions in apatite and as free particles, 90 percent liberated. Allanite occurred to some degree in mixed grains with magnetite but also as free particles. Monazite mainly reported to the apatite concentrate, while allanite and titanite largely went to the tailings, the latter preferably to those fractions smaller than 38 μm. The amount of titanite in the finest tailings fraction was 2.3 weight percent, containing close to 1 percent REEs, with heavy rare earth elements (HREEs) making up 28 percent of the total REEs. However, a texturally distinct group of titanite grains showed an HREE/REE ratio of up to 67 percent. Furthermore, titanum dioxide analyses indicate that titanite is preferentially released into the tailings from the secondary magnetic separation step in the concentrator. Our data therefore suggest that titanite, occasionally enriched in HREEs, can be extracted from the processing stream and might thus be considered a new source for REEs at Kiirunavaara and similar deposits.
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| 24. |
- Warlo, Mathis, et al.
(författare)
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Automated quantitative mineralogy optimized for simultaneous detection of (precious/critical) rare metals and base metals in a production-focused environment
- 2019
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Ingår i: Minerals. - : MDPI. - 2075-163X. ; 9:7
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Tidskriftsartikel (refereegranskat)abstract
- 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
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| 25. |
- Warlo, Mathis, et al.
(författare)
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Gold and silver mineralogy of the Liikavaara Cu-(W-Au) deposit, northern Sweden
- 2019
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Ingår i: Proceedings of the 15th SGA Biennial Meeting, 27-30 August 2019, Glasgow, Scotland. - : Society for Geology Applied to Mineral Deposits. ; , s. 1532-1535
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Konferensbidrag (refereegranskat)abstract
- The Liikavaara Cu-(W-Au) deposit in northern Sweden is scheduled for production by the mining company Boliden AB in 2023. The ore will be processed in the plant of the nearby Aitik Cu-Au deposit. Copper will be the primary product and the trace metals Au andAg will be byproducts.The trace mineralogy of Liikavaara, however, differs from that of Aitik and this might have implications on the mineral processing and recovery efficiency. Gold occurs mostly as free <10μm-sized grains of native Au and electrum. Some Au is associated with native Bi, typically in <5μm Bi-melt drops. Gold grains commonly form inclusions in quartz and sulfide minerals. Silver is found in electrum, hessite and acanthite. Hessite is the most abundant Ag mineral and it is commonly intergrown with pilsenite. Similar to Au, inclusions and crack-fillings of Ag in sulfides and quartz are most prominent. The small grain size, the diverse mineralogy, the association with Bi-phases, and the occurrence as inclusions in quartz may lower the recovery of Au and Ag in Liikavaara compared to Aitik, where Au and Ag phases are mostly bound in sulfides. Hence, adaptation of the processing parameters may be necessary in order to increase recovery of Au and Ag from the Liikavaara ore.
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| 26. |
- Warlo, Mathis
(författare)
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Improving trace metal characterisation of ore deposits – a crucial step towards sustainable mining
- 2019
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Sustainable mining, including the utilisation of an ore body to its full potential, is becoming increasingly important for human society as the demand for metals increases. In order to maximise the recovery of useful metals, detailed characterisation of the ore prior to processing is vital. Characterisation should include major and minor ore minerals, gangue minerals, and also trace metals. Trace metals despite their low abundance are often particularly important, either due to their high economic value and criticality for society, or their negative impact on the quality of the main commodity recovered and/or the environment. To properly characterise trace metals in an ore deposit the use of micro-analytical techniques is necessary. Nowadays, a plethora of techniques exist, each with their own strengths and weaknesses. In the mining industry, automated scanning electron microscopy systems are widely used. These systems allow for rapid mineralogical characterisation and quantification of a sample and are commonly used to quantify the mineralogy of the ore feed and subsequent products. Operators of these systems benefit from prior knowledge of the mineralogy of a sample/deposit to fine-tune their processing software to deliver data of highest quality. In this study, a method to improve trace metal characterisation in ore deposits with automated scanning electron microscopy systems is presented. It is implemented as a case study on the Liikavaara Cu-(W-Au) deposit in northern Sweden. The deposit is enriched in several trace metals including Au, Ag, Bi and Sn, and is planned for production in 2023. The mine will produce Cu as the main product and Au and Ag as by-products, and the processing of the ore will be performed in the nearby Aitik plant. For this study, a detailed geological and mineralogical investigation of the deposit was performed prior to analysis with the automated scanning electron microscopy system. A good understanding of the mineralogy is necessary to be able to select a representative sample for the subsequent automated analysis and to guarantee optimal data quality produced by the automated system, and to judge the performance of the automated system, to improve the method of analysis.Manuscript 1 deals with the geological description and genetic aspects of the Liikavaara ore deposit. Results indicate that Liikavaara is an intrusion-related vein-style deposit. Mineralisation is hosted by quartz-tourmaline and calcite veins in a metadiabase that is partly metamorphosed to biotite schist. A 1.87 Ga granodiorite intrudes the footwall. Aplite dikes, genetically related to the intrusion, crosscut the metadiabase host rock. Mineralised veins are concentrated in and around these dikes.Manuscript 2 deals with method development of automated mineralogical analysis. A sample from a mineralised quartz-tourmaline vein at Liikavaara was analysed in great detail with the QEMSCAN® system. Apart from ore minerals in major and minor abundance the sample also contains ore minerals in trace quantities, e.g. Au and Ag minerals. The sample was analysed using two different analytical settings, at two different laboratories, one typical of a production-focused industrial approach and one quality-focused scientific approach. A first analysis using the industrial approach was unable to detect any Au and Ag minerals in the sample. By modification of the QEMSCAN® mineral reference library, through iterative use of the data from both the industrial- and the scientific approach, detection and quantification of Au and Ag minerals was successful. This method can be implemented as an add-on for routine industrial analysis by automated scanning electron microscopy systems to gain information on trace metal occurrence and distribution. This information can then be used for targeted sample selection for further in-depth analysis of the trace metal content and occurrence in the deposit.
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| 27. |
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| 28. |
- Warlo, Mathis, et al.
(författare)
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Mineralisation paragenesis of the Liikavaara Cu-(W-Au) deposit, northern Sweden
- 2017
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Ingår i: Mineral Resources to Discover. - : Society for Geology Applied to Mineral Deposits. - 9782981689801 ; , s. 971-974
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Konferensbidrag (refereegranskat)abstract
- 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.
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| 29. |
- Yousefi, Fazilat, et al.
(författare)
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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 Iran
- 2017
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Ingår i: Journal of Geochemical Exploration. - : Elsevier. - 0375-6742 .- 1879-1689. ; 178, s. 1-15
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 30. |
- Yousefi, Fazilat, et al.
(författare)
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Mineral chemistry and P-T conditions of the adakitic rocks from Torud–Ahmad Abad magmatic belt, S-SE Shahrood, NE Iran
- 2017
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Ingår i: Journal of Geochemical Exploration. - : Elsevier. - 0375-6742 .- 1879-1689. ; 182:A, s. 110-120
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 31. |
- Zeballos, Ariana, 1983-
(författare)
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Geological, geochemical and mineralogical characterization of non-metallic mineral deposits in the La Paz region, Bolivia
- 2018
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Industrial mineral resources are a promising source of economic development in Bolivia where the mining industry’s main focus is on metalliferous deposits. The industrial mineral resources in Bolivia are of large quantity, even though they remain only locally known, as well as understudied to a large degree.This thesis aims to show the industrial mineral mining potential of La Paz and Bolivia as a whole. Bolivia’s resources of industrial minerals can potentially be used for numerous industrial applications. Three deposits have been geologically and mineralogically characterized. In addition, the potential applications of the mined products are addressed.Firstly, the Micaya deposit, located at the Micaya village south-west of La Paz city, comprising two whitish kaolinite-bearing occurrences, was investigated. The material is currently used in tableware production. The Micaya deposit is situated in a Palaeozoic sequence in the Altiplano basin. The general mineral composition of the occurrences is 56 vol.% quartz, 21 vol.% muscovite, 18 vol.% kaolinite and <5 vol.% feldspar. The kaolinite-bearing sediments were formed through enhanced weathering of the muscovite-rich siltstones aided by groundwater remobilization along permeable fault zones. Micaya kaolinite is suggested to be suitable for industrial applications.Secondly, the Choquetanga deposit, located south-east of La Paz city and currently mined for Sn and W, is associated with a coarse-grained granitic batholith that was studied for its feldspar characteristics in this work. Geologically, the Choquetanga area is dominated by a Palaeozoic sedimentary sequence intruded by the porphyritic granite from the Quimsa Cruz batholith in the south-east of the Eastern Cordillera. The Quimsa Cruz batholith is composed of megacrystalline granite with 5–10 cm long orthoclase, albite and oligoclase crystals that contain a considerable alkali content of YK2O,Na2O=7.84–10.25 wt.%.Thirdly, the La Fabulosa deposit, located north-west of the Eastern Cordillera, was studied for its feldspar occurrences hosted in granites and pegmatites. The deposit is composed of a metasedimentary sequence of Palaeozoic age intruded by the Sorata batholith, which comprises two-mica granites, granodiorites and pegmatites with an alkali content of YK2O,Na2O=7.41–14.25 wt.%, hosted in the minerals microcline, orthoclase and oligoclase.The potential raw materials from the three studied industrial mineral deposits were evaluated for use in ceramic applications. In addition, nine non-metallic occurrences, most of them currently mined and located at Oruro (one zeolite occurrence), Potosí (one diatomite and one montmorillonite occurrence), La Paz (three clay deposits and one diatomite occurrence) and Santa Cruz (two kaolin deposits) have been sampled. Mineralogical and lithogeochemical characterization of the materials have been performed to address higher-value applications for the deposits.X-ray diffraction (XRD) and inductively coupled plasma mass spectrometry (ICP-MS) were used to identify the mineralogical and lithogeochemical composition of the host rocks to the deposits. Scanning electron microscopy (SEM) were performed on the kaolinite-bearing materials to characterize the microstructure in the rocks. This indicates mineral paragenesis and has therefore implications for mineral deposit formation. Physical tests on the ceramic specimens, such as drying shrinkage (Choquetanga 0.20 vol.%, La Fabulosa 0.31 vol.%), firing shrinkage (Choquetanga 1.66 vol.%, La Fabulosa 1.59 vol.%), bending strength (Choquetanga 69.55 N/mm2, La Fabulosa 70.20 N/mm2), water absorption (Choquetanga 2.13 vol.%, La Fabulosa 0.58 vol.%) and Mohs hardness value of 7, demonstrate the potential application of the studied industrial minerals in the production of floor tile ceramics.The results of this work show the geological potential for industrial mineral exploitation in Bolivia. It is expected that these investigations will serve as a starting point and encouragement for future geological research and mineral exploration with important implications for the supply of industrial minerals for the growing industrial sector of Bolivia.
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