Search

The Scandinavian Caledonides consist of disparate nappes of Baltican and exotic heritage, thrust southeastwards onto Baltica during the Mid-Silurian Scandian continent–continent collision, with structurally higher nappes inferred to have originated at increasingly distal positions to Baltica. New U–Pb zircon geochronological and whole-rock geochemical and Sm–Nd isotopic data from the Rödingsfjället Nappe Complex reveal 623 Ma high-grade metamorphism followed by continental rifting and emplacement of the Umbukta gabbro at 578 Ma, followed by intermittent magmatic activity at 541, 510, 501, 484 and 465 Ma. Geochemical data from the 501 Ma Mofjellet Group is indicative of arc magmatism at this time. Syntectonic pegmatites document pre-Scandian thrusting at 515 and 475 Ma, and Scandian thrusting at 429 Ma. These results document a tectonic history that is compatible with correlation with peri-Laurentian and/or peri-Gondwanan terranes. The data allow correlation with nappes at higher and lower tectonostratigraphic levels, including at least parts of the Helgeland, Kalak and Seve nappe complexes, implying that they too may be exotic to Baltica. Neoproterozoic fragmentation of the hypothesized Rodinia supercontinent probably resulted in numerous coeval, active margins, producing a variety of peri-continental terranes that can only be distinguished through further combined geological, palaeomagnetic and palaeontological investigations.

Background and Objectives: In recent years, there has been an increased focus among blood bank professionals on the health and safety of blood donors. In 2019, the Danish Haemovigilance Committee designed a national donor vigilance system to improve the registration of adverse reactions (AR) in blood donors. The new donor vigilance system was implemented on 1 January 2020 and we here present the results from the first year of registration. Materials and Methods: AR categories, severity level and imputability score were defined based on the definitions from the International Society of Blood Transfusion, AABB and the European Commission directive 2005/61/EC, respectively. Results: Across all severity levels, AR in Danish blood donors were found to be rare (1498 per 100,000 donations). Only 0.2% of the registered reactions were classified as serious (2.7 per 100,000 donations). Large regional differences were seen in the registration of citrate reactions and haematomas. Conclusion: Significant differences across regions in what to categorize as an AR were persistent even when including a severity score in the reporting. The Danish Haemovigilance Committee will commence a national work to align the definitions but suggests that this matter is raised to an international level as part of the current work to agree upon definitions for assessment of donor AR.

Identification of risk factors for contracting and developing serious illness following infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is of paramount interest. Here, we performed a retrospective cohort analysis of all Danish individuals tested for SARS-CoV-2 between 27 February 2020 and 30 July 2020, with a known ABO and RhD blood group, to determine the influence of common blood groups on virus susceptibility. Distribution of blood groups was compared with data from nontested individuals. Participants (29% of whom were male) included 473 654 individuals tested for SARS-CoV-2 using real-time polymerase chain reaction (7422 positive and 466 232 negative) and 2 204 742 nontested individuals, accounting for ∼38% of the total Danish population. Hospitalization and death from COVID-19, age, cardiovascular comorbidities, and job status were also collected for confirmed infected cases. ABO blood groups varied significantly between patients and the reference group, with only 38.41% (95% confidence interval [CI], 37.30-39.50) of the patients belonging to blood group O compared with 41.70% (95% CI, 41.60-41.80) in the controls, corresponding to a relative risk of 0.87 (95% CI, 0.83-0.91) for acquiring COVID-19. This study identifies ABO blood group as a risk factor for SARS-CoV-2 infection but not for hospitalization or death from COVID-19.

The coupling of CO2 emissions and tectonic activity in active plate margins is becoming increasingly prominent, as remote sensing techniques make this relationship readily observable on a global sc...

High-MgO (>12 wt%) magmas represent some of the most primary and high temperature melts from mantle plumes. The compositional diversity of high-MgO magmas gained by fractional melting within inhomogeneous mantle sources, is often overprinted by wall rock assimilation, magma mixing and fractional crystallisation within magma chambers at various depths within the crust. The deepest intrusions, at the base of the crust, are the first stop for magmas as they leave the mantle and such localities offer vital insights into the crustal processes that modify high-MgO melts. The Seiland Igneous Province (SIP) represents a rare exposure of a deep crustal magma conduit system that transported large volumes of mantle-derived melts through the lower continental crust. In this work, trace element compositions of clinopyroxenes in dunite, wehrlite and olivine clinopyroxenite samples from the Reinfjord intrusion were measured using laser-ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). The melts calculated to be in equilibrium with the clinopyroxenes represent derivatives of mantle-derived magmas and have steep rare earth element (REE) profiles with La/YbPM of 8.4–14., Sm/YbPM of 3.5–4.8, and negative anomalies in Nd, Zr and Hf. Assimilation, recharge and fractional crystallisation modelling shows that the ultramafic cumulates in the Reinfjord intrusion formed through concurrent fractional crystallisation and repetitive recharge (and mixing) of new primitive magmas from the mantle with very limited input from crustal sources. The recharge and mixing model is strongly supported by field and petrographic data. Two end-member ultramafic magmas are identified; the first end-member melt composition (MELTCPX0) is similar to the melt compositions that are in equilibrium with the most trace element depleted clinopyroxenes from Reinfjord. The second end-member melt composition (MELTPIC0) is similar to a number of picrite dykes found throughout the SIP, which have less steep LREE/HREE and lack strong negative anomalies in Zr and Hf. The REEBOX PRO melting model (Brown and Lesher, 2016) was used to forward model adiabatic decompression melting of lithologically homogeneous and heterogeneous sources containing anhydrous/hydrous peridotite ± pyroxenite. It was found that MELTPIC0 formed by melting of a peridotite source with up to 10% pyroxenite component and mantle potential temperatures of up to 1450 °C. MELTCPX0, however, formed by melting of a carbonate- metasomatised peridotite with potential temperatures of up to 1630 °C. These results indicate a compositionally and thermally inhomogeneous mantle plume beneath the SIP. /© 2020 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).

The Reinfjord Ultramafic Complex, Seiland Igneous Province represents a lower crustal magma chamber (25–30 km depth) that likely records a deep conduit system for mantle derived melts ascending through the continental crust. It consists of cumulates of dunite, wehrlite, olivine clinopyroxene as well as subordinate lherzolite and websterites, intruded into gabbro-norite and metasediment gneisses. Field, petrographic and geochemical data show that the intrusion developed through fractional crystallization and interactions between new batches of magma and partially solidified cumulates. This resulted in a ‘reverse fractionation sequence’ whereby cumulates became progressively more MgO and olivine rich with time. Contamination by partial melting of the gabbro-norite is evident in the marginal zones, but is limited in the central parts of the intrusion. Interrupted crystallization sequences of olivine → olivine + clinopyroxene and the absence of significant amounts of more evolved melts, suggests that large volumes of melt passed through the system to shallower levels in the crust leaving behind the cumulate sequences observed at Reinfjord. Therefore, the Reinfjord Ultramafic Complex represents a deep crustal conduit system, through which mantle derived melts passed. The parent melts are likely to have formed from partial melting of mantle with residual garnet and clinopyroxene.

The megacrystic, coarse-grained granite of the Land’s End granitic complex, SW England, has been investigated by analyzing fluid inclusions, trace elements, and cathodoluminescence textures of quartz. By applying the TitaniQ geothermobarometer together with the cathodoluminescence textures, a two-stage emplacement process is proposed. K-feldspar and quartz phenocrysts crystallized in a deep magma chamber at ca. 18–20 km depth. The phenocrysts were transported together with the melt to a shallow emplacement depth at ca. 5–9 km in multiple intrusive events, causing the composite appearance of the granitic complex. This model of emplacement concurs with similar granites from the Erzgebirge. At the emplacement level, the magma exsolved an aqueous fluid with average salinity of 17.3% m/m NaCl and 9.7% m/m CaCl2. Fluids with higher salinities were exsolved deeper in the system, as the magma experienced stages of water saturation and water undersaturation during ascent from the deep magma chamber. The complex fluid inclusion textures are the results of multiple stages of entrapment of aqueous fluids in the host phases as multiple recharge events from the deeper magma chamber supplied fresh melts and aqueous volatiles. Titanium contents in quartz are closely related to the panchromatic cathodoluminescence intensity, and the Al/Ti ratio is reflected by the 3.26 eV/2.70 eV ratio of hyperspectral cathodoluminescence.

Tourmaline from the St. Byron lobe of the Land’s End granite, SW England, was assessed by macroscopic, optical and quantitative microanalytical methods. In total, seven types of tourmaline were distinguished. The seven types reflect different crystallisation environments and stages in the magmatic-hydrothermal transition. Types 1-3 are interpreted to represent a gradual transition from tourmaline crystallising from a silicate melt to precipitation from magmatic aqueous fluids. Types 5-7 crystallised at subsolidus conditions from a different fluid generation than types 1-3. These fluids may be magmatic or mixed with other fluids (e.g., meteoric or formation waters). The Sn-mineralisation in the area is mostly related to the latter fluid generation, and the mineralising potential is reflected by the tourmaline composition.

This study aims to understand the process behind the worldwide connection between deep crustal/upper mantle earthquakes and CO2 emissions along faults in rift zones. We do this by studying CO2-induced mineral reactions that facilitate strain localization in peridotites from an ancient rift zone in the Seiland Igneous Province (SIP), North Norway. Strain localization in association with hydration processes is well documented in all types of tectonic settings and has major implications for rheological behavior in active plate margin processes. The implications of CO2-bearing fluids are less studied, though experiments have shown how CO2 can influence the flow laws of olivine by imposing a brittle and more localized type of deformation. This study documents narrow shear zones observed within ultramafic rocks from the Seiland Igneous Province (SIP) comprising large volumes (>20,000 km3) of mafic, ultramafic, silicic and alkaline melts that were emplaced into the lower continental crust (25–30 km) between 570 and 560 Ma under an extensional regime. The extensional shear zones are mm cm-scale and contain extremely fine-grained material with a distinct shape preferred orientation (SPO), but weak to absent crystallographic preferred orientation. The shear zones offset dykes across numerous micro-faults that are documented in areas close to a major fault zone cutting through the area. Within the shear zones, olivine and clinopyroxene react to form orthopyroxene and dolomite at approximately 11 kb and 850 °C according to the reaction: 2 Olivine + Clinopyroxene + 2 CO2 = Dolomite + 2 Orthopyroxene This reaction formed coronas of orthopyroxene and dolomite between olivine and clinopyroxene in the shear zones. In addition, large olivine grains proximal to the shear zones show a microfabric with subgrain walls decorated by rounded grains of dolomite and more irregular and elongated grains of orthopyroxene. Clinopyroxene grains are separated from the enstatite and dolomite by at least hundreds of microns, suggesting material transport within the shear zone. The shear zones thus provide a unique insight into the interplay between CO2-metasomatism and reaction accommodated strain softening. Carbonation-driven cracking and mineral reaction also serves to reduce grain size, making grain boundary sliding an efficient process, further enhancing the rheological contrast between the shear zone and the host rock. The sudden decrease in rock strength could lead to rapid deformation and triggered pseudotachylite formation during earthquake events in the near proximity of the micro-shear zones. Our observations match the relations between CO2 emissions and earthquakes observed in present rift environments such as the East African rift and in New Zealand, and underline the importance of active shear zones as fluid conduits in the lower crust and upper mantle. © 2019 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Magnetic properties from the Reinfjord Ultramafic Complex, in northern Norway, which formed as part of a deep magmatic conduit system, have been investigated to determine the magnetic signature of ultramafic rocks now exposed at the surface and deeper in the lower crust. The dominant carriers in these ultramafic rocks are a chrome‐spinel with Fe‐rich exsolution blebs and exsolution lamellae of magnetite in clinopyroxene. Except locally, in a fault zone and in discrete small fractures, these rocks show only minor to no alteration. We infer that the magnetic oxides characterized here are representative of pristine magnetic carriers in similar rocks deeper in the crust. These oxides can be stable in lower crustal, possibly upper mantle, depths when temperatures are below the Curie temperature of magnetite, taking into account pressure effects. These ultramafic rocks are candidates for potential sources of long‐wavelength anomalies. ©2019. American Geophysical Union. All Rights Reserved.

The Atchiza mafic and ultramafic-layered suite (hereafter, “Atchiza Suite) crops out in an area 330 km 2 west of the Mozambican Tete province. In an early account of the geology of this intrusion, it was considered the continuation of the Great Dyke of Zimbabwe, an idea that was aborted after detailed studies. Nevertheless, the Ni concentrations in the Atchiza outcrop rocks are considerable. Our investigation used field evidence, hand specimens and petrography descriptions, mineral chemistry studies using electron microprobe analysis and tectonic analysis to arrive at a plausible mineralogical composition and understanding of the tectonic setting for the igneous evolution. The mineral composition from the Atchiza Suite indicates that these are cumulates. The magmatic segregation from the petrographic and mineral composition reasoning indicates that dunite-lherzolitic peridotite-olivine gabbro-gabbronorite-gabbro-pegmatitic gabbro is the rock formation sequence. Olivine and chromite were the first phases formed, followed by pyroxene and plagioclase. In addition, it is shown that these minerals are near-liquidus crystallization products of basaltic magma with olivine Fo: 87.06 in dunite, mean values of clinopyroxene are (Wo: 36.4, En: 48.0, Fs: 15.2), orthopyroxene (Wo: 2.95, En: 73.0, Fs: 24.2) and plagioclase An: 71.3, respectively. Opaque minerals comprise Fe–Ti oxides and (Fe, Cr) spinel up to 4.8 vol.%, but chromitite layers are not present. Most of the opaque minerals are interstitial to pyroxene. Sulphides are common in gabbros, with pyrrhotite, pentlandite, chalcopyrite, pyrite and covellite together comprising 0.4–2.0 vol.%. The whole rock Rare Earth Element (REE) concentrations are mainly a result of differentiation, but slight crustal contamination/assimilation contributed to the REE contents. In addition, they also show Eu enrichment, suggesting that plagioclase fractionation was important in the rock. The Atchiza Suite preserves a deep-seated plumbing system of the continental rift environment. The intrusion resulted from the emplacement of mafic magma in space created by extensional forces. Space was created through a connecting fault generated as a result of overall extensional, torsion and slab displacement in a rift system. The geometry of the body is tectonically controlled, and it agrees with the tectonic framework of the Zambezi Belt during the Rodinia breakup in the early Neoproterozoic.

Trace element concentrations in quartz from 188 granitic pegmatites in the Froland and Evje-Iveland pegmatite fields, southern Norway, have been determined to establish exploration targets for high-purity quartz and to gain a better understanding of the genesis of pegmatites hosting these deposits. Both pegmatite fields were formed during the Sveconorwegian (Grenvillian) orogeny (1145–900 Ma) at the western margin of the Fennoscandian Shield. In situ raster analyses within single quartz crystals were undertaken by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS); spot size 75 μ m) to assess levels of lattice-bound impurities, rather than mineral and fluid inclusions that are relatively easily removed during high-purity quartz processing. Quartz in the Froland pegmatites has relatively pure and homogeneous compositions containing 46 ± 24 μ gg−1 Al, 8 ± 3 μ gg−1 Ti, 1.4 ± 0.8 μ gg−1 Ge, and 11 ± 7 μ gg−1 Li. The Ti-in-quartz geothermobarometer gives an average pegmatite crystallization temperature of 537° ± 39°C. Temperature estimates are highest along the northwestern margin of the pegmatite field (>550°C), whereas the most differentiated pegmatites occur toward the northeast. The area of greatest economic potential for high-purity quartz lies just north of the central part of the field where individual pegmatites contain >1 million metric tons (Mt) quartz with low average trace element contents of 67 ± 11 μ gg−1. From mineral-chemical criteria, and a range of other geologic factors, we propose that pegmatite melts in the Froland field were generated by fluid-present crustal melting at about 1060 Ma, in zones of localized high-strain deformation during progressive thrusting along the Porsgrunn-Kristiansand fault zone. Quartz in the Evje-Iveland pegmatites has more variable compositions with 69 ± 57 μ gg−1 Al, 19 ± 11 μ gg−1 Ti, 2.3 ± 1.8 μ gg−1 Ge, and 7 ± 5 μ gg−1 Li. From its Ti content, it crystallized at temperatures of 613° ± 70°C. The regional spatial distribution of Ti-in-quartz temperatures appears irregular mainly due to the scattered distributions of chemical evolved pegmatites with “amazonite”-“cleavelandite” replacement zones, which show crystallization temperatures down to 442°C. Quartz from the Evje-Iveland pegmatites is unlikely to be of current economic interest due to its moderate to high trace element contents, heterogeneous chemistry, and low volume. The Evje-Iveland pegmatites show no apparent genetic link to a granite intrusion; instead they probably formed as a result of partial melting at the depth of their amphibolite country rocks at around 910 Ma. This is related to a regional low-pressure/high-temperature metamorphic event at about 930 to 920 Ma.

The Seiland Igneous Province (SIP), Northern Norway, contains > 5000 km2 of mafic and ultramafic intrusions with minor alkaline, carbonatite and felsic rocks that were intruded into the lower continental crust at a depth of 25 to as much as 35 km. The SIP can be geochemically and temporally correlated to numerous dyke swarms throughout Scandinavia at 560–610 Ma, and is linked to magmatic provinces in W-Greenland and NE-America that are collectively known as the Central Iapetus Magmatic Province (CIMP). Revised mapping show that the SIP exposes 85–90% layered tholeiitic- alkaline- and syeno-gabbros, 8–10% peridotitic complexes, 2-5% carbonatite, syenite and diorite that formed within a narrow (< 10 Ma) time frame in the Ediacaran (560–570 Ma). Large peridotite complexes were emplaced into the still hot and unconsolidated gabbro (no dating available) and are regarded as the main-conduit systems. Gravimetric data implies an average thickness of igneous rocks of 4–5 km and also features six deep lithospheric roots of ultramafic rocks extending min 9 km into the crust. Together, the root structures represent the main volcanic conduits conveying thousands of km3 of mafic-ultramafic melts from the asthenosphere to the lithosphere. The ultramafic complexes were predominantly emplaced into the layered gabbros at four major igneous centres, respectively, Nordre Brumandsfjord, Melkvann, Kvalfjord and Reinfjord. All complexes are situated in a right-way-up position and are steep sided forming large plugs. A marginal hybrid zone forms at the contact with country-rock and transitions gradually from olivine-mela-gabbro over pyroxenites that grades in to an olivine-clinopyroxenite zone, which is followed by a wehrlite zone and, finally, the centre of the complexes comprises pure dunite. From pyroxenite to dunite, olivine changes from Fo72 to Fo85 and clinopyroxene from Di80 to Di92 i.e. the complexes observe a reverse fractional crystallisation sequence with time. Parental melt compositions modelled from early dykes indicate komatiitic to picritic melts with 16–22 wt% MgO, Cr of 1594 ppm and Ni of 611 ppm, which were emplaced at 1450–1500 °C. Melt compositions calculated from clinopyroxene compositions from Reinfjord are OIB-like with LREE enriched over HREE. The high abundance of carbonatites and lamproites demonstrates the volatile-rich nature of the mantle source region and is further corroborated by the unusually high abundance of magmatic sulphides (0.5–1%) and carbonated and hydrous assemblages (c. 1%) throughout the region. In Reinfjord, they are also closely associated with PGE-Cu-Ni reef deposits. Essentially, the ultramafic complexes in the SIP comprises deep-seated transient magma chambers that facilitated mixing and homogenisation of a rich diversity of fertile asthenospheric melts en route to the upper parts of the continental crust.

Quartz and carbonaceous materials, which are used in the production of silicon as well as electrodes and refractories in the silicon furnace, contain trace elements mostly in the form of oxides. These oxides can be reduced to gaseous compounds and leave the furnace or stay in the reaction products—metal and slag. This article examines the behavior of trace elements in hydrothermal quartz and quartzite in the reaction of SiO2 with Si or SiC. Mixtures of SiO2 (quartz or quartzite), SiC, and Si in forms of lumps or pellets were heated to 1923 K and 2123 K (1650°C and 1850°C) in high purity graphite crucibles under Argon gas flow. The gaseous compounds condensed in the inner lining of the tube attached to the crucible. The phases present in the reacted charge and the collected condensates were studied quantitatively by X-ray diffraction (XRD) and qualitatively by Electron Probe Micro Analyzer (EPMA). Contaminants in the charge materials, reacted charge and condensate were analyzed by Inductively Coupled Plasma-Mass Spectroscopy (ICP-MS). Muscovite in the mineral phase of quartz melted and formed two immiscible liquid phases: an Al-rich melt at the core of the mineral, and a SiO2-rich melt at the mineral boundaries. B, Mn, and Pb in quartz were removed during heating in reducing atmosphere at temperature above 1923 K (1650°C). Mn, Fe, Al and B diffused from quartz into silicon. P concentration was under the detection limit. Quartzite and hydrothermal quartz had different initial impurity levels: quartzite remained more impure after reduction experiment but approached purity of hydrothermal quartz upon silica reduction.

Silicon feedstock for production of solar-grade silicon should be as pure as possible to decrease the cost of manufacturing of solar cells. Impurities in quartz, carbonaceous materials, electrodes, and refractories are mostly present in the form of oxides. These oxides can be reduced to volatile gaseous compounds in presence of SiO(g) and CO(g) atmosphere and potentially leave the furnace or stay in the condensed reaction products, metal, and slag. This work investigates the conditions under which volatile impurities report to the gas phase in laboratory experiments with lumpy and pelletized mixtures of SiO2, SiC, and Si at 1923 K and 2123 K (1650 °C and 1850 °C), respectively, were carried out. The volatile compounds were generated by the reduction of quartz and collected in the form of condensate. The effects of the reaction temperature, quartz type, charge composition, pellets, and lumps on the composition of the condensate were studied. The trace elements in the charge input, reacting charge, and condensate were analyzed using inductively coupled plasma (ICP)-mass spectroscopy (MS) and X-ray diffraction (XRD). CO(g) and SiO(g), which are the major components in reduction reactions, formed four types of condensate: white, brown, green, and orange. The condensate constituents were amorphous SiO2, 3C:SiC, Si, and α-quartz. Each impurity present in the quartz charge entered the gas phase during quartz reduction and was detected in the condensate. Al and Fe show limited volatility. The volatility of Mn, P, and B depends on the charge mix: a higher PCO enhances the concentration of these elements in the gas phase. Fluid inclusions, common in hydrothermal quartz, enhance the distribution of the contaminants to the gas phase. Industrial campaigns on Si and Fe-Si production confirm the experimental results.

The availability of a selective liberation method to eliminate contaminating minerals in quartz is crucial to achieve high purity silicon feedstock for solar cell Si-production. In this study we evaluate and compare the effects of electrical fragmentation to conventional mechanical crushing; particularly to remove fine-grained trace-minerals that often jeopardize otherwise promising high purity quartz commodities. The possibility to combine both comminution techniques upstream in the solar silicon value chain is also discussed. A bulk hydrothermal vein quartz sample containing trace impurities of muscovite and orthoclase is fragmented. After fragmentation the particles are sieved in two fraction sizes [0.3–0.5 mm] and [0.5–4 mm] and are magnetically separated. The morphology of the particles, the crack distribution, and the degree of mineral liberation are studied by optical microscopy, electron probe micro-analyzer (EPMA), and X-ray diffraction (XRD). Electrical fragmentation generates particles with spherical geometries and deep cracks that selectively are pointing towards contaminant mineral inclusions, and produce a higher percentage of liberated minerals. Mechanical crushing, on the contrary, produces elongated fragments with fewer cracks that predominantly run parallel to the fragment surfaces. Muscovite fractures both along its cleavage planes and along its grain boundaries whereas orthoclase fractures along its grain boundaries, only. Muscovite containing 5.8 wt.% Fe was easily removed by magnetic separation.

Using synchrotron‐based analytical microprobe techniques, we determine micrometer‐scale elemental composition, spatial distribution, and oxidation state of impurities in raw feedstock materials used in the photovoltaic industry. Investigated Si‐ bearing compounds are pegmatitic quartz, hydrothermal quartz, and quartzite. Micrometer‐scale clusters containing Fe, Ti, and/or Ca are frequently observed at structural defects in oxidized states and in bulk concentrations equivalent to inductively coupled plasma mass spectroscopy measurements. Investigated C‐bearing compounds are pine wood, pine charcoal, and eucalyptus charcoal. Clustered metals are observed only in the charcoal samples. Impurity clustering implies that industrial processing could be adapted to take advantage of this “natural gettering” phenomenon, expanding the usable range of raw feedstock materials to dirtier, cheaper, and more abundant ones, currently underexploited for solar‐grade silicon production. Copyright © 2011 John Wiley & Sons, Ltd. *Correspondence

This study documents the textures and chemical evolution of igneous quartz (Qz) in granite from the Oslo Rift (Norway) during the magmatic-hydrothermal transition. Contrary to the other major igneous phases, primary quartz is well preserved. SEM-CL imaging documents four types of quartz (Qz1— Qz4). Qz1: bright primary magmatic quartz that grew under H2O-undersaturated conditions and developed a conspicuous sector zoning. Qz2: light grey luminescent secondary quartz that surrounds Qz1 and altered Qz1 in a ‘non-destructive’ process. Qz3: is usually darker than Qz2 and intersects Qz1 and Qz2. It is formed by dissolution/recrystallization processes involving saline deuteric fluids. Qz4: found in narrow cracks and patches of black quartz intersecting all the other types. EPMA in situ analyses of the different quartz generations confirm that the intensity of luminescence of quartz is positively correlated with the Ti content of the quartz. Aluminium and K are mostly incorporated in quartz in the form of [AlO4/K+]0 centre defects. In the Drammen granite, the Ti and Al contents of Qz1 averages 200 ppm and 80 ppm respectively. Titanium in Qz1 varies from 50 to 95 ppm in the peralkaline granite known as ekerite, whereas Al is irregular and ranges between 100 ppm and values below the limit of detection (LODAl at 2σ = 14 ppm). In all samples, Qz2 and Qz3 are strongly depleted in Ti and Al compared to Qz1. Either the Ti content in Qz2 is falling gradually towards Qz1 or more abruptly, whereas it is sharp from Qz3 towards Qz1 and Qz2. Potassium is variable in all four quartz types and samples, and ranges from values below the detection limit (LODk, at 2σ = 8 ppm) to 120 ppm. Grains in Qz4, being only 1–2µm wide, could not be resolved with the EPMA beam. In all granites, quartz crystallized from haplogranitic melts at P ~1.5 kbar and T = 700—750°C. SEM-CL and EPMA studies of igneous Oslo Rift quartz illustrate vividly the complex chemical and physical processes that characterize the magmatic-hydrothermal transition in shallow granitic systems and show that the chemistry of primary aqueous fluids is strongly modified from its primary igneous composition before eventually being expelled from the granitic system and perhaps incorporated in ore-forming hydrothermal convection systems.

article i nfo Trace element analyses of quartz from the layered charnockitic Kleivan granite in the Rogaland Igneous Province (Rogaland Municipality, SW-Norway) reveal that the trace element composition of quartz can track igneous evolution during differentiation of the magma. Combined SEM-CL imaging and LA-ICP-MS analyses allow identification and analysis of primary igneous quartz. Al, Ti, Li, and Ge are the most abundant trace elements in the Kleivan quartz and each element shows a characteristic evolution during differentiation of the granitic magma. The Ge/Ti ratio of quartz is a reliable index of the magmatic evolution of granitic igneous systems, since Ti and Ge show pronounced compatible and incompatible characteristics, respectively. The temperature of the quartz crystallisation varies from 850 °C during charnockite formation to 645 °C in the most evolved aplitic-granite and granitic pegmatite. Therefore, the regular evolution of Ti and Ge in quartz during cooling of the melt may be used as an igneous geothermometer. The Li evolution pattern of quartz is mostly controlled by the Li content of the melt hence by the absence or presence of Li-bearing phases forming during solidification of the melt. Al in quartz is controlled by the aluminium saturation index of the melt. Accordingly, Al in quartz is constant during crystallisation of a metaluminous magma and increases during peraluminous conditions. The study of rock mineralogy and whole rock geochemistry are not the only methods that can be used to assess the petrogenesis of silica oversaturated rocks. The purpose of this study is to demonstrate that the trace element chemistryof quartz, and inparticular the Ge/Ti ratio, can be used as a petrogenetic tool to characterise an evolving igneous system and, can provide information that otherwise may be difficult to obtain. Quartz is a good mineral for recording and storing the differentiation processes in granitic systems, compared to other

This study focuses on the retrograde rheological and chemical evolution of quartz and the behaviour of quartzites during retrograde metamorphism following dry high grade metamorphism at 750°C, 7 kbar. SEM-CL and LA-HR-ICP-MS are applied to document quartz texture and chemistry, respectively. Four generations of quartz were distinguished by SEM-CL; Qz1, Qz2, Qz3 and Qz4. Qz1, brecciated and partly dissolved old grains, is enriched in B, Al and Ti when compared with the other types. Qz2, formed during brecciation and partial dissolution of Qz1, has low Al contents (

The Nordic countries, including Greenland, have a long tradition in mining. The industrial minerals sector is expanding in most Nordic countries and extensive development has taken place during the last few years. The main commodities mined are carbonate rocks, quartz, feldspar, apatite, olivine and talc. A number of different types of dimension stones are quarried in all countries. Rock aggregates are increasingly important, replacing sand and gravel aggregate as construction materials in some countries due to the need to protect ground water supplies. Validerad; 2008; 20080821 (pawe)

Primary granophyres are differentiated from olivine tholeiitic magma and occur interstitially throughout the cumulus stratigraphy of the Skaergaard intrusion, East Greenland. Samples from the Lower Zones a–c (LZa–c), the Middle Zone (MZ) and the Sandwich Horizon (SH) are included in the present study together with granophyric accumulations in gabbroic pegmatite from LZa–c. Fluid inclusions in quartz and the mineral assemblage in the granophyres record the pressure under which the Skaergaard intrusion crystallised. Pegmatitic granophyre from LZa–c consists mainly of quartz, plagioclase (An 4–7 ) and alkali feldspar (Or 40–80 ) enclosing an earlier formed assemblage of ferrohastingsitic and ferroedenitic hornblende, fayalite (Fo 4–5 ), titanite, biotite and fluor-apatite. Granophyric quartz, albite and alkali feldspar crystallised from water-saturated granitic melts near eutectic minimum conditions between 680 and 660 °C. The pressure of granophyre crystallisation was modelled by the intercept between fluid inclusion isochores and the minimum melt solidus for granitic compositions. Pressures, recalculated to the roof pendant of the intrusion, are 0.7 ± 0.5 for LZa, 2.0 ± 0.2 for LZb–c, 2.3 ± 0.8 for MZ (the Triple Group level) and 3.3 ± 1.3 kb for SH. Amphibole geobarometry, independently, confirm the pressure estimates for pegmatitic granophyres in LZa–c. The granophyres formed as the intrusion cooled through the minimum melt solidus in LZa, LZb, LZc, MZ and SH, respectively. The pressure increase from LZa to SH granophyres is explained by progressive burial during cooling of the intrusion and contemporaneous outpouring of 5.3–6.3 ± 2.7 km of flood basalts during the initial opening of the Northeast Atlantic Ocean. Accordingly, the Skaergaard intrusion evolved from a subvolcanic magma chamber at emplacement to a more deep-seated igneous system during terminal crystallization when the majority of the intercumulus phases formed. The present cooling history suggests the intrusion cooled through the temperature of granophyre formation in less than 300,000 years. The increase in the pressure of granophyre formation therefore implies that 5.3–6.3 ± 2.7 km of flood basalts were emplaced within this time window.

Background. Routine pretransfusion testing for red cell alloantibodies (RBCab) in cesarean patients is standard practice in many obstetric centers. The objective of the present study was to evaluate the usefulness of this test. Method. A retrospective study was conducted using computerized registers to extract data on blood transfusions and the occurrence of RBCab in cesarean patients. Results. A total of 4434 admissions for cesarean section were identified. Only 10 patients (0.23%) had clinically significant RBCab, which had not been previously detected. Blood transfusions were required in relation to 147 cesarean sections (3.3%). A number of preoperative conditions, traditionally believed to be risk factors for preoperative and postpartum hemorrhage, occurred more frequently in transfused patients than in nontransfused. The probability of a cesarean patient having a previously undetected clinically significant RBCab and receiving a blood transfusion during admission for delivery was estimated to be 9.0 ...

The present study documents that the trace-element distribution in granitic quartz is highly sensitive to CAFC processes in granitic melts. Igneous quartz efficiently records both the origin and the evolution of the granitic pegmatites. Aluminium, P, Li, Ti, Ge and Na in that order of abundance, comprises >95% of the trace elements. Most samples feature >1 ppm of any of these elements. The remnant 5% includes K, Fe, Be, B, Ba and Sr whereas the other elements are present at concentrations lower than the detection limit. Potassium, Fe, Be and Ti are relatively compatible hence obtain the highest concentrations in early formed quartz. Phosphorous, Ge, Li and Al are relatively incompatible and generally obtain the highest concentrations in quartz that formed at lower temperatures from more evolved granitic melts. The Ge/Ti, the Ge/Be, the P/Ge and the P/Be ratios of quartz are strongly sensitive to the origin and evolution of the granitic melts and similarly the Rb/Sr and the Rb/K ratios of K-feldspars may be utilised in petrogenetic interpretations. However, the quartz trace element ratios are better at distinguishing similarities and differences in the origin and evolution of granitic melts. After evaluating the different trace element ratios, the Ge/Ti ratio appears to be most robust during subsolidus processes in the igneous systems, hence probably should be the preferred ratio for analysing and understanding petrogenetic processes in granitic igneous rocks.

last crystallization, and are significantly higher in Sr and Sn, and isotopically heavier. Tourmaline associated with Sn mineralization is also high in Sr and Sn, but has boron isotopic compositions close to that of the magmatic tourmaline, and is not formed by the same fluids responsible for the blue overgrowths. The ore-forming fluids precipitating tourmaline and cassiterite are likely derived from the same magma source as the granite, but exsolved deeper in the magma chamber, and at a later stage than orbicule formation. Tourmaline from massive quartz–tourmaline rocks is concentrically zoned, with major and trace element compositions indicating crystallization from a similar melt as for the orbicules, but shows a more evolved signature.

In situ micro analysis of ultra trace element composition of quartz using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) allows rapid screening of lattice bound impurities of potential high-purity quartz resources and samples for petrological research without the need to remove solid and liquid inclusions by expensive dressing techniques prior to chemical analysis. Information of the analysed trace element content can not only be used to determine the economic quality of quartz but also the conditions of quartz crystallisation and the origin of the quartz-forming fluids and melts. The main purpose of this paper is to describe an efficient and precise analytical method for estimating the concentrations of lattice-bound trace elements in quartz. The best choice of instrument is considered to be a double focusing sector field inductively coupled plasma mass spectrometry ICP-MS that provides high sensitivity and a mass resolution high enough to separate K from its interferences. The ICP-MS should be coupled to a 193 nm excimer laser, a femto second laser or a similar ablation system. The following elements are included in the standard analytical protocol applied at the Geological Survey of Norway (NGU): Al, B, Be, Ca, Cr, Fe, Ga, Ge, K, Li, Mg, Mn, Na, P, Rb, Sb, Sr, Ti and Zn. Any element with isotopes that can be ionised in an Ar plasma can easily be included if suitable reference materials are available. External calibration was done using the international reference materials NIST SRM 610, 612, 614, 616 and 1830 from the National Institute of Standards and Technology (NIST), BCS 313/1 from the Bureau of Analysed Samples (BAS) and the certified reference material “pure substance No. 1” silicon dioxide SiO2 from the Federal Institute for Material Research and Testing, Berlin, Germany (BAM). To improve the lower limit of quantification and analytical uncertainty at low concentrations, it is important to have calibration curves with well defined intercepts. This can be achieved by the use of certified standards, with trace element concentrations lower than the quantification limit. Even better is to use a standard where the analyte is not present, however in laserablation matrixmatcing is usually important and a standard blank is usually not avilable. In this work, BAM no. 1 SiO2 is the reference material used whith the lowest consentration of the analytes. Because of the absence of a SiO2 blank, the BAM no. 1 SiO2 is used for the estimation of detection limits. Detection limits for most of the elements are between 1 and 0.02 μg g−1. Analysis time and laser spot size are adjusted to the size of the quartz crystal and the thickness (~300 μm) of the polished thick section. The size of the ablation raster is commonly 100 × 350 μm with a depth of 10–20 μm applying the analysis time of less than 1 min.

The K-feldspar from strongly zoned gadolinite-type REE–Nb–Ta-rich granitic pegmatites from the Evje–Iveland and Froland pegmatite fields in southern Norway was analyzed for the entire spectrum of rare-earth elements, as well as for a suite of majo r and trace elements, with the HR–LA–ICP–MS technique. Earlier results imply that the two pegmatite fields are nearly indistinguishable in terms of their origin and igneous evolution. An evaluation of the distribution of K, Rb, Sr and Ba in Kfeldspar, elements that are strongly sensitive to igneous processes in felsic rocks, confirm this conclusion. However, the distribution of the ultra-trace elements, and particularly the REE, in K-feldspar is incompatible with a common origin of the two fields. The REE distribution in K-feldspar is buffered by the coexisting REE-phases. When compared to Evje–Iveland, the Froland suite of pegmatites was derived from a relatively LREE-deficient and HREE-enriched parent melt. Finally, the distribution of trace elements in feldspar implies that the Evje–Iveland pegmatites formed from progressively more differentiated melts that were emplaced in a southward-propagating system of vertical and horizontal faults and fractures.

Fluid inclusions in garnet, kyanite and quartz from microdiamond-bearing granulites in the Western Gneiss Region, Norway, document a conspicuous fluid evolution as the rocks were exhumed following Caledonian high- and ultrahigh-pressure (HP–UHP) metamorphism. The most important of the various fluid mixtures and daughter minerals in these rocks are: (N2 + CO2 + magnesian calcite), (N2 + CO2 + CH4 + graphite + magnesian calcite), (N2 + CH4), (N2 + CH4 + H2O), (CO2) and (H2O + NaCl + CaCl2 + nahcolite). Rutile also occurs in the N2 + CO2 inclusions as a product of titanium diffusion from the garnet host into the fluid inclusions. Volatiles composed of N2 + CO2 + magnesian calcite characterise the ambient metamorphic environment between HP–UHP (peak) and early retrograde metamorphism. During progressive decompression, the mole fraction of N2 increased in the fluid mixtures; as amphibolite-facies conditions were reached, CH4 and later, H2O, appeared in the fluids, concomitant with the disappearance of CO2 and magnesian calcite. Graphite is ubiquitous in the host lithologies and fluid inclusions. Thermodynamic modelling of the metamorphic volatiles in a graphite-buffered C-O-H system demonstrates that the observed metamorphic volatile evolution was attainable only if the fO2 increased from c. −3.5 (±0.3) to −0.8 (±0.3) log units relative to the FMQ oxygen buffer. External introduction of oxidising aqueous solutions along a system of interconnected ductile shear zones adequately explains the dramatic increase in the fO2. The oxidising fluids introduced during exhumation were likely derived from dehydration of oceanic crust and continental sediments previously subducted during an extended period of continental collision in conjunction with the Caledonian orogeny.

Volatile solutions composed of gas species constrained by the three-component system COH are encountered in igneous, ore geological, or metamorphic settings. These fluids contain important information on the geochemistry of the system in which the fluids equilibrated. Because the calculations of geochemical parameters in these solutions is a time-consuming and complex procedure, a FORTRAN 77 application termed “GEOFLUID” was written to allow easy and flexible computations and modeling on COH fluids. The geochemical scenarios which are considered by “GEOFLUID” are: (1) calculation of fluid specification in graphite buffered COH solutions; (2) calculation of fO2 and log K in COH fluids of known composition and not buffered by graphite; (3) calculation of molar volumes and fugacity coefficients of pure species. The output data depends on the request made by the user but includes: fluid speciation; O2 at various buffer conditions; fugacity coefficients and molar volumes for H2O, H2, CH4, CO2, and CO; and log K for various equilibrium reactions between the gas species in the COH system. GEOFLUID uses a variety of equations of state from the literature which in combination cover a temperature range of 450–3000 K and a pressure range of 1 bar-1 Mbar.

Solutions of H2O−NaCl−CH4 occur in fluid inclusions enclosed by quartz, apatite and feldspar from gabbroic pegmatitites, anorthositic structures and intercumulus minerals within the Skaergaard intrusion. The majority of the fluid inclusions resemble 10 μm diameter sub-to euhedral negative crystals. A vapour phase and a liquid phase are visible at room temperature, solids are normally absent. The salinity of the fluids ranges from 17.5 to 22.8 wt.% NaCl. CH4, which comprises less than six mole percent of the solution, was detected in the vapour phase of the fluid inclusions with Raman microprobe analysis. Homogenization of the fluid inclusions occurred in the liquid phase in the majority of the fluid inclusions, though 10% of the inclusions homogenized in the gas phase. Thermodynamic consideration of the stability of feldspars + quartz, and the C−O−H system, indicates that the solutions were trapped at temperatures between 655 and 770°C, at oxygen fugacities between 1.5 and 2.0 log units below the QFM oxygen buffer. Textural evidence and the composition of the solutions suggest that the fluids coexisted with late-magmatic intercumulus melts and the melts which formed gabbroic pegmatites. These solutions are thought to have contributed to late-magmatic metasomatism of the primocryst assemblages of the Skaergaard intrusion.

The Nordic countries, including Greenland, have a long tradition in mining. Documented mining dates back to the 8th century AD. Today this region is the most important metallic mining district of the European Union. Metals are producedfrom active mines in all countries except Iceland and related industries are thriving in all countries. Important ore deposit types include: volcanogenic massive sulphide deposits (Cu, Zn, Pb, Au, Ag), orogenic gold deposits (Au), layered intrusions (Ni, PGE, Ti±V), intrusive hosted Cu-Au, apatite-Fe deposits, Cr and anorthosite hosted Ti deposits. Besides these welldocumented deposits, new kinds of deposits are being explored, e.g., iron oxide-copper-gold (IOCG), and shalehosted Ni-Zn-Cu and different types of uranium deposits. Validerad; 2008; 20080821 (pawe)

Massif-type anorthosites are large igneous complexes of Proterozoic age. They are almost monomineralic, representing vast accumulations of plagioclase with subordinate pyroxene or olivine and Fe–Ti oxides—the 930-Myr-old Rogaland anorthosite province in southwest Norway1 represents one of the youngest known expressions of such magmatism. The source of the magma and geodynamic setting of massif-type anorthosites remain long-standing controversies in Precambrian geology, with no consensus existing as to the nature of the parental magmas or whether these magmas primarily originate in the Earth's mantle or crust. At present, massif-type anorthosites are believed to have crystallized from either crustally contaminated mantle-derived melts that have fractionated olivine and pyroxenes at depth2 or primary aluminous gabbroic to jotunitic melts derived from the lower continental crust3. Here we report rhenium and osmium isotopic data from the Rogaland anorthosite province that strongly support a lower crustal source for the parental magmas. There is no evidence of significantly older crust in southwest Scandinavia and models invoking crustal contamination of mantle-derived magmas fail to account for the isotopic data from the Rogaland province. Initial osmium and neodymium isotopic values testify to the melting of mafic source rocks in the lower crust with an age of 1,400–1,550 Myr.

Three grains of microdiamond were recovered from high-grade gneiss exposed in the Western Gneiss region, Norway. Identification and characterization of the diamond grains by Raman and infrared spectroscopy indicate the presence of substitutional impurities of H and N. Primary fluid inclusions in garnet and quartz in the diamond-bearing rock demonstrate the evolution of metamorphic volatile fluids from reduced N 2 -CO 2 compositions during the peak phase of metamorphism, to N 2 -CH 4 ± H 2 O–bearing compositions during retrograde metamorphism. Compatible geologic, petrologic, and fluid composition data imply a metamorphic origin for the microdiamonds; if so, the metamorphic and fluid conditions recorded by the microdiamonds and gneissic host may be applicable to microdiamond investigations in other high-pressure, regionally metamorphosed orogens.