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  • 251.
    Budd, David A.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Mineralogy Petrology and Tectonics.
    Troll, Valentin R.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Mineralogy Petrology and Tectonics. Ist Nazl Geofis & Vulcanol, Rome, Italy.
    Deegan, Frances M.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Mineralogy Petrology and Tectonics. Swedish Museum Nat Hist, Dept Geosci, Stockholm, Sweden.
    Jolis, Ester
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Mineralogy Petrology and Tectonics.
    Smith, Victoria
    Research Laboratory for Archaeology and the History of Art, University of Oxford, Oxford, UK.
    Whitehouse, Martin
    Department of Geosciences, Swedish Museum of Natural History, Stockholm, Sweden.
    Harris, Chris
    Department of Geological Sciences, University of Cape Town, South Africa.
    Freda, Carmela
    Istituto Nazionale di Geofisica e Vulcanologia, Rome, Italy.
    Hilton, David
    Scripps Institution of Oceanography, University of California, San Diego, USA.
    Halldórsson, Sæmundur
    Scripps Institution of Oceanography, University of California, San Diego, USA; Univ Iceland, Inst Earth Sci, Reykjavik, Iceland.
    Bindeman, Ilya
    Department of Geological Sciences, University of Oregon, Oregon, USA.
    Magma reservoir dynamics at Toba caldera, Indonesia, recorded by oxygen isotope zoning in quartz2017In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 7, article id 40624Article in journal (Refereed)
    Abstract [en]

    Quartz is a common phase in high-silica igneous rocks and is resistant to post-eruptive alteration, thus offering a reliable record of magmatic processes in silicic magma systems. Here we employ the 75 ka Toba super-eruption as a case study to show that quartz can resolve late-stage temporal changes in magmatic δ18O values. Overall, Toba quartz crystals exhibit comparatively high δ18O values, up to 10.2‰, due to magma residence within, and assimilation of, local granite basement. However, some 40% of the analysed quartz crystals display a decrease in δ18O values in outermost growth zones compared to their cores, with values as low as 6.7‰ (maximum ∆core−rim = 1.8‰). These lower values are consistent with the limited zircon record available for Toba, and the crystallisation history of Toba quartz traces an influx of a low-δ18O component into the magma reservoir just prior to eruption. Here we argue that this late-stage low-δ18O component is derived from hydrothermally-altered roof material. Our study demonstrates that quartz isotope stratigraphy can resolve magmatic events that may remain undetected by whole-rock or zircon isotope studies, and that assimilation of altered roof material may represent a viable eruption trigger in large Toba-style magmatic systems.

  • 252.
    Bukała, Michał
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Mineralogy Petrology and Tectonics. AGH Univ Sci & Technol, Fac Geol Geophys & Environm Protect, Krakow, Poland.
    Klonowska, Iwona
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Mineralogy Petrology and Tectonics.
    Barnes, Christopher
    AGH Univ Sci & Technol, Fac Geol Geophys & Environm Protect, Krakow, Poland.
    Majka, Jaroslaw
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Mineralogy Petrology and Tectonics. AGH Univ Sci & Technol, Fac Geol Geophys & Environm Protect, Krakow, Poland.
    Kośmińska, Karolina
    AGH Univ Sci & Technol, Fac Geol Geophys & Environm Protect, Krakow, Poland.
    Janák, Marian
    Slovak Acad Sci, Earth Sci Inst, Bratislava, Slovakia.
    Broman, Curt
    Stockholm Univ, Dept Geol Sci, Stockholm, Sweden.
    Luptáková, Jarmila
    Slovak Acad Sci, Earth Sci Inst, Banska Bystrica, Slovakia.
    UHP metamorphism recorded by phengite eclogite from the Caledonides of northern Sweden: P-T path and tectonic implications2018In: Journal of Metamorphic Geology, ISSN 0263-4929, E-ISSN 1525-1314, Vol. 36, no 5, p. 547-566Article in journal (Refereed)
    Abstract [en]

    The Seve Nappe Complex (SNC) of the Scandinavian Caledonides records a well‐documented history of high pressure (HP) and ultra‐high pressure (UHP) metamorphism. Eclogites of the SNC occur in two areas in Sweden, namely Jämtland and Norrbotten. The Jämtland eclogites and associated rocks are well‐studied and provide evidence for late Ordovician UHP metamorphism, whereas the Norrbotten eclogites, formed during the late Cambrian (Furongian)/Early Ordovician, have not been studied in such detail, especially in terms of the P–T conditions of their formation. Within the studied eclogite, clinopyroxene contains a high‐Na core and two rims: inner, medium‐Na and outer, low‐Na. Garnet consists of a high‐Ca euhedral core, low‐Ca inner rim and medium‐Ca outer rim. A similar pattern occurs within phengite, where high‐Si cores are enveloped by medium and low‐Si rims. The compositions of the mineral cores, inner rims and outer rims reflect three stages in the metamorphic evolution of the eclogite. Applied Quartz‐in‐Garnet geobarometry, coupled with Zr‐in‐rutile geothermometry reveal that garnet nucleation (E0 stage) took place at 1.5–1.6 GPa and 620–660°C. The eclogite peak‐pressure assemblage developed during the E1 stage, it consists of garnet+omphacite+phengite+rutile+coesite? and yields P–T conditions of 2.8–3.1 GPa and 660–780°C as constrained by conventional geothermobarometry and thermodynamic modelling in the NCKFMMnASHT system. Later, lower‐pressure stages E2 and E3 record conditions of 2.2–2.8 GPa, 680–780°C and 2.1 GPa, 735°C, respectively. The prograde metamorphic evolution of the eclogite is inferred from inclusions of epidote, amphibole and clinopyroxene within garnet. The presence of amphibole–quartz–plagioclase symplectites, secondary epidote/zoisite and titanite replacing rutile record the later retrograde changes taking place at <1.5 GPa (referred as E4 stage). The obtained P–T conditions indicate that the Norrbotten eclogites underwent a metamorphic evolution characterized by a clockwise P–T path with peak metamorphism reaching up to coesite stability field within a relatively cold subduction regime (7.8°C/km). The obtained results provide the first evidence for UHP metamorphism in the SNC above the Arctic Circle and document cold subduction regime and multistage exhumation of the deeply subducted Baltican margin at early stage of the Caledonian Orogeny.

  • 253.
    Bundschuh, Jochen
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering.
    Sracek, O.
    Hydrogeochemistry principles for geochemical modeling2011In: Geochemical Modeling of Groundwater, Vadose and Geothermal Systems, CRC Press , 2011, p. 3-26Chapter in book (Other academic)
    Abstract [en]

    A wide diversity of physical and chemical processes control the distribution of species in waters in the vadose zone above the water table, and in the saturated zone below. The mineralogical composition of rocks or sediments, chemical reactions between solid, aqueous and gas phases, and oxidation/reduction (redox) processes are principal factors that influence the chemical composition of vadose-zone, ground-and surface waters, and the concentrations and mobilities of individual species. 

  • 254. Burman, Jan-Ola
    Element transports in suspended and dissolved phases in the Kalix River1983In: Environmental biogeochemistry: proceedings of the 5th International symposium on environmental biogeochemistry (ISEB) arranged in Stockholm 1-5 June, 1981 / [ed] Rolf O. Hallberg, Stockholm: Forskningsrådsnämndens förlagstjänst , 1983, p. 99-113Conference paper (Refereed)
    Abstract [en]

    River water samples were collected ten times during a 24-month period at 16 stations in the Raane, Toere, Kalix and Torne rivers in northern Sweden. Silicon, Al, Mn, Fe, Ca, Mg, Na, Ba and Sr were measured in the aqueous phase and in addition Cu, Ni, Zr, Cr, Zn and V were determined in the suspended fraction. This report is restricted to six stations in the Kalix River. Silicon, Ca, Mg, Na, Sr and Ba are predominantly transported in dissolved phase, whereas most of the Fe and Al are in the suspended fraction. Mn is almost equally distributed between the phases. The annual run off from the Kalix River to the Bothnian Bay shows very high concentrations of Fe and Mn in the suspended matter. Furthermore, this fraction consists of at least four independent phases. Fe and Mn are not correlated and Mn might be of biogeochemical origin

  • 255. Burman, Jan-Ola
    Geochemical studies of north Swedish rivers using inductively coupled plasma optical emission spectroscopy for multielement determinations1982Doctoral thesis, comprehensive summary (Other academic)
  • 256. Burman, Jan-Ola
    et al.
    Boström, Kurt
    Luleå tekniska universitet.
    Comparison of different plasma excitation and calibration methods in the analysis of geological materials by optical emission spectrometry1979In: Analytical Chemistry, ISSN 0003-2700, E-ISSN 1520-6882, Vol. 51, no 4, p. 516-520Article in journal (Refereed)
    Abstract [en]

    A comparative study has been made of different dissolution and calibration methods for analyses by optical emission spectrometry (OES) utilizing inductively coupled plasma (ICP) and capacitively coupled microwave plasma (MWP) as excitation sources. The test substances were geological standard rocks, in which SlO2, Al2O3, TiO2, Fe2O3, MnO, MgO CaO, Na2O, Ba, and some traces were determined. The results show that analyses by MWP-OES are severely disturbed by matrix effects; only in the presence of large quantities of ionization buffers e.g., [Sr(NO3)2] can MWP-OES yield rock analyses of very good quality. No buffers are needed for analyses by ICP-OES, for which the matrix effects are remarkably low. ICP-OES may suffer from annoying nebulizer disturbances when concentrated solutions are used but, with properly diluted solutions, all major and many trace elements can routinely be analyzed in 50-mg rock samples. MWP-OES on the other hand is poorly suited for trace element determinationsA comparative study has been made of different dissolution and calibration methods for analyses by optical emission spectrometry (OES) utilizing inductively coupled plasma (ICP) and capacitively coupled microwave plasma (MWP) as excitation sources. The test substances were geological standard rocks, in which SlO2, Al2O3, TiO2, Fe2O3, MnO, MgO CaO, Na2O, Ba, and some traces were determined. The results show that analyses by MWP-OES are severely disturbed by matrix effects; only in the presence of large quantities of ionization buffers e.g., [Sr(NO3)2] can MWP-OES yield rock analyses of very good quality. No buffers are needed for analyses by ICP-OES, for which the matrix effects are remarkably low. ICP-OES may suffer from annoying nebulizer disturbances when concentrated solutions are used but, with properly diluted solutions, all major and many trace elements can routinely be analyzed in 50-mg rock samples. MWP-OES on the other hand is poorly suited for trace element determinations. © 1979 American Chemical Society.

  • 257.
    Burman, Jan-Ola
    et al.
    Luleå tekniska universitet.
    Boström, Kurt
    Use of ICP-AES in marine geochemistry1982In: Vol. 7, no 10, p. 493-Article in journal (Other academic)
  • 258. Burman, Jan-Ola
    et al.
    Johansson, B.
    Morefält, B.
    Närfeldt, K.-H.
    Olsson, L.
    Automated inductively-coupled plasma optical emission spectrometry based on a sequential reading monochromator1981In: Analytica Chimica Acta : Computer Techniques and Optimization, ISSN 0378-4304, Vol. 133, no 3, p. 379-392Article in journal (Refereed)
    Abstract [en]

    An automated computer-controlled sequential reading monochromator system for optical emission spectrometry with an inductively-coupled plasma as source is described. The system selects the set of emission lines which are best suited for each type of sample. Multi-element analysis of major and trace elements is done automatically, including sample changing, calibration, background correction and presentation of results

  • 259. Burman, Jan-Ola
    et al.
    Ponter, Christer
    Luleå tekniska universitet.
    Boströn, Kurt
    Luleå tekniska universitet.
    Metaborate digestion procedure for inductively coupled plasma-optical emission spectrometry1978In: Analytical Chemistry, ISSN 0003-2700, E-ISSN 1520-6882, Vol. 50, no 4, p. 679-680Article in journal (Refereed)
  • 260.
    Byggeth, Martin
    Luleå tekniska universitet.
    Biologiska indikatorsystem och indikatororganismer: en litteraturstudie med inriktning mot Bottenvikens havsområde1992Report (Other academic)
    Abstract [sv]

    Biologiska indikatorer, i form av indikatorsystem alternativt enskilda indikatororganismer, ger kvalitativ information om ett ekosystems historia, aktuella status och utvecklingstrender. Biologiska indikatorsystem baserade på interaktioner mellan arter i ekosystem ger kvalitativt unika resultat och bör ingå i effektiva miljöövervakningssystem. Interaktionerna i biologiska indikatorsystem kan vara svåra att utvärdera, vilket leder till att enskilda indikatororganismer används som indikatorer. Dock kan denna information aldrig ersätta den som indikatorsystemen ger. Krav på en enskild indikatororganism, är att den skall vara abundant och stationär inom undersökningsområdet, samt vara lätt att fånga eller att samla in. Organismen bör ackumulera föroreningar utan omfattande letalitet, kunna uppvisa föroreningsgradienter inom undersökningsområdet, samt vara av rimlig storlek för organ- eller vävnadsanalyser. Organismen skall leva tillräckligt länge för att möjliggöra åldersrelaterade studier, samt klara av att leva i laboratoriemiljö utan att predera den egna arten. Den bör även ha ett kontrollerbart reproduktionsmönster. Slutligen skall indikatororganismen ha en väl känd fysiologi och ekologi. För miljöövervakning inom Bottenvikens havsområde är följande arter intressanta för utveckling av biologiska indikatorsystem: Nitocra spinipes L., copepod; Saduria (Mesidothea) entomon L., skorv; Corophium volutator L., slammärla; Pontoporeia (Monoporeia) affinis LINDSTRÖM, vitmärla; Theodoxus fluviatilis L., algsnäcka; Lymnaea peregra L., dammsnäcka; Anodonta cygnea L., dammussla; Pisidium amnicum L., ärtmussla; Phoxinus phoxinus L., elritsa; Alburnus alburnus L., löja; Pomatoschistus (Gobius) minutus PALLAS, sandstubb och Myoxocephalus (Cottus) quadricornis L. hornsimpa.

  • 261.
    Bäckström, Mattias
    Örebro University, School of Science and Technology.
    Environmental impact from an alum shale deposit, Kvarntorp, Sweden: Present and future scenarios2010In: Mine water & innovative thinking: proceedings 2010 / [ed] Wolkersdorfer, C. and Freund, A., Nova Scotia, Canada: Cape Breton University Press , 2010, p. 551-554Conference paper (Refereed)
    Abstract [en]

    During the second World War it was decided to produce oil through pyrolysis of alum shalegiving rise to waste products (coke and ash). Waste was deposited in the open pits and in a waste deposit.Due to the high remaining energy in the waste materials the waste deposit still today has significantlyelevated temperatures (above 500 °c). remaining pyrite in the waste material has also led to ArDwith elevated trace metal concentrations. the waste deposit is no great environmental problemtoday but as soon as the waste pile cools off both the volumes of drainage and concentrations oftrace metals will increase dramatically

  • 262.
    Bäckström, Mattias
    et al.
    Örebro University, School of Science and Technology.
    Domeij, Joel
    Sartz, Lotta
    Örebro University, School of Science and Technology. Bergskraft Bergslagen AB, Kopparberg, Sweden.
    Flooding of oxidized waste rock amended with alkaline by-products2010In: 34th British Columbia Mine Reclamation & 35th CLRA/ACRSD National Conference, 2010, p. 10 pages-Conference paper (Refereed)
    Abstract [en]

    Leaching of trace elements (Cd, Cu, Pb and Zn) from oxidized waste rock amended with different alkaline by-products was studied during flooding. It has been argued that water covers for oxidized waste would significantly increase leaching through reductive dissolution of the pre-formed hydrous ferric oxides and the associated trace elements. After approximately three weeks pH in the reference had reached 2.5 and 3.3 in the pore and overlying water, respectively. This can be compared with pH from 6.1 (water works granules) to above 10 (lime kiln dust) in the amended systems. It is clear that the carbonate dominated alkaline by-products have lower pH than the oxide/hydroxide based by-products. However, the systems amended with carbonate based by-products have significantly higher alkalinity. Cadmium, Cu, Pb and Zn concentrations within the waste decreased with at least 99% compared to the reference. In most systems the surface waters can even be used as drinking water. Cadmium, copper and zinc concentrations are clearly related to pH with decreasing concentrations with increasing pH. Lead concentrations, on the other hand, decrease to pH 8, where the concentrations start to increase slightly again due to the formation of soluble Pb(OH)₃⁻ and Pb(OH)₄²⁻ species. The results indicate that flooding of oxidized waste rock amended with alkaline by-products can be used as a successful remediation technique.

  • 263.
    Bäckström, Mattias
    et al.
    Örebro University, School of Science and Technology.
    Sartz, Lotta
    Örebro University, School of Science and Technology. Bergskraft Bergslagen AB, Kopparberg, Sweden.
    Stabilization of acid generating waste rock with fly ash: Immobilization of arsenic under alkaline conditions2010In: Mine water & innovative thinking: proceedings 2010 / [ed] Wolkersdorfer, C. and Freund, A., ovaScotia, Canada: Cape Breton University Press , 2010, p. 555-558Conference paper (Refereed)
    Abstract [en]

    A fly ash was used to increase pH and decrease arsenic leaching from an acidic mine waste.Both the amended system as well as the control system was leached with ultra pure water. pH in thecontrol increased from 1.7 to 2.7 at the end of the experiment while the pH in the amended systemdecreased from 12.6 to 11.5. compared to the control the initial concentrations of arsenic decreasedwith almost three orders of magnitude in the amended systems. A combination of co precipita-tion with iron and calcium arsenate precipitation were identified as the major arsenic immobi-lization mechanisms.

  • 264.
    Bäckström, Mattias
    et al.
    Örebro University, School of Science and Technology.
    Sartz, Lotta
    Örebro University, School of Science and Technology. Bergskraft Bergslagen AB, Kumla, Sweden.
    Sädbom, Stefan
    Bergskraft Bergslagen AB, Kumla, Sweden.
    Mining Waste as an Exploration Tool and Secondary Resource2017In: Mine Water & Circular Economy / [ed] Wolkersdorfer, C., Sartz, L., Sillanpää, M. and Häkkinen, A, Lappeenranta, Finland: Lappeenranta University of Technology , 2017, Vol. II, p. 964-971Conference paper (Refereed)
    Abstract [en]

    There is today no overall information about how much mining waste there is in Sweden and what it contains. This project focused on samples from waste rock, tailings and slag from the historical mining region Bergslagen, Sweden. Modern dissolution and analytical methods were used in order to determine approximately 50 elements in the samples. Modern analytical data for the historical mining waste is useful as an exploration tool and can provide information about remaining or new resources underground. Results show that there is a potential for recovery of critical elements from mining waste as well as dealing with environmental problems.

  • 265.
    Bäckström, Mattias
    et al.
    Örebro University, School of Science and Technology.
    Sädbom, Stefan
    Bergskraft Bergslagen AB, Kopparberg, Sweden.
    Suggestion for a protocol for detailed investigation of historical mine sites2012In: 9th International Conference on Acid Rock Drainage (ICARD 2012) / [ed] Price, W.A., Hogan, C. and Tremblay, G., Red Hook, NY: Curran Associates, Inc., 2012, p. 1340-1350Conference paper (Refereed)
    Abstract [en]

    A protocol for detailed investigation of mine sites is suggested. Results from the investigation are important when planning mine site reclamation. Initially, the mine site is divided into several sub sites according to topography. For general appearance the following parameters were developed and estimated directly in the field for every sub site:

    (1) shape, (2) historical land use, (3) amount of waste rock, (4) weathering, (5) waste rock size, (6) carbonates and silicates, (7) vegetation cover, (8) low and high species, (9) moss and grass/herbs, (10) broad-leaf and coniferous, (11) spruce and pine, (12) birch and aspen, and (13) blueberries and lingonberries. Every parameter was designated a numerical value between 0 and 5. After sampling ocular mineral/rock classification was performed on composite samples from every sub site and the following major components were determined: (14) silicate, (15) mica, (16) granite/pegmatite, (17) carbonates, (18) iron oxide ore and (19) sulphide ore. In addition the relative distribution between the different sulphide minerals was also determined: (20) chalcopyrite vs sphalerite; (21) galena vs sphalerite; (22) chalcopyrite vs galena and (23) pyrite vs pyrrhotite.

    Results from a historical mine site in Kopparberg, Sweden, are used to illustrate the methodology

  • 266. Cabral, R.A.
    et al.
    Jackson, M.G.
    Koga, K.T.
    Rose-Koga, E.F.
    Hauri, E.H.
    Whitehouse, Martin J.
    Swedish Museum of Natural History, Department of Geology.
    Price, A.A:
    Day, J.M.D.
    Shimizu, N.
    Kelley, K.A.
    Volatile cycling of H2O, CO2, F, and Cl in the HIMU mantle: A new window provided by melt inclusions from oceanic hotspot lavas at Mangaia, Cook Islands.2014In: Geochemistry, Geophysics, Geosystems, ISSN 1525-2027, Vol. 15, p. 4445-4467Article in journal (Refereed)
    Abstract [en]

    Mangaia hosts the most radiogenic Pb-isotopic compositions observed in ocean island basalts and represents the HIMU (high µ = 238U/204Pb) mantle end-member, thought to result from recycled oceanic crust. Complete geochemical characterization of the HIMU mantle end-member has been inhibited due to a lack of deep submarine glass samples from HIMU localities. We homogenized olivine-hosted melt inclusions separated from Mangaia lavas and the resulting glassy inclusions made possible the first volatile abundances to be obtained from the HIMU mantle end-member. We also report major and trace element abundances and Pb-isotopic ratios on the inclusions, which have HIMU isotopic fingerprints. We evaluate the samples for processes that could modify the volatile and trace element abundances postmantle melting, including diffusive Fe and H2O loss, degassing, and assimilation. H2O/Ce ratios vary from 119 to 245 in the most pristine Mangaia inclusions; excluding an inclusion that shows evidence for assimilation, the primary magmatic H2O/Ce ratios vary up to ∼200, and are consistent with significant dehydration of oceanic crust during subduction and long-term storage in the mantle. CO2 concentrations range up to 2346 ppm CO2 in the inclusions. Relatively high CO2 in the inclusions, combined with previous observations of carbonate blebs in other Mangaia melt inclusions, highlight the importance of CO2 for the generation of the HIMU mantle. F/Nd ratios in the inclusions (30 ± 9; 2σ standard deviation) are higher than the canonical ratio observed in oceanic lavas, and Cl/K ratios (0.079 ± 0.028) fall in the range of pristine mantle (0.02–0.08).

  • 267.
    Cabri, Louis J.
    et al.
    Cabri Consulting Inc, Ottawa, Canada.
    Aiglsperger, Thomas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    A review of hexaferrum based on new mineralogical data2018In: Mineralogical magazine, ISSN 0026-461X, E-ISSN 1471-8022, Vol. 82, no 3, p. 531-538Article in journal (Refereed)
    Abstract [en]

    Hexaferrum, defined as an hcp Fe mineral containing varying amounts of Ru, Os, or Ir(Mochalov et al. 1998) was re-examined in the light of new analyses of similar alloys from the Loma Peguera and Loma Larga chromitites, in the central part of Loma Caribe peridotite, Cordillera Central of the Dominican Republic, together with a review of the phase chemistry inthe Fe-Ni-Ir and Fe-Ru-Ir systems. We conclude that the hcp (Fe,Ir) mineral corresponds to theε-phase of Raub et al. (1964) and should be differentiated from hexaferrum [(Fe,Os) and(Fe,Ru)] because it is separated by one to two miscibility gaps and therefore is not a continuous solid solution with Fe.

  • 268. Camino-Serrano, Marta
    et al.
    Guenet, Bertrand
    Luyssaert, Sebastiaan
    Ciais, Philippe
    Bastrikov, Vladislav
    De Vos, Bruno
    Gielen, Bert
    Gleixner, Gerd
    Jornet-Puig, Albert
    Kaiser, Klaus
    Kothawala, Dolly
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Lauerwald, Ronny
    Peñuelas, Josep
    Schrumpf, Marion
    Vicca, Sara
    Vuichard, Nicolas
    Walmsley, David
    Janssens, Ivan A.
    ORCHIDEE-SOM: Modeling soil organic carbon (SOC) and dissolved organic carbon (DOC) dynamics along vertical soil profiles in Europe2018In: Geoscientific Model Development, ISSN 1991-959X, E-ISSN 1991-9603, Vol. 11, no 3, p. 937-957Article in journal (Refereed)
    Abstract [en]

    Current Land Surface Models (LSMs) typically represent soils in a very simplistic way, assuming soil organic carbon (SOC) as a bulk, thus impeding a correct representation of deep soil carbon dynamics. Moreover, LSMs generally neglect the production and export of dissolved organic carbon (DOC) from soils to rivers, leading to overestimations of the potential carbon sequestration on land. These common oversimplified processing of SOC in LSMs is partly responsible for the large uncertainty in the predictions of the soil carbon response to climate change. In this study, we present a new soil carbon module called ORCHIDEE-SOM, embedded within the land surface model ORCHIDEE, which is able to reproduce the DOC and SOC dynamics in a vertically discretized soil to two meters. The model includes processes of biological production and consumption of SOC and DOC, DOC adsorption on- and desorption from soil minerals, diffusion of SOC and DOC and DOC transport with water through and out of the soils to rivers. We evaluated ORCHIDEE-SOM against observations of DOC concentrations and SOC stocks from four European sites with different vegetation covers: a coniferous forest, a deciduous forest, a grassland and a cropland. The model was able to reproduce the SOC stocks along their vertical profiles at the four sites and the DOC concentrations within the range of measurements, with the exception of the DOC concentrations in the upper soil horizon at the coniferous forest. However, the model was not able to fully capture the temporal dynamics of DOC concentrations. Further model improvements should focus on a plant- and depth- dependent parameterization of the new input model parameters, such as the decomposition times of DOC and the microbial carbon use efficiency. We suggest that this new soil module, when parameterized for global simulations, will improve the representation of the global carbon cycle in LSMs, thus helping to constrain the predictions of the future SOC response to global warming.

  • 269.
    Canfield, Donald E.
    et al.
    University of Southern Denmark.
    Ngombi Pemba, Lauriss
    Hammarlund, Emma
    Bengtson, Stefan
    Swedish Museum of Natural History, Department of Paleobiology.
    Chaussidon, Marc
    Gauthier Lafaye, François
    Meunier, Alain
    Riboulleau, Armelle
    Rollion Bard, Claire
    Rouxel, Olivier
    Asael, Dan
    Wickmann, Anne Catherine
    El Albani, Abderrazak
    Oxygen dynamics in the aftermath of the Great Oxidation of the Earth’s atmosphere.2013In: Proceedings of the National Academy of Sciences, ISSN 0027-8424, Vol. 110, no 42, p. 16736-16741Article in journal (Refereed)
    Abstract [en]

    The oxygen content of Earth’s atmosphere has varied greatly through time, progressing from exceptionally low levels before about 2.3 billion years ago, to much higher levels afterward. In the absence of better information, we usually view the progress in Earth’s oxygenation as a series of steps followed by periods of relative stasis. In contrast to this view, and as reported here, a dynamic evolution of Earth’s oxygenation is recorded in ancient sediments from the Republic of Gabon from between about 2,150 and 2,080 million years ago. The oldest sediments in this sequence were deposited in well-oxygenated deep waters whereas the youngest were deposited in euxinic waters, which were globally extensive. These fluctuations in oxygenation were likely driven by the comings and goings of the Lomagundi carbon isotope excursion, the longest–lived positive ?13C excursion in Earth history, generating a huge oxygen source to the atmosphere. As the Lomagundi event waned, the oxygen source became a net oxygen sink as Lomagundi organic matter became oxidized, driving oxygen to low levels; this state may have persisted for 200 million years.

  • 270. Carlsson, Eric
    et al.
    Holmström, Henning
    Öhlander, Björn
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Water-solid interactions in tailings remediated by covering with till, Kristineberg Mine, northern Sweden1999In: Vol. 4, no 1, p. 511-Article in journal (Other academic)
  • 271.
    Carlsson, Erik
    Luleå tekniska universitet.
    Geochemical effects of soil cover remediation on sulphide-rich tailings at the Kristineberg mine, northern Sweden2000Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Remediation of mine waste by the application of till cover is one of the more common methods used in Sweden to prevent oxidation of sulphide-rich minerals. Although the general conclusion from Swedish state-of-the-art field studies is that dry covers may be effective, they are expensive to construct. Further investigations are also needed to understand the processes occurring in till covered waste deposits. The Kristineberg mining area has been chosen as the main field site for the research program MiMi (Mitigation of the environmental impact of mining waste) funded by the Foundation for Strategic Environmental Research (MISTRA). MiMi focuses on finding new and improved methods to mitigate the environmental problems related to mining operations and disposal of mining waste. An extensive sampling programme was carried out in Kristineberg during 1998 and 1999. The Kristineberg mine is a Boliden mine, located within the Skellefte ore field. It is a Zn-Cu deposit developed in the 1940s and still in production. This thesis consists of three papers outlining the geochemical conditions prevailing in tailings Impoundment 1 at the Kristineberg mine, after remediation by applying till cover. The impoundment investigated was in use until the early 1950s and it was remediated in 1996. Two different remediation methods have been used; in the area with a shallow groundwater table 1.0 m of till was used to raise the groundwater table above the tailings. In other areas, with a deeper groundwater table, a sealing layer consisting of a 0.3 m thick layer of a compacted clayey till underlying a 1.5 m thick protective cover of unspecified till was used. Field studies include sampling of solid tailings, saturated tailings pore water as well as pore water from the vadose zone. Laboratory investigations consist of a five-step sequential extraction on solid tailings samples. Pre-remediation oxidation has resulted in a zonation of the tailings with an upper oxidised zone above unoxidised tailings. Just below the oxidation front, there is a secondary enrichment of especially Cu but also of other elements. Metals released by sulphide oxidation were thus secondarily enriched. Tailings remediated by the combination of a till cover and a raised groundwater table, resulted in a remobilisation of metals around and a few metres below the former oxidation front. Although the concentrations of several elements still are high in the pore water, they are lower than before the remediation. The general conclusion is that the remediation has succeeded in preventing further oxidation in this part of the impoundment. Sequential extractions performed on selected samples from the drilling of the impoundment show that most of the remaining sulphide-associated trace elements in the oxidised zone still belong to the sulphide fraction. At the level of the peaks of metal concentrations in the pore water (and the solid secondary enrichment) substantial concentrations of the trace elements Cd, Co, Cu, Ni, and Zn is present in the adsorbed/exchangeable/carbonate fraction. Other trace elements are retained with other secondary formations such as amorphous or crystalline iron oxyhydroxides e.g., As, Ba, and Pb. Especially the adsorbed/exchangeable/carbonate fraction is easily dissolved and the raised groundwater table remobilise these trace elements into the pore water, as could be seen from the pore water extractions. In Impoundment 1, where the sealing layer was applied, sampling of the infiltrating water was performed by tension lysimeters. Tension lysimeters were installed in the protective till cover, in the oxidised tailings, in the uppermost unoxidised tailings and at an intermediate depth. The groundwater at the same location was also sampled. The tension lysimeters in the till protective cover contained relatively low concentrations of most elements. Elements such as Al, Cd, Co, Cu, Fe, Mn, Ni, S, Si, and Zn had the highest concentrations in the second tension lysimeter in the tailings. Between the second and the third tension lysimeters the concentration of most elements decreased. The increase between the first and the second tension lysimeters can be explained by remobilisation of secondarily retained oxidation products. The decrease between the second and the third tension lysimeters is interpreted as co-precipitation with different iron oxyhydroxides as well as adsorption onto secondarily formed minerals and primary mineral surfaces. Between the deepest tension lysimeter and the groundwater table, the element concentrations decrease further. Most of the pre-remediation oxidation products that are secondarily retained below the oxidation front and are released by the small amount of infiltrating water, is tertiarily retained during continued downward transport. Thus, if the depth to the groundwater table is large enough, the metals released by infiltrating water do not reach it.

  • 272.
    Carlsson, Erik
    Luleå tekniska universitet.
    Sulphide-rich tailings remediated by soil cover: evaluation of cover efficiency and tailings geochemistry, Kristineberg, northern Sweden2002Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The efficiency of soil cover as a method of remediation of sulphide-rich tailings has been studied at an impoundment at the Kristineberg mine, Northern Sweden. Two variations of soil cover were used in the remediation. The major part of the impoundment was covered with a 1.0 m layer of till where the groundwater table was shallow. In combination with the removal of the water dividing ditches surrounding the impoundment, saturation of the tailings as well as the till cover was achieved. In areas with a deeper groundwater it was not possible to saturate the tailings by means of this method. Instead, a sealing layer consisting of a 0.3 m compacted clayey till, acting as an oxygen diffusion barrier, situated underneath a 1.5 m protective cover was used. Field studies at the impoundment cover pore-water extraction and solid-sample collection at five locations. Solid tailings were subject to sequential extractions in the laboratory. Open groundwater pipes for measuring groundwater levels as well as BAT® groundwater pipes for geochemical sampling of the groundwater were installed over the entire impoundment. At a location in the area with the sealing layer, tension lysimeters were installed in a profile in the vadose zone down to the unoxidised tailings. Nearby, one oxygen diffusion lysimeter and one water infiltration lysimeter were installed below 1.5, 1.0, and 0.3 m of protective till cover, respectively. The sealing layer has been investigated in the laboratory with respect to its susceptibility to the effects of freezing and thawing. The solid samples from the tailings revealed that in some areas, the sulphide oxidation prior to the remediation had been intense. In other areas, with a shallower pre-remediation groundwater table, the oxidation seemed to have ceased upon reaching it. In the area with water- saturated tailings increased pore water concentrations around and below the oxidation zone were visible, due to release of secondarily retained elements. Elements with peaks at this level were As, Cd, Co, Cr, Cu, Mo, Ni, Pb, and Zn. However, compared with pre-remediation data the concentrations are generally lowered, indicating that sulphide oxidation has slowed down. Sequential extraction of the solid tailings samples showed that a large part of the elements below the oxidation front, in the secondary enrichment layer, are relatively mobile and are released within the adsorbed, or the amorphous iron (oxy)hydroxide fractions. This was the case for elements such as Fe, As, Ba, Cd, Co, Cr, Cu, Ni, and Zn. The continuous measurements performed in the groundwater pipes show that elements released by raising the groundwater table are transported out of the impoundment, and that the overall water quality is constantly improving due to the inflow of uncontaminated groundwater from the adjacent hill slope. A model for the water transport has been developed and prediction of the future behaviour of the impoundment is proposed. The tension lysimeter measurements show that infiltrating water and diffusing oxygen cause remobilisation of metals around the oxidation front. However, most of these metals are retained again prior to reaching the groundwater table. The mass flow caused by this mobilisation is very small compared to that of the laterally flowing groundwater. Mobilised elements are Fe, S, Si, Al, Cd, Co, Hg, Mg, Mn, Mo, Ni, Pb, and Zn. The freeze/thaw laboratory experiments stress that the compaction degree is very important for achieving a hydraulic conductivity low enough for the requirements of a sealing layer. If a high enough compaction degree is obtained, the corresponding hydraulic conductivity is very low, approximately 5x10-10 m/s with the clayey till used at the study site. The freeze/thaw experiments also revealed that when properly compacted the clayey till is sensitive to frost penetration, leading to an increase of hydraulic conductivity, up to ~10-8 m/s. Oxygen diffusion measurements indicate that the effective diffusion through the sealing layer is low for all three different protective till-cover thicknesses, and so is the water infiltration. However, during the field measurements, no frost penetration into the sealing layer was monitored.

  • 273.
    Carlsson, Erik
    et al.
    Luleå University of Technology.
    Thunberg, Jonas
    Luleå University of Technology.
    Öhlander, Björn
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Holmström, Henning
    Envipro Miljöteknik AB, Linköping.
    Sequential extraction of sulfide-rich tailings remediated by the application of till cover, Kristineberg mine, northern Sweden2002In: Science of the Total Environment, ISSN 0048-9697, E-ISSN 1879-1026, Vol. 299, no 1-3, p. 207-226Article in journal (Refereed)
    Abstract [en]

    A sequential extraction has been carried out on sulfide-rich mine tailings. The purpose was to investigate how elements released by oxidation are secondarily retained in the tailings and the possible consequences of the remediation. After investigating the solid tailings, seven samples were chosen for sequential extractions. Two samples were oxidised, situated just above the oxidation front; two samples from just below the former oxidation front with increased concentrations of several elements; two unoxidised samples were from an intermediate depth, and the deepest sample was from the tailings-peat boundary at the bottom of the impoundment. Five phases were extracted: adsorbed/exchangeable/carbonate; labile organics; amorphous Fe-oxyhydroxides/Mn-oxides; crystalline Fe-oxides; and organics/sulfides. The addition from dried porewater to the extracted fractions has been calculated and considered as minor. In the oxidised tailings, the sulfide fraction still dominates for elements such as Fe, S, Cd, Co, Cu, Hg and Zn, although the concentrations are low compared to the unoxidised tailings. Generally, the second most important fraction is the adsorbed/exchangeable/carbonate fraction. Below the oxidation front, the sulfide content of the tailings sharply increases. In the secondary enrichment zone, the total element concentrations increase compared with the deeper unoxidised samples, mainly due to secondary retention. For some elements, secondary retention is greater than the total amount extracted for the deeper unoxidised samples. In the secondary enrichment zone the adsorbed/exchangeable/carbonate fraction represents approximately 20 wt.% or more for Cd, Co, Mn, Ni and Zn. The amorphous iron oxyhydroxide or the crystalline iron oxide fractions are less important at this level, although for As, Ba and Cu the amorphous iron oxyhydroxide fraction represents up to 20 wt.. At the lower border of the enrichment zone, the total concentration for most metals is lower, but the importance of the adsorbed/exchangeable/carbonate fraction is further enhanced for Cd, Cu, Ni and Zn. These elements have 35-60 wt.% of the total amount from this fraction. For As, Cd, Cu, Ni and Pb, the secondary fractions extracted (extractions A-D) represent between 60 and 80 wt.% of the total content. At greater depth in the impoundment the relative importance of the adsorbed/exchangeable/carbonate fraction decreases, whilst the importance of amorphous iron oxyhydroxide and crystalline iron oxide fractions increases. The adsorbed/exchangeable/carbonate fraction is the most easily remobilised fraction. A raised groundwater table previously situated below the enrichment zone may result in the release of secondarily retained metals.

  • 274.
    Carlsson, Erik
    et al.
    Luleå tekniska universitet.
    Öhlander, Björn
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Holmström, Henning
    Envipro Miljöteknik AB, Linköping.
    Geochemistry of the infiltrating water in the vadose zone of a remediated tailings impoundment, Kristineberg, northern Sweden2003In: Applied Geochemistry, ISSN 0883-2927, E-ISSN 1872-9134, Vol. 18, no 5, p. 659-674Article in journal (Refereed)
    Abstract [en]

    At the remediated tailings Impoundment 1 at Kristineberg, Northern Sweden, installations of tension lysimeters were performed in the protective cover (10, 50, and 100 cm), in the oxidised tailings (150 cm), in the unoxidised secondarily enriched tailings (200 cm) and in the unoxidised tailings (260 cm). The lysimeters in the till protective cover contained relatively low concentrations of most elements. After infiltration through the sealing layer, consisting of 0.3 m compacted clayey till, pH decreased and conductivity, together with the concentrations of several major and trace elements, increased significantly. In the lysimeters installed in the tailings at depths of 150 and 200 cm average pH decreased to 3.4 at 150 cm and 3.2 at 200 and average conductivity increased to 2.9 mS/cm. Elements such as Al, Cd, Co, Fe, Mn, Mo, Ni,Pb, S, Si and Zn had the highest concentrations in the lysimeter at 200 cm depth. Examples of concentration averages for this lysimeter are Cd 600 μg/L, Fe 1500 mg/L, Mn 11 mg/L, Ni 1.06 μg/L, S 1800 mg/L, and Zn 190 mg/L. Between the depths of 200 and 260 cm the concentration of most elements decreased. The increase between the lysimeters at the depths of 150 and 200 cm can be explained by remobilization of secondarily retained oxidation products as well as from the continued oxidation. The decrease between the second and the third lysimeters is interpreted as co-precipitation with different Fe oxyhydroxides as well as adsorption onto secondarily formed minerals and primary mineral surfaces. Calculations of saturation indices indicate that several different hydroxides might precipitate at this level. This retainment takes place mainly due to the increase in pH. The pH increases from 3.2 up to 4-4.4 in this depth interval. Between the deepest lysimeter and the groundwater table, the element concentrations probably decrease even further. pH increases to 5-6.5 in the groundwater. Most of the pre-remediation oxidation products that are secondarily retained above or below the oxidation front and are released by the small amount of infiltrating water together with the present oxidation products are retained again during continued transport downwards. If the depth to the groundwater table is large enough, most of the metals released by the infiltrating water and the diffusing O2 do not reach the groundwater.

  • 275.
    Carranza, Giovanni
    Luleå tekniska universitet.
    Geological setting and geochemistry of epithermal gold deposits in the Libertad and the Limon Areas, Nicaragua1991Licentiate thesis, comprehensive summary (Other academic)
  • 276.
    Cassidy, Mike
    et al.
    Institute of Geosciences, University of Mainz, D-55122 Mainz, Germany.
    Castro, Jonathan
    Institute of Geosciences, University of Mainz, D-55122 Mainz, Germany .
    Helo, Christoph
    Institute of Geosciences, University of Mainz, D-55122 Mainz, Germany .
    Troll, Valentin R.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Mineralogy Petrology and Tectonics.
    Deegan, Frances M.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Mineralogy Petrology and Tectonics.
    Muir, Duncan
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Mineralogy Petrology and Tectonics.
    Neave, David
    Institute of Mineralogy, Leibniz University of Hannover, 30167 Hannover, Germany.
    Mueller, Sebastian
    Institute of Geosciences, University of Mainz, D-55122 Mainz, Germany .
    Volatile dilution during magma injections and implications for volcano explosivity2016In: Geology, ISSN 0091-7613, E-ISSN 1943-2682, Vol. 44, no 12, p. 1027-1030Article in journal (Refereed)
    Abstract [en]

    Magma reservoirs underneath volcanoes grow through episodic emplacement of magma batches. These pulsed magma injections can substantially alter the physical state of the resident magma by changing its temperature, pressure, composition, and volatile content. Here we examine plagioclase phenocrysts in pumice from the 2014 Plinian eruption of Kelud (Indonesia) that record the progressive capture of small melt inclusions within concentric growth zones during crystallization inside a magma reservoir. High-spatial-resolution Raman spectroscopic measurements reveal the concentration of dissolved H2O within the melt inclusions, and provide insights into melt-volatile behavior at the single crystal scale. H2O contents within melt inclusions range from ∼0.45 to 2.27 wt% and do not correlate with melt inclusion size or distance from the crystal rim, suggesting that minimal H2O was lost via diffusion. Instead, inclusion H2O contents vary systematically with anorthite content of the host plagioclase (R2 = 0.51), whereby high anorthite content zones are associated with low H2O contents and vice versa. This relationship suggests that injections of hot and H2O-poor magma can increase the reservoir temperature, leading to the dilution of melt H2O contents. In addition to recording hot and H2O-poor conditions after these injections, plagioclase crystals also record relatively cold and H2O-rich conditions such as prior to the explosive 2014 eruption. In this case, the elevated H2O content and increased viscosity may have contributed to the high explosivity of the eruption. The point at which an eruption occurs within such repeating hot and cool cycles may therefore have important implications for explaining alternating eruptive styles.

  • 277. Cathalot, C.
    et al.
    Rabouille, C.
    Tisnerat-Laborde, N.
    Toussaint, F.
    Kerherve, P.
    Buscail, R.
    Loftis, K.
    Sun, M. -Y
    Tronczynski, J.
    Azoury, S.
    Lansard, B.
    Treignier, C.
    Pastor, L.
    Tesi, Tommaso
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    The fate of river organic carbon in coastal areas: A study in the Rhone River delta using multiple isotopic (delta C-13, Delta C-14) and organic tracers2013In: Geochimica et Cosmochimica Acta, ISSN 0016-7037, E-ISSN 1872-9533, Vol. 118, p. 33-55Article in journal (Refereed)
    Abstract [en]

    A significant fraction of the global carbon flux to the ocean occurs in River-dominated Ocean Margins (RiOMar) although large uncertainties remain in the cycle of organic matter (OM) in these systems. In particular, the OM sources and residence time have not been well clarified. Surface (0-1 cm) and sub-surface (3-4 cm) sediments and water column particles (bottom and intermediate depth) from the Rhone River delta system were collected in June 2005 and in April 2007 for a multi-proxy study. Lignin phenols, black carbon (BC), proto-kerogen/BC mixture, polycyclic aromatic hydrocarbons (PAHs), carbon stable isotope (delta C-13(OC)), and radiocarbon measurements (delta C-14(OC)) were carried out to characterize the source of sedimentary organic material and to address degradation and transport processes. The bulk OM in the prodelta sediment appears to have a predominantly modern terrigenous origin with a significant contribution of modern vascular C-3 plant detritus (Delta C-14(OC) = 27.9 parts per thousand, delta C-13(OC) = -27.4 parts per thousand). In contrast, the adjacent continental shelf, below the river plume, seems to be dominated by aged OM (Delta C-14(OC) = -400 parts per thousand, delta C-13(OC) = -24.2 parts per thousand), and shows no evidence of dilution and/or replacement by freshly produced marine carbon. Our data suggest an important contribution of black carbon (50% of OC) in the continental shelf sediments. Selective degradation processes occur along the main dispersal sediment system, promoting the loss of a modern terrestrial OM but also proto-kerogen-like OM. In addition, we hypothesize that during the transport across the shelf, a long term resuspension/deposition loop induces efficient long term degradation processes able to rework such refractory-like material until the OC is protected by the mineral matrix of particles.

  • 278.
    Chadwick, J.P.
    et al.
    Department of Petrology, Vrije Universiteit, De Boelelaan 1085, 1081 HV Amsterdam, The Netherlands.
    Troll, Valentin
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Solid Earth Geology.
    Waight, T.E.
    Department of Geography and Geology, University of Copenhagen, Øster Voldgade 10, 1350 Copenhagen, Denmark.
    van der Zwan, F.M.
    Department of Petrology, Vrije Universiteit, De Boelelaan 1085, 1081 HV Amsterdam, The Netherlands.
    Schwarzkopf, L.M.
    GeoDocCon, Unterpferdt 8, 95176 Konradsreuth, Germany.
    Petrology and geochemistry of igneous inclusions in recent Merapi deposits: a window into the sub-volcanic plumbing system2013In: Contributions to Mineralogy and Petrology, ISSN 0010-7999, E-ISSN 1432-0967, Vol. 165, no 2, p. 259-282Article in journal (Refereed)
    Abstract [en]

    Recent basaltic-andesite lavas from Merapi volcano contain abundant and varied igneous inclusions suggesting a complex sub-volcanic magmatic system for Merapi volcano. In order to better understand the processes occurring beneath Merapi, we have studied this suite of inclusions by petrography, geochemistry and geobarometric calculations. The inclusions may be classified into four main suites: (1) highly crystalline basaltic-andesite inclusions, (2) co-magmatic enclaves, (3) plutonic crystalline inclusions and (4) amphibole megacrysts. Highly crystalline basaltic-andesite inclusions and co-magmatic enclaves typically display liquid–liquid relationships with their host rocks, indicating mixing and mingling of distinct magmas. Co-magmatic enclaves are basaltic in composition and occasionally display chilled margins, whereas highly crystalline basaltic-andesite inclusions usually lack chilling. Plutonic inclusions have variable grain sizes and occasionally possess crystal layering with a spectrum of compositions spanning from gabbro to diorite. Plagioclase, pyroxene and amphibole are the dominant phases present in both the inclusions and the host lavas. Mineral compositions of the inclusions largely overlap with compositions of minerals in recent and historic basaltic-andesites and the enclaves they contain, indicating a cognate or ‘antelithic’ nature for most of the plutonic inclusions. Many of the plutonic inclusions plot together with the host basaltic-andesites along fractional crystallisation trends from parental basalt to andesite compositions. Results for mineral geobarometry on the inclusions suggest a crystallisation history for the plutonic inclusions and the recent and historic Merapi magmas that spans the full depth of the crust, indicating a multi-chamber magma system with high amounts of semi-molten crystalline mush. There, crystallisation, crystal accumulation, magma mixing and mafic recharge take place. Comparison of the barometric results with whole rock Sr, Nd, and Pb isotope data for the inclusions suggests input of crustal material as magma ascends from depth, with a significant late addition of sedimentary material from the uppermost crust. The type of multi-chamber plumbing system envisaged contains large portions of crystal mush and provides ample opportunity to recycle the magmatic crystalline roots as well as interact with the surrounding host lithologies.

  • 279.
    Charette, M
    et al.
    Woods Hole Oceanographic Institution, USA.
    Lam, P.J.
    University of California Santa Cruz, USA.
    Lohan, M.C.
    University of Southhampton, UK.
    Kwon, E.Y.
    Seoul National University,Korea.
    Hatje, V
    Universidade Federal da Bahia, Brazil.
    Jeandel, C
    University of Toulouse, France.
    Shiller, A.M.
    University of Southern Mississippi, USA.
    Cutter, G.A.
    Old Dominion University, USA.
    Thomas, A
    University of Edinburgh, UK.
    Boyd, P.W.
    University of Tasmania, Australia.
    Homoky, W.B.
    University of Oxford, UK.
    Milne, A.
    Plymoth University, UK.
    Thomas, H.
    Dalhousie University, Canada.
    Andersson, P.S.
    Swedish Museum of Natural History, Department of Geology.
    Porcelli, D.
    University of Oxford,Uk.
    Tanaka, T
    University of Tokyo, Japan.
    Geibert, W
    Alfred Wegener Institute, Germany.
    Dehairs, F.
    Vrije Universiteit, Belgium.
    Garcia-Orellana, J.
    Universitat Autonoma de Barcelona, Spain.
    Coastal ocean and shelf-sea biogeochemical cycling of trace elements and isotopes: lessons learned from GEOTRACES2016In: Philosopical Transactions of the Royal Society A, ISSN 1364–503X, Vol. 374, no 2081Article, review/survey (Refereed)
    Abstract [en]

    Continental shelves and shelf seas play a central role in the global carbon cycle. However,

    their importance with respect to trace element and isotope (TEI) inputs to ocean basins

    is less well understood. Here, we present major findings on shelf TEI biogeochemistry

    from the GEOTRACES programme as well as a proof of concept for a new method to

    estimate shelf TEI fluxes. The case studies focus on advances in our understanding of TEI

    cycling in the Arctic, transformations within a major river estuary (Amazon), shelf sediment

    micronutrient fluxes and basin-scale estimates of submarine groundwater discharge. The

    proposed shelf flux tracer is 228-radium (T1/2 =5.75 yr), which is continuously supplied to

    the shelf from coastal aquifers, sediment porewater exchange and rivers. Model-derived shelf

    228Ra fluxes are combined with TEI/ 228Ra ratios to quantify ocean TEI fluxes from the

    western North Atlantic margin. The results from this new approach agree well with previous

    estimates for shelf Co, Fe, Mn and Zn inputs and exceed published estimates of atmospheric

    deposition by factors of approximately 3–23. Lastly, recommendations are made for additional

    GEOTRACES process studies and coastal margin-focused section cruises that will help refine

    the model and provide better insight on the mechanisms driving shelf-derived TEI fluxes

    to the ocean.

    This article is part of the themed issue ‘Biological and climatic impacts of ocean trace element

    chemistry’.

  • 280. Chatterjee, D.
    et al.
    Biswas, A.
    Bhowmick, S.
    Halder, D.
    Hazra, R.
    Majumder, S.
    Mukherjee-Goswami, A.
    Saha, D.
    Nath, B.
    Bhattacharya, Prosun
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering (moved 20130630).
    Geochemistry of arsenic in Bengal Delta Plain (West Bengal, India)2010In: Arsenic in Geosphere and Human Diseases, As 2010 - 3rd International Congress: Arsenic in the Environment, 2010, p. 125-126Conference paper (Refereed)
  • 281. Chen, J.H.
    et al.
    Andersson, Per S.
    Wasserburg, G.J.
    Ingri, Johan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Uranium geochemistry in the Baltic Sea: mixing of different sources deduced from 234U - 238U1993In: EOS: Transactions, ISSN 0096-3941, E-ISSN 2324-9250, Vol. 74, no 16, p. 329-Article in journal (Other academic)
  • 282. Cherevatova, M.
    et al.
    Smirnov, M. Yu.
    Jones, A. G.
    Pedersen, Laust Börsting
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Geophysics.
    Becken, M.
    Biolik, M.
    Ebbing, J.
    Gradmann, S.
    Gurk, M.
    Huebert, J.
    Junge, A.
    Kamm, Jochen
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Geophysics.
    Korja, T.
    Lahti, I.
    Lower, A.
    Nittinger, C.
    Savvaidis, A.
    Smirnov, M.
    Magnetotelluric array data analysis from north-west Fennoscandia2015In: Tectonophysics, ISSN 0040-1951, E-ISSN 1879-3266, Vol. 653, p. 1-19Article in journal (Refereed)
    Abstract [en]

    New magnetotelluric (MT) data in north-west Fennoscandia were acquired within the framework of the project "Magnetotellurics in the Scandes" (MaSca). The project focuses on the investigation of the crustal and upper mantle lithospheric structure in the transition zone from stable Precambrian cratonic interior to passive continental margin beneath the Caledonian orogen and the Scandinavian Mountains in western Fennoscandia. An array of 59 synchronous long period and 220 broad-band MT sites was occupied in the summers of 2011 to 2013. We estimated MT transfer functions in the period range from 0.003 to 10(5) s. The Q-function multi-site multi-frequency analysis and the phase tensor were used to estimate strike and dimensionality of MT data. Dimensionality and strike analyses indicate generally 2-D behaviour of the data with 3-D effects at some sites and period bands. In this paper we present 2-D inversion of the data, 3-D inversion models are shown in the parallel paper. We choose to invert the determinant of the impedance tensor to mitigate 3-D effects in the data on our 2-D models. Seven crustal-scale and four lithospheric-scale 2-D models are presented. The resistive regions are images of the Archaean and Proterozoic basement in the east and thin Caledonian nappes in the west. The middle and lower crust of the Svecofennian province is conductive. The southern end of the Kittila Greenstone Belt is seen in the models as a strong upper to middle crustal conductor. In the Caledonides, the highly conductive alum shales are observed along the Caledonian Thrust Front. The thickest lithosphere is in the Palaeoproterozioc Svecofennian Domain, not in the Archaean. The thickness of the lithosphere is around 200 km in the north and 300 km in the south-west.

  • 283. Chi Fru, Ernest
    et al.
    Ivarsson, Magnus
    Swedish Museum of Natural History, Department of Paleobiology.
    Kilias, Stephanos P
    Bengtson, Stefan
    Swedish Museum of Natural History, Department of Paleobiology.
    Belivanova, Veneta
    Swedish Museum of Natural History, Department of Paleobiology.
    Marone, Federica
    Paul Scherrer Institute.
    Fortin, Danielle
    Broman, Curt
    Stampanoni, Marco
    ETH Zürich.
    Fossilized iron bacteria reveal pathway to biological origin of banded iron formation.2013In: Nature Communications, ISSN 2041-1723, Vol. 4, no 2050, p. 1-7Article in journal (Refereed)
    Abstract [en]

    Debates on the formation of banded iron formations in ancient ferruginous oceans are dominated by a dichotomy between abiotic and biotic iron cycling. This is fuelled by difficulties in unravelling the exact processes involved in their formation. Here we provide fossil environmental evidence for anoxygenic photoferrotrophic deposition of analogue banded iron rocks in shallow marine waters associated with an Early Quaternary hydrothermal vent field on Milos Island, Greece. Trace metal, major and rare earth elemental compositions suggest that the deposited rocks closely resemble banded iron formations of Precambrian origin. Well-preserved microbial fossils in combination with chemical data imply that band formation was linked to periodic massive encrustation of anoxygenic phototrophic biofilms by iron oxyhydroxide alternating with abiotic silica precipitation. The data implicate cyclic anoxygenic photoferrotrophy and their fossilization mechanisms in the construction of microskeletal fabrics that result in the formation of characteristic banded iron formation bands of varying silica and iron oxide ratios.

  • 284.
    Chi Fru, Ernest
    et al.
    Stockholm University, Department of Geological Sciences.
    Rodríguez, Nathalie
    Stockholm University Department of Geological Sciences.
    Partin, Camille
    University of Saskatchewan, Canada.
    Lalonde, Stefan
    Université de Bretagne Occidentale, France.
    Andersson, Per
    Swedish Museum of Natural History, Department of Geology.
    Weiss, Dominik
    Imperial College, London, UK.
    El Albani, Abderrazak
    Université de Poitiers, France.
    Rodushkin, Ilia
    ALS Scandinavia, Sweden.
    Konhauser, Kurt
    University of Alberta, Canada.
    Cu isotopes in marine black shales record the Great Oxidation Event2016In: Proceedings of the National Academy of Sciences of the United States of America, ISSN 0027-8424, E-ISSN 1091-6490, Vol. 113, no 18, p. 4941-4946Article in journal (Refereed)
    Abstract [en]

    The oxygenation of the atmosphere ∼2.45–2.32 billion years ago (Ga) is one of the most significant geological events to have affected Earth’s redox history. Our understanding of the timing and processes surrounding this key transition is largely dependent on the development of redox-sensitive proxies, many of which remain unexplored. Here we report a shift from negative to positive copper isotopic compositions (δ65CuERM-AE633) in organic carbon-rich shales spanning the period 2.66–2.08 Ga. We suggest that, before 2.3 Ga, a muted oxidative supply of weathering-derived copper enriched in 65Cu, along with the preferential removal of 65Cu by iron oxides, left seawater and marine biomass depleted in 65Cu but enriched in 63Cu. As banded iron formation deposition waned and continentally sourced Cu became more important, biomass sampled a dissolved Cu reservoir that was progressively less fractionated relative to the continental pool. This evolution toward heavy δ65Cu values coincides with a shift to negative sedimentary δ56Fe values and increased marine sulfate after the Great Oxidation Event (GOE), and is traceable through Phanerozoic shales to modern marine settings, where marine dissolved and sedimentary δ65Cu values are universally positive. Our finding of an important shift in sedimentary Cu isotope compositions across the GOE provides new insights into the Precambrian marine cycling of this critical micronutrient, and demonstrates the proxy potential for sedimentary Cu isotope compositions in the study of biogeochemical cycles and oceanic redox balance in the past.

  • 285.
    Chlot, Sara
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Nitrogen and phosphorus interactions and transformations in cold-climate mine water recipients2013Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Process water discharged from mine sites may contain elevated concentrations of nitrogen (N) and phosphorus (P), which both are nutrients for phytoplankton and macrophytes. Thus, discharge of nutrient rich mine water can result in algal blooms, eutrophication, oxygen deficiency and changed species composition in the recipients. This thesis is focused on the speciation and transformation processes of N and P in streams and lakes receiving mine effluents from the Kiruna and Boliden mine sites. The thesis also aimed at evaluating N removal capacity of these aquatic systems. Research methods in the thesis included collection of field data, laboratory and field experiments and computer simulations. The question of limiting nutrient for production of phytoplankton and macrophytes in these mine water recipients was investigated. For this reason, total nitrogen (TN), total phosphorus (TP) and TN:TP ratios in water, sediment and macrophytes were analysed and evaluated. Depending on the ammonium concentration in the effluent at the Boliden site, TN:TP-ratios of the water column shifted from being >22, indicating P-deficiency for phytoplankton, to between 9-22, indicating a transition from N to P deficiency (co-limitation). However, water column TN:TP ratios at the Kiruna site always indicated P deficiency. On the other hand, the TN:TP ratios of macrophytes revealed that both sites may vary from N to P limitation. These aspects have implications for assessing the environmental influence of nutrient-rich mine effluents. A downstream decrease in inorganic N (NH4+ and NO3-) as well as lower concentrations during summer was observed in the receiving streams and lakes. To identify and quantify the major N transformation and removal processes responsible for these changes, a dynamic biogeochemical model was developed, calibrated and validated using hydrological and water chemistry data for the clarification pond Nya Sjön (Boliden). The model calculates concentrations of six N species and simulates the rate of 16 N transformation processes occurring in the water column and sediment as well as water-sediment and water-atmosphere interactions. The calibrated model rendered coefficients of determination (R2) of 0.93, 0.79 and 0.86 for the inorganic nitrogen species ammonium, nitrate and organic nitrogen, respectively. When applying the model in the downstream Lake Bruträsket, the corresponding R2 values were 0.86, 0.76 and 0.54. Model simulations in the two systems suggested that nitrification controlled the reaction rate of the coupled nitrification-denitrification process and that approximately 60 – 65% of permanent removal occurred though denitrification, followed by burial in the sediment (~30-35 %) (May - October). A stable nitrogen isotope (15N) was employed to trace N cycling in the various plant parts of common reed (P. australis) growing in the littoral zone of Lake Bruträsket. Isotope enrichment data indicated a significantly more effective assimilation of N in the roots. Maximum tracer uptake rates of 0.25 µg g-1 min-1 (NO3-) and 1.4 µg g-1 min-1 (NH4+) are similar to model simulated rates of macrophyte N uptake. Simulation results and results from the tracer study indicated that direct N removal through N uptake in macrophytes and phytoplankton may be of minor importance relative to nitrification and denitrification. A sediment incubation experiment using lake water and sediment from Lake Bruträsket (Boliden) resulted in a sedimentary flux of soluble reactive phosphorus (SRP) of 1.1 mg SRP m-2 d-1. Field measurements suggested that oxidation of organic matter and inorganic mining related chemicals (e.g. NH4+ and thiosalts) may result in increased internal SRP flux. These findings point to a possible interaction between the cycles of N (oxygen consumption) and P (flux from sediment) that may be important for nutrient regulation in mine water recipients. Sediment proxy data (δ13C, δ15N, C/N ratios) was used to reconstruct historical changes in organic matter (OM) accumulation in lakes receiving nutrient-rich mine waters in the Boliden and Kiruna mine sites. Sediment accumulation rates increased upwards in all cores, which correlates with an increase in suspended load in the mining effluents discharging to the systems. Similarδ15N values in dissolved inorganic N (DIN) and surface sediments most likely reflect biological assimilation of DIN and subsequent settling of phytoplankton and macrophyte organic detritus. The improved knowledge on N and P dynamics in mine water recipients can be used in selection of mine water management strategies that may lead to reduced N discharge.

  • 286.
    Chlot, Sara
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Nitrogen effluents from mine sites in northern Sweden: nitrogen transformations and limiting nutrient in receiving waters2011Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Process water discharged from mine sites may contain elevated concentrations of nitrogen (N) and phosphorus (P), which both are nutrients for algae and aquatic plants. Thus, discharge of nutrient rich mine water can result in algal blooms, eutrophication, oxygen deficiency and changed species composition in the receiving waters. This thesis is focused on the speciation and transformation processes of N and N:P ratios in streams and lakes receiving mine effluents from the Kiruna and Boliden mine sites. In this work, a dynamic biogeochemical model was developed for the clarification pond receiving ammonium-rich mine effluents from the Boliden concentration plant. A number of such models have been developed that simulate N transformations in wastewater stabilization ponds. However, few biogeochemical models have been developed that primarily focus on simulation of processes regulating transport and removal of N in waters receiving mine effluents. The presented model calculates concentrations of six N species and simulates the rate of 16 N transformation processes occurring in the water column and sediment as well as water-sediment and water-atmosphere interactions. A six-year simulation of ammonium concentrations showed stable behaviour over time, and the calibrated model rendered coefficients of determination (R2) of 0.93, 0.79 and 0.86 for the inorganic nitrogen species ammonium, nitrate and organic nitrogen, respectively. This indicates a stable model behaviour. The simulated denitrification rate was on average five times higher than the ammonia volatilization rate, and about three times higher than the permanent burial of sedimentary nitrogen. Hence, denitrification was the most important process for the permanent removal of N. The model can be used to simulate possible measures to reduce the N load and, after some modification and recalibration, it can be applied at other mine sites affected by N-rich effluents. In addition, it was investigated which nutrient that limits bioproduction in the two aquatic systems. Total nitrogen (TN), total phosphorus (TP) and N:P ratios in water, sediment and macrophytes were used to examine (1) spatial variations within the systems, (2) differences between the systems and (3) seasonal variations. The TN content from the discharge point at the Kiruna site was on average about seven times higher than at the Boliden discharge point, while the TP content was 10 times lower than in the discharge point at the Boliden site. Depending on the ammonium concentration in the effluent at the Boliden site, N:P-ratios of the water column shifted from being >22, indicating P-deficiency, to between 9-22, indicating a transition from N to P deficiency (co-limitation). However, water column N:P ratios at the Kiruna site always indicated P deficiency. On the other hand, the N:P ratios of macrophytes revealed that both sites may vary from N to P limitation. These differences are important to consider when establishing a monitoring programme for assessing the environmental influence of nutrient rich mine effluents. Such a programme should include the major N and P species of the water as well as samples of phytoplankton, sediment and macrophytes.

  • 287.
    Chlot, Sara
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Widerlund, Anders
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    The fate of nitrogen in a lake occupied by Phragmites australis: a stable isotope tracer study2013In: Vol. 56, no 2-3, p. 139-141Article in journal (Refereed)
  • 288.
    Chlot, Sara
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Widerlund, Anders
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Using DGT to estimate soluble reactive phosphorus in a stream receiving nutrient rich mine water2013Conference paper (Refereed)
  • 289.
    Chlot, Sara
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Widerlund, Anders
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Husson, Eva
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Öhlander, Björn
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Ecke, Frauke
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Effects on nutrient regime in two recipients of nitrogen-rich mine effluents in northern Sweden2013In: Applied Geochemistry, ISSN 0883-2927, E-ISSN 1872-9134, Vol. 31, p. 12-24Article in journal (Refereed)
    Abstract [en]

    The question of the limiting nutrient(s) for production of phytoplankton and macrophytes was explored in two contrasting freshwater systems receiving N- and P-rich mine effluents from the Boliden and Kiruna mine sites, northern Sweden. For both sites, total N (TN), total P (TP) and TN:TP mass ratios in water, sediment and macrophytes were used to examine (1) spatial variations within the systems, (2) differences between the systems and (3) seasonal variations. The TN concentration from the discharge point at the Kiruna site was about seven times higher than at the Boliden discharge point, while the TP concentration was 10 times lower than in the discharge point at the Boliden site. The majority of the studied lakes showed elevated biomass of phytoplankton, with maximum values found in Lake Bruträsket (Boliden). Mining activities have affected the nutrient regime of the two recipients by contributing to elevated TN and TP concentrations and TN:TP mass ratios as well as elevated production of phytoplankton and macrophytes compared to the reference sites. Depending on the NH4 concentration in the effluent at the Boliden site, water column TN:TP mass ratios shifted from being >22, indicating P-deficiency, to between 9 and 22, indicating a transition from N- to P-deficiency (co-limitation). However, water column TN:TP mass ratios at the Kiruna site always indicated P-deficiency, while TN:TP mass ratios of macrophytes indicate that both sites may vary from N- to P-limitation. The study suggests that for the design of efficient monitoring programmes and remediation measures, it is important to consider the major N and P species in water, phytoplankton, sediment and macrophytes.

  • 290.
    Chlot, Sara
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Widerlund, Anders
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Siergieiev, Dmytro
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Ecke, Frauke
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Husson, Eva
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Öhlander, Björn
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Modelling nitrogen transformations in waters receiving mine effluents2011In: Science of the Total Environment, ISSN 0048-9697, E-ISSN 1879-1026, Vol. 409, no 21, p. 4585-4595Article in journal (Refereed)
    Abstract [en]

    This paper presents a biogeochemical model developed for a clarification pond receiving ammonium nitrogen rich discharge water from the Boliden concentration plant located in northern Sweden. Present knowledge about nitrogen (N) transformations in lakes is compiled in a dynamic model that calculates concentrations of the six N species (state variables) ammonium-N (Nam), nitrate-N (Nox), dissolved organic N in water (Norg), N in phytoplankton (Npp), in macrophytes (Nmp) and in sediment (Nsed). It also simulates the rate of 16 N transformation processes occurring in the water column and sediment as well as water–sediment and water–atmosphere interactions. The model was programmed in the software Powersim using 2008 data, whilst validation was performed using data from 2006 to 2007. The sensitivity analysis showed that the state variables are most sensitive to changes in the coefficients related to the temperature dependence of the transformation processes. A six-year simulation of Nam showed stable behaviour over time. The calibrated model rendered coefficients of determination (R2) of 0.93, 0.79 and 0.86 for Nam, Nox and Norg, respectively. Performance measures quantitatively expressing the deviation between modelled and measured data resulted in values close to zero, indicating a stable model structure. The simulated denitrification rate was on average five times higher than the ammonia volatilisation rate and about three times higher than the permanent burial of Nsed and, hence, the most important process for the permanent removal of N. The model can be used to simulate possible measures to reduce the nitrogen load and, after some modification and recalibration, it can be applied at other mine sites affected by N rich effluents.

  • 291.
    Chlot, Sara
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Widerlund, Anders
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Öhlander, Björn
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Carbon and nitrogen concentrations and isotopic composition in sediments of lakes receiving nitrogen rich mine effluents2011Conference paper (Refereed)
  • 292.
    Chlot, Sara
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Widerlund, Anders
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Öhlander, Björn
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Interaction between nitrogen and phosphorus cycles in mining-affected aquatic systems-experiences from field and laboratory measurements2013In: Environmental science and pollution research international, ISSN 0944-1344, E-ISSN 1614-7499, Vol. 20, no 8, p. 5722-5736Article in journal (Refereed)
    Abstract [en]

    The main objectives of this study were to (a) study the interaction between N and P cycles in mining-affected aquatic systems and (b) to quantify release rates of sedimentary soluble reactive phosphorus (SRP) that may be related to this interaction. Sediment cores and water from Lake Bruträsket (Boliden, northern Sweden) were collected and a time series of water sampling and flow measurements was conducted in the Brubäcken stream connected to the lake. Factors affecting SRP release were studied in a sediment incubation experiment and water column experiments. Field and laboratory measurements indicated that pH and dissolved oxygen are two important factors for SRP release. At the end of the low-oxygen incubation, an SRP concentration of 56 μg L-1 resulted in a sedimentary flux of 1.1 mg SRP m-2 day-1. This is ∼10 times higher than the flux of 0.12 mg SRP m-2 day-1 obtained from depth integration of vertical SRP profiles measured in the lake, and ∼100 times higher than the external flux of 0.014 mg SRP m-2 d-1 into the lake (based on catchment area). Field measurements indicated that oxidation of organic matter and mining-related chemicals (ammonium and thiosulphates) may result in increased internal SRP flux from the sediment. Increased P loading in the lake as a result of low-oxygen conditions could change water column total nitrogen/total phosphorus ratios from 27 to 17, consequently changing the lake from being P-limited to be co-limited by N and P. The obtained findings point to possible interaction between the cycles of nitrogen (oxygen consumption) and P (flux from sediment) that may be important for nutrient regulation in mine water recipients.

  • 293. Chlot, Sara
    et al.
    Widerlund, Anders
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Öhlander, Björn
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Nitrogen uptake and cycling in Phragmites australis in a lake-receiving nutrient-rich mine water: a 15 N tracer study2015In: Environmental Earth Sciences, ISSN 1866-6280, E-ISSN 1866-6299, Vol. 74, no 7, p. 6027-6038Article in journal (Refereed)
    Abstract [en]

    Uptake and cycling of nitrogen (N) in the littoral zone of a lake-receiving nutrient-rich mine water located in Boliden, northern Sweden, was investigated. Stable isotope tracer solutions of 15N as NH4 + (NAM mesocosm) or NO3 − (NOX mesocosm) were added to mesocosms enclosing plants of common reed (Phragmites australis). The 15N abundance in various plant parts was measured at pre-defined time intervals over an experimental period of 22 days. During the course of the experiment, plant parts from the NAM mesocosms were significantly more enriched in 15N than plant parts from the NOX mesocosms. On day 13, Δδ15N values of the fine roots from the NAM mesocosms had reached +8220 ‰, while the maximum Δδ15N value in NOX roots was considerably lower at +4430 ‰. Using 15N values in macrophyte tissues present at the end of the experiment enabled calculations of uptake rates and % of tracer N recovered in the plant (%tracerNrecov). Maximum tracer uptake rates were higher for the NAM mesocosms (1.4 µg g−1 min−1 or 48 mg N m−2 d−1) compared to the NOX mesocosms (0.23 µg g−1 min−1 or 8.5 mg N m−2 d−1). Calculations of %tracerNrecov indicated that 1–8 and 25–44 % of added N was assimilated by plants in the NOX and NAM mesocosms, respectively. Hence, P. australis was more effective in assimilating NH4 +, and a larger portion of the tracer N accumulated in the roots compared to the other plant parts. Consequently, macrophyte N removal is most effective for cold-climate aquatic systems receiving mine water dominated by NH4 +. For permanent removal of N, the whole plant (including the roots) should be harvested.

  • 294.
    Chlot, Sara
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Widerlund, Anders
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Öhlander, Björn
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Studying nitrogen cycling and uptake by macrophytes using 15N tracer techniques2011Conference paper (Refereed)
  • 295.
    Claesson, Lars-Åke
    Luleå tekniska universitet.
    The geochemistry and palaeotectonic setting of lower proterozoic metavolcanic rocks and related intrusives in the Skellefte massive sulphide ore district, northern Sweden1994Licentiate thesis, comprehensive summary (Other academic)
  • 296.
    Clayton, R.E
    et al.
    Research School of Earth Sciences, UCL-Birkbeck, Gower St., London.
    Hudson-Edwards, K.A.
    Research School of Earth Sciences, UCL-Birkbeck, Gower St., London.
    Malinovskiy, Dmitry
    Andersson, P.
    Laboratory for Isotope Geology. Swedish Museum of Natural History, Stockholm.
    Fe isotope fractionation during the precipitation of ferrihydrite and transformation of ferrihydrite to goethite2005In: Mineralogical magazine, ISSN 0026-461X, E-ISSN 1471-8022, Vol. 69, no 5, p. 667-676Article in journal (Refereed)
    Abstract [en]

    Ferrihydrite and goethite are amongst the most important substrates for the sorption of contaminants in soil and other environmental media. Isotopic studies of the transition elements, particularly those that exhibit more than one oxidation state and show pH- and/or redox-sensitive behaviour at low temperatures, have been shown to be potentially useful present-day and past proxies for redox (or palaeoredox) conditions. We have made preliminary investigations of Fe isotope fractionation that take place during the formation of FeIII (oxy)hydroxides (FeIIIox) from an aqueous FeIII(NO3)3 solution (FeIIIaq) under laboratory conditions. We have attempted to keep the chemical system simple by excluding 'vital effects' and major changes in redox through the maintenance of abiotic conditions and use of FeIIIaq. Isotopic measurements (56Fe/54Fe, 57Fe/54Fe) of the FeIII(NO3)3 stock solution, the original ferrihydrite and the mixed ferrihydrite/goethite-supernatant FeIIIaq 'pairs' were carried out using a double focusing multicollector inductively coupled plasma mass spectrometer. The results reveal an apparent systematic variation indicating larger ΔFeIIIaq-FeIIIox with decrease in the ferrihydrite:goethite ratio, which reflects the time allowed for isotopic exchange. These values range from virtually zero (0.03‰) after 24 h to 0.30‰ after 70 h. In each FeIIIox-FeIIIaq 'pair' the lighter Fe isotope is partitioned into the FeIIIox, leaving the FeIIIaq isotopically heavier. The observed fractionation reflects isotopic exchange of Fe between the FeIIIox and FeIIIaq upon at least a two step transition of ferrihydrite to goethite.

  • 297.
    Clayton, Robon E.
    et al.
    Department of Earth Sciences, University College London.
    Nederbragt, Alexandra J.
    Department of Earth Sciences, University College London.
    Malinovskiy, Dmitry
    Andersson, Per
    Laboratory for Isotope Geology. Swedish Museum of Natural History, Stockholm.
    Thurow, Jürgen
    Department of Earth Sciences, University College London.
    Data report: Iron isotope geochemistry of mid-Cretaceous organic-rich sediments at Demerara Rise (odp leg 207)2005In: Ocean Drilling Program. Scientific Results. Proceedings. Scientific Results, ISSN 0884-5891, Vol. 207Article in journal (Refereed)
  • 298.
    Cockell, Charles S.
    et al.
    UK Centre for Astrobiology, SUPA, School of Physics and Astronomy, University of Edinburgh, Edinburgh, Midlothian, UK.
    Martin-Torres, Javier
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology. UK Centre for Astrobiology, SUPA, School of Physics and Astronomy, University of Edinburgh, Edinburgh, Midlothian, UK; Instituto Andaluz de Ciencias de la Tierra (UGR-CSIC), Granada, Spain .
    Zorzano, Maria-Paz
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology. Centro de Astrobiología (CSIC-INTA), Torrejon de Ardoz, 28850 Madrid, Spain.
    Bhardwaj, Anshuman
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Soria-Salinas, Álvaro
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Mathanla, Thasshwin
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Israel Nazarious, Miracle
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Vakkada Ramachandran, Abhilash
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Suckling, Barbara
    Boulby Underground Laboratory, Boulby, UK.
    Subsurface scientific exploration of extraterrestrial environments (MINAR 5): analogue science, technology and education in the Boulby Mine, UK2019In: International Journal of Astrobiology, ISSN 1473-5504, E-ISSN 1475-3006, Vol. 18, no 2, p. 157-182Article in journal (Refereed)
    Abstract [en]

    The deep subsurface of other planetary bodies is of special interest for robotic and human exploration. The subsurface provides access to planetary interior processes, thus yielding insights into planetary formation and evolution. On Mars, the subsurface might harbour the most habitable conditions. In the context of human exploration, the subsurface can provide refugia for habitation from extreme surface conditions. We describe the fifth Mine Analogue Research (MINAR 5) programme at 1 km depth in the Boulby Mine, UK in collaboration with Spaceward Bound NASA and the Kalam Centre, India, to test instruments and methods for the robotic and human exploration of deep environments on the Moon and Mars. The geological context in Permian evaporites provides an analogue to evaporitic materials on other planetary bodies such as Mars. A wide range of sample acquisition instruments (NASA drills, Small Planetary Impulse Tool (SPLIT) robotic hammer, universal sampling bags), analytical instruments (Raman spectroscopy, Close-Up Imager, Minion DNA sequencing technology, methane stable isotope analysis, biomolecule and metabolic life detection instruments) and environmental monitoring equipment (passive air particle sampler, particle detectors and environmental monitoring equipment) was deployed in an integrated campaign. Investigations included studying the geochemical signatures of chloride and sulphate evaporitic minerals, testing methods for life detection and planetary protection around human-tended operations, and investigations on the radiation environment of the deep subsurface. The MINAR analogue activity occurs in an active mine, showing how the development of space exploration technology can be used to contribute to addressing immediate Earth-based challenges. During the campaign, in collaboration with European Space Agency (ESA), MINAR was used for astronaut familiarization with future exploration tools and techniques. The campaign was used to develop primary and secondary school and primary to secondary transition curriculum materials on-site during the campaign which was focused on a classroom extra vehicular activity simulation.

  • 299. Colla, Christopher A.
    et al.
    Casey, William H.
    Ohlin, C. André
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Computational prediction of Mg-isotope fractionation between aqueous [Mg(OH2)6]2+ and brucite2018In: Geochimica et Cosmochimica Acta, ISSN 0016-7037, E-ISSN 1872-9533, Vol. 227, p. 64-74Article in journal (Refereed)
    Abstract [en]

    The fractionation factor in the magnesium-isotope fractionation between aqueous solutions of magnesium and brucite changes sign with increasing temperature, as uncovered by recent experiments. To understand this behavior, the Reduced Partition Function Ratios and isotopic fractionation factors (Δ26/24Mgbrucite-Mg(aq)) are calculated using molecular models of aqueous [Mg(OH2)6]2+ and the mineral brucite at increasing levels of density functional theory. The calculations were carried out on the [Mg(OH2)6]2+·12H2O cluster, along with different Pauling-bond-strength-conserving models of the mineral lattice of brucite. Three conclusions were reached: (i) all levels of theory overestimate 〈Mg‒O〉 bond distances in the aqua ion complex relative to Tutton’s salts; (ii) the calculations predict that brucite at 298.15 K is always enriched in the heavy isotope, in contrast with experimental observations; (iii) the temperature dependencies of Wimpenny et al. (2014) and Li et al. (2014) could only be achieved by fixing the 〈Mg‒O〉 bond distances in the [Mg(OH2)6]2+·12H2O cluster to values close to those observed in crystals that trap the hydrated ion.

  • 300.
    Collomp, Magali
    Luleå tekniska universitet.
    Comparison of the geochemistry of the regulated Lule River and the unregulated Kalix River, Northern Sweden2001Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Hydropower production in Sweden represents nearly 50% of the total electricity production in Sweden. The aim of this study is to evaluate the impact of stream regulation on the geochemistry of the Lule River, northern Sweden, which is the largest and the most important river for waterpower production in Sweden. Impacts of river regulation were evaluated by comparison with the natural geochemical seasonal variations in the pristine Kalix River, which is very close geographically and has comparable watershed with similar bedrock, soil type, climate and vegetation. Seasonal variations of the geochemical constituents in the regulated Lule River have been studied during a whole year cycle (May 2000 to June 2001) at the Boden powerstation near the mouth of the river. Data from the Kalix River were obtained from a previous study realised from 1990 to 1992. Additional data about transport in the Kalix River were achieved from the study of the impact on the Kalix River system of the tailings dam failure at the Aitik copper mine that occurred in September 2000. These results were used to calibrate the parameters of a model that will be developed for geochemical transports in the regulated Lule River.

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