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  • 1. Adamczyk, A.
    et al.
    Malinowski, M.
    Malehmir, Alireza
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Geophysics.
    High-resolution near-surface velocity model building using full-waveform inversion-a case study from southwest Sweden2014In: Geophysical Journal International, ISSN 0956-540X, E-ISSN 1365-246X, Vol. 197, no 3, p. 1693-1704Article in journal (Refereed)
    Abstract [en]

    Full-waveform inversion (FWI) is an iterative optimization technique that provides high-resolution models of subsurface properties. Frequency-domain, acoustic FWI was applied to seismic data acquired over a known quick-clay landslide scar in southwest Sweden. We inverted data from three 2-D seismic profiles, 261-572 m long, two of them shot with small charges of dynamite and one with a sledgehammer. To our best knowledge this is the first published application of FWI to sledgehammer data. Both sources provided data suitable for waveform inversion, the sledgehammer data containing even wider frequency spectrum. Inversion was performed for frequency groups between 27.5 and 43.1 Hz for the explosive data and 27.5-51.0 Hz for the sledgehammer. The lowest inverted frequency was limited by the resonance frequency of the standard 28-Hz geophones used in the survey. High-velocity granitic bedrock in the area is undulated and very shallow (15-100 m below the surface), and exhibits a large P-wave velocity contrast to the overlying normally consolidated sediments. In order to mitigate the non-linearity of the inverse problem we designed a multiscale layer-stripping inversion strategy. Obtained P-wave velocity models allowed to delineate the top of the bedrock and revealed distinct layers within the overlying sediments of clays and coarse-grained materials. Models were verified in an extensive set of validating procedures and used for pre-stack depth migration, which confirmed their robustness.

  • 2.
    Alakangas, Lena
    et al.
    Luleå tekniska universitet, Geovetenskap och miljöteknik.
    Bark, Glenn
    Luleå tekniska universitet, Geovetenskap och miljöteknik.
    Ericsson, Magnus
    Luleå tekniska universitet, Samhällsvetenskap.
    Martinsson, Olof
    Luleå tekniska universitet, Geovetenskap och miljöteknik.
    Söderholm, Patrik
    Luleå tekniska universitet, Samhällsvetenskap.
    Wanhainen, Christina
    Luleå tekniska universitet, Geovetenskap och miljöteknik.
    Weihed, Pär
    Luleå tekniska universitet, Geovetenskap och miljöteknik.
    Widerlund, Anders
    Luleå tekniska universitet, Geovetenskap och miljöteknik.
    Öhlander, Björn
    Luleå tekniska universitet, Geovetenskap och miljöteknik.
    Norrbottens malm- och mineralresurs och dess potentiella betydelse för innovation, samhälle och miljö2014Report (Other academic)
    Abstract [sv]

    Gruvindustrins betydelse för samhällsutveckling och infrastruktur i Sverige och inte minst i Norrbottens län är mycket stor. De geologiska förutsättningarna att hitta nya brytvärda förekomster i Norrbotten är goda. Länet är tillsammans med Västerbotten en av Europas viktigaste regioner för utvinning av metaller. Det syns också i den nyligen framtagna regionala mineralstrategin för Norrbotten och Västerbotten. Visionen för den regionala mineralstrategin: ”Genom långsiktigt hållbart nyttjande av Norrbottens och Västerbottens läns mineralresurser har ytterligare tillväxt skapats i regionen och hela Sverige. Vi har utvecklat och stärkt vår ställning som ledande gruv- och mineralnation.”Eftersom framtidspotentialen för gruvnäringen är mycket god men okunnigheten hos både allmänhet och beslutsfattare om näringens betydelse för innovation och samhällsutveckling är stor, kopplat med en utbredd oro för miljöpåverkan, måste dessa viktiga framtidsfrågor belysas. Med finansiering från Länsstyrelsen i Norrbotten bedrevs därför under första hälften av 2014 en förstudie som syftade till att sammanfatta kunskapsläget om framtidens gruvindustri i Norrbotten. Resultaten av förstudien redovisas i den här rapporten. En viktig slutsats är att det under nästa strukturfondsperiod (med start 2015) behövs ett framtidsinriktat forskningsprogram för att belysa de möjligheter som finns. Denna förstudie utgör grund för en kommande ansökan till strukturfonderna. Kompetensen som finns vid Luleå tekniska universitet, Sveriges centrum för gruvrelaterad forskning och utbildning, bör användas för att studera troliga framtidsmöjligheter och hur de ska kunna användas för att få en så positiv utveckling som möjligt för länet. Projektet bör innehålla följande tre huvudinriktningar, som naturligtvis hör ihop:Vilka malm- och mineralresurser finns det potential för i Norrbotten, och vilka kommer sannolikt att exploateras i framtiden?Vad kommer den exploateringen att ha för betydelse för innovation och samhällsutveckling?Vad kommer den exploateringen att få för miljöeffekter och hur ska man göra för att minska miljöbelastningen?En annan slutsats är att nedlagda gruvområden inte måste ses som förstörd natur. Betydande mervärden som gruvturism skulle kunna skapas om vilja, kreativitet och beslutsamhet finns. Detta är ett givet utvecklingsområde där småföretag och entreprenörer kan göra stor insats om de politiska och myndighetsmässiga förutsättningarna finns. Dessa aspekter skulle också kunna belysas i det föreslagna forskningsprogrammet eller i ett eget projekt.

  • 3.
    Aldahan, Ala
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    Scherer, Reed
    Sjunneskog, C
    Possnert, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, För teknisk-naturvetenskapliga fakulteten gemensamma enheter, Tandem Laboratory. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Ion Physics.
    Berggren, A-M
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    Cosmogenic 10Be as an environmental tracer in subglacial Antarctic Lake2006In: SALE advanced Science and Technology Workshop, 24-26 April, Grenoble, France,, 2006, p. 2-3Conference paper (Refereed)
  • 4.
    Alsadi, Aram
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL. Sektionen för geokemi och hydrologi, Sveriges lantbruksuniversitet..
    Dynamiken hos organiskt kol i Mälarens avrinningsområde: flöden, drivande faktorer och modellering2015Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In this report, it has been investigated how the amount of organic carbon, TOC, varies in time and space in the basin of Mälaren, and what controls the TOC content in the lake. It is important to understand the dynamics of the TOC in the lake and its catchment because increased TOC in the water affects water quality and causes problems in the preparation of drinking water. Particularly, it can react with chlorine / UV- light and form carcinogenic substances. It can also increase the number of microbes in water distribution systems.

    In addition the work includes analysis of the relation between water chemistry variables, annual fluxes calculations (g/m2/year) of element flows to the lake and a modeling approach to a watershed.

    Annual fluxes calculations (g/m2/year) indicate that the largest supply of TOC to the lake comes from the northeast of the lake. Fyrisån accounts for the largest input of TOC to the lake. The high TOC-flux is due to a small proportion of open water in the catchment.

    Hydrological, chemical and meteorological data have been included in models to estimate the TOC content in the Mälaren. Input data processing, especially precipitation data, has been an important part of the work as it affects the whole model. Temperature, evapotranspiration and precipitation data were used in a hydrological model, HBV model, to simulate the flow from the catchment area. Then a process-based model, INCA-C, operated by the hydrological data and soil moisture, has been used to simulate the temporal patterns in TOC. The input variables to INCA-C- model, soil moisture and HER (Hydrological effective rainfall), have been simulated using the HBV- model.

    Those models were applied in Kolbäcksån, one of the lake's largest catchments. The modeling of Kolbäcksån resulted in a model that captured the dynamics of a few periods of the whole time series. The modeling of Kolbäcksån TOC-concentration resulted in a model that captured the dynamics between 1996 and 2009, but misses it between 2009 and June 2010. R2 and NS values obtained for the model were 0.086 and -0.059, respectively.

  • 5.
    Andrén, Jonathan
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Potentiellt hög urlakning av arsenik till grundvattnet från rödfyrshög i Kinne-Kleva2016Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    For Sweden to achieve the environmental goal of a nontoxic environment, knowledge is required about harmful elements’ movement and mobility in nature. One of those elements is arsenic that for a long time has been known to cause health ailments. The most common and dangerous path into the human body is through drinking water. It is therefore of great importance to study sources that can impact and contribute to elevated concentrations of arsenic in the groundwater. One such path is the anthropogenic soil called rödfyr, which is what is left after the burning of black shale. This activity was common in areas rich in limestone, which after being heated can be used as cement in concrete. Heaps of rödfyr of varying sizes have been found at a number of localities in the area around Kinnekulle in Västergötland. Earlier studies of leach water indicate arsenic content high enough to be considered hazardous to health. At Kinne-Kleva south of Kinnekulle there is an unusually large heap of rödfyr, situated around land used for agricultural purposes as well as some houses. To have a good understanding about how rödfyr impacts the environment is key to predict and negate negative environmental consequences. The aim of this independent project is with fieldwork and leach tests study in which concentrations arsenic can be found in rödfyr at the Kinne-Kleva heap. Results show that high concentrations of arsenic exists, up to 137 mg/kg rödfyr. They also indicate that arsenic leakage occurs to a large extent, both in high and low pH environment. The amount of arsenic is however expected to be drastically reduced due to dilution, which increases with distance. Exposure is therefore confined to the close vicinity of the pile.

  • 6.
    Andrén, Margareta
    et al.
    Stockholm Univ, Dept Geol Sci, Stockholm, Sweden.
    Stockmann, Gabrielle
    Stockholm Univ, Dept Geol Sci, Stockholm, Sweden.
    Skelton, Alasdair
    Stockholm Univ, Dept Geol Sci, Stockholm, Sweden.
    Sturkell, Erik
    Univ Gothenburg, Dept Earth Sci, Gothenburg, Sweden.
    Mörth, Carl-Magnus
    Stockholm Univ, Dept Geol Sci, Stockholm, Sweden.
    Guðrúnardóttir, Helga Rakel
    Stockholm Univ, Dept Geol Sci, Stockholm, Sweden.
    Keller, Nicole Simone
    Univ Iceland, Inst Earth Sci, Reykjavik, Iceland.
    Odling, Nic
    Univ Edinburgh, Sch Geosci, Edinburgh, Midlothian, Scotland.
    Dahrén, Börje
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Mineralogy Petrology and Tectonics.
    Broman, Curt
    Stockholm Univ, Dept Geol Sci, Stockholm, Sweden.
    Balic-Zunic, Tonci
    Univ Copenhagen, Nat Hist Museum, Copenhagen, Denmark.
    Hjartarsson, Hreinn
    Landsvirkjun, Reykjavik, Iceland.
    Siegmund, Heike
    Stockholm Univ, Dept Geol Sci, Stockholm, Sweden.
    Freund, Friedemann
    NASA, Ames Res Ctr, Div Earth Sci, Moffett Field, CA 94035 USA.
    Kockum, Ingrid
    NASA, Ames Res Ctr, Div Earth Sci, Moffett Field, CA 94035 USA.
    Coupling between mineral reactions, chemical changes in groundwater, and earthquakes in Iceland2016In: Journal of Geophysical Research - Solid Earth, ISSN 2169-9313, E-ISSN 2169-9356, Vol. 121, no 4, p. 2315-2337Article in journal (Refereed)
    Abstract [en]

    Chemical analysis of groundwater samples collected from a borehole at Hafralækur, northernIceland, from October 2008 to June 2015 revealed (1) a long-term decrease in concentration of Si and Naand (2) an abrupt increase in concentration of Na before each of two consecutive M > 5 earthquakes whichoccurred in 2012 and 2013, both 76 km from Hafralækur. Based on a geochemical (major elements and stableisotopes), petrological, and mineralogical study of drill cuttings taken from an adjacent borehole, we areable to show that (1) the long-term decrease in concentration of Si and Na was caused by constant volumereplacement of labradorite by analcime coupled with precipitation of zeolites in vesicles and along fracturesand (2) the abrupt increase of Na concentration before the first earthquake records a switchover tononstoichiometric dissolution of analcime with preferential release of Na into groundwater. We attributedecay of the Na peaks, which followed and coincided with each earthquake to uptake of Na along fracturedor porous boundaries between labradorite and analcime crystals. Possible causes of these Na peaks are anincrease of reactive surface area caused by fracturing or a shift from chemical equilibrium caused by mixingbetween groundwater components. Both could have been triggered by preseismic dilation, which was alsoinferred in a previous study by Skelton et al. (2014). The mechanism behind preseismic dilation so far from thefocus of an earthquake remains unknown.

  • 7.
    Barker, Abigail
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Solid Earth Geology.
    Holm, Paul Martin
    Unniversity of Copenhagen.
    Troll, Valentin
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Solid Earth Geology.
    The role of eclogite in the mantle heterogeneity at Cape Verde2014In: Contributions to Mineralogy and Petrology, ISSN 0010-7999, E-ISSN 1432-0967, Vol. 168, no 3, p. 1052-Article in journal (Refereed)
    Abstract [en]

    The Cape Verde hotspot, like many other Ocean Island Basalt provinces, demonstrates isotopic heterogeneity on a 100–200 km scale. The heterogeneity is represented by the appearance of an EM1-like component at several of the southern islands and with a HIMU-like component present throughout the archipelago. Where the EM1-like component is absent, a local DMM-like component replaces the EM1-like component. Various source lithologies, including peridotite, pyroxenite and eclogite have been suggested to contribute to generation of these heterogeneities; however, attempts to quantify such contributions have been limited. We apply the minor elements in olivine approach (Sobolev et al. in Nature 434:590–597, 2005; Science, doi:10.1126/science.1138113,2007), to determine and quantify the contributions of peridotite, pyroxenite and eclogite melts to the mantle heterogeneity observed at Cape Verde. Cores of olivine phenocrysts of the Cape Verde volcanics have low Mn/FeO and low Ni*FeO/MgO that deviate from the negative trend of the global array. The global array is defined by mixing between peridotite and pyroxenite, whereas the Cape Verde volcanics indicate contribution of an additional eclogite source. Eclogite melts escape reaction with peridotite either by efficient extraction in an area of poor mantle flow or by reaction of eclogite melts with peridotite, whereby an abundance of eclogite can seal off the melt from further reaction. Temporal trends of decreasing Mn/FeO indicate that the supply of eclogite melts is increasing. Modelling suggests the local DMM-like end-member is formed from a relatively peridotite-rich melt, while the EM1-like end-member has a closer affinity to a mixed peridotite–pyroxenite–eclogite melt. Notably the HIMU-like component ranges from pyroxenite–peridotite-rich melt to one with up to 77 % eclogite melt as a function of time, implying that sealing of melt pathways is becoming more effective.

  • 8.
    Barker, Abigail
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Mineralogy Petrology and Tectonics.
    Troll, Valentin
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Mineralogy Petrology and Tectonics. Univ Las Palmas, GEOVOL, La Palmas Gran Canaria 35017, Spain.
    Carracedo, Juan Carlos
    Univ Las Palmas, GEOVOL, La Palmas Gran Canaria 35017, Spain.
    Nicholls, Peter A.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Mineralogy Petrology and Tectonics.
    The magma plumbing system for the 1971 Teneguía eruption on La Palma, Canary Islands2015In: Contributions to Mineralogy and Petrology, ISSN 0010-7999, E-ISSN 1432-0967, Vol. 170, no 5-6, article id 54Article in journal (Refereed)
    Abstract [en]

    The 1971 Teneguía eruption is the most recent volcanic event of the Cumbre Vieja rift zone on La Palma. The eruption produced basanite lavas that host xenoliths, which we investigate to provide insight into the processes of differentiation, assimilation and magma storage beneath La Palma. We compare our results to the older volcanomagmatic systems of the island with the aim to reconstruct the temporal development of the magma plumbing system beneath La Palma.

    The 1971 lavas are clinopyroxene-olivine-phyric basanites that contain augite, sodic-augite and Aluminium augite. Kaersutite cumulate xenoliths host olivine, clinopyroxene including sodic-diopside, and calcic-amphibole, whereas an analysed leucogabbro xenolith hosts plagioclase, sodic-augite-diopside, calcic-amphibole and hauyne. Mineral and mineral-melt thermobarometry indicate that clinopyroxene and plagioclase in the 1971 Teneguía lavas crystallised at 20 to 45 km depth, coinciding with clinopyroxene and calcic-amphibole crystallisation in the kaersutite cumulate xenoliths at 25 to 45 km and clinopyroxene, calcic-amphibole and plagioclase crystallisation in the leucogabbro xenolith at 30 to 50 km.

    Combined mineral chemistry and thermobarometry suggest that the magmas had already crystallised, differentiated and formed multiple crystal populations in the oceanic lithospheric mantle. Notably, the magmas that supplied the 1949 and 1971 events appear to have crystallised deeper than the earlier Cumbre Vieja magmas, which suggests progressive underplating beneath the Cumbre Vieja rift zone. In addition, the lavas and xenoliths of the 1971 event crystallised at a common depth, indicating a reused plumbing system and progressive recycling of Ocean Island plutonic complexes during subsequent magmatic activity. 

  • 9.
    Berg, Sylvia E.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences. Nordic Volcanological Center, Institute of Earth Sciences, University of Iceland.
    Silicic Magma Genesis in Basalt-dominated Oceanic Settings: Examples from Iceland and the Canary Islands2016Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The origin of silicic magma in basalt-dominated oceanic settings is fundamental to our understanding of magmatic processes and formation of the earliest continental crust. Particularly significant is magma-crust interaction that can modify the composition of magma and the dynamics of volcanism. This thesis investigates silicic magma genesis on different scales in two ocean island settings. First, volcanic products from a series of voluminous Neogene silicic centres in northeast Iceland are investigated using rock and mineral geochemistry, U-Pb geochronology, and oxygen isotope analysis. Second, interfacial processes of magma-crust interaction are investigated using geochemistry and 3D X-ray computed microtomography on crustal xenoliths from the 2011-12 El Hierro eruption, Canary Islands.

    The results from northeast Iceland constrain a rapid outburst of silicic magmatism driven by a flare of the Iceland plume and/or by formation of a new rift zone, causing large volume injection of basaltic magma into hydrated basaltic crust. This promoted crustal recycling by partial melting of the hydrothermally altered Icelandic crust, thereby producing mixed-origin silicic melt pockets that reflect the heterogeneous nature of the crustal protolith with respect to oxygen isotopes. In particular, a previously unrecognised high-δ18O end-member on Iceland was documented, which implies potentially complex multi-component assimilation histories for magmas ascending through the Icelandic crust. Common geochemical traits between Icelandic and Hadean zircon populations strengthen the concept of Iceland as an analogue for early Earth, implying that crustal recycling in emergent rifts was pivotal in generating Earth’s earliest continental silicic crust.

    Crustal xenoliths from the El Hierro 2011-2012 eruption underline the role of partial melting and assimilation of pre-island sedimentary layers in the early shield-building phase of ocean islands. This phenomenon may contribute to the formation of evolved magmas, and importantly, the release of volatiles from the xenoliths may be sufficient to increase the volatile load of the magma and temporarily alter the character and intensity of an eruption.

    This thesis sheds new light on the generation of silicic magma in basalt-dominated oceanic settings and emphasises the relevance of magma-crust interaction for magma evolution, silicic crust formation, and eruption style from early Earth to present.

    List of papers
    1. Iceland's best kept secret
    Open this publication in new window or tab >>Iceland's best kept secret
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    2014 (English)In: Geology Today, ISSN 0266-6979, E-ISSN 1365-2451, Vol. 30, no 2, p. 54-60Article in journal (Refereed) Published
    Abstract [en]

    The ‘forgotten fjords’ and ‘deserted inlets’ of NE-Iceland, in the region between Borgarfjörður Eystri and Loðmundarfjörður, are not only prominent because of their pristine landscape, their alleged elfin settlements, and the puffins that breed in the harbour, but also for their magnificent geology. From a geological point of view, the area may hold Iceland's best kept geological secret. The greater Borgarfjörður Eystri area hosts mountain chains that consist of voluminous and colourful silicic rocks that are concentrated within a surprisingly small area (Fig. 1), and that represent the second-most voluminous occurrence of silicic rocks in the whole of Iceland. In particular, the presence of unusually large volumes of ignimbrite sheets documents extremely violent eruptions during the Neogene, which is atypical for this geotectonic setting. As a group of geoscientists from Uppsala University (Sweden) and the Nordic Volcanological Center (NordVulk, Iceland) we set out to explore this remote place, with the aim of collecting material that may allow us to unravel the petrogenesis of these large volumes of silicic rocks. This effort could provide an answer to a long-standing petrological dilemma; the question of how silicic continental crust is initially created. Here we document on our geological journey, our field strategy, and describe our field work in the remote valleys of NE-Iceland.

    National Category
    Geosciences, Multidisciplinary
    Research subject
    Earth Science with specialization in Mineral Chemistry, Petrology and Tectonics
    Identifiers
    urn:nbn:se:uu:diva-213020 (URN)DOI: 10.1111/gto.12042 (DOI)
    Available from: 2013-12-17 Created: 2013-12-17 Last updated: 2017-12-06
    2. Rapid generation of high-silica magmas in basalt-dominated rift settings
    Open this publication in new window or tab >>Rapid generation of high-silica magmas in basalt-dominated rift settings
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    (English)Manuscript (preprint) (Other academic)
    National Category
    Geology Geochemistry
    Research subject
    Mineral Chemistry, Petrology and Tectonics
    Identifiers
    urn:nbn:se:uu:diva-272262 (URN)
    Available from: 2016-01-13 Created: 2016-01-13 Last updated: 2016-02-19
    3. Zircons from northeast Iceland analogous to those from early Earth
    Open this publication in new window or tab >>Zircons from northeast Iceland analogous to those from early Earth
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    (English)Manuscript (preprint) (Other academic)
    National Category
    Geochemistry
    Identifiers
    urn:nbn:se:uu:diva-272264 (URN)
    Available from: 2016-01-13 Created: 2016-01-13 Last updated: 2016-02-19
    4. Origin of high whole-rock δ18O values in rhyolites from northeast Iceland
    Open this publication in new window or tab >>Origin of high whole-rock δ18O values in rhyolites from northeast Iceland
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    (English)Manuscript (preprint) (Other academic)
    National Category
    Geochemistry
    Identifiers
    urn:nbn:se:uu:diva-272315 (URN)
    Available from: 2016-01-13 Created: 2016-01-13 Last updated: 2016-02-19
    5. Floating stones off El Hierro, Canary Islands: xenoliths of pre-island sedimentary origin in the early products of the October 2011 eruption
    Open this publication in new window or tab >>Floating stones off El Hierro, Canary Islands: xenoliths of pre-island sedimentary origin in the early products of the October 2011 eruption
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    2012 (English)In: Solid Earth, ISSN 1869-9510, E-ISSN 1869-9529, Vol. 3, no 1, p. 97-110Article in journal (Refereed) Published
    Abstract [en]

    A submarine eruption started off the south coast of El Hierro, Canary Islands, on 10 October 2011 and continues at the time of this writing (February 2012). In the first days of the event, peculiar eruption products were found floating on the sea surface, drifting for long distances from the eruption site. These specimens, which have in the meantime been termed "restingolites" (after the close-by village of La Restinga), appeared as black volcanic "bombs" that exhibit cores of white and porous pumice-like material. Since their brief appearance, the nature and origin of these "floating stones" has been vigorously debated among researchers, with important implications for the interpretation of the hazard potential of the ongoing eruption. The "restingolites" have been proposed to be either (i) juvenile high-silica magma (e. g. rhyolite), (ii) remelted magmatic material (trachyte), (iii) altered volcanic rock, or (iv) reheated hyaloclastites or zeolite from the submarine slopes of El Hierro. Here, we provide evidence that supports yet a different conclusion. We have analysed the textures and compositions of representative "restingolites" and compared the results to previous work on similar rocks found in the Canary Islands. Based on their high-silica content, the lack of igneous trace element signatures, the presence of remnant quartz crystals, jasper fragments and carbonate as well as wollastonite (derived from thermal overprint of carbonate) and their relatively high oxygen isotope values, we conclude that "restingolites" are in fact xenoliths from pre-island sedimentary layers that were picked up and heated by the ascending magma, causing them to partially melt and vesiculate. As they are closely resembling pumice in appearance, but are xenolithic in origin, we refer to these rocks as "xeno-pumice". The El Hierro xeno-pumices hence represent messengers from depth that help us to understand the interaction between ascending magma and crustal lithologies beneath the Canary Islands as well as in similar Atlantic islands that rest on sediment-covered ocean crust (e. g. Cape Verdes, Azores). The occurrence of "restingolites" indicates that crustal recycling is a relevant process in ocean islands, too, but does not herald the arrival of potentially explosive high-silica magma in the active plumbing system beneath El Hierro.

    Place, publisher, year, edition, pages
    Copernicus Publications, 2012
    National Category
    Geology Geochemistry
    Identifiers
    urn:nbn:se:uu:diva-171483 (URN)10.5194/se-3-97-2012 (DOI)000309884400008 ()
    Funder
    Swedish Research Council
    Note

    Correction in Solid Earth. Vol. 3(2) p. 189. DOI: 10.5194/se-3-189-2012

    Available from: 2012-03-19 Created: 2012-03-19 Last updated: 2017-05-03Bibliographically approved
    6. Heterogeneous vesiculation of 2011 El Hierro xeno-pumice revealed by X-ray computed microtomography
    Open this publication in new window or tab >>Heterogeneous vesiculation of 2011 El Hierro xeno-pumice revealed by X-ray computed microtomography
    Show others...
    2016 (English)In: Bulletin of Volcanology, ISSN 0258-8900, E-ISSN 1432-0819, Vol. 78, no 12, article id 85Article in journal (Refereed) Published
    Abstract [en]

    During the first week of the 2011 El Hierro submarine eruption, abundant light-coloured pumiceous, high-silica volcanic bombs coated in dark basanite were found floating on the sea. The composition of the light-coloured frothy material ('xeno-pumice') is akin to that of sedimentary rocks from the region, but the textures resemble felsic magmatic pumice, leaving their exact mode of formation unclear. To help decipher their origin, we investigated representative El Hierro xeno-pumice samples using X-ray computed microtomography for their internal vesicle shapes, volumes, and bulk porosity, as well as for the spatial arrangement and size distributions of vesicles in three dimensions (3D). We find a wide range of vesicle morphologies, which are especially variable around small fragments of rock contained in the xeno-pumice samples. Notably, these rock fragments are almost exclusively of sedimentary origin, and we therefore interpret them as relicts an the original sedimentary ocean crust protolith(s). The irregular vesiculation textures observed probably resulted from pulsatory release of volatiles from multiple sources during xeno-pumice formation, most likely by successive release of pore water and mineral water during incremental heating and decompression of the sedimentary protoliths.

    Keywords
    El Hierro, Xeno-pumice, X-CT imaging, Vesicle morphologies, Vesicle size distribution, Heterogeneous vesiculation, Sedimentary ocean crust
    National Category
    Geology
    Identifiers
    urn:nbn:se:uu:diva-272316 (URN)10.1007/s00445-016-1080-x (DOI)000394130700001 ()
    Funder
    The Royal Swedish Academy of SciencesSwedish Research Council
    Note

    The manuscript version of this article was used under the name "Heterogeneous vesiculation of 2011 El Hierro xeno-pumice revealed by synchrotron μ-CT" in the following thesis: Silicic Magma Genesis in Basalt-dominated Oceanic Settings: Examples from Iceland and the Canary Islands http://uu.diva-portal.org/smash/record.jsf?pid=diva2:893923

    Available from: 2016-01-13 Created: 2016-01-13 Last updated: 2017-11-30Bibliographically approved
    7. Hur bildades kontinenterna?
    Open this publication in new window or tab >>Hur bildades kontinenterna?
    2014 (Swedish)In: Geologiskt Forum, ISSN 1104-4721, Vol. 84, p. 12-13Article in journal (Other (popular science, discussion, etc.)) Published
    Place, publisher, year, edition, pages
    Jönköping: Geologiska Föreningen, 2014
    National Category
    Geology
    Identifiers
    urn:nbn:se:uu:diva-272317 (URN)
    Available from: 2016-01-13 Created: 2016-01-13 Last updated: 2016-02-19
  • 10.
    Berg, Sylvia E.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Troll, Valentin
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Burchardt, Steffi
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Riishuus, Morten
    Nordic Volcanological Center, Institute of Earth Sciences, University of Iceland.
    Deegan, Frances
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Harris, Chris
    Dept. of Geological Sciences, University of Cape Town.
    Whitehouse, Martin
    Department of Geosciences, Swedish Museum of Natural History.
    Krumbholz, Michael
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Gústafsson, Ludvik
    Samband Islenskra Sveitarfélag.
    Rapid generation of high-silica magmas in basalt-dominated rift settingsManuscript (preprint) (Other academic)
  • 11.
    Berg, Sylvia E.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Troll, Valentin
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Deegan, Frances
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Burchardt, Steffi
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Ellis, Ben
    Inst. f. Geochemie und Petrologie, ETH.
    Riishuus, Morten
    Nordic Volcanological Center, Institute of Earth Sciences, University of Iceland.
    Meade, Fiona
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Zircons from northeast Iceland analogous to those from early EarthManuscript (preprint) (Other academic)
  • 12.
    Berg, Sylvia E.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Troll, Valentin
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Harris, Chris
    Dept. of Geological Sciences, University of Cape Town.
    Riishuus, Morten
    Nordic Volcanological Center, Institute of Earth Sciences, University of Iceland.
    Deegan, Frances
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Burchardt, Steffi
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Origin of high whole-rock δ18O values in rhyolites from northeast IcelandManuscript (preprint) (Other academic)
  • 13.
    Berg, Sylvia
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Mineralogy Petrology and Tectonics.
    Troll, Valentin
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Mineralogy Petrology and Tectonics.
    Burchardt, Steffi
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Mineralogy Petrology and Tectonics.
    Deegan, Frances
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Mineralogy Petrology and Tectonics.
    Riishuus, Morten S.
    Nordic Volcanological Center. Institute of Earth Sciences, University of Iceland, Sturlugata 7, 101 Reykjavik.
    Whitehouse, Martin J.
    Dept. of Geosciences, Swedish Museum of Natural History, SE-104 05, Stockholm, Sweden.
    Harris, Chris
    Dept. of Geological Sciences, University of Cape Town, Rondebosch, South Africa,.
    Freda, Carmela
    Istituto Nazionale di Geofisica e Vulcanologia (INGV), Rome, Italy.
    Ellis, Ben S.
    Inst. f. Geochemie und Petrologie, ETH, Clausiusstrasse 25, 8092, Zurich, Switzerland.
    Krumbholz, Michael
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Mineralogy Petrology and Tectonics.
    Gústafsson, Ludvik E.
    Samband Islenskra Sveitarfélag, Borgartúni 30, pósthólf 8100, 128 Reykjavik, Iceland.
    Rapid high-silica magma generation in basalt-dominated rift settings2015Conference paper (Other academic)
  • 14.
    Berg, Sylvia
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Solid Earth Geology.
    Troll, Valentin
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Solid Earth Geology.
    Riishuus, M.S.
    Burchardt, Steffi
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Solid Earth Geology.
    Deegan, Frances
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Solid Earth Geology.
    Harris, C.
    Voluminous outburst of silicic low d18O magma in NE-Iceland inferred from zircon d18O and U-Pb geochronology2013Conference paper (Other academic)
  • 15. Bergqvist, Claes
    et al.
    Herbert, Roger
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    Persson, Ingmar
    Greger, Maria
    Plants influence on arsenic availability and speciation in therhizosphere, roots and shoots of three different vegetables2014In: Environmental Pollution, ISSN 0269-7491, E-ISSN 1873-6424, Vol. 184, p. 540-546Article in journal (Refereed)
    Abstract [en]

    The toxicity of arsenic (As) in the environment is controlled by its concentration, availability andspeciation. The aims of the study were to evaluate the accumulation and speciation of As in carrot,lettuce and spinach cultivated in soils with various As concentrations and to estimate the concomitanthealth risks associated with the consumption of the vegetables. Arsenic concentration and speciation inplant tissues and soils was analysed by HPLC, AAS and XANES spectroscopy. To estimate the plants influencein the rhizosphere, organic acids in lettuce root exudates were analysed by ion chromatography.The results showed that the As accumulation was higher in plants cultivated in soil with higher Asextractability. Arsenate predominated in the soils, rhizosphere and root exudates of lettuce. Succinic acidwas the major organic acid in lettuce root exudates. Ingestion of the tested vegetables may result in anintake of elevated levels of inorganic As.

  • 16.
    Björnerås, C.
    et al.
    Lund University, Lund, Sweden.
    Weyhenmeyer, Gesa A.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Evans, C. D.
    Environm Ctr Wales, Bangor, Wales.
    Gessner, M. O.
    Leibniz Inst Freshwater Ecol & Inland Fisheries I, Stechlin, Germany; TU Berlin, Berlin, Germany.
    Grossart, H. P.
    Potsdam Univ, Potsdam, Germany.
    Kangur, K.
    Estonian Univ Life Sci, Rannu, Estonia.
    Kokorite, I.
    Univ Latvia, Riga, Latvia.
    Kortelainen, P.
    Finnish Environm Inst, Helsinki, Finland.
    Laudon, H.
    Swedish Univ Agr Sci, Umeå, Sweden.
    Lehtoranta, J.
    Finnish Environm Inst, Helsinki, Finland.
    Lottig, N.
    Univ Wisconsin, Madison, USA.
    Monteith, D. T.
    Lancaster Environm Ctr, Lancaster, England.
    Nõges, P.
    Estonian Univ Life Sci, Tartu, Estonia.
    Nõges, T.
    Estonian Univ Life Sci, Tartu, Estonia.
    Oulehle, F.
    Czech Geol Survey, Prague, Czech Republic.
    Riise, G.
    Norwegian Univ Life Sci NMBU, As, Norway.
    Rusak, J. A.
    Ontario Minist Environm & Climate Change, Dorset, Canada.
    Räike, A.
    Finnish Environm Inst, Helsinki, Finland.
    Sire, J.
    Latvian Environm Geol & Meteorol Ctr, Riga, Latvia.
    Sterling, S.
    Dalhousie Univ, Halifax, Canada.
    Kritzberg, E. S.
    Lund University, Lund, Sweden.
    Widespread Increases in Iron Concentration in European and North American Freshwaters2017In: Global Biogeochemical Cycles, ISSN 0886-6236, E-ISSN 1944-9224, Vol. 31, no 10, p. 1488-1500Article in journal (Refereed)
    Abstract [en]

    Recent reports of increasing iron (Fe) concentrations in freshwaters are of concern, given the fundamental role of Fe in biogeochemical processes. Still, little is known about the frequency and geographical distribution of Fe trends or about the underlying drivers. We analyzed temporal trends of Fe concentrations across 340 water bodies distributed over 10 countries in northern Europe and North America in order to gain a clearer understanding of where, to what extent, and why Fe concentrations are on the rise. We found that Fe concentrations have significantly increased in 28% of sites, and decreased in 4%, with most positive trends located in northern Europe. Regions with rising Fe concentrations tend to coincide with those with organic carbon (OC) increases. Fe and OC increases may not be directly mechanistically linked, but may nevertheless be responding to common regional-scale drivers such as declining sulfur deposition or hydrological changes. A role of hydrological factors was supported by covarying trends in Fe and dissolved silica, as these elements tend to stem from similar soil depths. A positive relationship between Fe increases and conifer cover suggests that changing land use and expanded forestry could have contributed to enhanced Fe export, although increases were also observed in nonforested areas. We conclude that the phenomenon of increasing Fe concentrations is widespread, especially in northern Europe, with potentially significant implications for wider ecosystem biogeochemistry, and for the current browning of freshwaters.

  • 17.
    Blum, Kristin M.
    et al.
    Umea Univ, Dept Chem, S-90187 Umea, Sweden..
    Norström, Sara H.
    Umea Univ, Dept Chem, S-90187 Umea, Sweden..
    Golovko, Oksana
    Univ South Bohemia Ceske Budejovice, Fac Fisheries & Protect Waters, South Bohemian Res Ctr Aquaculture & Biodivers Hy, Zatisi 728-2, Vodnany 38925, Czech Republic..
    Grabic, Roman
    Univ South Bohemia Ceske Budejovice, Fac Fisheries & Protect Waters, South Bohemian Res Ctr Aquaculture & Biodivers Hy, Zatisi 728-2, Vodnany 38925, Czech Republic..
    Järhult, Josef D.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Sciences, Infectious Diseases. Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Biochemistry and Microbiology.
    Koba, Olga
    Univ South Bohemia Ceske Budejovice, Fac Fisheries & Protect Waters, South Bohemian Res Ctr Aquaculture & Biodivers Hy, Zatisi 728-2, Vodnany 38925, Czech Republic..
    Söderström Lindström, Hanna
    Umea Univ, Dept Chem, S-90187 Umea, Sweden.;Umea Univ, Dept Publ Hlth & Clin Med, Occupat & Environm Med, S-90187 Umea, Sweden..
    Removal of 30 active pharmaceutical ingredients in surface water under long-term artificial UV irradiation2017In: Chemosphere, ISSN 0045-6535, E-ISSN 1879-1298, Vol. 176, p. 175-182Article in journal (Refereed)
    Abstract [en]

    This study investigated the i) kinetics, and ii) proportion of photolysis of 30 relatively stable active pharmaceutical ingredients (APIs) during artificial UV irradiation for 28 d in ammonium acetate buffer, filtered and unfiltered river water. Buffer was included to control removal kinetics under stable pH conditions and without particulate matter. Dark controls were used to determine removal due to other processes than photolysis and calculate the proportion of photolysis of the total removal. The removal of each API in each matrix was determined using online solid phase extraction/liquid chromatography tandem mass spectrometry (online SPE/LC-MS/MS). Most APIs transformed during the 28 d of UV irradiation and the dark controls showed that photolysis was the major removal process for the majority of the APIs studied. The half-lives ranged from 6 h (amitriptyline) in unfiltered river water to 884 h (37 d, carbamazepine) in buffer. In unfiltered river water, the proportion of APIs with short half-lives (<48 h) was much higher (29%) than in the other matrices (4%), probably due to additional organic carbon, which could have promoted indirect photolysis. Furthermore, two APIs, memantine and fluconazole, were stable in all three matrices, while alprazolam was stable in buffer and unfiltered river water and four additional APIs were stable in buffer. Considering the relatively long-term UV-exposure, this study enabled the investigation of environmentally relevant half-lives in natural waters. Many APIs showed high persistence, which is environmentally concerning and emphasizes the importance of further studies on their environmental fate and effects.

  • 18.
    Blythe, Lara S.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Solid Earth Geology.
    Understanding Crustal Volatiles: Provenance,  Processes and Implications2012Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Knowledge of the provenance of crustal volatiles and the processes by which they are released is extremely important for the dynamics of magmatic systems. Presented here are the results of multiple investigations, which aim to understand magmatic volatile contamination from contrasting but complementary perspectives. The main methodologies used include He and C isotope values and CO2/3He ratios of volcanic gases and fluids; simulation of magma-carbonate interaction using high-pressure high-temperature experimental petrology; X-ray microtomography of vesiculated xenoliths and computer modeling.

    Findings show that the contribution from upper crustal volatiles can be substantial, and is dependant on the upper crustal lithology on which a volcano lies, as well as the composition of the magma supplied. Carbonate dissolution in particular is strongly controlled by the viscosity of the host magma. The details of the breakdown of vesiculated xenoliths is complex but has wide reaching implications, ranging from the dissemination of crustally derived materials through a magma body to highlighting that crustal volatiles are largely unaccounted for in both individual volcano and global volatile budgets. In synthesizing the conclusions from each of the individual perspectives presented, I propose the contribution of volatiles from crustal sources to play a significant role in many geological systems. This volatile component should be taken into consideration in future research efforts.

    List of papers
    1. Mantle versus crustal volatile sources along the Java – Bali segment of the Sunda arc, Indonesia.
    Open this publication in new window or tab >>Mantle versus crustal volatile sources along the Java – Bali segment of the Sunda arc, Indonesia.
    (English)Manuscript (preprint) (Other academic)
    Keywords
    Helium isotopes, carbon isotopes, Indonesia, volcanic gases and fluids, upper crustal volatile contamination, GAC, JAC
    National Category
    Geochemistry Geology
    Research subject
    Earth Science with specialization in Mineral Chemistry, Petrology and Tectonics
    Identifiers
    urn:nbn:se:uu:diva-171478 (URN)
    Available from: 2012-03-19 Created: 2012-03-19 Last updated: 2012-04-13
    2. Concentration of commercially-viable geothermal resources in W-Java controlled by crustal thickness and composition
    Open this publication in new window or tab >>Concentration of commercially-viable geothermal resources in W-Java controlled by crustal thickness and composition
    Show others...
    (English)Manuscript (preprint) (Other academic)
    National Category
    Geochemistry Geology
    Research subject
    Earth Science with specialization in Mineral Chemistry, Petrology and Tectonics
    Identifiers
    urn:nbn:se:uu:diva-171480 (URN)
    Available from: 2012-03-19 Created: 2012-03-19 Last updated: 2012-04-13
    3. Time-monitored vesiculation and dissolution during magma-carbonate interaction experiments: Merapi (Indonesia) and Vesuvius (Italy).
    Open this publication in new window or tab >>Time-monitored vesiculation and dissolution during magma-carbonate interaction experiments: Merapi (Indonesia) and Vesuvius (Italy).
    Show others...
    (English)Manuscript (preprint) (Other academic)
    Keywords
    Merapi, Vesuvius, carbonate assimilation, volatile exsolution, carbon dioxide, viscosity, bubbles, vesicles
    National Category
    Geosciences, Multidisciplinary Geology
    Identifiers
    urn:nbn:se:uu:diva-171481 (URN)
    Available from: 2012-03-19 Created: 2012-03-19 Last updated: 2012-04-13
    4. Floating stones off El Hierro, Canary Islands: xenoliths of pre-island sedimentary origin in the early products of the October 2011 eruption
    Open this publication in new window or tab >>Floating stones off El Hierro, Canary Islands: xenoliths of pre-island sedimentary origin in the early products of the October 2011 eruption
    Show others...
    2012 (English)In: Solid Earth, ISSN 1869-9510, E-ISSN 1869-9529, Vol. 3, no 1, p. 97-110Article in journal (Refereed) Published
    Abstract [en]

    A submarine eruption started off the south coast of El Hierro, Canary Islands, on 10 October 2011 and continues at the time of this writing (February 2012). In the first days of the event, peculiar eruption products were found floating on the sea surface, drifting for long distances from the eruption site. These specimens, which have in the meantime been termed "restingolites" (after the close-by village of La Restinga), appeared as black volcanic "bombs" that exhibit cores of white and porous pumice-like material. Since their brief appearance, the nature and origin of these "floating stones" has been vigorously debated among researchers, with important implications for the interpretation of the hazard potential of the ongoing eruption. The "restingolites" have been proposed to be either (i) juvenile high-silica magma (e. g. rhyolite), (ii) remelted magmatic material (trachyte), (iii) altered volcanic rock, or (iv) reheated hyaloclastites or zeolite from the submarine slopes of El Hierro. Here, we provide evidence that supports yet a different conclusion. We have analysed the textures and compositions of representative "restingolites" and compared the results to previous work on similar rocks found in the Canary Islands. Based on their high-silica content, the lack of igneous trace element signatures, the presence of remnant quartz crystals, jasper fragments and carbonate as well as wollastonite (derived from thermal overprint of carbonate) and their relatively high oxygen isotope values, we conclude that "restingolites" are in fact xenoliths from pre-island sedimentary layers that were picked up and heated by the ascending magma, causing them to partially melt and vesiculate. As they are closely resembling pumice in appearance, but are xenolithic in origin, we refer to these rocks as "xeno-pumice". The El Hierro xeno-pumices hence represent messengers from depth that help us to understand the interaction between ascending magma and crustal lithologies beneath the Canary Islands as well as in similar Atlantic islands that rest on sediment-covered ocean crust (e. g. Cape Verdes, Azores). The occurrence of "restingolites" indicates that crustal recycling is a relevant process in ocean islands, too, but does not herald the arrival of potentially explosive high-silica magma in the active plumbing system beneath El Hierro.

    Place, publisher, year, edition, pages
    Copernicus Publications, 2012
    National Category
    Geology Geochemistry
    Identifiers
    urn:nbn:se:uu:diva-171483 (URN)10.5194/se-3-97-2012 (DOI)000309884400008 ()
    Funder
    Swedish Research Council
    Note

    Correction in Solid Earth. Vol. 3(2) p. 189. DOI: 10.5194/se-3-189-2012

    Available from: 2012-03-19 Created: 2012-03-19 Last updated: 2017-05-03Bibliographically approved
    5. A global record of xeno-pumice: evidence for magma-crust interaction and crustal volatile remobilisation.
    Open this publication in new window or tab >>A global record of xeno-pumice: evidence for magma-crust interaction and crustal volatile remobilisation.
    Show others...
    (English)Manuscript (preprint) (Other academic)
    Keywords
    crustal volatiles, xenoliths, xeno-pumice, assimilation, contamination, explosive eruptive activity, X-ray microtomography, volcanic volatile budgets
    National Category
    Geology
    Research subject
    Earth Science with specialization in Mineral Chemistry, Petrology and Tectonics
    Identifiers
    urn:nbn:se:uu:diva-171484 (URN)
    Available from: 2012-03-19 Created: 2012-03-19 Last updated: 2012-04-13
    6. Sink or swim: The fate of crustal xenoliths in shallow magma chambers
    Open this publication in new window or tab >>Sink or swim: The fate of crustal xenoliths in shallow magma chambers
    Show others...
    (English)In: Article in journal (Other academic) Submitted
    Keywords
    xenolith, magmatic stoping, assimmilation, magma contamination, pluton emplacement, magma chamber dynamics
    National Category
    Geology
    Identifiers
    urn:nbn:se:uu:diva-171485 (URN)
    Available from: 2012-03-19 Created: 2012-03-19 Last updated: 2017-01-25
  • 19.
    Blythe, Lara
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Solid Earth Geology.
    Troll, Valentin
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Solid Earth Geology.
    Hilton, David
    Geosciences Research Division, Scripps Institution of Oceanography.
    Schwarzkopf, Lothar
    Geo Doc Con, Unterpferdt 8, 95176, Konradsreuth, Germany.
    Mantle versus crustal volatile sources along the Java – Bali segment of the Sunda arc, Indonesia.Manuscript (preprint) (Other academic)
  • 20. Boskabadi, Ahmad
    et al.
    Pitcairn, Iain K.
    Stern, Robert J.
    Ayer, Mokhles K.
    Broman, Curt
    Mohamed, Fathz H.
    Majka, Jaroslaw
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Solid Earth Geology.
    Carbonatite crystallization and alteration in the Tarr carbonatite–albitite complex, Sinai Peninsula, Egypt2013In: Precambrian Research, ISSN 0301-9268, E-ISSN 1872-7433, Vol. 239, p. 24-41Article in journal (Refereed)
    Abstract [en]

    Carbonate dykes occurring in the Arabian-Nubian Shield (ANS) are clearly intrusive in origin and carbonatites according to the IUGS classification, yet previous investigations refer to them as “intrusive carbonates”, due mainly to their low Sr, Ba, Nb, Y, Th and rare earth element (REE) contents. The Tarr carbonatite albitite complex (TCA) in SE Sinai, Egypt contains a series of small (<1.2 km2) albitite intrusions surrounded by small veins and dykes of carbonatite, which occur predominantly in a narrow zone of brecciation surrounding the intrusions. Fennitic alteration surrounding TCA has been reported but there is little consensus on the extent and origin of this alteration. Fennitic alteration surrounding the TCA carbonatites is not abundant. Alteration is dominated by precipitation of carbonates in the breccia zone surrounding the albitite intrusion with associated actinolite, chlorite, sericite and epidote. Geochemical compositions are consistent with addition of carbonates and associated secondary minerals because the altered rocks contain higher CaO, MgO, Fe2O3 and MnO and lower SiO2, Al2O3, Na2O and K2O compared to their less altered rocks. Fluid inclusion investigations show that the carbonatite magma contained a high-salinity H2O–CO2–NaCl–CaCl2fluid, although the lack of fennitic alteration implies that this fluid was not abundant. The crystallization conditions of the carbonatite dykes and carbonatite matrix in the breccia zones have been constrained using Zr-in-rutile thermometry and fluid inclusion microthermometry. Crystallization of the carbonatite in the dykes and in the breccia zone occurred between 565 ± 38 °C and 420–480 °C, respectively and at 0.75–1.3 kbar, which corresponds to a depth of 2.8–4.9 km. Rutile hosted within the carbonatite crystallized earlier at high temperature and the carbonate matrix crystallized later after cooling. Immiscible fluid from carbonatite magma would have altered the surrounding country rocks at lower temperature (between 400 °C and 150 °C deduced from the fluid inclusion thermometry) after the intrusion of the carbonatite melt.

  • 21.
    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.

  • 22. 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.

  • 23.
    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.

  • 24.
    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.

  • 25. 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.

  • 26.
    Das, Pallavi
    et al.
    Tezpur Univ, Dept Environm Sci, Napaam 784028, Assam, India.
    Sarma, Kali
    Tezpur Univ, Dept Environm Sci, Napaam 784028, Assam, India.
    Kumar Jha, Pawan
    Univ Allahabad, Ctr Environm Studies, Allahabad 211002, Uttar Pradesh, India.
    Ranjan, Rajnish
    North Eastern Elect Power Corp NEEPCO, Kameng Hydroelect Project, West Kameng, Arunachal Prade, India.
    Herbert, Roger
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    Kumar, Manish
    Tezpur Univ, Dept Environm Sci, Napaam 784028, Assam, India.
    Understanding the Cyclicity of Chemical Weatheringand Associated CO2Consumption in the BrahmaputraRiver Basin (India): The Role of Major Rivers in ClimateChange Mitigation Perspective2016In: Aquatic geochemistry, ISSN 1380-6165, E-ISSN 1573-1421, Vol. 22, no 3, p. 225-251Article in journal (Refereed)
    Abstract [en]

    Weathering of rocks that regulate the water chemistry of the river has been used to evaluate the CO2 consumption rate which exerts a strong influence on the global climate. The foremost objective of the present research is to estimate the chemical weathering rate (CWR) of the continental water in the entire stretch of Brahmaputra River from upstream to downstream and their associated CO2 consumption rate. To establish the link between the rapid chemical weathering and thereby enhance CO2 drawdown from the atmosphere, the major ion composition of the Brahmaputra River that drains the Himalaya has been obtained. Major ion chemistry of the Brahmaputra River was resolved on samples collected from nine locations in pre-monsoon, monsoon and post-monsoon seasons for two cycles: cycle I (2011-2012) and cycle II (2013-2014). The physico-chemical parameters of water samples were analysed by employing standard methods. The Brahmaputra River was characterized by alkalinity, high concentration of Ca2+ and HCO3 (-) along with significant temporal variation in major ion composition. In general, it was found that water chemistry of the river was mainly controlled by rock weathering with minor contributions from atmospheric and anthropogenic sources. The effective CO2 pressure (log) for pre-monsoon, monsoon and post-monsoon has been estimated. The question of rates of chemical weathering (carbonate and silicate) was addressed by using TDS and run-off (mm year(-1)). It has been found that the extent of CWR is directly dependent on the CO2 consumption rate which may be further evaluated from the perspective of climate change mitigation The average annual CO2 consumption rate of the Brahmaputra River due to silicate and carbonate weathering was found to be 0.52 (x10(6) mol Km(-2) year(-1)) and 0.55 (x10(6) mol Km(-2) year(-1)) for cycle I and 0.49 (x10(6) mol Km(-2) year(-1)) and 0.52 (x10(6) mol Km(-2) year(-1)) for cycle II, respectively, which were significantly higher than that of other Himalayan rivers. Estimation of CWR of the Brahmaputra River indicates that carbonate weathering largely dominates the water chemistry of the Brahmaputra River.

  • 27.
    de Campos Pereira, Hugo
    Institutionen för mark och miljö, Sveriges Lantbruksuniversitet.
    Löslighet och transport av sällsynta jordartsmetaller i Källfallsfältets gruvsandsmagasin2014Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Solubility and transport of rare earth elements in the mine tailings of Källfallsfältet

    Hugo de Campos Pereira

    The mechanisms which govern the solubility of rare earth elements (REEs) in sulfide-containing tailings at the former mine site of Källfallsfältet (Västmanland, Sweden) were studied by the means of soil water and ground water sampling, leaching tests and geochemical modeling using Visual MINTEQ ver. 3.0.

    The results showed that weathering of sulfides is the primary process governing pH in the tailings, and thus also REE solubility. However, weathering of sulfides is no source for REE in itself since the elements are not bound in sulfides, which the oxidized availability test NT ENVIR 006 showed. Instead REE are released into solution by weathering of easily weathered silicates. Usually, metal bound in silicate form is not considered geochemically active.

    A kinetic (time dependent) factor, associated with the weathering of silicates, was found to affect pH and thus also metal solubility in leaching tests performed on the tailings. The standardized pH static leaching test (SIS-CEN/TS 14997) showed limitations in observing kinetic effects because of its relatively short equilibration time (48 h). Thus, in future studies with similar materials, leaching test kinetics should be taken into account when comparing leached concentrations with field measured concentrations. Acid titration and one step batch test (SIS-CEN ISO/TS 21268-2:2010) proved to be applicable and relatively well applicable to the tailings, respectively, in order to estimate soil solution concentrations.

    Speciation calculations using Visual MINTEQ ver. 3.0 showed that pH and DOC concentration are the most important factors which affect REE speciation in soil solution, ground water and surface water associated with the tailings. In acid sulfate rich solutions, low in DOC, speciation is dominated by sulfate complexes, mainly (REE)SO4+, followed by free dissolved ions as the second most common form. These results are in accordance with previous modeling studies of REE speciation in acid sulfate rich waters resulting from tailings. This, together with previous results showing that REE ecotoxicity seems to follow the free ion model, implies that the toxicity of the elements is expected to increase with decreasing pH value.

  • 28.
    Deegan, Frances M.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Mineralogy Petrology and Tectonics. Department of Geosciences, Swedish Museum of Natural History, SE-104 05, Stockholm, Sweden.
    Whitehouse, Martin
    Department of Geosciences, Swedish Museum of Natural History, SE-104 05, Stockholm, Sweden.
    Troll, Valentin R.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Mineralogy Petrology and Tectonics.
    Budd, David A.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Mineralogy Petrology and Tectonics.
    Harris, Chris
    Department of Geological Sciences, University of Cape Town, Rondebosch 7701, South Africa.
    Geiger, Harri
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Mineralogy Petrology and Tectonics.
    Hålenius, Ulf
    Department of Geosciences, Swedish Museum of Natural History, SE-104 05, Stockholm, Sweden.
    Pyroxene standards for SIMS oxygen isotope analysis and their application to Merapi volcano, Sunda arc, Indonesia2016In: Chemical Geology, ISSN 0009-2541, E-ISSN 1872-6836, Vol. 447, p. 1-10Article in journal (Refereed)
    Abstract [en]

    Measurement of oxygen isotope ratios in common silicate minerals such as olivine, pyroxene, feldspar, garnet, and quartz is increasingly performed by Secondary Ion Mass Spectrometry (SIMS). However, certain mineral groups exhibit solid solution series, and the large compositional spectrum of these mineral phases will result in matrix effects during SIMS analysis. These matrix effects must be corrected through repeated analysis of compositionally similar standards to ensure accurate results. In order to widen the current applicability of SIMS to solid solution mineral groups in common igneous rocks, we performed SIMS homogeneity tests on new augite (NRM-AG-1) and enstatite (NRM-EN-2) reference materials sourced from Stromboli, Italy and Webster, North Carolina, respectively. Aliquots of the standard minerals were analysed by laser fluorination (LF) to establish their δ18O values. Repeated SIMS measurements were then performed on randomly oriented fragments of the same pyroxene crystals, which yielded a range in δ18O less than ± 0.42 and ± 0.58‰ (2σ) for NRM-AG-1 and NRM-EN-2, respectively. Homogeneity tests verified that NRM-AG-1 and NRM-EN-2 do not show any crystallographic orientation bias and that they are sufficiently homogeneous on the 20 μm scale to be used as routine mineral standards for SIMS δ18O analysis. We subsequently tested our new standard materials on recently erupted pyroxene crystals from Merapi volcano, Indonesia. The δ18O values for Merapi pyroxene obtained by SIMS (n = 204) agree within error with the LF-derived δ18O values for Merapi pyroxene but differ from bulk mineral and whole-rock data obtained by conventional fluorination. The bulk samples are offset to higher δ18O values as a result of incorporation of mineral and glass inclusions that in part reflects crustal contamination processes. The Merapi pyroxene SIMS data, in turn, display a frequency peak at 5.8‰, which allows us to estimate the δ18O value of the primary mafic magma at Merapi to ~ 6.1‰ when assuming closed system differentiation.

  • 29.
    Drake, Alexandra
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Separating Acetate, Formate and MSA from natural samples using ion chromatography2013Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Anions from three short organic acids: acetate, formate and MSA are interesting to measure since they can be used for different environmental studies. The ion-chromatographer at the Department of Earth Sciences is currently not able to separate these three substances; therefore six new methods were developed in this project to solve this problem. Short organic test 5 ended up to be the best method, where acetate and formate were separated. The result was considered good, even if MSA were not separated.

    Method 5 was then tested on a couple of natural water, snow and ice samples. All these samples showed a larger amount of formate than of acetate, which in some cases was not even found. The results seemed plausible; not many of them were sticking out compared to others of the same phase. The shallowest sample from the Lomonosovfonna ice cap did however differ quite a lot in amount of formate compared with samples from other depths of this ice core; probably because of contamination which could have occurred at both the ice cap and in the lab during the handling of the samples.

    MSA can however also be measured if the amount of acetate and formate in the sample is known. This is done by adding known amounts of MSA to the same sample in subsequent runs to then be able to calculate the concentration of MSA in the sample. The problem with the use of this method is that the concentration of MSA needs to be high enough in contrast to acetate and formate in order to get reliable results, which was not the case in the samples measured in this project.

  • 30.
    Egli, M.
    et al.
    Department of Geography, University of Zurich, Switzerland.
    Filip, D.
    Department of Geography, University of Zurich, Switzerland.
    Mavris, C.
    Department of Geography, University of Zurich, Switzerland.
    Fischer, B.
    Department of Geography, University of Zurich, Switzerland.
    Götze, J.
    TU Bergakademie Freiberg, Institute of Mineralogy, Freiberg, Germany.
    Raimondi, S.
    Dipartimento Sistemi Agro-Ambientali, Università degli Studi di Palermo, Palermo, Italy.
    Seibert, J.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    Rapid transformation of inorganic to organic and plant-available phosphorous in soils of a glacier forefield2012In: Geoderma, Vol. 189-190, p. 215-226Article in journal (Refereed)
    Abstract [en]

    Chemical weathering of rocks or sediments is extremely important for the generation of soils, for the evolution of landscape, and as a main source of inorganic nutrients for plant growth and therefore for life. Temporal trends in weathering mechanisms, plant succession and nutrients availability in cold environments can be successfully studied in soil chronosequences along a glacier forefield. In the present paper, this was carried out in the pro-glacial area of Morteratsch. Different forms of phosphorous in the soil, stream and spring water chemistry were investigated. Apatite constitutes the main source of P, but it occurs only as a minor accessory mineral phase in the granitic/gneiss parent material. The identification of apatite was performed using SEM-EDX and cathodoluminescence. Water chemistry data indicated some calcite dissolution at the earliest phase of exposure, pyrite and - on older surfaces increasingly - feldspar weathering. Apatite also seemed to contribute to Ca which is leached from the soils. The concentrations of dissolved P in the stream and spring waters were, however, extremely low (only a few μg P/l). In the topsoil, the total stocks of P showed a slight decrease with time. Losses were rather difficult to detect even though the water fluxes through the soils and discharges are relatively high. Soil organic P is almost identical to the EDTA-extractable fraction. In an 11.5. ky-old soil outside the glacier forefield the concentration and proportions of organic P, EDTA-extractable P and inorganic P forms did not differ that much from the oldest soils (max. 150. years) of the glacier forefield. In the bulk soil, about 78% of total P was transformed into an organic form (40% already after 150. years) and, in the fine earth, about 81% (40-70% after about 150. years of soil evolution). Thus the P transformation reactions are shown to be very rapid, occur predominantly in the early phase of soil formation, and could be best described by an exponential decay model. © 2012 Elsevier B.V.

  • 31.
    Enholm, Zacharias
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Petrografisk-mineralkemisk karakterisering av Muonionalustameteoriten2012Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Denna uppsats består av två delar, den första behandlar kortfattat elementens och solsystemets genes för att fortsätta med en mer omfattande beskrivning av meteoriterna, deras klassifikation, mineralogi och upprinnelse. Den andra delen av uppsatsen beskriver prepareringen, innefattande montering, slipning, polering och etsning, samt undersökningen av Muonionalustameteoriten. Muonionalusta är en Fe,Ni-meteorit av typen oktaedrit tillhörande den kemiska gruppen IVA. Meteoriten undersöks både med hjälp av malmmikroskopi och med FE-EPMA/WDS-analys. Fem stycken metalliska faser identifierades, nämligen kamacit, taenit, troilit, schreibersit och daubréelit samt viss förekomst av vad som tros vara kromit. Texturer av olika slag identifierades även, däribland chockinducerade Neumannlinjer.

  • 32.
    Eriksson, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    Hydrokemi: Om de kemiska processerna i vattnets kretslopp2012Book (Other academic)
  • 33.
    Eriksson, Sarah
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Tracing the Origin of Metasedimentary Rocks in the Faroe-Shetland Basin2016Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The Faroe-Shetland region has been exposed to a long history of tectonic events and the geology in the area is rather complex. This history has led to the formation large metasedimentary deposits, though the origin of these deposits is not yet fully understood. Possible source areas are Greenland, Norway and Scotland. To give a further understanding of the geology in the Faroe-Shetland basin and its regional relationship this study will analyze metasediments to classify them and compare them with other related sediments. Geochemical, petrographical and isotopic data will be for classification. Through this comparison it is evident that the metasediments from the Faroe-Shetland basin contain remnants from several different deposits and cannot be rated to one specific origin. This is shown by the 143Nd/ 144Nd , 87Sr/ 86Sr and 206Pb/204Pb , 207Pb/204Pb, 208Pb/204Pb isotope ratios found in the Faroe-Shetland basin compared with other possible source areas from Greenland, Norway and Scotland. This has shown that the isotope from the Faroe region correlate well with Caledonian traces from both Greenland and Scotland. Though the Torridonian sandstone from Scotland can also be correlated with the metasediments in the Faroe-Shetland basin.

  • 34.
    Es-Soufi, H.
    et al.
    Univ Moulay Ismail, Equipe Physicochim Mat Condensee, PCMC, Fac Sci Meknes, Meknes, Morocco..
    Bih, L.
    Univ Moulay Ismail, Equipe Physicochim Mat Condensee, PCMC, Fac Sci Meknes, Meknes, Morocco..
    Manoun, B.
    Univ Hassan 1Er, Lab Sci Mat Mat & Modelisat LS3M, Settat 26000, Morocco.;Mohammed VI Polytech Univ, Mat Sci & Nanoengn Dept MSN, Lot 660 Hay Moulay Rachid, Ben Guerir 43150, Morocco..
    Lazor, P.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Mineralogy Petrology and Tectonics.
    Structure, thermal analysis and optical properties of lithium tungsten-titanophosphate glasses2017In: Journal of Non-Crystalline Solids, ISSN 0022-3093, E-ISSN 1873-4812, Vol. 463, p. 12-18Article in journal (Refereed)
    Abstract [en]

    A melt-quenching method is used to prepare homogeneous glasses inside the 20Li(2)O-(50-x)Li2WO4-xTiO(2)-30P(2)O(5) (x = 0, 5, 8,10 and 15 mol%) system. The amorphous and glassy states of the glasses are evidenced by the X-ray diffraction and differential scanning calorimetry (DSC) analysis, respectively. The glasses were found to be colorless. The determined parameters for the glasses such as density, molar volume and glass transition temperature (T-g) depend strongly on the chemical composition of the glasses. The density and T-g are found to decrease and increase with TiO2 content, respectively. Infrared (IR) spectroscopy is used to characterize their structural approach. This technique has allowed the identification of different phosphate structural units mainly pyrophosphate and metaphosphate in their structure. From the absorption edge studies, the values of the optical band gap, E-g, and Lirbach energy, Delta E, were evaluated. The optical band gap is found to depend on the glass composition and it decreases as the content of the TiO2 increases. (C) 2017 Elsevier B.V. All rights reserved.

  • 35.
    Farzipour-Saein, Ali
    et al.
    Univ Isfahan, Fac Sci, Dept Geol, PO Code 81746-73441, Esfahan, Iran..
    Koyi, Hemin
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Mineralogy Petrology and Tectonics.
    Intermediate decollement activation in response to the basal friction variation and its effect on folding style in the Zagros fold-thrust belt, an analogue modeling approach2016In: Tectonophysics, ISSN 0040-1951, E-ISSN 1879-3266, Vol. 687, p. 56-65Article in journal (Refereed)
    Abstract [en]

    Although the role of various basal and intermediate decollement levels on structural style is well documented individually in many folded terrains, the interaction between basal and intermediate decollements is poorly constrained. This study uses results of two scaled sand-box models shortened from one end to study the variation in structural development in response to varying basal friction and its consequent interaction with intermediate decollement horizons. Two models with similar incompetent intermediate decollement, but with different basal friction (with and without a thick basal decollement), were prepared analogous for the eastern and the western parts of the Razak basement fault in the Fars Region of the eastern part of the Zagros fold thrust belt (ZFTB). Combined results of scaled models with geological observations are used to argue that the basal decollement friction characteristics govern propagation of deformation front. In addition, model results, analogues to north-south direction, show that deformation complexity and disharmonic folding exist in the section where the intermediate decollement has been activated in response to the shortening without the basal decollement (throughout the western part of the Razak basement fault where less thickness of the Hormuz series as the basal decollement has been documented compared to its eastern part). In other words, the complexity in deformation is less portrayed along sections where basal friction beneath the model decreases (e.g. the eastern part of the Razak basement fault). We argue here that, in addition to other parameters (not presented in this study) interaction of intermediate decollement levels with basal decollement friction characteristics could explain decoupling between structures within the sedimentary column of the Fars Region of the eastern part of the Zagros fold thrust belt.

  • 36.
    Fiola, Markus L.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Influence of Sample Preparation on Portable XRF-analyses of Aeolian Sediments: a Case Study2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The geochemical composition of aeolian sediments like windblown dust particles is of major importance for the exploration of dust origin and weathering conditions. This allows for the reconstruction of dust transport pathways and thus wind directions and palaeoclimate conditions. The loess deposits of the Carpathian Basin are the most complete terrestrial sediment climate archive in Europe, yet their development is still not fully understood. With the advancement of accurate field portable X-ray fluorescence (XRF) spectrometers, field applications have become possible, allowing in-situ geochemical analysis and potential advances in understanding the source of Carpathian Basin loess. However, previous work has failed to address the question of sample preparation and device interchangeability in the context of loess analyses.

    This study uses both Bruker Tracer 5i and Titan S1, as well as secondary data obtained with an Ametek SpectroXepos, to investigate sample preparation influences on aeolian sediment samples from Irig (Serbia) and Madaras (Hungary). Results showed that although absolute values deviate substantially between devices using different calibrations, some elemental ratios like Ca/Ti or Rb/Sr can still be compared when only relative changes are interpreted. Absolute concentrations of light elements, such as magnesium and calcium, were strongly influenced by milling or acid treatment. Absolute concentrations of light elements were also strongly influenced by changes in sample moisture, whereas the effect on the absolute concentrations of heavier elements was comparably small. Results also show that the influence of sample moisture needs to be considered when computing paleoclimatic indicator ratios involving aluminium or strontium, as sample moisture has a strong effect on the absolute concentration of these elements.

    Most deviations in measured absolute concentrations between untreated and prepared samples were attributed to the special nature of compositional data and could be removed through the application of additive or centred log-ratio transformations. This highlights the importance of considering the closure effect, using proper and robust statistical analyses in sediment provenance research.The geochemical data provided in this study shed light on dust provenance and the paleoclimatic development of the southeast European loess and highlight the effects of analysis technique on interpretation of this geochemical data.

    The full text will be freely available from 2019-08-01 08:01
  • 37. Fornieles-Callejon, J.
    et al.
    Salinas, A.
    Toledo-Redondo, Sergio
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Porti, J.
    Mendez, A.
    Navarro, E. A.
    Morente-Molinera, J. A.
    Soto-Aranaz, C.
    Ortega-Cayuela, J. S.
    Extremely low frequency band station for natural electromagnetic noise measurement2015In: Radio Science, ISSN 0048-6604, E-ISSN 1944-799X, Vol. 50, no 3, p. 191-201Article in journal (Refereed)
    Abstract [en]

    A new permanent ELF measurement station has been deployed in Sierra Nevada, Spain. It is composed of two magnetometers, oriented NS and EW, respectively. At 10 Hz, their sensitivity is 19 V/pT and the signal-to-noise ratio (SNR) is 28 dB for a time-varying signal of 1 pT, the expected field amplitude in Sierra Nevada. The station operates for frequencies below 24 Hz. The magnetometers, together with their corresponding electronics, have been specifically designed to achieve such an SNR for small signals. They are based on high-resolution search coils with ferromagnetic core and 10(6) turns, operating in limited geometry configuration. Different system noise sources are considered, and a study of the SNR is also included. Finally, some initial Schumann resonance measurements are presented in order to validate the performance of the measurement station, including 1 h length spectra, daily variations of resonance amplitudes and frequencies for the different seasons, and a 3 day spectrogram.

  • 38.
    Forsberg, Agnes
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences. Sveriges Lantbruksuniversitet, Institutionen för mark och miljö.
    Utvärdering av två markbaserade dagvattenreningssystem2015Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Stormwater is a source of pollution to water bodies but can also cause flooding. To treat stomwater locally is an issue of emerging importance due to a changing climate with an increased frequency of heavy rains, but also as a result of more strict guidelines concerning pollution to water bodies. Densification of cities is also a contributing factor. Several methods for sustainable stormwater treatment are used today but the state of knowledge regarding function and capacity is in need of improvement.

    This thesis aimed to evaluate two ground-based stormwater treatment methods, a filter strip and a retention tank. This was done through both literature review and field studies. The field study of the retention tank was limited due to insufficient outflow volumes from the tank. Oil from the filter strip was sampled and analysed for the heavy metals arsenic (As), barium (Ba), cadmium (Cd), cobalt (Co), chromium (Cr), copper (Cu), nickel (Ni), lead (Pb), vanadium (V), and zinc (Zn). According to the study, the filter strip had an elevated concentration of metals in the first 20 meters. Of the total load of heavy metals 20 % of As, 21 % of Cr, 4 % of Cu, 23 % of Ni, 16 % of Pb and 19 % of Zn was retained in the strip. The remaining portion of the heavy metals was assumed to settle in the level spreader before the filter strip or transported past the filter strip. Potential leachability for the metals was analysed with two types of extraction solutions, 1 mM CaCl2 and 0.1 M HNO3. The leaching potential for the studied metals was relatively low, averaging 31% of geochemically active metals. Obtained Kd -values showed the lowest mobility for Pb and Co and the largest mobility for As and Ni. Retrieved mobility for arsenic may be overrated when HNO3 is inefficient for extraction of arsenic. Zinc and cobolt were the limiting metals that can first exceed the limits for sensitive land use; however, this is expected to take place after about 50-60 years.

  • 39.
    Geiger, Harri
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Mineralogy Petrology and Tectonics.
    Barker, Abigail K.
    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. Univ Las Palmas Gran Canaria, Dept Phys GEOVOL, La Palmas Gran Canaria, Spain.
    Locating the depth of magma supply for volcanic eruptions, insights from Mt. Cameroon2016In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 6, article id 33629Article in journal (Refereed)
    Abstract [en]

    Mt. Cameroon is one of the most active volcanoes in Africa and poses a possible threat to about half a million people in the area, yet knowledge of the volcano’s underlying magma supply system is sparse. To characterize Mt. Cameroon’s magma plumbing system, we employed mineral-melt equilibrium thermobarometry on the products of the volcano’s two most recent eruptions of 1999 and 2000. Our results suggest pre-eruptive magma storage between 20 and 39 km beneath Mt. Cameroon, which corresponds to the Moho level and below. Additionally, the 1999 eruption products reveal several shallow magma pockets between 3 and 12 km depth, which are not detected in the 2000 lavas. This implies that small-volume magma batches actively migrate through the plumbing system during repose intervals. Evolving and migrating magma parcels potentially cause temporary unrest and short-lived explosive outbursts, and may be remobilized during major eruptions that are fed from sub-Moho magma reservoirs.

  • 40.
    Goluchowska, Karolina
    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, Al Mickiewicza 30, PL-30059 Krakow, Poland.
    Barker, Abigail
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Mineralogy Petrology and Tectonics.
    Czerny, Jerzy
    AGH Univ Sci & Technol, Fac Geol Geophys & Environm Protect, Al Mickiewicza 30, PL-30059 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, Al Mickiewicza 30, PL-30059 Krakow, Poland.
    Manecki, Maciej
    AGH Univ Sci & Technol, Fac Geol Geophys & Environm Protect, Al Mickiewicza 30, PL-30059 Krakow, Poland.
    Farajewicz, Milena
    AGH Univ Sci & Technol, Fac Geol Geophys & Environm Protect, Al Mickiewicza 30, PL-30059 Krakow, Poland.
    Dwornik, Maciej
    AGH Univ Sci & Technol, Fac Geol Geophys & Environm Protect, Al Mickiewicza 30, PL-30059 Krakow, Poland.
    Magma storage of an alkali ultramafic igneous suite from Chamberlindalen, SW Svalbard2016In: Mineralogy and Petrology, ISSN 0930-0708, E-ISSN 1438-1168, Vol. 110, no 5, p. 623-638Article in journal (Refereed)
    Abstract [en]

    An alkali mafic-ultramafic igneous suite of composite intrusions, lenses and associated greenstones are hosted by Neoproterozoic metasedimentary sequences in Chamberlindalen, Southwest Svalbard. This study focuses on the alkali igneous suite of Chamberlindalen with a view to determining the conditions of magma storage. The rocks from Chamberlindalen display cumulate textures, are highly magnesian and are classified as alkaline by the occurrence of kaersutite. They have textures that indicate cocrystallization of primary magmatic minerals such as diopside, kaersutite-ferrokaersutite and biotite-phlogopite in different proportions. The historic magma plumbing system for the alkaline cumulates has been reconstructed by thermobarometry. Diopside and kaersutite crystallization in the alkaline cumulates show a dominant level of magma storage between 30 and 50 km in the subcontinental lithospheric mantle.

  • 41.
    Guilbaud, R.
    et al.
    Univ Lancaster, Lancaster Environm Ctr, Lancaster, England; Univ Cambridge, Dept Earth Sci, Cambridge, England.
    Slater, Ben J.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology. Univ Cambridge, Dept Earth Sci, Cambridge, England.
    Poulton, S. W.
    Univ Leeds, Sch Earth & Environm, Leeds, W Yorkshire, England.
    Harvey, T. H. P.
    Univ Leicester, Dept Geol, Leicester, Leics, England.
    Brocks, J. J.
    Australian Natl Univ, Res Sch Earth Sci, Canberra, ACT, Australia.
    Nettersheim, B. J.
    Australian Natl Univ, Res Sch Earth Sci, Canberra, ACT, Australia; Max Planck Inst Biogeochem, Jena, Germany.
    Butterfield, N. J.
    Univ Cambridge, Dept Earth Sci, Cambridge, England.
    Oxygen minimum zones in the early Cambrian ocean2018In: Geochemical Perspectives Letters, ISSN 2410-339X, Vol. 6, p. 33-38Article in journal (Refereed)
    Abstract [en]

    The relationship between the evolution of early animal communities and oceanic oxygen levels remains unclear. In particular, uncertainty persists in reconstructions of redox conditions during the pivotal early Cambrian (541-510 million years ago, Ma), where conflicting datasets from deeper marine settings suggest either ocean anoxia or fully oxygenated conditions. By coupling geochemical palaeo-redox proxies with a record of organic-walled fossils from exceptionally well-defined successions of the early Cambrian Baltic Basin, we provide evidence for the early establishment of modern-type oxygen minimum zones (OMZs). Both inner- and outer-shelf environments were pervasively oxygenated, whereas mid-depth settings were characterised by spatially oscillating anoxia. As such, conflicting redox signatures recovered from individual sites most likely derive from sampling bias, whereby anoxic conditions represent mid-shelf environments with higher productivity. This picture of a spatially restricted anoxic wedge contrasts with prevailing models of globally stratified oceans, offering a more nuanced and realistic account of the Proterozoic-Phanerozoic ocean transition.

  • 42.
    Guldstrand, F.
    et al.
    Univ Oslo, Dept Geosci, Phys Geol Proc, Oslo, Norway..
    Burchardt, S.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Mineralogy Petrology and Tectonics.
    Hallot, E.
    Univ Rennes 1, Geosci Rennes, UMR 6118, OSUR,CNRS, Rennes, France..
    Galland, O.
    Univ Oslo, Dept Geosci, Phys Geol Proc, Oslo, Norway..
    Dynamics of Surface Deformation Induced by Dikes and Cone Sheets in a Cohesive Coulomb Brittle Crust2017In: Journal of Geophysical Research - Solid Earth, ISSN 2169-9313, E-ISSN 2169-9356, Vol. 122, no 10, p. 8511-8524Article in journal (Refereed)
    Abstract [en]

    The analysis of surface deformation associated with intruding magma has become an established method to study subsurface processes and intrusion architecture. Active subsurface magmatism induces deformation that is commonly modeled using static elastic models. To what extent, Coulomb failure of the crust affects surface deformation remains, so far, largely unexplored. In this contribution we present quantitative laboratory results of surface deformation induced by the emplacement of simulated dikes and cone sheets in a cohesive Coulomb material. The analysis of the experimental surface deformation shows that these intrusion types produce distinct and characteristic surface deformation signatures, which reflect the evolution of the intrusion at depth. Generally, dikes show a two-phase evolution while cone sheets develop gradually. In comparison, cone sheets induce larger uplifted areas and volumes than dikes relative to the depth of the injection source. Dike formation is, in turn, is likely accommodated, to a larger degree than cone sheets, by lateral opening of the host consistent with our current understanding of dike emplacement mechanics. Notably, only surface uplifts develop above the experimental dikes, consistent with a viscous indenter propagation mechanism, that is, a dike pushing ahead. The measured surface deformation patterns associated with dikes starkly contrast with established static, elastic models that predict local subsidence above the tip of a dike. This suggests that Coulomb failure of crustal rocks may considerably affect surface deformation induced by propagating igneous intrusions. This is especially relevant when a relatively high viscosity magma intrudes a weak host, such as unconsolidated sedimentary and volcaniclastic rocks.

  • 43.
    Hagerfors, Erika
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Formation of Sulphides in the Canadian High Arctic Large Igneous Province; Testing the Influence of Sedimentary Rocks2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Large Igneous Provinces (LIPs) form during short-lived pulses of extensive magmatic activity. LIPs are known for their ability to affect global climate as well as for their Ni-Cu-PGE ore potential. A key factor that controls the intensity of the climate impact of a LIP and its ore potential is the assimilation of volatile-rich sedimentary host rocks. Magmas of the High Arctic Large Igneous Province (HALIP), exposed in the Arctic, intruded volatile-rich black shales, carbonates and evaporites in the Canadian Arctic Islands, offering a great opportunity for studying magma-sediment interaction. The purpose of this study is to test whether assimilation of sedimentary sulphide can promote sulphide immiscibility in magma and thus aid formation of Ni-Cu-PGE ore bodies. This is done by analysing sulphur isotopes in pyrite grains hosted in a HALIP dolerite sill, which was emplaced into black shale, by using Secondary Ion Mass Spectrometry (SIMS). Four dolerite samples are analysed; two coming from the lower contact margin of the sill, one from 60 cm into the sill and one sample from a basaltic vein at the upper contact margin of the sill. A total of 14 pyrite grains (n = 246 individual SIMS spot analyses) were analysed for their sulphur isotope ratios. The results of the SIMS analyses show that all analysed sulphides have highly negative δ34S values ranging from -19.5 to -5.7‰ (average δ34S = -8.2 ± 0.83‰, 2SD), which therefore differ largely from that of the primitive mantle (0 ± 1.8‰). In order to put our four analysed dolerite samples into a broader context, δ34S data of our sulphides are compared with whole-rock δ34S and δ18O data from Hare Fiord shale and dolerite samples. The δ34S values of the sulphide samples from the sill typically trend toward the negative sulphur isotope composition of the sulphides in the surrounding shale, and the shale surrounding the sill experiences a loss of 32S near the contact of the sill. This indicates that sedimentary light sulphur (32S) has been locally incorporated into the sill by the surrounding shale, resulting in negative δ34S values in the magmatic sulphides. Since sulphide immiscibility in the Hare Fiord sill was triggered by assimilation of sulphur from host rock shale, the igneous rocks of the HALIP may be prospective for Ni-Cu-PGE mineralization, though more studies are needed. Furthermore, our results suggest that incorporation of crustal sulphur increased the volatile budget of HALIP magmas, which therefore could have contributed to a deterioration of the environmental conditions during the emplacement of the HALIP.

  • 44.
    Halldórsson, S.A.
    et al.
    Fluids and Volatiles Laboratory, Scripps Institution of Oceanography, University of California, San Diego, La Jolla, CA 92093-0244, USA.
    Hilton, D.R.
    Fluids and Volatiles Laboratory, Scripps Institution of Oceanography, University of California, San Diego, La Jolla, CA 92093-0244, USA.
    Troll, Valentin
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Solid Earth Geology.
    Fischer, T.P.
    Department of Earth and Planetary Sciences, University of New Mexico, Albuquerque, NM 87131-1116, USA.
    Resolving volatile sources along the western Sunda arc, Indonesia2013In: Chemical Geology, ISSN 0009-2541, E-ISSN 1872-6836, Vol. 339, no SI, p. 263-282Article in journal (Refereed)
    Abstract [en]

    We present the chemical and isotope (HeCN) characterization of active fumaroles and hydrothermal gases and waters from the summits and flanks of 19 volcanic centers along the western Sunda arc, Indonesia. Samples were collected over two field expeditions (1991 and 2010) and cover 13 volcanic centers in Sumatra, 5 in Java and one in Bali. In addition, we present data from three geothermal sites in Sumatra associated with active fault systems in-between volcanic centers (IBVC). The overall aim is to resolve volatiles associated with the sub-arc mantle (subducting slab and mantle wedge) from inputs derived from the over-riding arc crust. The western Sunda arc is a prime locality to assess controls on volatile provenance at subduction zones due to changes in composition and thickness of over-riding crust and variations in sediment input rates along the strike of the arc.

    The dry gas chemistry of the majority of volcanic samples is dominated by CO2 with inert gas variations (HeArN2) typical of subduction zone gases. However, there is a strong crustal control on the HeCO2 isotope and relative abundance systematics on a number of volcanic centers: this effect is most clearly observed at flank localities and in water phase samples. Filtering the entire database for modifications due to air contamination, degassing-induced fractionation (C-isotopes and CO2/3He ratios) and crustal contamination associated with volatile transport within shallow-level hydrothermal systems allows recognition of the magmatic volatile signature of individual volcanoes along the arc. Helium isotopes at all but two volcanic centers (Talang and Dempo on Sumatra) range from 5.3 RA to 8.1 RA (RA = air 3He/4He) pointing to the mantle wedge as the principal source of He but with a small input of crustal (radiogenic) He at some localities. Samples from Java and Bali span an even more limited range (6.6 to 7.9 RA) implying a relatively smaller input of crustal He. Carbon isotope and CO2/3He ratios vary from − 1.4‰ to − 6.4‰ and 4.38 to 150 (× 109), respectively, with higher and more variable values to the north of Sumatra. This latitudinal effect is not apparent in air-corrected N-isotope values (δ15NC = − 3.91 to + 5.92‰) or various elemental ratios such as N2/Ar and N2/He. The three IBVC sites, all located in Sumatra, have significantly lower 3He/4He ratios (< 3.6 RA) with CO2/3He values both higher and lower than volcanic centers. Their δ13C, δ15NC and gas ratios overlap with the volcanic centers.

    The elemental and isotopic characteristics of carbon and helium have been modified at IBVC sites due to crustal processes. However, based upon relationships between CH4 and 3He as well as co-variations between HeCN isotopes, the over-riding crust and associated sediments add minimal volatiles to volcanic centers throughout the western Sunda arc. In turn, subducted sediment, particularly the Nicobar Fan which supplies Himalayan-derived sediment to the slab off Sumatra, exerts a strong control on the magmatic CO2 characteristics although it is less influential for N2. In spite of large sections of incoming sedimentary material being off-scraped during subduction, our data suggest that a significant fraction must enter the trench, enhancing fluid/melt production in the mantle wedge. We propose that subduction-related source contamination plays the dominant role over thick/old crustal basement in supplying the major volatile output budget of the western Sunda arc.

  • 45.
    Hawkes, Jeffrey A.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Analytical Chemistry. Carl von Ossietzky Univ Oldenburg, Inst Chem & Biol Marine Environm ICBM, Res Grp Marine Geochem, D-26129 Oldenburg, Germany..
    Hansen, Christian T.
    Univ Bremen, Dept Geosci, D-28359 Bremen, Germany.;MARUM Ctr Marine Environm Sci, D-28359 Bremen, Germany..
    Goldhammer, Tobias
    MARUM Ctr Marine Environm Sci, D-28359 Bremen, Germany..
    Bach, Wolfgang
    Univ Bremen, Dept Geosci, D-28359 Bremen, Germany.;MARUM Ctr Marine Environm Sci, D-28359 Bremen, Germany..
    Dittmar, Thorsten
    Carl von Ossietzky Univ Oldenburg, Inst Chem & Biol Marine Environm ICBM, Res Grp Marine Geochem, D-26129 Oldenburg, Germany..
    Molecular alteration of marine dissolved organic matter under experimental hydrothermal conditions2016In: Geochimica et Cosmochimica Acta, ISSN 0016-7037, E-ISSN 1872-9533, Vol. 175, p. 68-85Article in journal (Refereed)
    Abstract [en]

    Marine dissolved organic matter (DOM) is a large (660 Pg) pool of reduced carbon that is subject to thermal alteration in hydrothermal systems and sedimentary basins. In natural high-temperature hydrothermal systems, DOM is almost completely removed, but the mechanism and temperature dependence of this removal have not been studied to date. We investigated molecular-level changes to DOM that was solid-phase extracted (SPE-DOM) from the deep ocean of the North Pacific Ocean. This complex molecular mixture was experimentally exposed to temperatures between 100 and 380 degrees C over the course of two weeks in artificial seawater, and was then characterised on a molecular level via ultrahigh-resolution Fourier-transform ion cyclotron mass spectrometry (FT-ICR-MS). Almost 93% of SPE-DOM was removed by the treatment at 380 degrees C, and this removal was accompanied by a consistent pattern of SPE-DOM alteration across the temperatures studied. Higher molecular weight and more oxygen rich compounds were preferentially removed, suggesting that decarboxylation and dehydration of carboxylic acid and alcohol groups are the most rapid degradation mechanisms. Nitrogen containing compounds followed the same overall trends as those containing just C, H and O up to 300 degrees C. Above this temperature, the most highly altered samples contained very little of the original character of marine DOM, instead being mainly composed of very low intensity N- and S-containing molecules with a high H/C ratio (>1.5). Our results suggest that abiotic hydrothermal alteration of SPE-DOM may already occur at temperatures above 68 degrees C. Our experiments were conducted without a sedimentary or mineral phase, and demonstrate that profound molecular alteration and almost complete removal of marine SPE-DOM requires nothing more than heating in a seawater matrix.

  • 46.
    Hawkes, Jeffrey A.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Analytical Chemistry. Carl von Ossietzky Univ Oldenburg, Res Grp Marine Geochem, ICBM MPI Bridging Grp, Inst Chem & Biol Marine Environm ICBM, D-26129 Oldenburg, Germany..
    Rossel, Pamela E.
    Carl von Ossietzky Univ Oldenburg, Res Grp Marine Geochem, ICBM MPI Bridging Grp, Inst Chem & Biol Marine Environm ICBM, D-26129 Oldenburg, Germany.;Alfred Wegener Inst, HGF MPG Grp Deep Sea Ecol & Technol, D-27570 Bremerhaven, Germany..
    Stubbins, Aron
    Univ Georgia, Skidaway Inst Oceanog, Marine Sci, Savannah, GA 31411 USA..
    Butterfield, David
    Univ Washington, Joint Inst Study Atmosphere & Oceans, Seattle, WA 98115 USA.;NOAA PMEL, Seattle, WA 98115 USA..
    Connelly, Douglas P.
    Univ Southampton, Natl Oceanog Ctr, Southampton SO14 3ZH, Hants, England..
    Achterberg, Eric P.
    Univ Southampton, Natl Oceanog Ctr, Southampton SO14 3ZH, Hants, England.;GEOMAR Helmholtz Ctr Ocean Res, D-24148 Kiel, Germany..
    Koschinsky, Andrea
    Jacobs Univ Bremen, D-28759 Bremen, Germany..
    Chavagnac, Valerie
    Univ Toulouse, Lab Geosci Environm Toulouse, F-31400 Toulouse, France..
    Hansen, Christian T.
    Univ Bremen, MARUM Ctr Marine Environm Sci, D-28359 Bremen, Germany.;Univ Bremen, Dept Geosci, D-28359 Bremen, Germany..
    Bach, Wolfgang
    Univ Bremen, MARUM Ctr Marine Environm Sci, D-28359 Bremen, Germany.;Univ Bremen, Dept Geosci, D-28359 Bremen, Germany..
    Dittmar, Thorsten
    Carl von Ossietzky Univ Oldenburg, Res Grp Marine Geochem, ICBM MPI Bridging Grp, Inst Chem & Biol Marine Environm ICBM, D-26129 Oldenburg, Germany..
    Efficient removal of recalcitrant deep-ocean dissolved organic matter during hydrothermal circulation2015In: Nature Geoscience, ISSN 1752-0894, E-ISSN 1752-0908, Vol. 8, no 11, p. 856-+Article in journal (Refereed)
    Abstract [en]

    Oceanic dissolved organic carbon (DOC) is an important carbon pool, similar in magnitude to atmospheric CO2, but the fate of its oldest forms is not well understood(1,2). Hot hydrothermal circulation may facilitate the degradation of otherwise un-reactive dissolved organic matter, playing an important role in the long-term global carbon cycle. The oldest, most recalcitrant forms of DOC, which make up most of oceanic DOC, can be recovered by solid-phase extraction. Here we present measurements of solid-phase extractable DOC from samples collected between 2009 and 2013 at seven vent sites in the Atlantic, Pacific and Southern oceans, along with magnesium concentrations, a conservative tracer of water circulation through hydrothermal systems. We find that magnesium and solid-phase extractable DOC concentrations are correlated, suggesting that solid-phase extractable DOC is almost entirely lost from solution through mineralization or deposition during circulation through hydrothermal vents with fluid temperatures of 212-401 degrees C. In laboratory experiments, where we heated samples to 380 degrees C for four days, we found a similar removal efficiency. We conclude that thermal degradation alone can account for the loss of solid-phase extractable DOC in natural hydrothermal systems, and that its maximum lifetime is constrained by the timescale of hydrothermal cycling, at about 40 million years(3).

  • 47.
    Hedayati, Maryeh
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    Wigston, Andrew
    Wolf, Jan Lennard
    Rebscher, Dorothee
    Niemi, Auli
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    Impacts of SO2 gas impurity within a CO2 stream on reservoir rock of a CCS pilot site: Experimental and modelling approach2018In: International Journal of Greenhouse Gas Control, ISSN 1750-5836, E-ISSN 1878-0148, Vol. 70, p. 32-44Article in journal (Refereed)
    Abstract [en]

    In order to evaluate chemical impacts of SO2 impurity on reservoir rock during CO2 capture and storage in deep saline aquifers, several batch reactor experiments were performed on laboratory scale using core rock samples from the pilot CO2 injection site in Heletz. In this experiment, the samples were exposed to pure N-2(g), pure CO2(g), and CO2(g) with an impurity of 1.5% SO2(g) under reservoir conditions for pressure and temperature (14.5 MPa, 60 degrees C). Based on the set-up and the obtained experimental results, a batch chemical model was established using the numerical simulation program TOUGHREACT V3.0-OMP. Comparing laboratory and simulation data provides a better understanding of the rock-brine-gas interactions. In addition, it offers an evaluation of the capability of the model to predict chemical interactions in the target injection reservoir during exposure to pure and impure CO2. The best match between the geochemical model and experimental data was achieved when the reactive surface area of minerals in the model was adjusted in order to calibrate the kinetic rates of minerals. The simulations indicated that SO2(g) tends to dissolve rather quickly and oxidizes under a kinetic control. Hence, it has a stronger effect on the acidity of the brine than pure CO2(g) and as a result, increased mineral dissolution and caused the precipitation of sulfate and sulfide minerals. Ankerite, dolomite, and siderite, the most abundant carbonates in the sandstone rock sample, are subject to stronger dissolution in the presence of SO2 gas. The performed simulations confirmed a slower dissolution rate for ankerite and siderite than for dolomite. The model reproduced the precipitation of pyrite and anhydrite as observed in the laboratory. The dissolution of dolomite observed in the batch reaction test with pure N-2 is assumed to be due to slight contamination with oxygen and modelling supported this. The inclusion of SO2 increased the porosity over that of the pure CO2 case, and is thus considered to increase the permeability and injectivity of the reservoir as well. Exposure to SO2 also increased the concentration of trace elements. The calibrated kinetic parameters determined in this study will be used to model the injection and long-term behavior of CO2 at the Heletz field site, and may be used for similar geologic reservoirs.

  • 48.
    Herbert, Roger
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    Winbjörk, Harry
    LKAB.
    Pilot-scale barrier system for removal of nitrate in mine drainage2012In: Proceedings of the 22nd V.M. Goldschmidt Conference, 2012Conference paper (Other academic)
    Abstract [en]

    Introduction

    Undetonated ammonium nitrate - based explosives are readily soluble in water and quickly enter into the mine water and process water at a mine site. Process water is eventually discharged to a surface water body and, without treatment, can lead to eutrophication in the recipient. In order to investigate the application of nitrate removal by denitrification in the cold climate of northern Sweden, laboratory and field experiments have been conducted. Laboratory column experiments were designed to determine denitrification rates at relevant temperatures for northern Sweden. Based on the column experiments at low temperature, a hydraulic residence time of ca. 24 hours was one of the design criteria used for dimensioning a barrier system in the field. In autumn 2009, a pilot-scale barrier system was constructed of sheet metal at the Malmberget iron ore mine. The barrier (9m x 2m x 1.5m) appears as an open basin with three inner dividing walls, and is filled with a reactive mixture consisting of crushed rock, sawdust, and sewage sludge. A small fraction of the water discharging from the Malmberget clarification pond was fed by pump to the barrier at a rate of ca. 5 m3 day-1.

    Results

    In the pilot-scale barrier system, analytical results from 2010 indicated that nitrate (NO3-) removal generally lay in the range between 11 and 77% of influent nitrate concentrations. In order to achieve a higher removal rate, the barrier system needed to be supplemented with an additional carbon and energy source for denitrifying bacteria. In 2011, a sodium acetate solution as an external electron donor was continuously added to the barrier system along with the influent water. Analytical results from 2011 indicate that the barrier system in Malmberget removes >95% of the incoming nitrate during summer months (average daily temperature 14oC for 2011) with the addition of acetate. The barrier did exhibit decreases in performance toward the end of the study period in 2011, but this is likely the result of a lower hydraulic residence time in the barrier at this time.

    Nitrite (NO2-) concentrations in effluent waters were initially in excess of influent values, indicating the production of nitrite in the barrier. However, both nitrite and ammonium (NH4+) concentrations decreased to below detection limits after the addition of acetate (CH3COO-), suggestion the occurrence of anaerobic ammonium oxidation (anommox) in the barrier substrate. During this period, alkalinity values peaked at 500 mg HCO3- L-1 in effluent waters, indicative of organic carbon (acetate) oxidation through denitrification:

    5CH3COO- + 8NO3- + 3H+ → 4N2(g) + 10HCO3- + 4H2O

    Stable isotope analyses of δ15N and δ18O in nitrate demonstrate an enrichment in 15N and 18O along the flowpath, supporting the conclusion that denitrification is responsible for nitrate removal.

  • 49.
    Herbert, Roger
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    Winbjörk, Harry
    Pilot-scale barrier system for removal of nitrate in mine drainage2011In: Mineralogical magazine, ISSN 0026-461X, E-ISSN 1471-8022, Vol. 75, p. 1012-1012Article in journal (Other academic)
    Abstract [en]

    Undetonated ammonium nitrate is readily soluble in water and quickly enters into the mine water and process water at amine site. In order to investigate the application of nitrate removal by denitrification in the cold climate of northern Sweden, a pilot-scale barrier system was constructed of sheet metal in autumn 2009 at the Malmberget iron ore mine.

    The barrier (9m x 2m x 1.5m) appears as an open basin with three inner dividing walls, and is filled with a reactive mixture consisting of crushed rock, sawdust, and sewage sludge. Water flows through the barrier at ca. 0.45 m3/hour.The chemical analyses of water flowing into and out of thebarrier during 2010 indicate that the degree of nitrate removal generally lay in the range between 11 and 77% of influent nitrate concentrations. Stable isotope analyses of δ15N and δ18O in nitrate demonstrate an enrichment in 15N and 18O in nitrate as water flows through the barrier, supporting theconclusion that denitrification is responsible for nitrateremoval. Ammonium concentrations in the barrier effluents are initially high, but these high levels are subsequently flushed from the barrier.

    In order to increase the degree of nitrate removal by denitrification in the barrier, a reactive carbon source needs to be added to the influent waters; this will be tested during the 2011 field season.

  • 50.
    Hjeltström, Anna
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Copper minerals under the microscope2015Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    From many perspectives copper is a very important metal for the modern society. It can be found in everything from jewellery to electronics. For this reason it is very important for geologists to be able to develop efficient methods for identification, characterisation, extraction and processing of copper. One method for the identification of copper bearing minerals is ore microscopy which has been used in this paper along with a general introduction. Samples from the study collection of the Department of Earth Sciences and the area of Långban and Månhöjden have been examined, documented and described in detail. The thesis begins with an introduction to the history and geochemistry of copper along with some ore forming processes.

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