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  • 201.
    Alm, Micael
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    Probability Modelling of Alpine Permafrost Distribution in Tarfala Valley, Sweden2017Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    A field data collection has been carried out in Tarfala valley at the turn of March to April 2017. The collection resulted in 36 BTS-measurements (Bottom Temperature of Snow cover) that has been used in combination with data from earlier surveys, to create a model of the occurrence of permafrost around Tarfala. To identify meaningful parameters that permafrost relies on, independent variables were tested against BTS in a stepwise regression. The independent variables elevation, aspect, solar radiation, slope angle and curvature were produced for each investigated BTS-point in a geographic information system.                 The stepwise regression selected elevation as the only significant variable, elevation was applied to a logistic regression to model the permafrost occurrence. The final model showed that the probability of permafrost increases with height. To distinguish between continuous, discontinuous and sporadic permafrost, the model was divided into three zones with intervals of probability. The continuous permafrost is the highest located zone and therefore has the highest likelihood, this zone delimits the discontinuous permafrost at 1523 m a.s.l. The discontinuous permafrost has probabilities between 50-80 % and its lower limit at 1108 m a.s.l. separates the discontinuous zone from the sporadic permafrost. 

  • 202.
    Almeida, Jaime
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Kinematic Evolution of aTranscurrent Fault Propagating Through Consecutive Volcanic Cones:a Case of Rheology and Separation2016Independent thesis Advanced level (degree of Master (Two Years)), 30 credits / 45 HE creditsStudent thesis
    Abstract [en]

    The main objective of this work is to test the effect of two conical-shaped positive topographic obstacleson propagation of a discrete basement dextral strike-slip or transcurrent fault. A set of sandbox analogue (physical) models was constructed, in which two consecutive sand cones were placed progressivelycloser to each other. Key structural and strain parameters, such axial strain ratios and angular strain, aswell as the width and direction of the basins which formed during deformation were measured and analyzed. This procedure was then repeated with a basal decoupling layer of PDMS beneath each cone,to test the influence of this layer on the deformation.The results show that, for models without a basal decoupling layer, the distance between the two cones governs the end-stage deformation patterns of the topographic obstacles. The proximity of the topographic obstacles causes an increase of their deformation, i.e., results in higher axial strain ratios and angular strain. This effect is particularly noticeable in the first obstacle, which is affected by a strong clockwise rotation. The basal ductile which partly decouples the basement fault from the cover units nullifies the previous effect (the increase in deformation caused by proximity) and, when present, localizes the deformation by not only producing narrower pull-apart basins within the obstacles but alsoby increasing their rotation.

  • 203.
    Almgren, E.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences.
    Karlsö2000In: Reallexikon der Germanischen Altertumskunde, Vol. 16, p. 282-285Article in journal (Refereed)
  • 204.
    Alm-Kübler, Kerstin
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences.
    Herring and Heather in the pollen diagrams fron Ottenby, Southern Öland, Sweden1996In: Poster and abstract : the 22nd Nordic Geological Winter Meeting, , p. 10Other (Other scientific)
  • 205.
    Alm-Kübler, Kerstin
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences.
    Eriksson, Jemt Anna
    Lindström, Helen
    Kvartär paleoekologi -samspelet i naturen under kvartärtiden1995In: Geologiskt Forum, ISSN 1104-4721, no 7, p. 7-19Article in journal (Other scientific)
  • 206.
    Alm-Kübler, Kerstin
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences.
    Ranheden, Håkan
    En landskapshistorisk studie av Gullringskärret : Södermanland, Österhaninge socken2000Report (Other scientific)
  • 207.
    Almqvist, Bjarne
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Geophysics.
    Biedermann, Andrea
    Klonowska, Iwona
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Mineralogy Petrology and Tectonics.
    Misra, Santanu
    Petrofabric development during experimental partial melting and recrystallization of a mica-schist analogue2015In: Geochemistry Geophysics Geosystems, ISSN 1525-2027, E-ISSN 1525-2027, Vol. 16, no 10, p. 3472-3483Article in journal (Refereed)
  • 208.
    Almqvist, Bjarne
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Geophysics.
    Björk, Andreas
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences. CSIRO, Mineral Resources, Bradfield Road, West Lindfield, NSW 2070, Australia.
    Mattsson, Hannes B.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Mineralogy Petrology and Tectonics.
    Hedlund, Daniel
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Gunnarsson, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Malehmir, Alireza
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Geophysics.
    Högdahl, Karin
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Mineralogy Petrology and Tectonics.
    Bäckström, Emma
    Nordic Iron Ore, Ludvika, Sweden.
    Marsden, Paul
    Nordic Iron Ore, Ludvika, Sweden.
    Magnetic characterisation of magnetite and hematite from the Blötberget apatite-iron-oxide deposits (Bergslagen), south-central Sweden2019In: Canadian journal of earth sciences (Print), ISSN 0008-4077, E-ISSN 1480-3313, Vol. 56, no 9, p. 948-957Article in journal (Refereed)
    Abstract [en]

    Rock magnetic measurements were carried out on drill core material and hand specimens from the Blötberget apatite-iron oxide deposit in the Bergslagen ore province, south-central Sweden, to characterise their magnetic properties. Measurements included several kinds of magnetic susceptibility and hysteresis parameters. Petrographic and scanning electron microscopy (SEM) were used to independently identify and quantify the amount and type of magnetite and hematite. Two hematite-rich samples were studied with laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) to quantify the trace element chemistry in hematite and investigate the potential influence of trace elements on magnetic properties. Three aspects of this study are noteworthy. 1) Hematite-rich samples display strong anisotropy of magnetic susceptibility, which is likely to affect the appearance and modelling of magnetic anomalies. 2) The magnitude-drop in susceptibility across Curie and Néel temperature transitions show significant correlation with the respective weight percent (wt%) of magnetite and hematite. Temperature dependent magnetic susceptibility measurements can therefore be used to infer the amounts of both magnetite and hematite. 3) observations of a strongly depressed Morin transition at ca -60 to -70 C (200 to 210 K) are made during low-temperature susceptibility measurements. This anomalous Morin transition is most likely related to trace amounts of V and Ti that substitute for Fe in the hematite. When taken together, these magnetic observations improve the understanding of the magnetic anomaly signature of the Blötberget apatite-iron oxide deposits and may potentially be utilised in a broader context when assessing similar (Paleoproterozoic) apatite-iron oxide systems.

  • 209.
    Almqvist, Bjarne
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Geophysics.
    Bosshard, Sonja
    Hirt, Ann
    Mattsson, Hannes Björn
    Hetényi, György
    Internal flow structures in columnar jointed basalt from Hrepphólar, Iceland: II. Magnetic anisotropy and rock magnetic properties2012In: Bulletin of Volcanology, ISSN 0258-8900, E-ISSN 1432-0819Article in journal (Refereed)
    Abstract
  • 210.
    Almqvist, Bjarne
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Geophysics.
    Burg, Jean-Pierre
    Berger, Julien
    Burlini, Luigi
    Seismic properties of the Kohistan oceanic arc root: insights from laboratory measurements and thermodynamic modeling2013In: Geochemistry Geophysics Geosystems, ISSN 1525-2027, E-ISSN 1525-2027, Vol. 14, no 6, p. 1819-1841Article in journal (Refereed)
    Abstract [en]

    P-wave velocities (Vp) have been measured in the laboratory and calculated using thermodynamic modeling for seven representative rock samples from the lower crust to mantle section of the Kohistan paleo-island arc. Lower crustal rocks comprise plagioclase-rich gabbro, garnet-bearing gabbro, and hornblendite; mantle rocks comprise garnetite, pyroxenite, websterite, and dunite. Measurements were performed at confining pressures up to 0.5GPa and temperatures up to 1200 degrees C. Vp were also calculated using rock major element chemistry with the Perple_X software package. Calculated Vp match closely the laboratory measurements. At depths representative for the arc root, Vp of upper mantle rocks vary from 7.7-8.1km/s, whereas the lower crustal rocks have velocities between 6.9-7.5km/s. P-wave anisotropy is small, with exceptions of sheared gabbros. Measured and calculated seismic properties are consistent with, and complement a growing database of published seismic properties from the Kohistan arc. In the light of such data, we discuss seismic imaging of present-day island arcs. Intermediate Vp (7.4-7.7km/s) in arc roots can be explained by pyroxenites and garnet-bearing mafic rocks. Strong seismic reflectors may be related to garnetites (8.0-8.2km/s).

  • 211.
    Almqvist, Bjarne
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Geophysics.
    Burlini, Luigi
    Mainprice, David
    Hirt, Ann
    Elastic properties of anisotropic synthetic calcite-muscovite aggregates2010In: Journal of Geophysical Research, ISSN 0148-0227, E-ISSN 2156-2202, Vol. 115Article in journal (Refereed)
  • 212.
    Almqvist, Bjarne
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Geophysics.
    Henry, Bernard
    Jackson, Mike
    Werner, Tomasz
    Lagroix, France
    Methods and applications of magnetic anisotropy: A special issue in recognition of the career of Graham J. Borradaile2014In: Tectonophysics, ISSN 0040-1951, E-ISSN 1879-3266, Vol. 629, p. 1-5Article in journal (Refereed)
  • 213.
    Almqvist, Bjarne
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Geophysics.
    Herwegh, Marco
    Schmidt, Volkmar
    Pettke, Thomas
    Hirt, Ann
    Magnetic susceptibility as a tool to study deformed calcite with variable impurity content2010In: Geochemistry Geophysics Geosystems, ISSN 1525-2027, E-ISSN 1525-2027, Vol. 11, no 1Article in journal (Refereed)
  • 214.
    Almqvist, Bjarne
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Geophysics.
    Hirt, Ann
    Herwegh, Marco
    Ebert, Andreas
    Walter, Jens
    Leiss, Bernd
    Burlini, Luigi
    Seismic anisotropy in the Morcles nappe shear zone: Implications for seismic imaging of crustal scale shear zones2013In: Tectonophysics, ISSN 0040-1951, E-ISSN 1879-3266, Vol. 603, p. 162-178Article in journal (Refereed)
    Abstract [en]

    Microstructures and textures of calcite mylonites from the Morcles nappe large-scale shearzone in southwestern Switzerland develop principally as a function of 1) extrinsic physical parameters including temperature, stress, strain, strain rate and 2) intrinsic parameters, such as mineral composition. We collected rock samples at a single location from this shear zone, on which laboratory ultrasonic velocities, texture and microstructures were investigated and quantified. The samples had different concentration of secondary mineral phases (<5 up to 40 vol.%). Measured seismic P waveanisotropy ranges from 6.5% for polyphase mylonites (similar to 40 vol.%) to 18.4% in mylonites with <5 vol.% secondary phases. Texture strength of calcite is the main factor governing the seismic P wave anisotropy. Measured S wave splitting is generally highest in the foliation plane, but its origin is more difficult to explain solely by calcite texture. Additional texture measurements were made on calcite mylonites with low concentration of secondary phases (<= 10 vol.%) along the metamorphic gradient of the shear zone (15 km distance). A systematic increase in texture strength is observed moving from the frontal part of the shear zone (anchimetamorphism: 280 degrees C) to the higher temperature, basal part (greenschist facies: 350-400 degrees C). Calculated P wave velocities become increasingly anisotropic towards the high-strain part of the nappe, from an average of 5.8%in the frontal part to 13.2% in the root of the basal part. Secondary phases raise an additional complexity, and may act either to increase or decrease seismic anisotropy of shear zone mylonites. Inlight of our findings we reinterpret the origin of some seismically reflective layers in the Grone-Zweisimmen line in southwestern Switzerland (PNR20 Swiss National Research Program). We hypothesize that reflections originate in part from the lateral variation in textural and microstructural arrangement of calcite mylonites in shear zones. 

  • 215.
    Almqvist, Bjarne
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Geophysics.
    Hirt, Ann
    Herwegh, Marco
    Leiss, Bernd
    Magnetic anisotropy reveals Neogene tectonic overprint in higly strained carbonate mylonites from the Morcles nappe, Switzerland2011In: Journal of Structural Geology, ISSN 0191-8141, E-ISSN 1873-1201, Vol. 33, p. 1010-1022Article in journal (Refereed)
  • 216.
    Almqvist, Bjarne
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Geophysics.
    Hirt, Ann
    Schmidt, Volkmar
    Dietrich, Dorothee
    Magnetic fabrics of the Morcles nappe complex2009In: Tectonophysics, ISSN 0040-1951, E-ISSN 1879-3266, Vol. 466, p. 89-100Article in journal (Refereed)
  • 217.
    Almqvist, Bjarne
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Geophysics.
    Koyi, Hemin
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Mineralogy Petrology and Tectonics.
    Bulk strain in orogenic wedges based on insights from magnetic fabrics in sandbox models2018In: Geology, ISSN 0091-7613, E-ISSN 1943-2682, Vol. 46, no 6, p. 483-486Article in journal (Refereed)
    Abstract [en]

    Anisotropy of magnetic susceptibility (AMS) analysis is used as a petrofabric indicator for a set of four identical-setup sandbox models that were shortened by different amounts and simulate contraction in a fold-and-thrust belt. During model shortening, a progressive reorientation of the initial magnetic fabric occurs due to horizontal compaction of the sand layers. At the early stages of shortening, magnetic lineation (k(1) axis) rotates parallel to the model backstop with subhorizontal orientation, whereas the minimum susceptibility (k(3) axis) is subvertical, which indicates a partial tectonic overprint of the initial fabric. With further shortening, the k(3) axis rotates to subhorizontal orientation, parallel to shortening direction, marking the development of a dominant tectonic magnetic fabric. A near-linear transition in magnetic fabric is observed from the initial bedding to tectonic fabric in all four models, which reflects a progressive transition in deformation from foreland toward hinterland. Model results confirm a long-held hypothesis where the AMS pattern and degree of anisotropy have been suggested to reflect the amount of layer-parallel shortening, based on field observations in many mountain belts. Results furthermore indicate that grain rotation may play a significant role in low-grade compressive tectonic regimes. The combination of analogue models with AMS enables the possibility to predict magnetic fabrics in different tectonic settings and to develop quantitative links between AMS and strain.

  • 218.
    Almqvist, Bjarne
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Geophysics.
    Mainprice, David
    Seismic properties and anisotropy of the continental crust: Predictions based on mineral texture and rock microstructure2017In: Reviews of geophysics, ISSN 8755-1209, E-ISSN 1944-9208, Vol. 55, no 2, p. 367-433Article, review/survey (Refereed)
  • 219.
    Almqvist, Bjarne
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Geophysics.
    Mainprice, David
    Madonna, Claudio
    Burlini, Luigi
    Hirt, Ann
    Application of differential effective medium, magnetic pore fabric analysis, and X-ray microtomography to calculate elastic properties of porous and anisotropic rock aggregates2011In: Journal of Geophysical Research, ISSN 0148-0227, E-ISSN 2156-2202, Vol. 116Article in journal (Refereed)
  • 220.
    Almqvist, Bjarne
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Geophysics.
    Misra, Santanu
    Klonowska, Iwona
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Mineralogy Petrology and Tectonics.
    Mainprice, David
    Majka, Jaroslaw
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Mineralogy Petrology and Tectonics.
    Ultrasonic velocity drops and anisotropy reduction in mica-schist analogues due to melting with implications for seismic imaging of continental crust2015In: Earth and Planetary Science Letters, ISSN 0012-821X, E-ISSN 1385-013X, Vol. 425, p. 24-33Article in journal (Refereed)
  • 221. Al-Qayim, Basim
    et al.
    Omer, Azad
    Koyi, Hemin
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Solid Earth Geology.
    Tectonostratigraphic overview of the Zagros Suture Zone, Kurdistan Region, Northeast Iraq2012In: GeoArabia, ISSN 1025-6059, Vol. 17, no 4, p. 109-156Article in journal (Refereed)
    Abstract [en]

    The northwestern segment of the Zagros Orogenic Belt of the Kurdistan Region of Iraq includes the Zagros Suture Zone which is consisting of allochthonous Tethyan Triassic-Eocene thrust sheets. The zone is bounded by the Zagros Main Reverse Fault in the northeast, and the Zagros Thrust Front in the southwest. Parts of this zone's rocks are represented by stacks of thrust mega-sheets obducted over the autochthonous Cretaceous-Cenozoic sequence of the Arabian Plate margin. Each sheet represents a specific Tethyan tectonostratigraphic facies, and includes (from older to younger): isolated Triassic carbonate platforms (Avroman Limestone), Jurassic carbonate imbricates (Chia Gara, Sargelu and other formations), radiolarites (Qulqula Group), sedimentary melange (sedimentary-volcanic units of the Qulqula Group), ophiolites (Mawat and Penjwin ultramafics complexes), and Cenozoic fore-arc volcano-sedimentary sequences (Walash Group). Petrography, facies interpretation and lithostratigraphic correlation of these allochthons along four traverses across the Zagros Suture Zone of the examined area indicate that they evolved during the closure of the Neo-Tethys Ocean. Their stacking pattern and tectonic association resulted from two important events: the Late Cretaceous obduction processes, and the Late Miocene Pliocene collision, uplift, folding and suturing between the Arabian Plate and the Sanandaj-Sirjan Block of Iran. Based on these field observations and by using the model of the Iranian Zagros evolution, a tectonic scenario is proposed to explain the history and evolution of the Zagros Suture Zone in this area.

  • 222.
    Al-Ramadan, Khalid
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences.
    Impact of Diagenetic Alterations on Reservoir Quality and Heterogeneity of Paralic and Shallow Marine Sandstones: Links to Depositional Facies and Sequence Stratigraphy2006Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis constrains the distribution of diagenetic alterations and their impact on reservoir-quality and heterogeneity evolution pathways in relation to depositional environments and sequence stratigraphy (systems tracts and key sequence stratigraphic surfaces) of four selected paralic and shallow marine siliciclastic successions.

    Typical eogenetic alterations encountered include the dissolution and kaolinitization of framework silicates, which are closely associated to shoreface facies of forced regressive systems tract (FRWST), lowstand systems tract (LST), upper part of the highstand systems tract (HST), and below the sequence boundary (SB). These alterations are attributed to incursion of meteoric water owing to rapid and considerable fall in the relative sea level. Extensive carbonate cementation is most evident below marine and maximum flooding surfaces (MFS), whereas dissolution of carbonate cement and detrital dolomite occur in LST, HST and below SB. Parameters controlling the patterns and texture (microcrystalline vs. poikilotopic) of calcite cement have been constrained within sequence stratigraphic framework of the sandstones. Coarse crystalline to poikilotopic calcite textures of meteoric water origin are thus closely linked to the FRWST, LST and upper part of the HST sandstones and occur mainly as stratabound concretions, whereas microcrystalline calcite, which was precipitated from marine porewaters, occurs as continuously cemented layers in the transgressive systems tract (TST) and lower part of the HST sandstones.

    Eogenetic alterations impose, in turn, profound control on the distribution pattern of mesogenetic alterations, and hence on reservoir quality evolution (destruction vs. preservation) pathways of sandstones. Eogenetic infiltrated clays, which occur in the tidal estuarine TST and HST sandstones, have helped preserving porosity in deeply buried sandstone reservoirs (≈ 5 km) through inhibition of extensive cementation by quartz overgrowths. Other essential findings of this thesis include deciphering the control on the formation of authigenic illite and chlorite by ultra-thin (≤ 1 µm thick), grain-coating clay mineral substrate.

  • 223.
    Al-Ramadan, Khalid
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences.
    Morad, Sadoon
    El-Khoriby, Essam
    Distribution of Diagenetic Alterations in Sequence Stratigraphic Context of Tidal Flat Sandstones: Evidence From The Adedia Formation (Cambro-Ordovician), Sinai, Egypt.Manuscript (Other academic)
  • 224.
    Al-Ramadan, Khalid
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Morad, Sadoon
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Norton, A. Kent
    Hulver, Michael
    Linking Diagenesis and Porosity Preservation to Sequence Stratigraphy of Gas Condensate Reservoir Sandstones; the Jauf Formation (Lower to Middle Devonian), Eastern Saudi Arabia2013In: Linking Diagenesis to Sequence Stratigraphy (Special Publication 45 of the IAS) / [ed] Sadoon Morad, Marcelo Ketzer, Luis F. de Ros, John Wiley & Sons, 2013, p. 297-336Chapter in book (Refereed)
  • 225.
    Al-Ramadan, Khalid
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Morad, Sadoon
    Plink-Björklund, Piret
    Distribution of Diagenetic Alterations in Relationship to Depositional Facies and Sequence Stratigraphy of a Wave- and Tide-Dominated Siliciclastic Shoreline Complex: Upper Cretaceous Chimney Rock Sandstones, Wyoming and Utah, USA2013In: Linking Diagenesis to Sequence Stratigraphy (Special Publication 45 of the IAS) / [ed] Sadoon Morad, Luis F De Ros, John Wiley & Sons, 2013Chapter in book (Refereed)
  • 226.
    Al-Ramadan, Khalid
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Morad, Sadoon
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Proust, Jean-Noel
    Al-Aasm, Ihsan
    Distribution of Diagenetic Alterations in Siliciclastic Shoreface Deposits within a Sequence Stratigraphic Framework: Evidence from the Upper Jurassic, Boulonnais, NW France2005In: Journal of Sedimentary Research, ISSN 1527-1404, E-ISSN 1938-3681, Vol. 75, no 5, p. 943-959Article in journal (Refereed)
    Abstract [en]

    The distribution of diagenetic alterations in Upper Jurassic, siliciclastic shoreface sediments from NW France has been linked to the sequence stratigraphic framework. Calcite cement in mudrocks and sandstones of the transgressive (TST) and lower part of the highstand (HST) systems tracts is microcrystalline and occurs as continuously cemented layers and stratabound concretions. The average δ18OV-PDB (−2.6‰) and 87Sr/86Sr (0.7078) compositions of microcrystalline calcite indicate precipitation from largely marine pore waters.

    Calcite cement in sandstones of the forced regressive wedge (FRWST) and lowstand (LST) systems tracts is poikilotopic and occurs mainly as stratabound concretions. Complete dissolution of the carbonate grains and concomitant precipitation of poikilotopic calcite cement with low average δ18O (−5.3‰) and radiogenic Sr-isotope (0.70882) signatures suggest incursion of meteoric waters into sandstones during relative sea-level lowstand. The poorly lithified sandstones interbedded with sandstones cemented by poikilotopic calcite concretions display evidence of diagenesis under episodes of arid to semiarid paleoclimate, including: (i) partial cementation by opal, chalcedony, gypsum, and minor vadose calcite cement, (ii) mechanically infiltrated clays and Fe-oxides, and (iii) secondary porosity owing to partial dissolution of carbonate grains. The integration of diagenesis into sequence stratigraphy allows better elucidation and prediction of the spatial and temporal distribution of diagenetic alterations and related reservoir-quality modifications in shoreface sediments.

  • 227.
    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.

  • 228. Alshamsi, Dalal M.
    et al.
    Murad, Ahmed A.
    Aldahan, Ala
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    Hou, Xiaolin
    Uranium isotopes in carbonate aquifers of arid region setting2013In: Journal of Radioanalytical and Nuclear Chemistry, ISSN 0236-5731, E-ISSN 1588-2780, Vol. 298, no 3, p. 1899-1905Article in journal (Refereed)
    Abstract [en]

    Groundwater in arid and semiarid regions is vital resource for many uses and therefore information about concentrations of uranium isotopes among other chemical parameters are necessary. In the study presented here, distribution of U-238 and U-235 in groundwater of four selected locations in the southern Arabian peninsula, namely at two locations within the United Arab Emirates (UAE) and two locations in Oman are discussed. The analyses of the uranium isotopes were performed using ICP-MS and the results indicated a range of concentrations for U-235 and (238) U at 3-39 ng L-1 (average: 18 ng L-1) and 429-5,293 ng L-1 (average: 2,508 ng L-1) respectively. These uranium concentrations are below the higher permissible WHO limit for drinking water and also comparable to averages found in groundwater from similar aquifers in Florida and Tunisia. Negative correlation between rainfall and uranium concentrations suggests that in lithologically comparable aquifers, climate may influence the concentration of uranium in subtropical to arid regions.

  • 229.
    Alsmyr, Michaela
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    Utvärdering av lufthalts- och nedfallsmätningar gjorda vid Korsnäsverken: Samband mellan miljöförbättrande arbete i pappers- och massaindustrin och föroreningar i närområdet2013Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    A decline has been seen in Sweden and Europe when it comes to air pollution the last decades. The decline is partly due to reduced emissions from industries, switching from heating using oil and coal boilers to district heating and better fuel quality. This study evaluates deposition and air concentration measurements made in the vicinity of the pulp and paper industry Korsnäs in Gävle. The measurement series starts at the late 1970s and goes up to year-end 2009/2010. Deposition of dust, sulphate, sodium, calcium and air concentrations of sulphur dioxide and soot were studied. Comparisons were made with Korsnäs environmental measures and emissions during the same time period and with other measurements made in Sweden and Gävleborgs County.

    The study showed a decrease in sulphur dioxide concentrations in the air. This fits well with a major reduction of sulphur emissions from the factory area in the early 1990s when installations of treatment plants were made at the largest emission sources of sulphur dioxide. Reducing the sulphur content of fuel oil from Karskär Energi AB, an energy combine owned by Korsnäs in the same factory area, contributed to the decrease during the same time period. Air concentrations of soot showed no downward trend over the years, but were seasonal, with higher average soot concentrations in the winter. This was most likely caused by the burning of fuel oil from both the private sector and Karskär Energi AB. The largest air concentrations did not show higher levels of sulphur dioxide and soot when the mean wind direction was easterly and thus blew from factory area toward the monitoring station but when the wind direction was southwesterly and blew from inland. The total dust and calcium deposition showed no decline but had higher average measured levels in the summer. Sulphate deposition showed high levels during the late 1980s but has thereafter decreased. The sodium deposition decreased a little during the time period. No clear connection was found between deposition/air concentrations and emissions from the factory area when the data series were sorted by wind direction, wind speed and after the summer and winter months. Depositions and air concentrations were not higher except for sulphur dioxide when the comparison was made with other measurements in Sweden and Gävleborg County. All measurements were below the then current national limits.

  • 230.
    Alsterhag, Elin
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Förslag till modell av kemikaliespridning i mark anpassad för användning vid räddningsinsats - Kemspill Mark 4.02005Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    After emergencies involving chemical spills it is of great importance that correct measures are taken with short notice, both for the security of people and in order to minimize future environmental consequences. The RIB-unit at the Swedish Rescue Services Agency initiated this study, the aim of which is to propose changes to the existing chemical transport calculation tool: Chemical Spill 3.4, included in RIB - Integrated Decision Support for Civil Protection, so that it can be used for decision support as well as in preventive work. A rough estimation of chemical transport in the subsurface is considered being of great importance when making decisions during emergency response operations.

    The proposition presented in this report is a non site specific chemical transport model which is designed to give a rough estimation of NAPL flow in homogenous isotropic soil shortly after an instantaneous release. The model can be used at two levels; both in situations without access to information on subsurface properties, and with more accuracy in situations with knowledge of the included parameters. For that reason the user can choose among predefined alternatives or assign the parameters a numeric value to increase the quality of the model output. The predefined alternatives are represented by default values for different parameters in the model.

    Suggested model output are vertical and horizontal transport of NAPL phase, horizontal transport of dissolved chemical in the aqueous phase, as well as the amounts of spill that are evaporated and entrapped in the soil, all at the time specified by the user. Moreover the maximum transport of the chemical phase and time to groundwater pollution are given. To make the uncertainty of the model clear for the user the results are given as the most likely value together with the smallest and largest values that can be expected.

    Equations presented in this report describe a selection of subsurface processes which occur after a release of chemicals. The selection is made with the aim to reach satisfying result when the model is used within its domain without making the model complicated for the user. Therefore simplifying assumptions have been made in the descriptions of some processes while some other processes are neglected. Simplifications have been based on recognized references or on theoretical arguments, but the overall performance of the model as well as some of the default input parameters need to be further tested and validated before the new version of the model can be included in RIB. However, compared with the existing version Chemical Spill 3.4 several changes have been suggested; including additional processes, development of default values and making model uncertainty clear to the user. These changes are thought to significantly improve the existing model.

  • 231.
    Altenburger, Andreas
    et al.
    Section for Evolutionary Genomics, Natural History Museum of Denmark, University of Copenhagen, Copenhagen, Denmark.
    Martinez, Pedro
    Department of Genetics, University of Barcelona, Barcelona, Spain; Institut Català de Recerca i EstudisAvancats, Barcelona, Spain.
    Budd, Graham E.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Holmer, Lars E.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Gene Expression Patterns in Brachiopod Larvae Refute the "€œBrachiopod-Fold"€ Hypothesis2017In: Frontiers in Cell and Developmental Biology, Vol. 5, p. 1-3, article id 74Article in journal (Refereed)
  • 232. Altenburger, Andreas
    et al.
    Wanninger, Andreas
    Holmer, Lars E.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Metamorphosis in Craniiformea revisited: Novocrania anomala shows delayed development of the ventral valve2013In: Zoomorphology, ISSN 0720-213X, E-ISSN 1432-234X, Vol. 132, no 4, p. 379-387Article in journal (Refereed)
    Abstract [en]

    We revisited the brachiopod fold hypothesis and investigated metamorphosis in the craniiform brachiopod Novocrania anomala. Larval development is lecithotrophic and the dorsal (brachial) valve is secreted by dorsal epithelia. We found that the juvenile ventral valve, which consists only of a thin layer that was previously described as periostracal, is not a valve and is not secreted by the same epithelia as the dorsal valve. It is secreted by the attachment area of the larva at the posterior-most tip of the posterior larval lobe. The same attachment area is used by larvae of rhynchonelliform brachiopods during metamorphosis to cement their pedicle to the substrate. N. anomala is therefore not initially attached by a valve but by material corresponding to pedicle cuticle. This is different to previous descriptions, which had led to speculations about a folding event in the evolution of Brachiopoda. We show that the “brachiopod fold hypothesis,” which argues that brachiopods are transversely “folded” across the ontogenetic anterior–posterior axis, should be rejected at least with respect to the craniiforms. The data now suggest that the Craniiformea may be a derived group within the Rhynchonelliformea. This interpretation suggests that the last common ancestor of the Craniiformea has lost the pedicle and the ventral valve in early juvenile development. Characters that have previously been considered to be shared between the Craniiformea and the Linguliformea (clade Inarticulata), such as a through-gut and missing hinge articulation, may thus be secondarily derived characters of the Craniiformea within the Rhynchonelliformea.

  • 233.
    Alterbeck, Jonas
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Förbrukningsreduktion: Ett alternativ till gasturbiner som snabb aktiv störningsreserv?2014Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The gas turbines in the Swedish secondary reserve are reaching the end of their technical lifetime, hence alternative solutions need to be considered. One of the solutions thought to have the greatest potential is the use of so called consumptionreduction. By entering contracts with large consumers, agreements are made to reduce consumption in the event of major disturbances in the power system and thus being used as a secondary reserve. This thesis investigates the feasibility of consumption reduction as part of the secondary reserve. This has been achieved by developing a requirement specification for the disturbance reserve and by studying the technical and economic potential for consumption reduction among a range of consumers.The technical potential for consumption reduction that fulfils the requirements for participating in the secondary reserve are on average 750 MW in SE 3 and 98 MW in SE 4. The result of this study shows that consumption reduction could work as a supplement to the gas turbines, but could not entirely replace the current solution. Furthermore, replacing the gas turbines would cause loss of features such as black start and automatic frequency regulation. Nevertheless, consumption reduction is considered as a workable solution for the disturbance reserve that is both cheaper and more environmentally friendly. Before launching consumption reduction as a reserve, a market model has to be developed, taking the findings of this thesis into account: high electricity prices have negative effect on availability and that low liquidity on the market causes short endurance.

  • 234.
    Alvarez, Manuel
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Improving the modelling of marine operations in the installation of offshore wind farms2016Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
  • 235.
    Alvesson Due Billing, Miha
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Small Scale Sustainability: A Qualitative Study of Corporate Sustainability in Swedish SMEs2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This qualitative study aims to contribute to the research field on corporate sustainability (CS) in small and medium-sized enterprise (SMEs), in hopes of helping policymakers better understand the circumstances for Swedish SMEs and how they work with CS. Empirical data about motivations behind working with CS, implementation of CS activities, and effects of CS work were collected through in-depth interviews with 18 company representatives. The major reason for motivation was found to be personal interest and commitment to these kind of practices, followed by strengthening the competitiveness, marketing, initiative from management and board, and profitability aspects. The implementation process is often informal in nature with concrete measures and activities rather than formal policies and strategies, although a few of the companies make use of tools such as environmental management systems. How the companies communicate their CS work differs and the response from stakeholders varies too. Lastly, profitability was found to be an important effect for some, while others more heavily emphasize the personal satisfaction from doing the right thing and being sustainable. The social effects were mostly improved working conditions and more engagement from stakeholders, while the environmental impact was understood to mostly concern a decrease in consumption of finite resources, and a more efficient use of material and energy. Suggestions for improving CS work in Swedish SMEs are increased support and encouragement from the government, and more education and information about what companies can do and how they can do it with appropriate tools. Concluding, CS in Swedish SMEs must be studied further to gain a more comprehensive picture of how to support those SMEs already working with CS and those in the path of transitioning towards a more sustainable development.

  • 236.
    Amanda, Eskebaek
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    Spridning av släckvattenpartiklar: En studie på spridning av partiklar genererade från brand2015Independent thesis Advanced level (degree of Master (Two Years)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    During a fire large amounts of particles and unhealthy agents occur.  Polyaromatic hydrocarbons (PAH) and toxic metals are examples among many others. These agents have a capacity to bond to particles and when the fire is extinguished, the particles can be transferred with the extinguish water into the soil and to the groundwater.

    Recent studies in particles have been conducted. A study by Ulrika Iverfelt (2014) reviled that the particles from a fire contained large amounts of both PAH and metals, which is consistent with earlier analyses. Her column experiments with particles in the size ≤ 11 microns and ≤100 microns in silica sand, reviled that the larger particles was immobilized because the transportation was influenced by sieving or physiochemical particle and surface interactions.

    The transport of the particles in soil and groundwater is regulated by two main mechanisms: physiochemical surface interactions and straining. The particle size and the surface charge are examples of properties that affect the transport. The particle charge is described by the zeta potential, which is an important characteristic for surface interactions with the solid medium. The zeta potential depends on the water chemistry which varies in different extinguish water. The zeta potential was measured to be negative in Iverfelts (2014) study.

    In order to predict and understand the transport of the particles, more column experiments with different properties were requested. In this study several transport experiments where made. The four parameters: grain size, particle size, ionic strength and pH were investigated systematically. The same type of column, sand and source of extinguish water as in Iverfelts study was used. 

    The results from the study indicated that the smaller particles were not affected by sieving, as the larger particles. When the pH was lowered, the results indicated that some of the smaller particles, ≤11 microns were immobilized. This was probably because the zeta potential of the particles was reduced, which allowed the physiochemical particle and surface interactions.

  • 237.
    Ambjörnsson, Linn
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Ewald, Katti
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Johansson Kling, Erika
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Larsson, Anna
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Marie, Selenius
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Elin, Svedberg
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Purification of arsenic contaminated water using ferrihydrite with consideration to current circumstances in Burkina Faso2016Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Ferrihydrite in a suspension has been studied as a solution for purification of arsenic contaminated water. Many development countries, amongst them Burkina Faso, have arsenic in their groundwater and the current methods for purification are too expensive. Measurements have shown extremely high levels of arsenic in the groundwater in several places in Burkina Faso. Since the availability of surface water is limited, the groundwater is still used as drinking water.

     

    A suspension of ferrihydrite has capacity to adsorb arsenic in water due to its chemical characteristics. Small-scale laboratory work with ferrihydrite suspensions has been performed in parallel in Uppsala, Sweden, and Ouagadougou, Burkina Faso. To purify the water with regard to the economical and practical circumstances in Burkina Faso, a column with safety filter was made out of simple materials such as plastic bottles, plastic tubes and glass wool. The contaminated water was flowing upwards through the column to prevent the filter from clogging.

     

    In Uppsala it was discovered that a 1 L ferrihydrite suspension containing 10 g ferrihydrite can adsorb 0.7 g arsenic while it was shaken and centrifuged well. In Ouagadougou it was possible, in the setup, to clean 2 L arsenic contaminated water with the concentration of 100 µg/L. The conclusions from the experiments in this project are that ferrihydrite can adsorb arsenic in contaminated water but that the setup used needs to be further evaluated and developed

  • 238.
    Amcoff, Örjan
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences.
    Nysten, Per
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. Uppsala University, Museums etc., Museum of Evolution.
    Bonanzamalm i mikroskala1998In: Geologiskt forum, ISSN 1104-4721, no 18, p. 9-11Article in journal (Other (popular scientific, debate etc.))
  • 239.
    Amcoff, Örjan
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences.
    Nysten, Per
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences.
    Mechanism of formation of witichenite rims around native bismuth in chalcocite and bornite from Långban, Sweden1990In: Geologiska Föreningens i Stockholm Förhandlingar, ISSN 1103-5897, Vol. 112, p. 45-50Article in journal (Refereed)
  • 240.
    Ameli, A. A.
    et al.
    Univ Western Ontario, Dept Biol, Biol & Geol Sci Bldg, London, ON N6A 3K7, Canada.;Univ Saskatchewan, Global Inst Water Secur, Saskatoon, SK, Canada.;Uppsala Univ, Dept Earth Sci Air Water & Landscape Sci, Uppsala, Sweden..
    McDonnell, J. J.
    Univ Saskatchewan, Global Inst Water Secur, Saskatoon, SK, Canada.;Univ Aberdeen, Sch Geosci, Aberdeen, Scotland..
    Bishop, Kevin
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Uppsala Centre for Sustainable Development, CSD Uppsala. Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL. Swedish Univ Agr Sci SLU, Dept Aquat Sci & Assessment, Uppsala, Sweden..
    The exponential decline in saturated hydraulic conductivity with depth: a novel method for exploring its effect on water flow paths and transit time distribution2016In: Hydrological Processes, ISSN 0885-6087, E-ISSN 1099-1085, Vol. 30, no 14, p. 2438-2450Article in journal (Refereed)
    Abstract [en]

    The strong vertical gradient in soil and subsoil saturated hydraulic conductivity is characteristic feature of the hydrology of catchments. Despite the potential importance of these strong gradients, they have proven difficult to model using robust physically based schemes. This has hampered the testing of hypotheses about the implications of such vertical gradients for subsurface flow paths, residence times and transit time distribution. Here we present a general semi-analytical solution for the simulation of 2D steady-state saturated-unsaturated flow in hillslopes with saturated hydraulic conductivity that declines exponentially with depth. The grid-free solution satisfies mass balance exactly over the entire saturated and unsaturated zones. The new method provides continuous solutions for head, flow and velocity in both saturated and unsaturated zones without any interpolation process as is common in discrete numerical schemes. This solution efficiently generates flow pathlines and transit time distributions in hillslopes with the assumption of depth-varying saturated hydraulic conductivity. The model outputs reveal the pronounced effect that changing the strength of the exponential decline in saturated hydraulic conductivity has on the flow pathlines, residence time and transit time distribution. This new steady-state model may be useful to others for posing hypotheses about how different depth functions for hydraulic conductivity influence catchment hydrological response.

  • 241.
    Ameli, A.A.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL. Department of Biology, Western University, London, Ontario, Canada.
    Amvrosiadi, Nino
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    Grabs, T.homas J.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    Laudon, Hjalmar
    Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, Umeå, Sweden.
    Creed, I.F.
    Department of Biology, Western University, London, Ontario, Canada.
    McDonnell, J.J.
    Global Institute for Water Security, School of Environment and Sustainability, University of Saskatchewan, Saskatoon, Saskatchewan, Canada; School of Geosciences, University of Aberdeen, Aberdeen, UK.
    Bishop, Kevin
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL. Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, Uppsala, Sweden.
    Hillslope permeability architecture controls on subsurface transit time distribution and flow paths2016In: Journal of Hydrology, Vol. 543, no A, p. 17-30Article in journal (Refereed)
    Abstract [en]

    Defining the catchment transit time distribution remains a challenge. Here, we used a new semi-analytical physically-based integrated subsurface flow and advective–dispersive particle movement model to assess the subsurface controls on subsurface water flow paths and transit time distributions. First, we tested the efficacy of the new model for simulation of the observed groundwater dynamics at the well-studied S-transect hillslope (Västrabäcken sub-catchment, Sweden). This system, like many others, is characterized by exponential decline in saturated hydraulic conductivity and porosity with soil depth. The model performed well relative to a tracer-based estimate of transit time distribution as well as observed groundwater depth–discharge relationship within 30 m of the stream. Second, we used the model to assess the effect of changes in the subsurface permeability architecture on flow pathlines and transit time distribution in a set of virtual experiments. Vertical patterns of saturated hydraulic conductivity and porosity with soil depth significantly influenced hillslope transit time distribution. Increasing infiltration rates significantly decreased mean groundwater age, but not the distribution of transit times relative to mean groundwater age. The location of hillslope hydrologic boundaries, including the groundwater divide and no-flow boundary underlying the hillslope, changed the transit time distribution less markedly. These results can guide future decisions on the degree of complexity that is warranted in a physically-based rainfall–runoff model to efficiently and explicitly estimate time invariant subsurface pathlines and transit time distribution.

  • 242.
    Ameli, Ali A.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL. Univ Saskatchewan, Global Inst Water Secur, Saskatoon, SK, Canada.;Western Univ, Dept Biol, London, ON, Canada..
    Controls on subsurface transport of sorbing contaminant2017In: Hydrology Research, ISSN 1998-9563, E-ISSN 2224-7955, Vol. 48, no 5, p. 1226-1239Article in journal (Refereed)
    Abstract [en]

    Subsurface transport of a sorbing contaminant is poorly understood and characterized. Here, a new semi-analytical saturated-unsaturated flow and transport model is coupled to a kinetic sorption algorithm to assess the impact of changes in the subsurface permeability architecture and flow rate on sorption characteristics. The model outputs reveal the pronounced effect of the rate of vertical decline in K-s on the frequency of occurrence and spatial distribution of subsurface sorption as well as the timing and rate of sorbing contaminants discharged into stream. Sorption potential is weakened with infiltration rate. The impact of infiltration rate on the decline in sorption potential becomes more accentuated as the degree of subsurface vertical heterogeneity in saturated hydraulic conductivity increases. Porosity pattern also impacts sorption characteristics; but its effects highly depend upon the degree of vertical heterogeneity in Ks. The results and methodology presented in this paper have potential implications for assessing water quality in integrated groundwater-surface water systems as well as designing remediation systems.

  • 243.
    Ameli, Ali A.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL. Univ Saskatchewan, Global Inst Water Secur, Saskatoon, SK, Canada.;Western Univ, Dept Biol, London, ON, Canada.
    Beven, Keith
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL. Univ Lancaster, Lancaster Environm Ctr, Lancaster, England..
    Erlandsson, Martin
    Stockholm Univ, Dept Phys Geog, Stockholm, Sweden..
    Creed, Irena F.
    Western Univ, Dept Biol, London, ON, Canada..
    McDonnell, Jeffrey J.
    Univ Saskatchewan, Global Inst Water Secur, Saskatoon, SK, Canada.;Univ Aberdeen, Sch Geosci, Aberdeen, Scotland.;Oregon State Univ, Dept Forest Engn Resources & Management, Corvallis, OR 97331 USA..
    Bishop, Kevin
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL. Swedish Univ Agr Sci, Dept Aquat Sci & Assessment, Uppsala, Sweden..
    Primary weathering rates, water transit times, and concentration-discharge relations: A theoretical analysis for the critical zone2017In: Water resources research, ISSN 0043-1397, E-ISSN 1944-7973, Vol. 53, no 1, p. 942-960Article in journal (Refereed)
    Abstract [en]

    The permeability architecture of the critical zone exerts a major influence on the hydrogeochemistry of the critical zone. Water flow path dynamics drive the spatiotemporal pattern of geochemical evolution and resulting streamflow concentration-discharge (C-Q) relation, but these flow paths are complex and difficult to map quantitatively. Here we couple a new integrated flow and particle tracking transport model with a general reversible Transition State Theory style dissolution rate law to explore theoretically how C-Q relations and concentration in the critical zone respond to decline in saturated hydraulic conductivity (K-s) with soil depth. We do this for a range of flow rates and mineral reaction kinetics. Our results show that for minerals with a high ratio of equilibrium concentration ( Ceq) to intrinsic weathering rate ( Rmax), vertical heterogeneity in K-s enhances the gradient of weathering-derived solute concentration in the critical zone and strengthens the inverse stream C-Q relation. As <mml:mfrac>CeqRmax</mml:mfrac> decreases, the spatial distribution of concentration in the critical zone becomes more uniform for a wide range of flow rates, and stream C-Q relation approaches chemostatic behavior, regardless of the degree of vertical heterogeneity in K-s. These findings suggest that the transport-controlled mechanisms in the hillslope can lead to chemostatic C-Q relations in the stream while the hillslope surface reaction-controlled mechanisms are associated with an inverse stream C-Q relation. In addition, as <mml:mfrac>CeqRmax</mml:mfrac> decreases, the concentration in the critical zone and stream become less dependent on groundwater age (or transit time).

  • 244.
    Amini, Samar
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Geophysics.
    Roberts, Roland
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Geophysics.
    Raeesi, Mohammad
    SeisAnalysis AS, Bergen, Norway.
    Shomali, Zaher Hossein
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Geophysics.
    Lund, Björn
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Geophysics.
    Zarifi, Zoya
    Univ Western Ontario, Dept Earth Sci, London, ON, Canada.
    Fault slip and identification of the second fault plane in the Varzeghan earthquake doublet2018In: Journal of Seismology, ISSN 1383-4649, E-ISSN 1573-157X, Vol. 22, no 4, p. 815-831Article in journal (Refereed)
    Abstract [en]

    An intraplate earthquake doublet, with 11-min delay between the events, devastated the city of Varzeghan in northwestern Iran on August 11, 2012. The first Mw 6.5 strike-slip earthquake, which occurred after more than 200 years of low seismicity, was followed by an Mw 6.4 oblique thrust event at an epicentral separation of about 6 km. While the first event can be associated with a distinct surface rupture, the absence of a surface fault trace and no clear aftershock signature makes it challenging to identify the fault plane of the second event. We use teleseismic body wave inversion to deduce the slip distribution in the first event. Using both P and SH waves stabilize the inversion and we further constrain the result with the surface rupture extent and the aftershock distribution. The obtained slip pattern shows two distinct slip patches with dissimilar slip directions where aftershocks avoid high-slip areas. Using the estimated slip for the first event, we calculate the induced Coulomb stress change on the nodal planes of the second event and find a preference for higher Coulomb stress on the N-S nodal plane. Assuming a simple slip model for the second event, we estimate the combined Coulomb stress changes from the two events on the focal planes of the largest aftershocks. We find that 90% of the aftershocks show increased Coulomb stress on one of their nodal planes when the N-S plane of the second event is assumed to be the correct fault plane.

  • 245.
    Amini, Samar
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Geophysics.
    Shomali, Z. Hossein
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Geophysics.
    Koyi, Hemin
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Solid Earth Geology.
    Roberts, Roland G.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Geophysics.
    Tomographic upper-mantle velocity structure beneath the Iranian Plateau2012In: Tectonophysics, ISSN 0040-1951, E-ISSN 1879-3266, Vol. 554-557, p. 42-49Article in journal (Refereed)
    Abstract [en]

    The Iranian plateau is one of the most structurally complex and tectonically inhomogeneous regions in the world. In this study, we analyze Pn arrival-times from regional seismicity in order to resolve lateral velocity variations within the uppermost-mantle under the Iranian Plateau. More than 48,000 Pn first arrival times selected from the EHB catalog were used with epicentral distances of 200 to 1600 km. We used regularized isotropic and anisotropic damped least-squares inversion to image lateral velocity variations in the upper mantle. Our velocity model, with high lateral resolution, shows positive anomalies in the Zagros mountain belt with a distinct transition approximately along the Main Zagros Thrust to the lower mantle velocity zone of Central Iran. Anomalously low velocities are observed predominantly beneath NW Iran and eastern Turkey, suggesting a zone of relatively weak mantle. Low velocity region under the Damavand volcano reveals the hot upper mantle beneath the central Alborz mountains.

  • 246.
    Amland, Sølvi
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Hvor er de markene i Sverige som er mest sensitive ovenfor forsuring og nitrogentap?2012Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Several factors affect whether the ground is prone to acidification and nitrogen loss. Removal of biological materials is an important factor that can trigger this. In Sweden, three dominant forest tree species are spruce, pine and birch trees. For forestry purposes, these trees are being logged at their potimal harvesting ages which are averaged at 70 years of age. This is of interest beacuse the forest ages can be used to predict future forestry practices, specifically in Dalarna, Sweden. The forest ages were observed at a catchment based level so that the effects of forestry can easily be measured. It was found that cathcments in the north of Dalarna consist of higher percentages of forest over the age of 70 in comparsion to the south and areas surrounding lakes. From this, it is expected that forestry will occur in the near future in the north.

    Hopefully the work that has been done in Dalarna, can be used as a model for the rest of Sweden.

  • 247.
    Amvrosiadi, Nino
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    Temporal Dynamics of Total Organic Carbon Export Rates in Swedish Streams: Importance of discharge conditions and seasonal effects2012Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The amount of total organic carbon (TOC) in water is a rough indicator of the waterquality. Driven by the question how the TOC concentration would vary acrossstreams in Sweden under different climate conditions (e.g. more extreme dischargeevents), the temporal dynamics of TOC were examined for different stream subgroupswith six orders of magnitude catchment area span. In addition, the relationshipbetween dissolved inorganic carbon (DIC) export (both downstream and evasion) anddischarge conditions was also studied. Another question addressed was if the amountof TOC exported can be affected by export conditions dominating the previousseason. TOC export followed closely the discharge, which is in agreement withprevious studies, and all 42 catchments studied across Sweden were described by thispositive relationship regardless their size. A linear TOC export response to dischargewas identified during extreme discharge conditions. Furthermore, the TOC export wassignificantly related to the antecedent TOC export conditions for approximately halfof the 18 studied catchments with areas ranging between 2.5·10-3 and 67 km2.

  • 248.
    Amvrosiadi, Nino
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    The value of experimental data and modelling for exploration of hydrological functioning: The case of a till hillslope2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Successfully modeling one system response (e.g. hydrograph or solute transport) sometimes gives the false sense of well-characterizing the modeled system. This is partly because of the well-known equifinality issue; during the calibration process multiple parameter combinations can produce similarly good results. One step forward towards a better-defined system is using measured (at relevant scale) values for the model parameters, as well as using multiple conditions to constrain the model.

    But when not enough, or relevant, field measurements are available, virtual experiments (VE’s) can be used as a supplementary method to model calibration. The advantage of VE’s over model calibration is that they can also be used to explore assumptions both on the system hydrological processes, and on the model structure.

    One goal of this study was to utilize both field measurements and models for better characterization of the S-transect hillslope, located in Västrabäcken catchment, Northern Sweden. This included (a) characteristics in space: system vertical boundaries, hydraulic parameters, pore water velocity distribution, spatial correlation of flowpaths, soil water retention properties; (b) characteristic of system’s dynamic behavior: storage – discharge relationship, transit time distribution, turnover time; and (c) outputs’ sensitivity to external forcing, and to small scale structure assumptions. The second goal was to comment on the value of field measurements and virtual experiments for extracting information about the studied system.

    An intensely monitored study hillslope was chosen for this work. Although the hillslope has already been the subject of multiple field and modelling studies, there are still open questions regarding the characteristics listed above. The models used were the Vertical Equilibrium Model (VEM), and the Multiple Interacting Pathways (MIPs) model.

    It was found that the hillslope was well connected; from the near-stream areas up to the water divide the storage – discharge relationship could be described as an exponential function. Also, the dynamic storage (which controls the hydrograph dynamics) was much smaller comparing to the total hillslope storage. The unsaturated soil storage was found to be more sensitive to water table positions than vertical flux magnitude. The dynamic condition of external forcing (precipitation and evapotranspiration) affected the transit time distribution (TTD) shape. And, opposite to expectations, TTD was not sensitive to micro-scale structural assumptions tested here.

  • 249.
    Amvrosiadi, Nino
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    Beven, Keith
    Bishop, Kevin
    Laudon, Hjalmar
    Seibert, Jan
    Value of virtual experiments for a hillslope scale system understandingManuscript (preprint) (Other academic)
  • 250.
    Amvrosiadi, Nino
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    Beven, Keith
    Bishop, Kevin
    Seibert, Jan
    Water age dependence on vertical flux assumptionsManuscript (preprint) (Other academic)
2345678 201 - 250 of 8496
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