Sökning: "geokemi"

Visar resultat 1 - 5 av 243 avhandlingar innehållade ordet geokemi.

  1. 1. Origin of organic compounds in fluids from ultramafic-hosted hydrothermal vents of the Mid-Atlantic Ridge

    Detta är en avhandling från Stockholm : Department of Geology and Geochemistry, Stockholm University

    Författare :Cécile Konn; Stockholms universitet.; [2009]
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Serpentinisation; hydrocarbons; organic compounds; ultramafic; hydrothermal; geochemistry; origin of life; NATURAL SCIENCES Earth sciences Other earth sciences; NATURVETENSKAP Geovetenskap Övrig geovetenskap; NATURAL SCIENCES Chemistry Other chemistry; NATURVETENSKAP Kemi Övrig kemi; NATURAL SCIENCES Earth sciences Exogenous earth sciences Exogenous geochemistry; NATURVETENSKAP Geovetenskap Exogen geovetenskap Exogen geokemi; geokemi; Geochemistry;

    Sammanfattning : Natural gas, primarily methane (CH4), is produced in substantial amounts in ultramafic-hosted hydrothermal systems. These systems could also generate oil (heavier hydrocarbons) and the first building blocks of life (prebiotic molecules). In the presence of iron bearing minerals, serpentinisation reactions generate H2. LÄS MER

  2. 2. Geochronology of the Oklo and Bangombé fossil natural fission reactors : tracing the effects of geological events

    Detta är en avhandling från Stockholm : Department of Geology and Geochemistry, Stockholm University

    Författare :Lena Zetterström Evins; Stockholms universitet.; [2002]
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Historisk geologi; Geology; geologi; geokemi; Geochemistry;

    Sammanfattning : Thesis to be publicly defended for the degree of Doctor of Philosophy, in lecture room De Geersalen, Svante Arrhenius väg 8a, Stockholm, Friday February 1, 2002 at 10.00 am. Two billion years ago, natural fission reactions took place in the Oklo and Bangombé uranium ores in Gabon, West Equatorial Africa. LÄS MER

  3. 3. Sveconorwegian metallogenesis in Sweden

    Detta är en avhandling från Stockholm : Stockholm University

    Författare :Elisabet Alm; Stockholms universitet.; [2000]
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; geokemi; Geochemistry;

    Sammanfattning : Two main ore types are found in the Sveconorwegian Orogen in southwestern Sweden (Southwest Scandinavian Domain). One of them comprises stratabound Cu mineralizations in the Dal group, located west of lake Vänern. LÄS MER

  4. 4. Late-orogenic, ductile shear zones and protolith ages in the Svecofennian domain, central Sweden

    Detta är en avhandling från Stockholm : Stockholm University

    Författare :Karin Högdahl; Stockholms universitet.; [2000]
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Mineralogy; Petrology and Geochemistry; mineralogi; petrologi och geokemi;

    Sammanfattning : The timing of deformation along ductile shear zones in the Svecofennian Domain in central Sweden has generally been constrained by their relationship to magmatic and metamorphic events of known age. A better resolution for the timing of the deformation can be obtained by direct, radiometric dating of minerals which are constituents of the shear fabric. LÄS MER

  5. 5. Benthic metabolism and sediment nitrogen cycling in Baltic sea coastal areas the role of eutrophication, hypoxia and bioturbation

    Detta är en avhandling från Department of Geological Sciences, Stockholm Univeristy

    Författare :Stefano Bonaglia; Stockholms universitet.; [2012]
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Eutrophication; Sediment; Benthic Flux; Nitrogen Cycle; Denitrification; Baltic Sea; Biogeochemistry; biogeokemi; marin- och brackvattensekologi; Marine and Brackish Water Ecology; marin ekologi; Marine Ecology; geokemi; Geochemistry;

    Sammanfattning : Eutrophication is one of the greatest threats for the Baltic Sea, and one of its more critical consequences is bottom water hypoxia. Nutrient enrichment and oxygen-depletion affect both the deep central basins and a number of coastal areas, even though strategies for nutrient reduction have lately been implemented. LÄS MER