Sökning: "Phanerozoic"

Visar resultat 1 - 5 av 14 avhandlingar innehållade ordet Phanerozoic.

  1. 1. The micrometeorite flux to Earth through the Phanerozoic Eon : Reconstructed using sediment-dispersed extraterrestrial spinels

    Författare :Ellinor Martin; Kärnfysik; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; chromite; chrome spinel; micrometeorites; Phanerozoic; asteroid breakup; ordinary chondrites; 3He anomalies; lunar impacts; ice age; impact craters; zircons;

    Sammanfattning : The purpose of this thesis is to add an astronomical component to the history and evolution of Earth by reconstructing the micrometeorite flux to Earth at different time intervals during the Phanerozoic Eon, using sediment-dispersed extraterrestrial spinel group minerals as a proxy. Chromite and chrome spinel are common refractory members of the spinel group, occurring in both extraterrestrial and terrestrial rocks. LÄS MER

  3. 2. Geochemical and sedimentary signatures of Phanerozoic events

    Författare :Jane Wigforss-Lange; Berggrundsgeologi; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; geokemi; Sedimentology; Petrology; mineralogy; geochemistry; Petrologi; mineralogi; Carbon and oxygen isotopes; Jurassic-Cretaceous boundary; K-T boundary; Late Silurian; Events; Trace elements; Sedimentologi;

    Sammanfattning : Geological and biological catastrophic events have occurred repeatedly in the Earth's history, leaving traces in the global stratigraphical record in the form of sedimentary features, geochemical anomalies and biotic turnovers. This thesis focuses on the sedimentological and geochemical signatures of several key events in the Phanerozoic stratigraphical record, and aims to interpret the different signals and the causal mechanisms behind each of these events. LÄS MER

  4. 3. Sediment structures in the Phanerozoic bedrock of the Baltic Proper

    Författare :Monica Bjerkeus; Jan Bergström; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Geology; geologi;

    Sammanfattning : .... LÄS MER

  5. 4. Thermal history of the Phanerozoic sedimentary succession of Skåne, southern Sweden, and implications for applied geology

    Författare :Ingela Olsson; Berggrundsgeologi; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; mineralogy; geochemistry; Petrologi; mineralogi; geokemi; Petrology; organic matter reflectance; organic geochemistry; illite crystallinity; clay mineralogy; thermal history; Phanerozoicum; Skåne; Sweden;

    Sammanfattning : Post-depositional thermal conditions have been investigated throughout the Phanerozoic sedimentary succession in Skåne. Clay mineralogy and illite crystallinity have been the main tools for the Lower Palaeozoic strata. Within the Mesozoic sequence thermal influence was examined using RockEval pyrolysis and vitrinite reflectance analysis. LÄS MER

  7. 5. The geology and genesis of lead-zinc veins in Sweden

    Författare :Åke Johansson; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

    Sammanfattning : The geology and genesis of Pb-Zn-bearing vein deposits in Sweden have been studied through investigations of their geological setting, vein and alteration mineralogy, wall rock geochemistry, lead and sulfur isotope composition and sphalerite composition, and through thermometric measurements on fluid inclusions from selected veins. The investigated deposits include Subjotnian veins from Älvdalen, Dalslandian veins from Dalsland and Värmskog, Caledonian quartz and calcite veins, Devonian deposits in the Siljan Ring structure, and Variscan veins in SE Scania. LÄS MER