Sökning: "Devonian"

Visar resultat 11 - 15 av 26 avhandlingar innehållade ordet Devonian.

  1. 11. Tectonic evolution of NW Svalbard

    Författare :Carl Pettersson; Stockholms universitet; []
    Nyckelord :Svalbard; Migmatization; Zircon; Provenance;

    Sammanfattning : The Neoproterozoic is a remarkable era in Earth’s history with dramatic variations in climate and biota, possibly resulting in global glaciations events (eg. “snowball earth”, Kirschvink, 1992) and the first appearance of metazoans (Conway Morris, 1993). LÄS MER

  3. 12. Precambrian and Caledonian history of Svalbard’s West Ny Friesland Terrane

    Författare :Fredrik Hellman; Berggrundsgeologi; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Geologi; physical geography; Geology; Detrital; Zircon; Svalbard; Caledonides; Spitsbergen; fysisk geografi; Petrology; mineralogy; geochemistry; Petrologi; mineralogi; geokemi;

    Sammanfattning : This thesis deals mainly with age-investigations of metasedimentary and magmatic rocks of Ny Friesland, located in the northeastern Svalbard. However, the provenance of quartz-porphyry clasts in a Devonian conglomerate have also been investigated in northwestern Svalbard. LÄS MER

  4. 13. 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

  5. 14. Berggrundsmorfologiska studier över kustslätten och Norrlandsterrängen inom delar av Umeå kommun, norra Norrland

    Författare :Karel Miškovský; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Precambrian bedrock; Fennoscandia; morphology; Umeå; weathering processes;

    Sammanfattning : The aim of this studv is to investigate interrelationships betweenbedrock relief and geological material. The area of investigation covers ca 350 km and is located in the Precambrian bedrock in the central part of Umeå commune, in northern Norrland. LÄS MER

  7. 15. The tectonic evolution of northwest Svalbard

    Författare :Carl Henrik Pettersson; Victoria Pease; Robert Strachan; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Svalbard; Rodinia; Laurentia; Zircon; Provenance; Migmatites; Clockwise P-T; Solid earth geology and petrology; Berggrundsgeologi och petrologi; Geology; geologi;

    Sammanfattning : Svalbard represents the uplifted and exhumed northwest corner of the Barents Sea Shelf. Pre-Carboniferous rocks of Svalbard are divided into the Eastern, Northwestern and Southwestern Terranes, were amalgamated during the Caledonian Orogen and are separated by north-south-trending strike-slip faults. LÄS MER