Sökning: "U-Pb zirkon dating"

Hittade 3 avhandlingar innehållade orden U-Pb zirkon dating.

  1. 1. The tectonic evolution of the western part of the Svecofennian orogen, central Sweden : Insight from U/Pb and 40Ar/39Ar geochronology at Forsmark

    Författare :Tobias Hermansson; Berggrundsgeologi; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; physical geography; Geology; Svecofennian orogen; Tectonic models; Tectonic cycles; Uplift; Cooling; Ductile deformation; Geochronology; U Pb; 40Ar 39Ar; Geologi; fysisk geografi; Petrology; mineralogy; geochemistry; Petrologi; mineralogi; geokemi;

    Sammanfattning : The Forsmark area, in the western part of the Svecofennian orogen, central Sweden, is situated between two major Palaeoproterozoic tectonic domains that show contrasting histories with respect to timing of igneous activity, ductile deformation and metamorphism. At Forsmark, WNW to NW trending, ductile deformation belts anastomose around tectonic lenses with an inferred lower degree of ductile strain. LÄS MER

  3. 2. Mesoproterozoic crustal evolution in Southern Africa

    Författare :Åsa Pettersson; Göteborgs universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Namaqua-Natal province; Mezoproterozoic; geochronology; U-Pb zirkon dating; Sm-Nd model ages; Ar-Ar dating; Southern Africa;

    Sammanfattning : The objects of this thesis were to use geochronology to investigate crustal evolution of part of Southern Africa that formed during a global event, resulting in the ~1 Ga supercontinent Rodinia. The timing of assembly by continent-continent collisions and the position of the individual continental blocks of this ancient landmass is still largely unknown. LÄS MER

  4. 3. Metamorphic zircon formation in gabbroic rocks – the tale of microtextures

    Författare :Victoria Beckman; Berggrundsgeologi; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Zircon formation; metamorphism; prograde; gabbr; zircon; baddeleyite; zircon; baddeleyite; metamorphic; prograde; zircon textures;

    Sammanfattning : Dating of metamorphic events is crucial for the understanding and reconstruction of large-scale geological processes such as orogenesis. Zircon is one of the most commonly used minerals for dating of igneous and metamorphic events. Zircon incorporates uranium and excludes lead during crystallization, and with time the uranium decays to lead. LÄS MER