Sökning: "U-Pb"

Visar resultat 11 - 15 av 41 avhandlingar innehållade ordet U-Pb.

  1. 11. The Mesoproterozoic Hallandian event - a region-scale orogenic event in the Fennoscandian Shield

    Författare :Linus Brander; Göteborgs universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Fennoscandian Shield; Hallandian orogeny; Eastern Segment; Protogine Zone; U-Pb geochronology; zircon; baddeleyite; Nd-isotopes; Hf-isotopes; tectonic model;

    Sammanfattning : The Sveconorwegian Province occupies the southwestern part of the Fennoscandian Shield. The easternmost tectonic unit of the Province is the 1710-1660 Ma parautochthonous Eastern Segment, which bears the imprint of at least two metamorphic events; the 1460-1380 Ma Hallandian and the 1150-970 Ma Sveconorwegian. LÄS MER

  3. 12. Understanding Zircon Geochronology - Constraints from Imaging and Trace Elements

    Författare :Andrius Rimsa; Berggrundsgeologi; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; hydrothermal; Petrology; mineralogy; hydraulic fracturing; Sveconorwegian; incipient charnockite; EBSD; cathodoluminescence; REE; Zircon; U-Pb geochronology; geochemistry; Petrologi; mineralogi; geokemi; Kerala Khondalite Belt;

    Sammanfattning : Formation of incipient charnockite in Söndrum, SW Sweden and the Kerala Khondalite Belt (KKB), S. India is accompanied by zircon growth. The age of the dehydration event is constrained by dating newly formed zircon to 1397±4 Ma (2?, MSWD=1.7) in Söndrum and ca. LÄS MER

  4. 13. U-Pb dating of detrital zircon from the Mt. Alfred area, Yilgarn Craton, Western Australia

    Författare :Ross Kielman; Martin Whitehouse; Alexander Nemchin; Victoria Pease; Åke Johansson; Jenny Andersson; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Detrital zircon; Geochronology; Archean; Hadean; Western Australia; Geology; geologi;

    Sammanfattning : Hadean and Paleo-Eoarchean aged detrital zircon provide a rare glimpse into the nature of the early Earth. Thus, the characterisation of new localities with rocks that host Hadean and Paleo-Eoarchean zircon provide invaluable insight into the Earth’s early crust. LÄS MER

  5. 14. Validating the existence of the supercraton Vaalbara in the Mesoarchaean to Palaeoproterozoic

    Författare :Ashley Gumsley; Berggrundsgeologi; []
    Nyckelord :Vaalbara; Kaapvaal Craton; Pilbara Craton; U-Pb geochronology; paleomagnetism; supercontinent; large igneous province; dyke swarm; sill province;

    Sammanfattning : In this thesis, the longevity and continuity of the Vaalbara supercraton is addressed in six papers aimed at placing new temporal and spatial constraints onthe supercraton in the Mesoarchean to Paleoproterozoic. It has been speculated since the 1960’s that the Kaapvaal Craton in southern Africa, together withthe Pilbara Craton in Western Australia existed as a single landmass during the Precambrian – the Vaalbara supercraton. LÄS MER

  7. 15. U-Pb geochronology of tectonothermal events related to the Rodinia and Gondwana supercontinents -observations from Antarctica and Baltica

    Författare :Oskar Paulsson; Berggrundsgeologi; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; klimatologi; pedology; climatology; Fysisk geografi; geomorfologi; marklära; kartografi; geomorphology; Physical geography; Gondwana; Rodinia; Antarctica; Baltica; Dronning Maud Land; cartography;

    Sammanfattning : This thesis presents data from two areas, Dronning Maud Land, Antarctica, and the Scandinavian Caledonides, Baltica. In addition, a comparative geochronological study is presented. The bedrock of Dronning Maud Land (DML) is dominated by migmatitic gneisses and post-tectonic intrusions. LÄS MER