Sökning: "zircon"

Visar resultat 11 - 15 av 53 avhandlingar innehållade ordet zircon.

  1. 11. Precambrian Crustal Evolution of the Rehoboth Province, Southern Africa

    Författare :Valby van Schijndel; Göteborgs universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Rehoboth Province; Rehoboth Basement Inlier; Kaaien Terrane; Dwyka Diamictite; U–Pb; Sm–Nd; Lu–Hf; Ar–Ar Geochronology; Oxygen isotopes; Zircon; Baddeleyite;

    Sammanfattning : This thesis uses U-Pb, Sm-Nd Lu-Hf, Ar-Ar and Oxygen isotope data on well-documented rock samples, to investigate crustal evolution of the Precambrian Rehoboth Province of Southern Africa. This province is defined by its smooth magnetic character, reflecting deep magnetic basement in contrast to the adjoining mobile belts and the Kaapvaal Craton. 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. 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

  5. 14. 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

  7. 15. 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