Search for dissertations about: "baddeleyite"

Showing result 1 - 5 of 9 swedish dissertations containing the word baddeleyite.

  2. 1. U-Pb baddeleyite geochronology of Precambrian mafic dyke swarms and complexes in southern Africa - regional scale extensional events and the origin of the Bushveld Complex

    Author : Johan Olsson; Berggrundsgeologi; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; U-Pb TIMS geochronology; geochemistry; baddeleyite; mafic dyke swarms; mantle plume; Bushveld Complex; Kaapvaal Craton; Zimbabwe Craton; Archean; Proterozoic;

    Abstract : Dolerite dykes are formed when iron- and magnesium-rich (mafic) mantle-derived magmas ascend through the lithosphere (upper part of the mantle) and crystallize as ‘hydro-fractures’ within the crust. Dykes may exist in great numbers to form dyke swarms (linear or radiating), which can be linked to time periods of continental break-up, or attempted break-up events, associated with voluminous volcanism. READ MORE

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

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

    Abstract : 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. READ MORE

  5. 3. New constraints on paleoreconstructions through geochronology of mafic dyke swarms in North Atlantic Craton

    Author : Mimmi Nilsson; Berggrundsgeologi; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; baddeleyit; U-Pb; geokronologi; large igneous province; mantelplym; superkontinent; paleorekonstruktion; North Atlantic craton; baddeleyite; Large Igneous Province; Mantle plume; supercontinent; paleoreconstruction; U-Pb; geochronology; North Atlantic craton;

    Abstract : Earth history is punctuated by a series of events of supercontinent amalgamation and break-up. Fragments of old continents display rifted margins and orogenic sutures that testify their involvement in supercontinent cycles. READ MORE

  6. 4. The Mesoproterozoic Hallandian event - a region-scale orogenic event in the Fennoscandian Shield

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

    Abstract : 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. READ MORE

  7. 5. Precambrian Crustal Evolution of the Rehoboth Province, Southern Africa

    Author : Valby van Schijndel; Göteborgs universitet; []
    Keywords : 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;

    Abstract : 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. READ MORE