Search for dissertations about: "Sm-Nd"

Showing result 1 - 5 of 8 swedish dissertations containing the word Sm-Nd.

  2. 1. Mesoproterozoic crustal evolution in Southern Africa

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

    Abstract : 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. READ MORE

  4. 2. Pressure, temperature and time constraints on tectonic models for southwestern Sweden

    Author : Eric Austin Hegardt; Göteborgs universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Sveconorwegian; Gothian; Hallandian; U‐Pb zircon ion probe dating; Sm-Nd garnet dating; thermobarometry; continental subduction; Eastern Segment; Median Segment; Western Segment;

    Abstract : In this work, a number of key localities have been investigated in detail in order to provide precise constraints on models for the tectonic evolution of southern Sweden. The new data presented in this thesis show that there are large differences in terms of pre-Sveconorwegian tectonic evolution between the Eastern and Median-Western Segments situated on either side of the Mylonite Zone, a major shear zone as well as a structural and lithological boundary. READ MORE

  5. 3. Proterozoic crustal growth along the Archaean continental margin in the Luleå and Jokkmokk areas, northern Sweden

    Author : Claes Mellqvist; Luleå tekniska universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Applied Geology; Tillämpad geologi;

    Abstract : Den Arkeisk-Proterozoiska plattgränsen i norra Sverige har undersökts med hjälp utav fältarbete med både berggrundskartering och provtagning för geokemisk och isotopgeokemisk analys. Gränsen har studerats i både Luleå och Jokkmokkområdena för att man där skall kunna dra gränsen mer i detalj. READ MORE

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

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

    Abstract : 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. READ MORE

  7. 5. New Zircon geochronological and Nd isotopic evidence for Neoproterozoic crust reworking events in the Abas terrane, Yemen

    Author : Fitsum Girum Yeshanew; Victoria Pease; Martin Whitehouse; Hugh Rollinson; Kjell Billström; Stockholms universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Precambrian; Arabian Shield; magmatism; U-Pb; zircon; post-collisional magmatism; Nd isotopes; Geology; geologi;

    Abstract : The Arabian-Nubian Shield is an excellent natural laboratory to study crust formation processes during the Neoproterozoic. It is one of the largest juvenile tracts of continental crust formed during this time. It diachronously evolved between the breakup of Rodinia (c.780 Ma) and amalgamation of Gondwana (c. READ MORE