Sökning: "Precambrian"

Visar resultat 1 - 5 av 37 avhandlingar innehållade ordet Precambrian.

  1. 1. P-T evolotion and High-temperature deformation of Precambrian eclogite, Sveconorwegian orogen

    Författare :Lorraine Tual; Berggrundsgeologi; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Eclogite; Precambrian; P–T path; Basal shear zone; Sveconorwegian orogen; Deformation; thermometry;

    Sammanfattning : The 1.1-0.9 Ga Sveconorwegian orogen is one of several Grenvillian-aged orogenic belts that mark the amalgamation of supercontinent Rodinia. The highest-pressure rocks in the Sveconorwegian orogen are eclogites in the Eastern Segment (SW Sweden). LÄS MER

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

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

    Sammanfattning : 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. LÄS MER

  4. 3. Precambrian geochronology of south-eastern Sweden

    Författare :Göran Åberg; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

    Sammanfattning : .... LÄS MER

  5. 4. Microfossils of eukaryotic cysts through time : A study of Precambrian-Ordovician organic-walled microbiota

    Författare :Heda Agić; Malgorzata Moczydlowska; Sebastian Willman; Frances Westall; Nicholas Butterfield; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; microfossils; eukaryotes; Proterozoic; reproductive cyst; Earth Science with specialization in Historical Geology and Palaeontology; Geovetenskap med inriktning mot historisk geologi och paleontologi;

    Sammanfattning : .... LÄS MER

  7. 5. 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