Search for dissertations about: "Phanerozoic"

Showing result 11 - 14 of 14 swedish dissertations containing the word Phanerozoic.

  2. 11. 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. 12. The flux of extraterrestrial matter to Earth as recorded in Paleogene and Middle Ordovician marine sediments

    Author : Anders Cronholm; Berggrundsgeologi; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; L-chondite; sediment-disperesed; chromite; break-up event; Arenig-Llanvirn;

    Abstract : This thesis aims at reconstructing events in the solar system, mainly collisional events in the asteroid belt, by searches for extraterrestrial minerals in Paleogene and Middle Ordovician marine sediments on Earth. Recent empirical evidence show that Earth has experienced a few brief periods during the Phanerozoic when the flux of extraterrestrial matter significantly increased. READ MORE

  5. 13. Fissure-hosted mineral formation and metallogenesis in the Långban Fe-Mn-(Ba-As-Pb-Sb...) deposit, Bergslagen, Sweden

    Author : Erik Jonsson; Ulf Hålenius; Tom Andersen; Stockholms universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; mineralogi; geologi; isotopgeokemi; mineraldiversitet; malmbildning; Palaeoproterozoikum; Bergslagen; Sverige; Earth sciences; Geovetenskap;

    Abstract : The Långban deposit in the Bergslagen ore province is one of the most mineral-rich and complex localities on Earth. Yet, despite more than 100 years of research, much about its origin and evolution has remained unknown. READ MORE

  6. 14. Changes in ocean geochemistry across the K-Pg boundary interval

    Author : Tjördis Störling; Berggrundsgeologi; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; K-Pg boundary; Paleocene; stable silicon isotopes; sponge spicules; radiolaria; Cerithium Limestone;

    Abstract : The Cretaceous - Paleogene boundary (K-Pg, 66 Ma) was a time interval with dramatic changes in the Earth’s climate and the ocean environment. It was characterized by severe disruptions of marine biogeochemical cycles due to a meteorite impact during a time of active volcanism. READ MORE