Sökning: "Baltoscandia"

Visar resultat 6 - 10 av 10 avhandlingar innehållade ordet Baltoscandia.

  1. 6. Late Ordovician Faunal Distribution and Ecospace Partitioning in Marine Impact Craters : The Aftermath of the Lockne and Tvären Events

    Författare :Åsa M Frisk; Lars Holmer; Jan Ove Ebbestad; Maurits Lindström; Alan Owen; Uppsala universitet; []
    Nyckelord :impact crater; Lockne; Tvären; ecospace; the Great Ordovician Biodiversification Event; NATURAL SCIENCES; NATURVETENSKAP;

    Sammanfattning : In the Middle to Late Ordovician a boost of marine biodiversity occurred which is regarded as the most rapid diversity in Earth’s history, and termed the Great Ordovician Biodiversification Event. This time is also unique in that at least four marine meteorite craters with a good record of post-impact sediments are preserved in Baltoscandia. LÄS MER

  3. 7. Middle and Upper Ordovician graptolites, trilobites, and biostratigraphy of Scania and Jämtland, Sweden

    Författare :Christian Pålsson; Berggrundsgeologi; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; physical geography; Geology; Sweden; Jämtland; Scania Skåne ; Upper Ordovician; Middle Ordovician; palaeoecology; biostratigraphy; lithostratigraphy; Graptolites; trilobites; Geologi; fysisk geografi; Palaeontology; Paleontologi;

    Sammanfattning : Graptolites and some trilobites from Middle–Upper Ordovician siliciclastic and calcareous rocks in Scania (Skåne), southern Sweden, and Jämtland, central Sweden, are described and discussed. Their stratigraphic distribution is discussed on the basis of new and old collections from outcrops and drill cores. LÄS MER

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

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

    Sammanfattning : 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. LÄS MER

  5. 9. Evolution and ecology of Baltic late Ordovician univalved molluscs

    Författare :Jan Ove Rõysi Ebbestad; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Earth sciences; Geovetenskap; Earth sciences; Geovetenskap; Historical Geology and Paleontology; historisk geologi och paleontologi;

    Sammanfattning : Univalved molluscs (Gastropoda and Tergomya) are common fossils in the Palaeozoic succession across Baltoscandia, but most of the more embracive descriptive works on this group appeared before or near the turn of the 19th century. The study presented here aims at revision and description of some Baltoscandian late Ordovician/early Silurian univalved molluscs with emphasis on their shell morphology. LÄS MER

  7. 10. The flux of extraterrestrial matter to Earth as recorded in Paleogene and Middle Ordovician marine sediments

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

    Sammanfattning : 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. LÄS MER