Sökning: "dateringar"

Visar resultat 11 - 13 av 13 avhandlingar innehållade ordet dateringar.

  1. 11. Treeline dynamics in short and long term perspectives : observational and historical evidence from the southern Swedish Scandes

    Författare :Lisa Öberg; Bengt-Gunnar Jonsson; Leif Kullman; Aage Paus; Mittuniversitetet; []
    Nyckelord :Betula pubescens ssp. czerepanovii; Picea abies; Pinus sylvestris; Larix sibirica; climate; Betula pubescens ssp. czerepanovii; Picea abies; Pinus sylvestris; Larix sibirica;

    Sammanfattning : Treelines in high-mountain regions are constrained by heat deficiency, although the working mechanisms are still not entirely understood. Observational and paleoecological studies on treeline performance may contribute to increased understanding of the treeline phenomenon in general. LÄS MER

  3. 12. The lower and middle Cambrian of Sweden: trilobites, biostratigraphy and intercontinental correlation

    Författare :Niklas Axheimer; Berggrundsgeologi; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Sedimentologi; Paleontologi; Palaeontology; fysisk geografi; Geologi; physical geography; Geology; Sweden; correlation; trilobites; biostratigraphy; Cambrian; Sedimentology;

    Sammanfattning : This thesis is based on studies of Cambrian successions in Sweden, with particular focus on the middle Cambrian biostratigraphy and its correlative relationship to the proposed global agnostoid zonation. The investigated material, mainly trilobites, was collected from both outcrops and drill cores from five provinces in Sweden: Skåne (Scania), Öland, Västergötland, Jämtland and Lapland. LÄS MER

  4. 13. Setting the Holocene clock using varved lake sediments in Sweden

    Författare :Lovisa Zillén; Kvartärgeologi; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; climate change; Physical geography; tephrochronology; palaeomagnetic secular variations; radiocarbon time-scale; Holocene varved lake sediments; varve chronology; geomorphology; pedology; cartography; climatology; Fysisk geografi; geomorfologi; marklära; kartografi; klimatologi;

    Sammanfattning : The aim of this thesis was to study annually laminated (varved) Holocene lake sediment in Sweden, their formation and their potential as chronological and palaeoecological archives. Five lakes with continuous Holocene varved lake sediment sequences in northern (Västerbotten) and west central Sweden (Värmland) were investigated. LÄS MER