Sökning: "Kvartärgeologi"

Visar resultat 11 - 15 av 157 avhandlingar innehållade ordet Kvartärgeologi.

  1. 11. Vegetation and climate during Weichselian ice free intervals in northern Sweden : Interpretations from fossil and modern pollen records

    Författare :Martina Hättestrand; Ann-Marie Robertsson; Donatella Magri; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Weichselian; interstadial; stadial; glacial history; northern Sweden; Tärendö; Riipiharju; Rissejauratj; Veiki moraine; pollen analysis; pollen deposition; pollen trap; PAR; Quaternary geology; Kvartärgeologi;

    Sammanfattning : In this thesis the Weichselian history of northern Sweden is investigated, with emphasis on vegetation and climate during ice-free intervals. The main method used has been pollen analysis of sediments from pre-Late Weichselian landforms. To interpret fossil pollen assemblages, comparisons with modern pollen spectra were made. LÄS MER

  3. 12. Holocene climate and environmental change in high latitudes as recorded by stable isotopes in peat deposits

    Författare :Päivi Kaislahti Tillman; Steffen Holzkämper; Stefan Wastegård; Peter Kuhry; Thomas W. D. Edwards; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; stable isotopes; Holocene; subarctic; climate; Sphagnum fuscum; kvartärgeologi; Quarternary Geology;

    Sammanfattning : In this thesis, stable carbon and oxygen isotopes in α-cellulose isolated from Sphagnum fuscum moss remains were used as climate proxies. The main focus was to implement the methods in records from high latitude peatlands in the Northern Hemisphere (west-central Canada and north-eastern European Russia), reconstruct palaeoclimate of the studied regions during the Holocene, and evaluate the compatibility of results with other proxy records, especially tree-ring isotope time-series. LÄS MER

  4. 13. Tephra horizons in the North Atlantic region during the Early Holocene

    Författare :Ewa Lind; Stefan Wastegård; Margareta Hansson; Britta Sannel; Victoria Smith; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Tephrochronology; geochemical composition; Saksunarvatn Ash; Vedde Ash; Fosen Tephra; Askja-S; palaeoclimate; Younger Dryas; Early Holocene; “XRF ITRAX”; sediment geochemistry; stable isotopes; Faroe Islands; Norway; Sweden; kvartärgeologi; Quaternary Geology;

    Sammanfattning : Uncertainties about the rate and magnitude of future climate change have drawn attention to the climate variability following the Late Glacial-Early Holocene transition, c. 12-8 ka BP. LÄS MER

  5. 14. Towards an Early Holocene Tephrochronology for the Faroe Islands: Methodology and first results

    Författare :Ewa Lind; Stefan Wastegård; Margareta Hansson; Britta Sannel; Jane Boygle; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Quarternary Geology; kvartärgeologi;

    Sammanfattning : The uncertainties regarding future climate change have put considerable notice to the climate variability following the Late Glacial-Holocene transition (ca. 13-9 ka BP) in the North Atlantic region as well as the forcing mechanisms behind climate changes. LÄS MER

  7. 15. Palaeoenvironmental changes in the northern boreal zone of Finland: local versus regional drivers

    Författare :Shyhrete Shala; Karin H. Helmens; Christian Bigler; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Palaeolimnology; Palaeoecology; Biological assemblages; Sediment geochemistry; Regional drivers; Local drivers; Quantitative temperature reconstructions; Transfer-functions; Holocene; MIS 5d-c; Northern boreal zone; NE Finland; kvartärgeologi; Quaternary Geology;

    Sammanfattning : Multiple proxies derived from the Lake Loitsana sediment sequence (NE Finland) are employed to determine the timing of deglaciation, characterise an early Holocene proglacial lake stage and reconstruct Holocene lake development. Local-scale processes causing shifts in biological assemblages are identified and the most likely Holocene mean July air temperature (Tjul) development is assessed. LÄS MER