Sökning: "glacial cycles"
Visar resultat 1 - 5 av 15 avhandlingar innehållade orden glacial cycles.
1. Northern Permafrost Region Soil Carbon Dynamics since the Last Glacial Maximum : a terrestrial component in the glacial to interglacial carbon cycle
Sammanfattning : At the Last Glacial Maximum (LGM), after ~100,000 years of relatively cold temperatures and progressively lower atmospheric carbon dioxide (CO2) concentrations, CO2 levels reached ~180 ppm, which is less than half of what we see today in a much warmer world (~400 ppm). Although much of this increase since the LGM is due to human-induced emissions, about 100 ppm of this increase can be attributed to natural variations seen over glacial to interglacial cycles. LÄS MER
2. Sulfur in polar ice and snow : Interpretations of past atmosphere and climate through glacial archives
Sammanfattning : Snow contains information on the atmosphere it is deposited from. This information is stored in polar ice sheets (Antarctica and Greenland), which are unique geochronological archives of past climate and atmospheric composition. On time scales from annual to glacial cycles, this thesis deals with the signals of sulfur compounds in these archives. LÄS MER
3. Glacial geology and palaeo-ice dynamics of two ice-sheet margins, Taymyr Peninsula, Siberia and Jameson Land, East Greenland
Sammanfattning : The North Taymyr ice-marginal zone (NTZ) on the Taymyr Peninsula, Arctic Siberia and the Ugleelv Valley on Jameson Land, East Greenland, have been investigated with the aim of reconstructing the glacial history, including depositional processes and environments. Geomorphological, sedimentological, stratigraphical and remote sensing methods have been combined to give a comprehensive view of developments in the two areas. LÄS MER
4. Dansgaard-Oeschger cycles and Heinrich events in western Europe - A diatom perspective
Sammanfattning : The last glacial period was characterised by several abrupt climatic shifts referred to as Dansgaard-Oeschger (DO) cycles and Heinrich events. These shifts were most frequent between 60,000 and 20,000 years before present coinciding with Marine Isotope Stages (MIS) 3 and 2. LÄS MER
5. Ice Sheet, Climate, and Landscape Interactions in Dronning Maud Land, Antarctica
Sammanfattning : The impact of glaciers and ice sheets on the subglacial landscape are of fundamental importance for studies of glacial history and landscape development, both in previously glaciated areas and in areas that are glaciated today. The thesis concerns the present and past erosive capacity of the ice sheet in Dronning Maud Land, East Antarctica. LÄS MER
