Late Weichselian and early Holocene changes of vegetation, climate and sea level on the Skagi peninsula, northern Iceland

• Main Author: Rundgren, Mats
• Format: Doctoral or Postdoctoral Thesis
• Language: English
• Published: Department of Quaternary Geology, Lund University 1997
• Subjects: Geology; asthenosphere viscosity; glacial loading/unloading; marine polar front migrations; sea-level change; climate change; vegetation change; Early Holocene; Late Weichselian; Iceland; Lake sediments; Skagi peninsula; physical geography; Geologi; fysisk geografi; High Lake; Low Lake; North Atlantic; Sea ice; Tundra
• Online Access: https://lup.lub.lu.se/record/29383

Sediment sequences from five lakes on the Skagi peninsula, northern Iceland, were subjected to mineral magnetic analysis, carbon analysis, pollen analysis, plant macrofossil analysis, diatom analysis, radiocarbon dating and tephra analysis in order to make detailed reconstructions of vegetation, climate and sea level during the Late Weichselian and Early Holocene. The main purpose was to investigate if the dramatic deglacial climatic shifts recorded in proxy records from the North Atlantic region, such as ice cores, marine sediments and lake sediments, also are registered in Skagi lake sediments, which would be expected considering Iceland´s position in the middle of the North Atlantic Ocean, within the range of the Late Weichselian–Early Holocene migrations of the marine polar front. In addition, the project aimed at a better understanding of the environmental development on Iceland during the last deglaciation. The period 11,300-10,900 BP was found to be characterized by grass-tundra vegetation and low lake productivity, indicating cold climatic conditions. In addition, there was an overall fall in relative sea level. Milder conditions after 10,900 BP are reflected by an expansion of dwarf shrubs and increased limnic productivity, indicating long seasons without sea ice. Relative sea level continued to fall in the period 10,900-10,600 BP. An abrupt cooling at 10,600 BP caused a return to grass-tundra vegetation and low limnic productivity, and sea-ice conditions were probably heavy up to 9900 BP. A minor transgression occurred in the later part of this cold period. Abrupt warming at 9900 BP resulted in a change to herb-tundra vegetation and high lake productivity, indicating long seasons without sea ice. Relative sea level fell rapidly after 9900 BP, but turned into a minor transgression in the period 9800-9700 BP coincident with a short-lived cooling event. A dwarf-shrub expansion and raised limnic productivity at 9600 BP suggest milder conditions and absence of sea ice. Relative sea level fell below present ...