Centre d'études nordiques
Membre de projet
Freshwater Resources of the Eastern Canadian Arctic
Information pour les étudiants
Titre de thèse:
Paleoclimatic reconstruction of the central Baffin Island region, Nettilling Lake, Nunavut.
Résumé de thèse:
The Canadian Arctic has been affected by rapid fluctuations of its natural environmental state. However, the paleoclimate history of some regions, including the Nettilling Lake area, remains poorly known and documented. Nettilling Lake is located in what is believed to be a « hinge » zone between northern Quebec and Labrador, which has shown a high resilience to recent climate changes, and the Canadian High Arctic, which has already shown extremely marked and amplified responses to recent climate changes. In order to fill a very important knowledge void in the Arctic, this research uses physical and chemical properties preserved in lake sediments to reconstruct past environmental conditions of aquatic ecosystems and their watersheds. The overall goal is to reconstruct past climatic variability to help predict regional scenarios of climate warming impacts on freshwater and terrestrial ecosystems.
For this purpose, a one-meter long, laminated sedimentary sequence has been retrieved from a small bay in the northeastern part of Nettilling Lake during the summer 2010. This sampling area was chosen based on the hypothesis that variations in glacial meltwater inputs from the nearby Penny Ice Cap will leave a strong climate signal in the bay’s sediment archive. The sediment core was scanned for a series of non-destructive (X-ray, XRF, magnetic susceptibility) and destructive (LOI, grain size, water content) analyses. Radiometric AMS dating was used to establish the core chronology. Results yield excellent correlation between the variations in LOI, grain size and water content, and allow the Little Ice Age and the recent warming episode to be identified. Furthermore, the decrease of LOI and the high density of mineral particles in recent sediments suggest substantial increases in glacial meltwater inputs from the Penny Ice Cap which are associated with the rapid warming of the Arctic.
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