La cryosphère marine et continentale du domaine nord-ouest groenlandais: dynamique récente (Holocène) et lien avec le contexte climatique et océanographique régionale

• Main Author: Georgiadis, Eleanor
• Other Authors: Université de Bordeaux (UB), Universite de Bordeaux, Universite laval, Jacques Giraudeau, Guillaume Masse
• Format: Doctoral or Postdoctoral Thesis
• Language: English
• Published: HAL CCSD 2020
• Subjects: Sea ice; Greenland; Holocene; Paleoceanography; Micropalaeontology; Biomarker; Marine sediment core; Glace de mer; Groenland; Arctique; Paleoceanographie; Micropaleontologie; Biomarqueur; Carottes sédimentaires; [SDE]Environmental Sciences; Arctic; Arctic Ocean; Baffin Bay; Canadian Arctic Archipelago; Ellesmere Island; Nares; Arctic Archipelago; ArcticNet; Arctique*; Baffin; Climate change; groenlandais; Nares strait
• Online Access: https://tel.archives-ouvertes.fr/tel-03475990; https://tel.archives-ouvertes.fr/tel-03475990/document; https://tel.archives-ouvertes.fr/tel-03475990/file/GEORGIADIS_2020_PhDthesis.pdf

Nares Strait is one of three channels of the Canadian Arctic Archipelago (CAA) which connect the Arctic Ocean to Baffin Bay. The CAA throughflow is a major component of ocean circulation in western Baffin Bay. Nares Strait borders the CAA to the east, separating Ellesmere Island from Greenland, and is 80% covered in sea ice 11 months of the year. The heavy sea ice cover is constituted of (1) Arctic (multi-year) sea-ice having entered the strait by the north, and (2) locally formed first year sea ice, which consolidates the ice cover. The hydrological history of the area is intimately linked to the formation of land-fast sea ice in the strait, constituting ice arches. The seaice cover in Nares Strait regulates freshwater (liquid and solid) export towards Baffin Bay, and is integral to the formation of an area of open water in northernmost Baffin Bay: The North Water polynya.Nares Strait has been at the heart of major geomorphological changes over the past 10,000 years. Its deglacial and post-glacial history is marked by (1) rapid retreat of the Greenland and Innuitian ice-sheets which coalesced along Nares Strait during the Last Glacial Maximum, (2) post-glacial shoaling associated to isostatic rebound, and (3) variable multi-year and seasonal sea ice conditions. Little is known about the evolution of these three environmental components of the Nares Strait history, and they are poorly constrained in terms of chronology and synchronism with other regional changes. Nares Strait and its eventful Holocene history provide a unique case study of the response of the marine and continental cryosphere to rapid climate change, such as that affecting Arctic regions in modern times.The marine sediment archives that were retrieved during the ANR GreenEdge and ArcticNet (2014 and 2016) cruises of CCGS Amundsen offer a unique opportunity to investigate the Deglacial to Late Holocene history of Nares Strait. Our reconstructions are based on a multi-proxy study of these cores, including sedimentologic (grain size and ...