Alpine glacier fluctuations in southern Greenland during the Holocene
There are about 18,500 alpine mountain glaciers independent of the Greenland Ice sheet (GrIs). These glaciers, highly sensitive to climate variations are very good targets to document glacier fluctuations during the Holocene and explore forcing factors responsible for their evolution. However little is known about their chronology of evolution at a millennial-scale. This can be investigated by dating moraines with cosmic-ray exposure (CRE) ages. Recent advances revealed an asynchronous evolution depending on the latitude. On the eastern side of Greenland, north of 65°N, alpine glaciers recorded their Holocene largest advance, (i.e the maximum extent) during the early Holocene. By contrast the few records located south of 65°N on the eastern side of Greenland either from mountain glacier or from the GrIs or from lake sediment suggest a maximum Holocene extent during the late Holocene. This difference of mountain glacier behaviour in eastern Greenland would be related to the effects of oceanic currents on local climate conditions.
The main objectives of this project are to document the millennial-scale evolution of five local glaciers based on 10Be CRE dating of moraines. Here we will explore the role of oceanic current and other forcings on alpine glacier behavior. The Holocene moraines of three glaciers selected near Narsarsuaq (South of Greenland) and two other glaciers near Sisimiut (South-east) will be investigated. About 80 samples will be analysed at Cerege laboratory.
The potential links between glacier fluctuations and regional climate conditions will be investigated through a compilation of climate proxy records and temperature and precipitation changes from the two transient climate simulations (LOVECLIM and TraCE) using the different forcing experiments already available (C02, volcanism, Insolation, AMOC changes ….).
The duration of this project is 4 years, and is based on long term and effective collaboration between members of the team. It will be managed by V. Jomelli DR2 Cerege, assisted by R. Braucher CRCN Cerege who both will be in charge of the field sampling and the cosmogenic dating. External collaborations are developed with the IGE for the glaciological aspects and with EPOC and the University of Sydney (CCRC) for the climatic modeling aspects.