The aim is to constrain ice fluctuations of the Greenland ice sheet and local glaciers and ice caps during the last 10.000 years using threshold lake records. The concept is that when a glacier is in the catchment of the threshold lake it receives meltwater and clastic sediments (silt/sand) whereas gytja is deposited when the glacier is retracted and outside the catchment. These changes can easily be observed and the clastic layers representing periods with an expanded ice position can be dated because the gytja layers contain organic material. Two target sites are the present ice margin in the inner part of Godthåbfjord (64.959311°; -50.149056°) and the other is a threshold lake at a local glacier in Kobbefjord. An alternative and very interesting site to record a local ice cap is at the entrance to Buksefjord c. 45 km south of Nuuk (63.742326°; -51.344632°) where the are several potential threshold lakes. Besides taking cores from threshold lakes we wish to core “normal” lakes suited for long-term climate and palenvironmental reconstructions including detailed XRF, 10Be and 14C studies as well as stable isotope analysis on organic and inorganic matter (13Cbulk, 15Nbulk,13Ccellulose, 18Ocellulose, 13Ccarbonate and 18Ocarbonate).

Site: Isua area, Nuuk, Greenland

PI: Marit-Solveig Seidenkrantz