| Popis: |
Stable isotope studies of surface ice and water samples collected in the ablation zone of the Greenland ice-sheet margin at Paakitsup Akliarusersua ∼40 km northeast of Ilulissat/Jakobshavn, West Greenland, show that there is a large system-atic spatial variation of the 18 O 16 O ratio (δ 18 O) over the ablation area. δ 18 O can, therefore, be used as a natural tracer to locate the origin of the melt-water runoff. A simple model is set up for simulating the δ 18 O variation in the melt-water discharge from the area. Simulations are made with a drainage basin obtained by modelling the subglacial drainage conditions, which requires costly and time-consuming mapping of the subglacial topography. The simulated δ-values agree well with observed δ-values of water samples from three pro-glacial lakes which receive the melt-water discharge. This suggests that the stable isotope method can be used to give an initial estimate of melt-water drainage-basin boundaries on the Greenland ice-sheet margin. |
