Jökull - 01.01.2019, Síða 14

Terminus lakes on the south side of Vatnajökull
Figure 9. The development of terminus lakes by Skaftafellsjökull. For explanations and credits see Figures 3
and 7. – Þróun sporðlóna við Skaftafellsjökul (sjá nánari skýringar við 3. mynd og 7. mynd).
Virkisjökull and Falljökull
The map of the DGS (1905) and a photograph by
Magnús Ólafsson in 1925 show that the terminus of
Virkisjökull was covered by debris from a medial
moraine originating in Rauðikambur. The lower part
of the glacier tongue, therefore, melted rather slowly
in the early part of the 20th century. The total retreat
from the LIA position amounted to 600–800 m in the
1970s when the glacier margin started to readvance
(Figure 11).
The merged terminus of Virkisjökull and Falljök-
ull was more or less stationary in the last two decades
of the 20th century. Its downwasting created an area
of dead ice buried under debris, which has melted in
recent years (Everest and others, 2017), and a lake
started to form in front of the terminus in 2006 accord-
ing to oblique aerial images (Figures 5 and 11). Five
years later, several small ponds and lakes with a total
area of 0.02 km2 had formed. They had merged into a
single lake with an area of 0.23 km2 and water level at
127 m a.s.l. in 2018. Compared with Skaftafellsjök-
ull and Svínafellsjökull, the subglacial topography at
Virkisjökull and Falljökull does not feature a signifi-
cant subglacial trough (Magnússon and others, 2012).
Therefore, the < 1 km2 lake that may be formed by
further retreat of the terminus will be rather small in
comparison with the large potential future lakes of the
neighbouring glaciers to the north.
JÖKULL No. 69, 2019 13