Jökull - 01.01.2012, Qupperneq 141

Öræfajökull central volcano, SE-Iceland
Figure 6. The bedrock topography of Öræfajökull and surroundings shown as contour map (20 m contour inter-
val) and as a color coded image. The blue areas show bedrock below sea level. The blue lines outline glaciated
areas. – Botnkort Öræfajökuls (20 m hæðarlínur). Blá svæði eru undir sjávarmáli. Bláar línur sýna jökuljaðar
og sker 2011.
that the subglacial troughs below Öræfajökull outlets
were filled with sediments sometime prior to the Lit-
tle Ice Age, the volume of excavated sediment since
the troughs started to form again would be 3–3.5 km3.
Here we assume sediment plains with similar surface
gradient as in the nearby glacier free valleys. The sed-
iment volume excavated and transported by ice, stored
in terminal moraines in front of the glacier, is only
a fraction of the total excavated sediments. Large
majority of the excavated sediments has been trans-
ported to the sea by glacier rivers. The estimated vol-
ume of excavated sediments corresponds to around 6
x 1012 kg of dry sediment assuming specific weight of
1800 kg m−3. The recent annual sediment transport of
JÖKULL No. 62, 2012 139