Jökull - 01.12.1980, Blaðsíða 32

concentration of dissolved materials to those
of the flood water, but not to those of the
glacier ice as in samples of glacier ice collected
during the jökulhlaup the concentration of
dissolved materials was similar to that of
water in Skeiðará between jökulhlaups.
Very active formation of anchor ice had
taken place at the outlet of Skeiðará and large
quantities of sediment as well as water had
been absorbed by it. To explain the high con-
tent of dissolved solids in the sample of ice
taken in the channels at the outlet, the ice is
assumed to have been formed as anchor ice.
The formation of ice in running water differs
from ice formation in lakes and quiet streams
in that a continuous sheet of crystallized ice is
not formed. Instead individual crystals of ice
are formed and carried away by turbulence in
the running water. These crystals accumulate
into flakes of very loose consistence, named
Svifaur
Suspended load
Aur í grunnstingli
Sediment in anchor ice
Skeiðaró
21. 3. '72
SKU
Lag - I
Skeiðaró
25.3. '72
B o t n e f n i
B e d m a t e r i a /
Af brigðilegt
Abnorma!
L oytr - /
SKU-4
Normalt
Norma!
Fig. 8. Histograms for the grain size distribution of some typical sediment samples from
Skeiðará jökulhlaup 1972. Key: SKÚ: Skeiðará at glacier outlet; SKB: Skeiðará at bridge site;
SKG: Skeiðará at dikes. — Mynd 8. Komastœrðadreifing nokkurra einkennandi aursýna úr Skeiðarár-
hlaupi 1972. SKÚ: Skeiðará við útfall; SKB: Skeiðará við brúarstæði; Skeiðará við garða.
30 JÖKULL 30. ÁR