Jökull - 01.12.1968, Blaðsíða 15

S U M M A R Y
DEUTERIUM 1N GROUND WATER AND
GLACIERS IN ICELAND
Bragi Artiasoii
Science Institute, Universily of Iceland
Deuterium measurements in precipitation,
cold and hot springs in SW-Iceland show, that
the geothermal water in this area is of mete-
oric origin and does not change its deuterium
content during its passage underground. Furth-
ermore the hydrological conditions are such
that deuterium analysis can be used to trace
the recharge area of thermal springs as well as
cold springs of unknown or distant origin. The
conclusion drawn is that the water emerging
from hot springs and boreholes in SW-Iceland
has passed underground a distance of up to
70 km.
Deuterium measurements of samples of ice
and snow from Icelandic glaciers have shown
that deuterium exchange between ice and water
takes place in temperate glaciers and that iso-
topic equilibrium between ice and percolating
meltwater may be nearly reached. This pheno-
menon will be discussed in detail elsewhere.
Assuming that isotopic equilibrium is attained
between ice and water, deuterium measure-
ments, together with measurements of the water
content of the ice, can be used for estimating
the total yearly precipitation on Icelandic
glaciers and also to what extent the precipita-
tion is retained as ice in the glaciers. Such
measurements have been made at two locations
on Langjökull and one location on Vatna-
jökull. The results are in agreement with other
estimates based on meteorological observations.
Deuterium measurements of ice cores collect-
ed on Bárdarbunga, Vatnajökull, at an altitude
of 1830 m indicate that the glacier on Bárdar-
bunga is an arctic rather than a temperate
glacier. This suggests that deuterium measure-
ments of ice cores, collected by drilling through
the ice shield on Bárdarbunga, together with
age determinations of the ice, might reflect the
mean annual air temperature in Iceland, pos-
sibly back to the time of settlement.
The possibility is also discussed, that deuter-
ium measurements of ice might be used to
study the flow of ice in Icelandic glaciers.
JÖKULL 18. ÁR 349