Jökull - 01.12.1957, Blaðsíða 5

North-Western Peninsula
The low-temperature activity. The author
has elsewhere (Bodvarsson, 7) discussed the
overall heat balance of the thermal activity in
Iceland. The thermal areas are divided into
two groups, the high-temperature areas and the
low-temperature areas. The latter areas are be-
lieved to have no direct relation to the present
volcanism in Iceland and represent only a re-
latively deep circulation of meteoric water. The
water appears to flow mainly along dikes and
fault lines and reach such depth that it can be
heated appreciably.
The integrated measurable flow of the low-
temperature areas amounts to about 1.5 • 10°
cm3/sec and the integrated sensible heat flow
transported by this water amounts to about I08
cal/sec. There is, however, no doubt that the
low temperature areas dissipate more heat than
in the measurable flow of thermal water. Addi-
tional water ascends to the surface but is spread
in surface layers and escapes measurement.
Furthermore, heat is also conducted from the
channels of ascent.
It appears more reasonable that the total
heat dissipation of the group amounts to the
double or some 2 • 108 cal/sec, that is, to about
0.2 microcal/cm2 sec if averaged over the total
area of country. This amounts to around 18%
of the outflow of terrestrial heat in normal
areas.
l’his ratio is higher in the north-western
peninsula, the Vestfirdir, which no doubt has
a local ground water body independent of the
mainland. The total measureable flow of low-
temperature springs in this region is around
3- 10s cm3/sec and the sensible heat transport-
ed by the water amounts to around 1.5 • 107
cal/sec. It appears again reasonable to estimate
the integrated heat dissipation at the double,
that is, at 3 • 107 cal/sec. Dividing this figure
by the total area of the north-western penin-
sula we find a specific heat dissipation of
around 0.4 microcal/cm2 sec.
The last figure is around i/3 of the average
outflow of terrestrial heat in normal areas.
Given normal and steady state subsurface tem-
perature conditions in the region the flowing
ground water would have to take up around
i/3 of the total available heat flow. In order to
take up this relatively large amount of the
available heat the water would have to flow
along a very dense and regular system of sub-
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