Jökull - 01.12.1967, Page 74

CL,
ppm
I (
■10000
•7500
• Akranes
I I Húsavik
/\ Selfoss
+ Se/tjarnames
4 B Sötvho/t
Q /estmann tstands
■5000
5000
10000
15000
-►
Totat dissotved sotids pp m
Fig. 9. A diagram in which chloride content is plotted against total dissolved solids.
Mynd 9. Línurit, sem sýnir sambandið milli klórs og heildarrnagns uppleystra efna.
THE SYSTEM Na, Mg AND Ca
and a discussion of the relatively high chloride
content in some ground-iaater aquifers
in Icelancl
Evidence favours that certain changes take
place in the relative proportion of sodium,
magnesium and calcium in water which has
derived its chloride content from sea-water en-
trapped in sediments (IVhite 1965, Siever 1965).
Calcium increases while magnesium decreases.
Sometimes the sodium content decreases also.
The relative proportion of these elements in
the water from the deep well in Vestmann
Islands along with water from wells at Húsa-
vík, Leirá, Akranes, Seltjarnarnes, Selfoss and
Sölvholt has been plotted in Fig. 10. The loca-
tion of these areas is shown in Fig. 8. In all
these localities the chloride of the water is
assumed to be derived from sea-water which
has percolated into the ground-water system.
Fig. 9 illustrates how the chloride content
varies with total dissolved solids, suggesting
that this water is diluted sea-water, which has
reacted with the wall rock. The low tempera-
ture of the water (< 150° C) makes it prac-
tically impossible that the chloride has been
leached from the wall rock (see Ellis and Ma-
hon 1964, 1967).
Fig. 10. A triangular diagram showing the rela-
tive proportions of the components Ca, Na and
Mg.
Mynd 10. Þrihyrningalinurit, sem sýnir sam-
bandið milli natrium, kalsium og magnesium.
308 JÖKULL 17. ÁR