Rit (Vísindafélag Íslendinga) - 01.06.1976, Page 154

most Elliðaár wells, since the water in the wells G-23, G-25, G—26,
G-29 and G-30 could be a mixture of these two water systems.
The results obtained for the two wells, G-32 and G-33, located
some 2 to 3 km north-east of Elliðaár could then be explained in
the same way. The deeper aquifers of these wells discharge water
with ðD ~ — 64.0%0, hut the uppermost aquifers discharge water
wdth ðD — — 61.0%0.
The well K-1 in the Blesugróf area apparently receives water
from two different aquifers. Water sampled at a depth of 670 m in
the 1500 m deep well has ðD = — 72.9%0 and Cl_ = 37.9 mg/1. This
water has a very similar 8D-value to the water in the Seltjarnarnes
wells (see helow) and ohviously is derived from the same ground-
water system, although the Cl“ content is much less. The tempera-
ture of this aquifer, 90°C, is also similar to that on Seltjamames.
The water pumped out of the hole on the other hand has a 8D =
— 64.4%0 and Cl~ = 29.9 mg/1 and a temperature of 36°C. This is
obviously a mixture of the deep water and water with a higher
8D-value and lower Cl_.
From available data it is not possible to evaluate the 8D-value of
the uppermost aquifers in the hole K—1. The much lower tempera-
ture of the water pumped up from the hole compared with the deep
water aquifers, however, suggests mixing of deep groundwater with
cold near-surface water.
The well Hlíð on Álftanes (sample No. 105) has 8D = — 65.4%0.
Whether this water belongs to the Laugarnes system or is some
kind of mixture from the various systems cannot be decided from
the available data.
15. 103 Mosfellssveit.
The numerous wells from which water has been collected in this
area and measured for its deuterium content are shown in Fig. 37.
Based on geological studies and measurements of the water tem-
perature in available drill holes, Einarsson (1942) first proposed
the following model for the Mosfellssveit area:
The wells west of a NW-SE line, which can be drawn through
the thermal area S-Reykir, release water with a temperature of
99 °C, while the wells east of this line releasewater with a tempera-
150
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