Rit (Vísindafélag Íslendinga) - 01.06.1976, Page 138

15. 7.4 Biskupsíungur.
The geothermal area Biskupstungur is located west of Hreppar
and Skeið. This area includes many thermal springs discharging
large amounts of water (samples No. 37-44).
The sampling point Spóastaðir (No. 37), with 8D = — 65.1%0,
has considerably higher 8D-values than the geothermal water col-
lected from another quite closely located source, Spóastaðir (No.
38) , with 8d = — 78.6%0. Since the temperature and the Na+ and
Cl“ content of the water with 8D = — 65.1%0 are also considerably
lower than of the water with 8D = — 78.6%0 (see Table 11), it is
believed that sample No. 37 has been mixed with cold ground-
water of more or less local origin.
The 8D-values of the other sources vary from — 71.6%0 to — 80.4%0.
The three sources giving the lowest 8D-values are Sólheimar (No.
39) , Reykjavellir (No. 40) and Spóastaðir (No. 38), with 8D =
— 80.4%0, 8D = — 78.0%o and 8D = — 78.6%0 respectively. All of
these sources are located on a SW-NE line parallel to that in the
previously discussed area Hreppar and Skeið.
Assuming that the lowest 8D-values represent the 8D-value of the
deep groundwater and that the water with higher 8D-values has been
mixed with various amounts of more local groundwater, the re-
charge area for the deep groundwater is likely to be the central part
of Langjökull.
15. 7.5 BöðmóSsstaSir and SyÖri-Reykir.
The two hot springs Syðri-Reykir (No. 45), with 8D = — 71.4%0,
and Böðmóðsstaðir (No. 46), with 8D = — 74.0%o, are located still
farther towards the west. The water at Syðri-Reykir was collected
from a hot spring with a wide open surface. This water might
therefore possibly have been somewhat enriched in deuterium due
to evaporation from the open surface. We therefore believe that the
samples collected at Böðmóðsstaðir are more representative for the
deep circulating water in this district.
According to this, the mean recharge area for the thermal water
in this area should lie just south of the Langjökull glacier.
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