Rit (Vísindafélag Íslendinga) - 01.06.1976, Blaðsíða 165

values in the Skagafjörður thermal water are only found in pre-
cipitation in the northern part of the glacier Yatnajökull.
It is, however, obvious from glacier ice core studies, that before
1920 and at least several hundred years back in time, the precipita-
tion deposited on the glacier Hofsjökull and the area north-east of
it most likely had an average öD-value similar to the lowest ðD-values
in the Skagafjörður thermal water. The lowest öD-values found in
local cold springs at Laugafell north-east of Hofsjökull are ðD =
- 98%.
The hot springs Varmahlíð (No. 170), öD = — 102%, and Hofs-
vellir (No. 164), ðD = — 108%0, lie on a line which can be extended
to Laugafell. Other hot springs located on this line (samples No.
165—169 and No. 171-173), are then possibly mixed with more
local groundwater.
The three hot springs Egilsá (No. 174), Stekkjarflatir (No. 175)
and Víðivellir (No. 176), with ÖD = — 87.3%0 to — 91.7%0, in the
eastern part of the valley, are possibly also derived from the same
deep groundwater stream or, what is more likely, they originate in
the mountains east or north-east of Skagafjörður. The same may be
concluded for the hot spring Reykir in Hjaltadal (No. 177), with
ðD = — 99.5%0. According to the deuterium map, the precipitation
in the highest part of the mountainous area Tröllaskagi, between
Skagafjörður and Eyjafjörður, should have ðD ~ — 90%0, but since
there actually exist no direct measurements in the area this value
is rather uncertain.
15. 15 Tröllaskagi.
In this section we discuss the thermal areas located in the north
and north-eastem part of Tröllaskagi, which is a common name for
the high mountainous peninsula between the fjords Skagafjörður
and Eyjafjörður (see Fig. 40).
Deuterium measurements have been carried out on three hot
springs in Fljót (samples No. 179-181). The thermal water from
all of these hot springs has a similar ðD-value, ~ — 89%0, which is
about the same as found in precipitation deposited in the mountains
south of Fljót.
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