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SUMMARY
Application of geology
in geothermal research
in Iceland
by Krislján Sæmundsson
and Ingvar Birgir Friðleifsson
National Energy Authority, Reykjavík
The basic principles of the origin and flow
pattern of geothermal waters in Iceland
were recognized by Bunsen (1847). More
detailed work carried out a century later
specified two main types of geothermal
activity in Iceland (Böðvarsson 1960, 1961)
(a) high temperature geothermal fields situated
within active volcanic systems and (b) low
temperature hot water springs distributed
all over Iceland outside the active volcanic
zones. The former develop above shallow
level intrusive complexes, mostly in the roots
of central volcanoes. The latter form under
conditions where water descends deep into
the bedrock, draws heat from it and ascends
along fractures and dykes driven by the
hydrostatic gradient (Fig. 1). Geological
mapping and petrographic studies help to
define many important parameters which
control the flow of groundwater, such as
rock type, compaction, alteration and
vesicle filling, strike and dip of the lava pile
and the trace and attitute of faults, fractures
and dykes cutting it. Of main concern is to
define the nature of the aquifers and
whether they are localized steep fractures or
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