Geochemistry, Origin and Balneological Properties of a Geothermal Brine at Hofsstadir near StykkishÛlmur, Iceland

Abstract

The geothermal field at Hofsstadir northern SnÊfellsnes peninsula produces a low-temperature brine with about 5.4 â salinity or about 15 % of sea water salinity. The fluid temperature is 86 ?C, near to the resevoir temperatures of 90 ?C as assessed from mineral solution/equilibrium conditions. The stable isotopic ratios 2H and 18O reveal that the water is significantly lighter than present day precipitation in the mountains of the SnÊfellsnes peninsula. The water may either have its origin far north of the Bay of Breidafjˆr?ur in the highland of the western fjord-lands or dating back to a pre-Holocene age when local precipitation was considerably lighter due to the cold climate at that time. The water is used for heating of the small town StykkishÛlmur by a central heat-exchanger plant due to high salinity of the water. The outbuilding of a health resort has been planned and the water has been used successfully for the treatment of psoriasis and is claimed to be appropriate for health cures by drinking as well as for bathing therapy for rheumatism.