Abstract
In high temperature geothermal areas (T.200°C) in Iceland the alteration minerals formed show a regular zoning with increasing temperature i.e. smectite, chlorite, epidote and actinolite. To test the effect of varying composition of the hydrothermal circulation fluid drillhole chips from two contrasting areas were analyzed in detail. The Reykjanes area is fed with sea water while Krafla is fed with meteoric water and has a Cl- concentration of 28 ppm. Both areas have tholeiitic basalts, lavas and hyaloclastites as original reservoir rocks. Although both systems have the same sequence of alteration minerals the actual composition of the minerals differs between systems reflecting the different chemical composition of the circulating waters. In Reykjanes, with its brine fluid, the composition of the original rock appears not to affect the composition of the alteration minerals while the reverse appears to be the case in Krafla.
Original language | English |
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Pages (from-to) | 301-315 |
Number of pages | 15 |
Journal | Lithos |
Volume | 27 |
Issue number | 4 |
DOIs | |
Publication status | Published - Apr 1991 |