Description and interpretation of the composition of fluid and alteration mineralogy in the geothermal system, at Svartsengi, Iceland

Isotopic constraints on ice age fluids in active geothermal systems: Reykjanes, Iceland

“…The Svartsengi geothermal system has a mixed meteoric-seawater fluid origin, with chloride content corresponding to about 2/3 that of seawater and a fluid-hydrogen isotope composition consistent with the mixing of local meteoric water and seawater (Fig. 2a and b;Arnó rsson, 1978;Ragnarsdó ttir and Walther, 1984;Lonker et al, 1993;Arnó rsson, 1995).…”

Application of radium isotopes to determine crustal residence times of hydrothermal fluids from two sites on the Reykjanes Peninsula, Iceland

“…These have undergone extensive hydrothermal alteration and the mineralogy reflects increasing temperature with depth-with zeolites near the surface, succeeded by a mixed layer clay zone, chlorite-epidote zone and finally epidote-actinolite in the hotter Reykjanes area. Summaries of the subsurface geology and mineralogy in these regions have been made (Ragnarsdó ttir et al, 1984;Lonker et al, 1993;Fridleifsson and Albertsson, 2000).…”

The effect of iron on montmorillonite stability. (I) Background and thermodynamic considerations

“…Chloritisation of smectite is seen in several geological settings, including the hydrothermal alteration of volcaniclastic rocks (e.g., Inoue and Utada, 1991), metamorphism of pelitic rocks (e.g., Jiang and Peacor, 1994), hydrothermal and regional metamorphism of Mg-silicates and glass in basic igneous rocks (Ragnarsdottir et al, 1984;Schiffman and Fridleiffson, 1991;Shau and Peacor, 1992;Robinson et al, 1993;Schiffman and Staudigel, 1995; and Robinson, 1997) and the hydrothermal alteration of mafic minerals in amphibolites and gneisses (Beaufort and Meunier, 1994). Chloritisation of smectite in late-stage diagenetic to early-stage metamorphic systems may involve the progressive conversion of trioctahedral smectite to chlorite (often via corrensite, Merriman and Peacor, 1999).…”