|Hydrothermal silica chimney fields in the Galapagos Spreading Center at 86 degree W|
Herzig, P.M.; Becker, K.; Stoffers, P.; Bäcker, H.; Blum, N. (1988). Hydrothermal silica chimney fields in the Galapagos Spreading Center at 86 degree W. Earth Planet. Sci. Lett. 89(3-4): 261-272
In: Earth and Planetary Science Letters. Elsevier: Amsterdam. ISSN 0012-821X, more
Geochemical cycle; Hydrothermal springs; Oxygen isotope ratio; Radiometric dating; Siliceous rocks; Thorium isotopes; ISE, Galapagos Rift; Marine
|Authors|| || Top |
- Herzig, P.M.
- Becker, K.
- Stoffers, P.
Silica chimneys were discovered in 1985 at 86 degree W in the rift valley of the Galapagos Spreading Center at 2600 m depth ("Cauliflower Garden"). The inactive chimneys lack any sulfides and consist almost entirely of amorphous silica (up to 96 wt.% SiO2), opal-A); Fe and Mn oxides are minor constituents. Oxygen isotope data show that formation of the silica chimneys took place at temperatures between 32 degree C (+29.9 ppt delta18O) and 42 degree C (+27.8 ppt delta18O). Th/U dating reveals a maximum age of 1440 plus or minus 300 y. Amorphous silica solubility relations indicate that the silica chimneys were formed by conductive cooling of pure hydrothermal fluids or by conductive cooling of a fluid/seawater mixture.