Uniformity and diversity in the composition of mineralizing fluids from hydrothermal vents on the southern Juan de Fuca Ridge
Abundances of Li, Ni, K, Rb, Ca, Sr, Ba, Mn, Fe, Zn, and Si have been determined in fluid samples from seven vents located in three areas on the southern Juan de Fuca Ridge. The hydrothermal component estimated from the Mg contents of the samples ranges from 7% to 76%. Concentrations of Fe and Si, among the other elements, in acid-stabilized solutions appear to be generally representative of the parental hydrothermal fluids, but some Zn determinations and most Ba values appear to be too low. Thermodynamic calculations indicate that the acidified samples remain supersaturated with respect to silica, barite, and pyrite; unacidified samples are supersaturated, in addition with respect to ZnS, FeS, and many silicate phases. Within the constraints of limited sampling there appear to be differences in fluid compositions both within and between the three vent areas. Some uniform differences in the elemental abundances predicted for hydrothermal end-member fluids might be due to inmixing of fresh seawater at depth in the hydrothermal system. The Juan de Fuca hydrothermal fluids contain more Fe but otherwise have relative elemental abundances fairly similar to those in 13 /sup 0/N (East Pacific Rise) fluids, albeit at higher levels. In contrast, fluids from 21 /sup 0/N (East Pacific Rise) and Galapagos have lower K/Rb and much lower Sr and Na abundances; these compositional features probably result from interaction of these fluids with a different mineral assemblage, possibly more mature greenstone. copyright American Geophysical Union 1987
- Research Organization:
- U.S. Geological Survey, Reston, Virginia
- OSTI ID:
- 5648541
- Journal Information:
- J. Geophys. Res.; (United States), Journal Name: J. Geophys. Res.; (United States) Vol. 92:B11; ISSN JGREA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
580201 -- Geophysics-- Seismology & Tectonics-- (1980-1989)
580500* -- Oceanography-- (1980-1989)
ABUNDANCE
ALKALI METALS
ALKALINE EARTH METALS
CALCIUM
CHEMICAL COMPOSITION
ELEMENTS
FLUIDS
GEOTHERMAL FLUIDS
IRON
LITHIUM
MAGNESIUM
MANGANESE
METALS
PACIFIC OCEAN
POTASSIUM
RUBIDIUM
SEA-FLOOR SPREADING
SEAS
SEMIMETALS
SILICON
SODIUM
STRONTIUM
SURFACE WATERS
TRANSITION ELEMENTS
VENTS
ZINC