Petrographical and Geochemical Study of the Low Temperature Submarine Alteration of Basalt from Hole 396B, Leg 46

Petrographical and Chemical Study of Basement Basalts from the Galapagos Spreading Center, Leg 70

“…Hence/its analysis must be regarded as semi- quantitative. A similar mineral, called "light tan smectite," is described by Bohkle et al (1981) and Honnorez et al (1978), in basalts from Leg 46, Hole 496B. In Sample 510-9-3, 31-36 cm, we observed the most complete zonal alteration pattern.…”

“…Because of the lack of X-ray diffraction data we cannot precisely identify these clay minerals. But by comparing their chemistry and optical characteristics to other data (Bolhke et al, 1981;Honnorez et al, 1978;Mevel, 1980) we are able to assume that most of these clay minerals belong to the smectite group.…”

“…It is noticeable that the Co content in Sample 506G-2-1, 49-52 cm increased greatly during alteration (193 ppm). The opposite was observed in Hole 396B of Leg 46 by Honnorez et al (1978) for the brown rims where olivine was replaced by iron oxyhydroxides.…”

Major- and Trace-Element Chemistry of Hole 504B Basalts and Their Alteration Products (Costa Rica Rift, Deep Sea Drilling Project Leg 70)

“…The observed secondary alteration of the Hole 504B basement rocks is in many aspects similar to those produced by rock and sea-water interaction at low temperatures (e.g., Site 396, Mid-Atlantic Ridge; Honnorez et al, 1979;Böhlke et al, 1980). However, the development of Fe-hydroxides, calcites, and K-rich clay minerals (nearly celadonites) occurs only in the upper 300 meters of the drilled basement section.…”

Alkali and Sr Isotope Geochemistry of Waters Collected from Basaltic Basement, Deep Sea Drilling Project Hole 504B, Costa Rica Rift

“…A complete understanding of the chemical fluxes involved in this process depends on knowing the duration of convection and the chemistry of the fluids and solid alteration phases that result from the seawater/basalt interaction. The chemistry of solid alteration phases has received considerable attention recently (e.g., Andrews, 1977;Böhlke et al, 1980;Honnorez et al, 1979;Humphris and Thompson, 1978a, b;Staudigel, Muehlenbachs, et al, 1981;Mevel, 1980;Pritchard, 1980;Robinson et al, 1977). The chemistry of the circulating fluids has been studied only in two areas of the ridge system where hot springs of fluids exit the crust (Edmond, Measures, Mangum, et al, 1979;Edmond, Measures, McDuff, et al, 1979;Edmond, 1981); the fluids were sampled directly during both studies.…”