Filamentous iron-silica deposits from modern and ancient hydrothermal sites
Filamentous iron-silica deposits from modern and ancient hydrothermal sites (in Sea-floor hydrothermal mineralization, Timothy J. Barrett (editor) and John L. Jambor (editor))
The Canadian Mineralogist (September 1988) 26, Part 3: 859-869
- bacteria
- chemical composition
- crystal chemistry
- deposition
- East Pacific
- East Pacific Rise
- framework silicates
- geochemistry
- hydrothermal alteration
- hydrothermal vents
- iron
- iron oxides
- Juan de Fuca Ridge
- metals
- metasomatism
- microorganisms
- mid-ocean ridges
- North Pacific
- Northeast Pacific
- ocean floors
- opal
- oxides
- Pacific Ocean
- precipitation
- SEM data
- silica
- silica minerals
- silicates
- textures
- X-ray diffraction data
Numerous samples of Fe oxide/silica material from hydrothermal sites on the East Pacific Rise, Juan de Fuca/Explorer Ridges, and other areas are porous and consist of branching filaments of Fe oxides and amorphous silica (opal A). A similar filamentous microtexture characterizes cherts associated with terrestrial sulphides of oceanic origin (e.g. Troodos and Coast Range, California ophiolites). Zonation within these deposits and consideration of conditions necessary for the precipitation of Fe oxide and opal A suggest that filamentous structures existed on the sea-floor prior to mineral deposition. The presence of organic matter and identifiable filamentous bacteria in a sample from the Philospher Vent on Explorer Ridge suggest that the Fe and silica were deposited in association with filamentous microorganisms.
