thumbnail

Mineralogy and chemistry of massive sulfide deposits from the Juan de Fuca Ridge.

Geological Society of America Bulletin

By:
, ,

Links

  • The Publications Warehouse does not have links to digital versions of this publication at this time

Abstract

Two types of massive sulphide were dredged from one of the six vent sites located in the axial valley of the southern Juan de Fuca ridge. Type A samples are angular slabs of dark grey Zn-rich sulphide with interlayers and a thin, partly-oxidized crust of Fe-sulphide. These layered sulphide aggregates appear to be fragments of a sulphide wall enclosing an active hydrothermal vent. The outer sulphide wall is composed of colloform Fe sulphide and Fe-poor sphalerite deposited under low-T conditions when sea-water and hydrothermal fluid mix above the discharge point. Inside the wall the intensifying hydrothermal sytem deposits a higher-T assemblage of granular Fe-rich sphalerite, wurtzite, pyrite and minor Cu-Fe sulphide. Type B sulphide samples are sub-rounded, spongy-textured fragments composed almost entirely of dendritic aggregates of pale Fe-poor colloform sphalerite and opaline silica. This type of sulphide is deposited in settings peripheral to sites of focused discharge and in open spaces by moderate- to low-T fluid discharging at a slow but variable rate; the fluid becomes increasingly oxidizing, resulting in late-stage deposits of hematite, baryte and sulphur.-L.di H.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Mineralogy and chemistry of massive sulfide deposits from the Juan de Fuca Ridge.
Series title:
Geological Society of America Bulletin
Volume
95
Issue:
8
Year Published:
1984
Language:
English
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
First page:
930
Last page:
945
Number of Pages:
16