Title:

A geochemical model for sulfide paragenesis and zoning in the Cu Fe As S system (Tsumeb, South West Africa/Namibia)

Author(s):
Publication Year:
1984
Abstract:

The Cu-bearing hypogene mineralization at Tsumeb, South West Africa/Namibia, is interpreted to have resulted from the interaction of hot circulating Cu-rich saline solutions and host dolomites. Fluids attending formation of the main sulfide stage were warm (210–280°C) and moderately saline (6–12 wt.% NaCl equivalent). Phase relations within the CuFeAsS system suggest that the observed paragenetic sequence (chalcopyrite → bornite → chalcocite → enargite → tennantite) is consistent with a model calling for successive introduction of a single Cu-rich solution into a host dolomite. The Cu and As content of the solution decreased as it passed through the permeable dolomite precipitating CuAs-sulfides and sulfosalts. A concomitant increase in pH created by the dissolution and buffering effect of dolomite produced sufficient changes in the fluid chemistry to shift the stable sulfide mineral assemblage.

Publication Title:

Chemical Geology

Volume:
47
Issue:
3-4
Pages:
183-190
Item Type:
Journal Article
Language:
en

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