Russian Mineralogical Society
XIII All-Russian conference on thermobarogeochemistry in conjunction with IV APIFIS symposium
Formation conditions of the Otjihase massive sulfide deposit in the Matchless amphibolite belt (Namibia)

RMS-DPI code:  2008-1-71-0
Scientific session:  Fluid regime of hydrothermal ore-forming systems
Author listing:  Vikentyev I.V., Shikikumba T.H., Karpukhina V.S., Nosik L.P., Kerzin A.L.
Principal author:  Vikentyev Ilya V.
Language:  Russian
Abstract - Summary 
(short description):
The Otjihase copper deposit (Namibia) is deformed and metamorphosed massive sulphide deposit closely associated with the Matchless amphibolite belt. Hosted by mafic metavolcanic rocks (interpretated as tholeiitic oceanfloor basalts) and interbedded metasediments (PR1) strata-bound sulfide body has a thickness of 5 m and a length 7.5 km. Ores are copper dominant with pyrite, chalcopyrite, subordinate sphalerite, and rare pyrrhotite, cubanite and marcasite. Gold is mostly incorporated in sulphides: in pyrite 0.1-0.4 ppm Au (total range 0.002-3.5 ppm), in chalcopyrite 0.1-0.4 ppm Au (0.003-2 ppm) and in sphalerite (Sph-Py-Cp intergrowth) 0.008-8.5 ppm Au. Sulfide ore body and associated magnetite quartzite lenses were related to submarine exhalative oreforming process. Metal sulfides were precipitated from convecting hydrothermal fluids generated by subvolcanic basalt chamber and reacted with seawater and subsea-floor basalts and clastic sediments. Primary ores were metamorphosed at 750-300 (amphibolite facies). Fluid inclusions in quartz of ores are liquid-rich and O2-bearing. The observed Thom of fluid inclusions in the ores are corresponding to PT-conditions of ore recrystallization (t=435-290oC, P=1.8-0.9 kbar) and not connected with the ore composition./ amphibolites, massive sulfides, metamorphism, Lower Proterozoic, fluid inclusions, sulfur isotopes
Date of presentation:  22/09/2008
Presentation Place:  IGEM RAS, Conference Hall
RMS-DPI code:  2008-1-71-0
Proceeedings volume 
in the RMS catalogue:
Proceedings of XIII International conference on thermobarogeochemistry and IVth APIFIS symposium. Volume 2.
Pages:  19-22
File of proceedings 
 136 K
Status:  printed
Recieved:  19/03/2008
Accepted:  28/06/2008
Published on-line:  19/02/2009
Permanent address of publication:
Contact author(s):  Korytov, Fiodor Ya.

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