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Paper Number: 186
Ilboudo,
H.1, Wenmenga U.2, Lompo, M.5
2,3,
Department of Earth Sciences, University of Ouagadougou, 03 BP 7021
Ouaga 03 (Burkina Faso)
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The Kwademen birimian polymineral (Cu-Zn±Pb±Au) deposit is made of
mafic dominant volcanic, neutral and subordinate acid through a bimodal
volcanic suite. The metamorphic climate that affects the rocks is around
the green schist facies.
The associated volcano-sedimentary occurrences develop a steep
geomorphology marked by a maganiferous deposit. Gold and massive
sulphide deposits are hosted by felsic volcanic accommodated by a shear
zone which constitutes the track in uprising mineralizing fluid for gold
and base metal (Cu, Zn, Pb).
Hydrothermal alteration
mineral phases involved in the process are in order of importance: (i)
sericite, (ii) epidote, (iii) chlorite, (iv) carbonate, and (v) biotite.
The spatial organization of sulphide (notably pyrite) is conformable
with a stratiform deposit from hydrothermal provenance. High cupper
value recorded in felsic mylonite can explain enrichment controlled by
shearing. Finally the proximity of Kwademen with the Perkoa Zn-Ag-Pb
volcanogenic massive sulphide [1]. deposit is encouraging to target an
economic deposit type in relation with the style of the mineralization
within volcanic and plutonic terrane of that birimian.
Figure 1: Overview of Kwademen manganesiferous hill
Key words: Burkina Faso, Kwademen, massive sulphide, hydrothermal
alteration, bimodal suite, Palaeoproterozoic,
References:
[1] Schwartz M O and Melcher F (2003) Econ Geol 93:1463-1485
