TITLE:
Geochemical Mobility Associated to Gold and Base Metal Occurrences of Mangodara Sector, in Southern Burkina Faso, Banfora Greenstone Belts (West African Craton)
AUTHORS:
Bernadin Gnamou, Hermann Ilboudo, Wilfried Antoine Bassou Toé, Sâga Sawadogo
KEYWORDS:
Geochemical Mobility, Aluminous Alteration, Metamorphism, Gold, Base Metal, Banfora Greenstone Belts, Mangodara
JOURNAL NAME:
Open Journal of Geology,
Vol.13 No.10,
October
20,
2023
ABSTRACT: In the Mangodara area within the Banfora greenstone belts (Baoulé-Mossi
domain of the West African Craton), our study focused on geochemical assessment
of the mobility of major and trace elements. Gold and base metal occurrences are
hosted in highly metamorphic felsic (metarhyolite) and intermediate (metadacite
and metaandesite) formations. Common mineral assemblages made up of staurolite
- kyanite - pyrophyllite are interpreted to represent the metamorphosed
equivalent of aluminous hydrothermal alteration. Associated felsic and
intermediate volcanic rocks are enriched in Fe2O3, K2O
(metaandesite, metarhyolite) and depleted in MgO, Al2O3,
CaO, P2O5, Na2O (metarhyolite) and Fe2O3,
MgO, CaO (metaandesite). Al2O3 depletion in mineralized
kyanite-staurotide bearing metarhyolites suggests corroded minerals.
Mineralized metarhyolites show enrichment in Au, Ag, Ba, Bi, Cr, Cu, Eu, La,
Mo, Ni, Pb, S, Sc, V and depletion in As Sb Co, Sn, Zn while mineralized
metaandesites show enrichment in Au, Ag, As, Mo, S, Sb and depletion in Co, Sn,
Zn, Bi, Cr, Cu, Eu, Ni, Pb, Sc. Ba, La, V are immobile in metaandesites.
Finally, Ag, As, Sn appear as geochemical vectors for gold exploration in the
study area since gold mineralization is characterized by Au + Ba + Cu + Eu + La
+ Mo + Ni + S association in metarhyolites and Au + S + Sb + As + Ag + Bi in
metaandesites.