Petrographic and Geochemical Characters of Granites of the Banfora Belt, Burkina Faso (West Africa)

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Résumé

The Banfora’s birimian greenstones belt is located in the western part of Burkina Faso (west Africa). Recent petrographic and lithogeochemical studies have highlighted plutons intruding the metasedimentary and metavolcanic series. These plutonic rocks are composed of leucogranites belonging to the so called Ferkessedougou’s or Ferke’s batholith, granites, granodiorites, monzodiorites and quartz monzonites. From the lithogeochemical studies, these plutonic rocks have a calc-alkaline and peraluminous character. The rare earth elements spectra of the Ferke’s leucogranites let distinguished two sub-facies. One of the sub-facies is composed of quartz monzonite to granite, while the other is granitic sensu stricto. However, all these plutonic rocks were emplaced in a geodynamic context of subduction followed by collision.

Mots-clés

Burkina Faso, Banfora, Greenstones Belt, Plutons, Geodynamic Context, Subduction