We present new geochemical data on the volcanic rocks of the Mangodara sector (southeastern edge of the Banfora Paleoproterozoic belt) in the West African Craton and discuss their petrology and geodynamic context. Three main volcanic units are described, notably andesites, dacites, and rhyolites. These lithologies are dominated by volcanoclastite units, indicative of high-volatile explosive eruption products in the Mangodara sector. Andesite, with ƩREE=105.95 to 135.95 ppm, show LREE enrichment compared to HREE and (La/Yb)N = 6.19 - 8.25, (La/Sm)N = 3.32 - 3.95. All profiles show a Eu negative anomaly with a Eu/Eu* ratio = 0.72 - 0.94. Dacite, with ƩREE = 115.09 ppm to 118.75 ppm, shows LREE enrichment compared to HREE (La/Yb)N= 6.64 - 12.42, (La/Sm)N = 3.48 - 3.67, and Eu negative anomaly with Eu/Eu* = 0.77 - 0.83. Rhyolite, with ƩREE =110.93 to 142.18 ppm shows LREE enrichment compared to HREE (La/Yb)N = 6.65 - 13.95, (La/Sm)N = 3.37 - 3.68 and Eu/Eu* = 0.78 - 0.83. Dacite, felsic volcanoclastite (rhyolite) and andesite REE patterns are parallel, suggesting a cogenetic source. Negative Nb, Ta, Ti and Sr anomalies and the lack of garnet signature in andesite, dacite and felsic volcanoclastite (rhyolite) characterize partial melting to amphibolite facies. However, the rhyolite flow shows a garnet signature. The negative Nb, Ta and Sr anomalies, the positive Pb anomaly and the low Cr and Ni content indicate melting of the middle continental crust at the start of subduction. Volcanic rocks show generally positive correlations in the La versus (La/Sm)N diagram, indicating that they may originate from different degrees of partial melting of the same crustal source. The hypothetical scenario for the origin of the Banfora belt corresponds to an individual, isolated volcanic arc.

Volcanism, Subduction, Geodynamic, Paleoproterzozoic, West Africa Craton, Banfora Belt