Horizon 1 1 17 ACL : Articles dans des revues avec comité de lecture répertoriées par l'AERES Ore Geology Reviews 623-630 West African Craton Boromo Greenstone Belt Burkina Faso Orogenic gold Shear zone BURKINA FASO 2016 fdi:010067639 ENG Ore Geology Reviews 0169-1368 ISI:000378450300038 10.1016/j.oregeorev.2015.11.026 https://www.documentation.ird.fr/hor/fdi:010067639 https://www.documentation.ird.fr/intranet/publi/2016/08/010067639.pdf 78 Horizon (IRD) The Nassara-Au prospect is located in the Birimian Boromo Greenstone Belt in southwestern Burkina Faso. It is part of a larger mineralized field that includes the Cu-Au porphyry system of Gaoua, to the north. At Nassara, mineralization occurs within the West Bade Shear Zone that follows the contact between volcanic rocks (basalt and andesite) and volcano-sediments (pyroclastics and black shales) at the southern termination of the Boromo Belt. Gold is associated with pyrite and other Fe-bearing minerals that occur disseminated within the sheared volcanic and volcano-sedimentary rocks. In particular, highest grades are distinguished in alteration halos of small quartz-albite-ankerite veins that form networks along the shear zone. Here, pyrites are marked by As-poor and As-rich growth zones, the latter containing gold inclusions. Gold mineralization formed during D2(NA). Subsequent shear fractures related to D3(NA) related are devoid of gold. Nassara is a classical orogenic gold occurrence where gold is associated to disseminated pyrite along quartz veins. 064 UR234 Burkina Faso / Sénégal