The Bagassi gold deposits on the eastern margin of the Houndé greenstone belt, Burkina Faso

• Bagassi gold deposits are high grade in quartz veins and shear zones in granitoids.
• Gold ore occurs in quartz–gold with accessory pyrite and absent of other sulphides.
• Granitoids that were emplaced prior to onset of the Eburnean Orogeny have potential to host gold.
• Bagassi deposits represent a unique exploration target in West Africa.

The Bagassi gold deposits are situated on the West African craton and hosted in Palaeoproterozoic rocks of the Houndé greenstone belt, southwest Burkina Faso. High-grade gold mineralisation is hosted in quartz–gold ± pyrite veins-lodes (V1A), in dilational zones and narrow shears in the Bagassi granitoid, and forms the majority of the resource–reserve portfolio in the Bagassi exploration permits, with gold grades of 18–21 g/t. Shear hosted gold-pyrite mineralisation in quartz veins in dilational jogs (V1B) occurs along narrow discontinuous shear zones that trend north-northwest in Birimian-aged metabasaltic units, and forms a secondary gold resource. Gold mineralisation is restricted to formation in the late Eburnean Orogeny and formed during a change from east-west to transcurrent compression and shearing. The Bagassi deposits demonstrate that granitoids emplaced prior to onset of the Eburnean Orogeny represent viable gold mineralisation in host rocks that are increasingly seen to be associated with significant gold resources.

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