500+ Moz West Africa: Premier Paleoproterozoic Gold Province
West Africa, with presently an approximate 10,000 metric ton (t) gold endowment, is one of the world’s great gold provinces and the largest Paleoproterozoic gold-producing region. The gold resources are concentrated within the 2250 to 2000 Ma (mega annum) greenstone belts of the Man-Leo Shield, forming the southern part of the West Africa craton.
Most of the major orebodies are best classified as orogenic gold despot types, although there are paleoplacer and porphyry-skarn despots within some of the greenstone belts, and perhaps local intrusion-related gold systems. The gold-hosting, mainly greenschist metamorphic facies greenstone belts are dominated by the tholeiitic volcanic rocks, with clastic and chemical sediments filling adjacent subbasins.
The West African Craton is known for multiple gold deposits, located in the lower Proterozoic volcano-sedimentary sequences. Some of the gold deposits in production include Obuassi, Ashafo and Boguso gold deposit in Ghana; the Sadiola, Fecola, and Tabakoto deposits in Mali; the Saboala deposits in Senegal; the Essakane, Taparko-Borum, Mana and Youga deposits in Burkina Faso.
Based on tectonic and geochronological data, it is presumed that the Amazonian and West African Craton were part of the Gondwana continent and were joined before the opening of the Atlantic Ocean during the Mesozoic Era.