The Mesoproterozoic Kibaran belts host large amounts of mineral resources such as cassiterite, wolframite, gold, and columbite-group minerals (“coltan”), all of them in high demand for new technologies and related industries. Most of these mineral occurrences are linked to the latest Mesoproterozoic to early Neoproterozoic G4 granitoid intrusions, also termed “tin(-bearing) granites”. Three main parts constitute the Kibaran belts: the Kibaride Belt (KIB) in the south, the Karagwe-Ankole Belt (KAB) in the east, and the Kivu Belt (KVB) in the west. Geological detail concerning the metallogeny of the KVB, which hosts large parts of these mineral resources, is very sparse. Previously, there was an assumed time gap of about 200 Ma between the formation of the last Kibaran terranes (1250 to 1200 Ma) and the emplacement of the G4 granites (ca. 1050 to 970 Ma), which generated the main mineralizations. Recent studies dated the last Kibaran tectono-thermal events younger than 1120 to 1110 Ma, which gave evidence for a drastic reduction in this time gap. Thus, the two newly recognized tectono-thermal events have likely contributed to the remobilization of older mineralized granites. These new data allow us to link the G4 granitoids and the associated mineralizations with the terminal Kibaran orogeny. However, the G4 emplacement and its relationships with older granites, with their host rocks and associated mineralizations, are not yet understood. Here, the main occurrences of the KVB are reviewed, and comparisons with similar mineralizations in the adjacent KAB are undertaken to improve our understanding on these complex relationships.

The Variscan Orogen was formed during the closure of the Rheic Ocean and the final collision between the North American and West African cratons in the Late Paleozoic. This collision led to the multistage building of the Mauritanide Belt to the east of the Variscan suture and to the building of the well-known Appalachian Belt to the west. Both led to opposite vergences in this part of the Variscan belt. The earliest records of the main collision episode begin at ∼360 Ma and end about 250 myr ago, while a late extensional phase lasted until ∼190 Ma. Three distinct stages are recognized in West Africa. The first stage ( c. 350–300 Ma) records the indentation of the Reguibat Shield into the central Appalachian margin of Laurentia. This indentation led to thrusting of the Souttoufide and Akjoujt ‘nappes’ onto the Reguibat Shield, to southward motion of the Senegalese block (SB), and to strike-slip motion in the Appalachians. The motion of the SB to the south is coeval with: (1) folding of the northern part of the Bové Basin, (2) north–south sinistral strike-slip motions in the central Mauritanides, and (3) the end of sedimentation in the Bové and Taoudeni Basins by the Late Devonian. The second stage ( c. 300–250 Ma) involves the eastward motion of the Western Thrust Block (WTB) against the SB and, likely, some of the westward thrusts in the Appalachians. This second ‘Variscan’ event includes: (1) closure of parts of the lower Diourbel Carboniferous basin, which is now concealed beneath the Senegalo-Mauritanian Basin, (2) thrusting to the east of the Simenti Group over the Koulountou Group in the Bassaride Belt, (3) thrusting to the east of the Wa-Wa Group, (4) thrusting of the Mauritanide Belt onto the Taoudeni Basin in the central Mauritanide Belt, and finally (5) thrusting of the Agualilet Group over the Akjoujt nappes and eastward motion of the western units over the Dhloat Ensour (Late Ordovician to early Devonian) autochthonous unit in the Souttoufides. West of the supposed ‘Variscan’ suture, Appalachian thrusting affected parts of Appalachian Belt. The third stage ( c. 250 to 190 Ma) began with the opening of Triassic rift basins in the Senegalo-Mauritanian basin and also in the north of Florida. As numerous previous correlations across the Variscan system do not include the West African part, our sythesis is intended to enhance these correlations.

Correlations between the Neoproterozoic belts surrounding the West African Craton and northern Brazilian cratons have long been a subject of interest and controversies. Due to the splitting of African and South American continents by the Atlantic oceanic domains, no direct links are preserved, requiring relying on various geological or geophysical characteristics to propose such correlations. In addition to the opening of the Atlantic oceanic domains, another difficulty arises from the covering of northern Brazilian belts by upper Paleozoic and Mesozoic basins, making these correlations speculative. Here, we propose new correlations based on the comparison between African and Brazilian belts. Recently, new geochronological and geodynamical data obtained in West Africa have evidenced four orogens in the Neoproterozoic belts of the western margin of the West Africa Craton, while the belts on the eastern side underwent only one orogeny. Similarities with the Pan-African I (900–650 Ma) and with the Pan-African II (650–480 Ma) orogenic events have been evidenced in the western Brazilian belts (Araguay and Paraguay). The first two orogens on the western margin (Pan-African I and Pan-African II) can thus be extended to the western Brazilian belts and can be considered as parts of a single geodynamic system running from the Mauritania to the Paraguay including the “Gurupi rift” as an aulacogen connected to the NNW-SSE Panafrican I and II oceanic domains. Consequently, the eastern Brazilian belt should rather be linked the Eastern Trans-Saharan belts.

Correlations between the Neoproterozoic belts surrounding the West African Craton and northern Brazilian cratons have long been a subject of interest and controversies. Due to the splitting of African and South American continents by the Atlantic oceanic domains, no direct links are preserved, requiring relying on various geological or geophysical characteristics to propose such correlations. In addition to the opening of the Atlantic oceanic domains, another difficulty arises from the covering of northern Brazilian belts by upper Paleozoic and Mesozoic basins, making these correlations speculative. Recently, four orogens have been evidenced in the Neoproterozoic belts of the western margin of the West Africa Craton, while the belts on the eastern side underwent only one orogeny. Similarities with the Pan-African I (900-650 Ma) and with the Pan-African II (650-480 Ma) orogenic events have been evidence in the western Brazilian belts (Araguay and Paraguay). The two first orogens on the western margin (Pan-African I and Pan-African II) can thus be extended to the western Brazilian belts and can be considered as parts of a single geodynamic system running from the Mauritania to the Paraguay including the “Gurupi rift” as an aulacogen connected to the NNW-SSE Panafrican I and II oceanic domains. Consequently, the eastern Brazilian belt should rather be linked the Eastern Trans-Saharan belts.