Proterozoic – Paleozoic orogenic gold mineralization along the southwestern margin of the Tanzania Craton: A review

Abstract The southwestern margin of the Archean Tanzania Craton in central East Africa is flanked by the poly-orogenic Ubendian Belt. This belt represents a metacratonic margin with a magmatic history dating back to the Archean. Since then, this belt has been reworked by three orogenic events (Ubendian, Kibaran/Irumide and Pan-African) during the mid-Proterozoic to early-Paleozoic. The fertile nature of this belt is highlighted by the widespread occurrence of structurally-controlled gold deposits, which collectively define four goldfields (Mpanda, Lupa, Amani and Niassa) that are temporally related to the orogenic events. Geochronological studies conducted during the last decade have brought forward new evidence to suggest that the Ubendian Belt experienced at least three temporally distinct gold mineralization events which are associated with these orogenies : a ∼1.8 Ga event in the Lupa Goldfield, a ∼1.2 Ga event in the Mpanda Mineral Field and a ∼0.45–0.6 Ga event in the Niassa and Amani Goldfields. Although gold mineralization in the Ubendian Belt occurred over a period of more than 1 billion years, the different goldfields all share broadly similar features (i.e. proximal to major lithospheric-scale lineaments , gold mineralization hosted in shear zones and quartz – carbonate veins with chalcopyrite – pyrite  ±  pyrrhotite sulphide assemblages and hydrothermal alteration assemblages consisting of quartz + sericite + chlorite + carbonates). The characteristics of these goldfields are comparable to other orogenic gold deposits occurring along reworked Archean cratonic margins. Artisanal mining remains the dominant mode of extraction within these goldfields and large-scale gold production is currently only active in the Lupa Goldfield. This belt remains largely underexplored, particularly towards its southern margin, and is relatively immature from an exploration perspective. Here, we review the characteristics of each goldfield and provide prospective targets for future gold exploration endeavours.