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 Africa 2000 The Gold Deposits of East & West Africa 24 Oct to 9 Nov, 2000 | |||||||||||
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Porter GeoConsultancy conducted a two module professional development course that visited nine major gold deposits across Africa, from the Indian Ocean to the Atlantic. These deposits included examples associated with Neoarchaean and Palaeoproterozoic greenstone belts in East and West Africa respectively.
The deposits visited covered a wide range of mineralisation styles, representing transgressive orogenic hydrothermal systems within the greenstone belts and overlying clastic sequences; conformable blanket like orebodies in Proterozoic conglomerates; as well as those hosted by granite and greywacke adjacent to Palaeoproterozoic greenstone belts; and major lateritic gold accumulations. The two modules included the following: East African Module, Tanzania - 6 days, from Mon. 23 to Sat. 28 Oct., 2000 Technical geological visits to the Golden Pride shear controlled gold deposit, hosted within deeply oxidised rocks of the Neoarchaean Nzega greenstone belt; the Bulyanhulu shear controlled quartz-sulphide veins within the Neoarchaean Sukumaland Greenstone Belt; and the Geita cluster of deposits associated with sheared BIF rich units within volcanic rocks of the Neoarchaean Geita Greenstone Belt, the northern arm of the regional Sukumaland Belt. West African Module, Ghana and Mali, 10 days, from Tues. 31 October to Thurs. 9 November, 2000 Technical geological visits to the Damang vein-type gold deposit hosted by the Palaeoproterozoic Tarkwaian clastic fluviatile sedimentary sequence; the Tarkwa deposit which occurs as stratabound disseminated gold within a hematitic conglomerate of the Tarkwaian sequence; and the Obuasi - Ashanti vein and disseminated gold deposit within the Palaeoproterozoic Birimian greenstone sequences of metamorphosed tholeiitic basalts and lesser andesites with intercalated graphitic phyllites; and the Yamfo-Sefwi project where gold veining and stockworks occur on the sheared margin of the Palaeoproterozoic greenstones. These deposits are all within Ghana, and the Sadiola deposit, occurring as fine veinlet and disseminated sulphides controlled by faulting at the contact between brittle Birimian siliciclastic rocks and ductile calc-silicate altered carbonates, which also hosts altered Palaeoproterozoic granitoids; much of the deposit is deeply weathered and oxidised; and Morila deposit, a heavily deformed polymetallic vein and stockwork zone hosted by hornfelsed biotite schist within a metamorphosed Birimian volcano-sedimentary enclave surrounded by ~2.1 Ga granitoids. These two deposits are ~600 km apart in southern Mali.
This study tour was planned, organised and managed by Porter GeoConsultancy as a professional development course on the curriculum of the Australian Mineral Foundation.
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