Episodes 2022; 45(3): 239-255
Published online September 1, 2022
Copyright © International Union of Geological Sciences.
Ralain Bryan Ngatcha1,2*, Cheo Emmanuel Suh2,3, Fongyen Naclyn Kah2, Elisha Mutum Shemang4, Siyasanga Mpelane5
1 Department of Geology, Pan African University Life and Earth Sciences Institute (PAULESI), University of Ibadan, Ibadan, Nigeria
2 Department of Geology, Mining and Environmental Science, The University of Bamenda, P.O. Box 39, Bamenda, North West Region, Cameroon
3 Economic Geology Unit, Department of Geology, University of Buea, P.O. Box 63 Buea, South West Region, Cameroon
4 Department of Earth and Environmental Sciences, Botswana International University of Science and Technology, Private Bag 16, Palapye, Botswana
5 Spectrum, University of Johannesburg, PO Box 524, Auckland Park 2006, Johannesburg, South Africa
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The Colomine and Bétaré Oya gold districts are among the main gold-producing districts in the reworked Paleoproterozoic terrain of eastern Cameroon. The characteristics of the mineralized and barren veins from these areas were investigated with the aim of helping artisanal gold miners and Small and Medium Size Enterprises (SME) active in the region to identify new gold targets. This could help boost the country’s annual gold production and also generate local revenue for the indigenous community. Gold mineralization occurs in gently dipping NNE–SSW to NE–SW-trending quartz veins hosted by hydrothermally altered granitic rocks in the Colomine gold district and weathered mica schist in the Bétaré Oya gold district. The hydrothermally altered granite wallrock hosts millimetric-sized quartz lamellae/veinlets characterised by a quartz-sericite-muscovite-biotite±chlorite±albite assemblage. The mineralized quartz veins in both districts are fractured, brecciated, sheared, and vuggy, characterised by a quartz±gold±sulphide±hematite±limonite±goethite ±carbonate assemblage. Hematite occurs in a botryoidal form, ind icating the strong influence of supergene processes. This alteration phase is associated with supergene gold enrichment in the veins and constitutes the most attractive part to be exploited by artisanal and SMEs. The barren veins trend NW–SW to N–S and are generally massive to foliated. Gold ranges between 5 and 32 ppb in the wall-rock and up to 2070 and 4600 ppb in hematite-bearing quartz veins. Bulk geochemistry reveals Au-Mo (±Ag) element association in Colomine and Au-Ag-Mo-Cu in Bétaré Oya indicative of a sulfide-bearing granitic source.