Episodes Vol. 45, No. 3 239 Article by Ralain Bryan Ngatcha 1,2 * , Cheo Emmanuel Suh 2,3 , Fongyen Naclyn Kah 2 , Elisha Mutum Shemang 4 , and Siyasanga Mpelane 5 Base metal-enriched gold-quartz veins in the eastern Camer- oon goldfields, West-Central Africa Department of Geology, Pan African University Life and Earth Sciences Institute (PAULESI), University of Ibadan, Ibadan, Nigeria; *Corresponding author, E-mail: bryanngatcha@gmail.com Department of Geology, Mining and Environmental Science, The University of Bamenda, P.O. Box 39, Bamenda, North West Region, Cameroon Economic Geology Unit, Department of Geology, University of Buea, P.O. Box 63 Buea, South West Region, Cameroon Department of Earth and Environmental Sciences, Botswana International University of Science and Technology, Private Bag 16, Palapye, Botswana Spectrum, University of Johannesburg, PO Box 524, Auckland Park 2006, Johannesburg, South Africa (Received: March 7, 2021; Revised accepted: July 19, 2021) https://doi.org/10.18814/epiiugs/2021/021019 The Colomine and Bétaré Oya gold districts are among the main gold-producing districts in the reworked Paleo- proterozoic terrain of eastern Cameroon. The characteristics of the mineralized and barren veins from these areas were investi- gated 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 Colo- mine gold district and weathered mica schist in the Bétaré Oya gold district. The hydrothermally altered granite wall- rock hosts millimetric-sized quartz lamellae/veinlets char- acterised 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. Introduction A broad spectrum of ore deposits is structurally controlled and the host structures include faults, fractures, folds, and shear zones. These structures provide pathways for the circulation of fluids and sites for the deposition of minerals. The location of Cameroon within the Pan- African Central African Shear Zone (Fig. 1a) network provides an opportunity to understand shear zone-related mineralization and pos- sibly correlate it with deposits within the Braziliano network in NE Brazil and other parts of the world. The CASZ hosts gold deposits containing millions of ounces of gold (Milési et al., 2006). Examples include the Pala gold deposit in southwestern Chad (Tchameni et al., 2013) and the Batouri, Bétaré Oya, Ngoura, and Colomine gold deposits in the eastern region of Cameroon (Vishiti et al., 2017 and references therein). In Cameroon, the CASZ is represented by the Central Cameroon Shear Zone (CCSZ; Fig. 1a, b) and is oriented NE– SW with its related features (Sanaga Fault and the Tcholliré-Banyo Faults) (Penaye et al., 2006). Studies related to primary gold mineralization in the eastern region of Cameroon are limited to the Batouri and Bétaré Oya gold districts (Suh et al., 2006; Asaah et al., 2014; Ateh et al., 2017; Vishiti et al., 2017, 2019, and references therein). Gold mineralization in these dis- tricts is spatially associated with sulphide minerals such as pyrite and arsenopyrite (Suh et al., 2006; Vishiti, 2017) in quartz veins within metamorphosed volcano-sedimentary sequences and altered granitic wall-rock. Silicification, sulphidation, sericitization, haematitization, and carbonatization are described as the main alteration processes. Fluid inclusion data from Batouri suggests moderately saline brine as ore-bearing fluid and mesothermal conditions of ore deposition con- sistent with the magmatic source of gold (Vishiti et al., 2019). The δ S values for this system reflect a single homogenous and generally light source of sulphur. The granitoid intrusions in the area include syn- to post-collisional I-type granites and show characteristics of intrusion-related gold deposits formed under reducing conditions (Asaah et al., 2014; Ateh et al., 2017; Tata et al., 2018). Few contributions to a better understanding of gold mineralization in Cameroon have been reported from the Colomine area (located north of Batouri and south of Bétaré Oya), despite the increasing interest of SMEs with local investors content in this area. This area comprises several small alluvial mining sites in the vicinity of granitic