Explanatory notes for the geological map of Southwest Ghana 1:100000

This volume details geological mapping and research conducted in southwestern Ghana, covering approximately 2000 km² south of latitude 5° N and between longitudes 1°30' W and 2°30' W. The area is rich in gold and manganese, featuring rocks from the Birimian Supergroup and Tarkwaian Group, along with late-kinematic granitoids, all of Paleoproterozoic age. Local Paleozoic and Cretaceous sediments are also present. The geological sheets at a scale of 1:100,000 (Axim and Sekondi) encompass the southern Ashanti volcanic belt, a key gold-producing region, and parts of the Kumasi sedimentary basin. The region mainly consists of three significant granitoid plutons with U-Pb zircon crystallization ages of 2172 + 2 Ma and 2174 + 2 Ma. Regional foliation trends NE-SW or NNE-SSW, resulting from Eburnean NW-SE compression, are noted. Three major high-strain zones are identified, including the southern extension of the gold-rich Prestea-Obuasi-Konongo zone. The study catalogs 26 gold occurrences and four manganese occurrences, detailing their characteristics. Key controls for gold deposition include high-strain zones and sheared granitoid/greenstone contacts. The volume includes introductory notes, summaries of Birimian and Tarkwaian knowledge, geological descriptions, isotopic constraints, and listings of abandoned mines and prospects, supported by two full-color map sheets.