Geochemistry and geochronology of the ~620 Ma gold-associated Batouri granitoids, Cameroon

Abstract

The Batouri gold mining area in southeastern Cameroon is part of the Adamawa–Yadé Domain of the Central African Fold Belt (Pan-African). It is underlain by a variety of granitic rocks, including alkali-feldspar granite, syeno-monzogranite, granodiorite, and tonalite. Geochemical data suggest that these rocks formed by differentiation of I-type tonalitic magma under oxidizing conditions in a continental volcanic arc setting. U–Pb dating of zircons from gold-associated monzogranite-granodiorite at Kambélé gave concordant ages of 619 ± 2 and 624 ± 2 Ma, while Ar–Ar dating of alkali-feldspar granite yielded a non-plateau maximum age of 640–620 Ma. These ages imply that the Batouri granitoids were emplaced during the collision of the West African Craton and the Congo Craton.

The geochemical characteristics of the Batouri granitoids as well as their oxidized state (magnetite series) are typical of gold-associated felsic rocks in subduction settings elsewhere. The similarities in age, composition, and geochemical affinities of these granitoids with those reported from other localities in the Adamawa–Yadé Domain reinforce the earlier assumption that the granitic rocks of this domain represent parts of a regional-scale batholith, with commonly small-scale, high-grade auriferous quartz veins in structurally favourable sites. The spatial and temporal association of gold mineralization and the Batouri granitoids may suggest potential for regional-scale, high-tonnage, granite-related gold ore.

Keywords:

• Batouri granitoids
• Cameroon
• geochemical characteristics
• U–Pb and Ar/Ar geochronology
• tectonic evolution

Additional information

Funding

This study was made possible through a scholarship from the German Academic Exchange Service (DAAD: Deutscher Akademischer Austauschdienst) awarded to A.V. Asaah. It also benefited from financial support from the Institute for Mineralogy and Mineral Resources, Technical University of Clausthal. Two research grants were provided by the Newmont Mining Corporation and the Hugh E. Mckinstry Fund, through their collaboration with the Society of Economic Geologists (SEG). SEG and the Geological Society of South Africa (GSSA) jointly provided A.V. Asaah a travel grant. We also acknowledge the financial support of the Society of Geology Applied to Mineral Deposits (SGA) to accomplish this work. Logistical support during the field work was provided by African Aura Resources Ltd. The manuscript benefitted from critical reading by John Ridley, an anonymous referee, and editorial handling by Vinod Singh and Robert J. Stern.