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 monzogranitegranodiorite 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.

Gold grade variation and particle microchemistry in exploration pits of the Batouri gold district, SE Cameroon

“…UePb dating of zircons from these gold-associated felsic plutons yielded concordant ages of 619e624 ± 2 Ma, while AreAr dating of the alkali-feldspar granite yielded an age of 640e620 Ma. These ages imply that the Batouri granitoids were emplaced during the collision of the West African Craton and the Congo Craton (Asaah et al, 2014) and gold mineralization is contemporaneous with UeMo mineralization in two mica granites within this domain (Mosoh Bambi et al, 2013). …”

“…1b and 2). In the Batouri area primary gold mineralization is related to structurally controlled discordant quartz veins/veinlets (Tremblay, 1975;Suh and Lehmann, 2003;Suh et al, 2006;Vishiti, 2009;Asaah et al, 2014), weathering profiles and altered wallrock restricted to NEeSW-trending shear zones (Suh et al, 2006) that cut across Pan African I-type granites (Asaah et al, 2014). In the Batouri gold district, gold is mined artisanally from alluvial workings (Fig.…”

“…The second deformation stage is characterized by the development of tight and upright folds with steeply dipping axial plane schistosity, plunging fold axes and stretching lineation (NNEeSSW to NEeSW, Toteu et al, 2004). The Batouri gold district is underlain by magnetite-bearing granitoids including alkali feldspar-to plagioclase feldspar-rich varieties (Asaah et al, 2014) that are derived from I-type parental magmas of tonalitic affinity. UePb dating of zircons from these gold-associated felsic plutons yielded concordant ages of 619e624 ± 2 Ma, while AreAr dating of the alkali-feldspar granite yielded an age of 640e620 Ma.…”

“…Primary gold occurrences in the Batouri area are related to PanAfrican granitoids (Asaah et al, 2014) especially along shear zones. Due to deep weathering, these primary features are poorly constrained and exploration has met with variable success (see www.…”

Microchemical signature of alluvial gold from two contrasting terrains in Cameroon

“…(a) Geological map of Cameroon (modified afterToteu et al, 2001;Asaah et al, 2014). The Central African Shear Zone is defined by a system of NE-trending faults comprisingTchollire-Banyo Fault (TBF), Adamawa Fault (AF), Sanaga Fault (SF), and Kribi-Campo Fault (KCF).…”