A general tectonic framework in the Sangmelina greenstone belt in southern Cameroon (NW Congo craton) : Mining exploration implications
Abstract
The Sangmelima Greenstone Belt in southern Cameroon (NW Congo Craton) displays a D2 regional fabrics that consist of an S2 sub-vertical foliation, L2 stretching lineation and F2 folds resulting from a dextral transpressive regime. D3 late granulitic deformation synchronous with a migmatisation episode is characterized by F3 post-folds with oblique axes, sometimes associated with localized C3 shear zones showing inverse movements alongside an anatexy phenomenon. The plutons were emplaced during the regional deformation. The regional structure, combined with the existence of contemporary intrusive and extrusive rocks in the surface today, buttress a vertical tectonic model with burial of supra-crustal rocks in soft underlying material during the ENE-WSW to EW horizontal crustal shortening. The important magmatic intake within the craton allows a warming and a general softening of the lithosphere. Finally, CN has been affected by the Eburnean orogeny (D4), characterized by the development of the N40-60E transverse step with a generally sinusoidal component, to which some dextral conjugate bands are associated.