The Sangmelima granite-greenstone belts (South Cameroon): Integration of remote sensing and aeromagnetic data for structural interpretation

Abstract

The integration of geology, geophysics and remote sensing data was used to map the Sangmelima granite-greenstone belt terrain located in the South Cameroon. The region was not easily accessible, because of dense vegetation and thick lateritic overburden. Aeromagnetic data were help in mapping new possible small greenstone belts and structural features in this area. Many of the identified lineaments are interpreted to represent fracture/fault zones, some of strike-slip faults. The NE–SW, NW–SE, N–S and E–W are the main revealed from remote sensing processing; while the NE–SW, E–W to ESE–WNW, NW–SE and N–S are the dominant structural trends revealed from aeromagnetic data. We distinguish three deformation events within the Sangmelima area: D1 is recorded by a sub-vertical penetrative S1 foliation bearing steeply plunging stretching lineations. D2 overprints D1 structures with tight-to-isoclinal folds with associated foliation, N160°−175°E and N05°−25°E ductile shear zones, indicating ENE–WSW shortening. The D3 strike slip shearing is likely the result of the Eburnean deformation phase. The mafic dykes are striking NE–SW, N–S and NW–SE, and field evidence and airborne magnetic data suggest that some of them intrude preexisting structures. Many faults/fractures might have originated during previous deformation phases and they were only reactivated during the pan-African events.