Structural Study of the Precambrian Basement of Kaele (Far North Cameroon): Contribution of Remote Sensing (Application of Landsat 8 OLI/TIRS Images) and Field Data

Abstract

The Kaele is located in the northern domain of the Pan-African fold belt of Central Africa in Cameroon, north of Mayo- Kébbi domain. The structural study carried out in this area is based on Landsat 8 OLI/ TIRS image processing techniques and traditional geological prospection methods. The objective is to evaluate the contribution of landsat 8 OLI/TIRS image processing and field data in the structural mapping of the Kaélé region. The application of the 7×7 directional filters of the Sobel type in the N-S, E-W, NE-SW and NW-SE directions, to the ETM+3 channels gives better results. The rose diagram of the lineament map (obtained from image processing) shows a major E-W direction (N100E) and a secondary direction N-S (N10E). The studied area is affected by a polyphase deformation D1 to D4. The first phase of deformation (D1) is tangential and has set up the sub-horizontal dipping S1 schistosity which bears a composite L1 lineation (stretching, mineral). The D2 phase is constrictional and responsible for the establishment of the subvertical S2 axial plane foliation of the P2 folds, carrying the composite L2 lineation (stretching, mineral) and the B2 boudinage. The dextral-moving C2 shear cuts the S1 foliation, the P2 folds are asymmetrical isopach and anisopach. The third phase D3 is a constriction and set up the S3 schistosity which appears in syn -tectonic granite and highlight the C3 shear planes. The C3 shear is dextral and the P3 folds are isopach, anisopach, intrafolial and sheath fold. The last phase of deformation D4 is brittle and has set up faults and joints. There exist similarities between orientation of lineament from image processing and direction of D2, D3 and D4 deformational phases structures.