Structural Styles and Tectonic evolution of the Kolia-Boboti sedimentary basin, Kédougou-Kéniéba inlier, Eastern Senegal

International audienceNew structural data obtained on the Birimian terranes of the Kolia-Boboti sedimentary Basin, the eastern part of the Diale´ -Dale´ma Supergroup in the Ke´dougou-Ke´ nie´ba inlier show two major phases of Eburnean compressional deformation: (1) a D1 phase of thrusting tectonics affected the Lower Birimian B1 tourmalinized sediments. This firsttectonic phase is characterized by isoclinals overturned to recumbent folds P1 with N0408208NE trending axis, associated with axial plane schistosity S0S1 which is mainly transposed in the bedding; (2) a D2 phase of compressional (D2a) and transpressional(D2b) tectonics is responsible for the crossfolds P2a-P2b exhibiting curved axes. These P2 folds are associated with the major schistosity S2, north-south to SW-NE trending, mainly dipping to the south-east. The S2 schistosity is mostly displayed in the large shear zones corridors where it steeply dips locally toward the north-west. A north-west vergence thrusting phase (D2c) of flats and ramps, associated with reverse folds, represents the last Eburnean event. This geometrical feature is characteristic of a ''positive flower structure''. These different Eburnean compressional phases are separated by extensional deformation which is characterized by sedimentary deposits and volcanic flows