Structural styles and tectonic evolution of the Kolia-Boboti sedimentary Basin,Kédougou-Kéniéba inlier,eastern Senegal |
| |
| Authors: | Moussa Dabo Tahar Aïfa |
| |
| Institution: | 1. Département de géologie, faculté des sciences et techniques, université Cheikh Anta Diop de Dakar, BP 5005, Dakar-Fann, Senegal;2. UMR 6118, CNRS Géosciences Rennes, université de Rennes 1, bâtiment 15, campus de Beaulieu, 35042 Rennes cedex, France |
| |
| Abstract: | New structural data obtained on the Birimian terranes of the Kolia-Boboti sedimentary Basin, the eastern part of the Dialé-Daléma Supergroup in the Kédougou-Kéniéba inlier show two major phases of Eburnean compressional deformation: (1) a D1 phase of thrusting tectonics affected the Lower Birimian B1 tourmalinized sediments. This first tectonic phase is characterized by isoclinals overturned to recumbent folds P1 with N040° 20°NE 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. |
| |
| Keywords: | Transpression Thrust &ldquo Positive flower structure&rdquo Shear zone Eburnean Kolia-Boboti Senegal |
| 本文献已被 ScienceDirect 等数据库收录！ |
|
