Evolution, Structure and Age-Determination of Basement Complex in the South Niger Regime of Neo-Proterozoic (750 Ma) Era

In this present study, the structural evolution of the Southern Maradi Basement was marked by two (2) phases of major structuring of Eburnean and Pan-African, each one characterized by several episodes of deformations. The Eburnean D1 deformation phase included three (3) stages (D1a, D1b, D1c) The D1a ductile, NW-SE trending shortening stage was responsible for the schistocity/foliation of N500 orientation in average. The D1b stage, also ductile was characterized by the reactivation of the large shearing zones of N500 orientations, in average. The D1c stage, which was relatively semi-ductile was marked by the reactivation of the large shearing zones. The D2a episode was marked by a pure flattening foliation of N200 to N500 trending, in average, strongly straightened and related to an E-W to NW-SE trending shortening The D2b episode was marked by a simple shear dextral mylonitic foliation.

Keywords: Evolution, Structure, Age determination, Basement Complexes, Neo-proterozoic, Niger.