Re-orientation of a NE-SW F1 fold during a retrograde F2 deformation in Southwestern Nigeria: Further signature of Pan-African tangential deformation

Abstract

The study area, Okedare/Babanloma locality, north east of Ilorin, falls within the south-western segment of the Basement Complex of Nigeria. The structural grain within the Basement Complex of Nigeria is generally N-S (Adedoyin, 2015) and constitutes the thermo-tectonic imprint of the Pan African orogenic event. The terrain evolved as a result of the several crustal remobilizations which occurred between about 3.0 to 0.45 Ga and lies within the southern part of the Trans Saharan Belt (Cahen et al., 1984) of North Africa. Imprints of four orogenic events have been identified within it but the dominant of the events is the Pan African, which post-dates the three other events: Liberian, Eburnean and Kibaran. Regardless of the polyphase deformations, the N-S structural trend is widely acknowledged and other fabrics contrary to that have been feebly reported (Affaton, 1991; Okonkwo, 2006; Adedoyin, 2015). The study area presents another scenario which supports possible imprints which developed as a result of deformation that were essentially tangential to those of the Pan African event.