Özet:

Investigation of basement rocks around Igarra, Southwestern Basement Complex of Nigeria was carried out to assess the impact of the Pan African Orogeny on the architecture and evolution of rocks in the study area. The area spans approximately 40 km2 covering Igarra town and environs in Akoko-Edo Local Government Area of Edo State, Nigeria. The investigation includes systematic mapping and interpretations of structural elements in the rocks using standard geological techniques. The granites and metasediments were dissected by a network of quartzo-feldspathic dykes and veins of various dimensions. The Pan-African orogeny had been documented as the most pervasive of all the tectonic events that affected the Nigeria Basement rocks. Field mapping of the area revealed that the Pan-African granites are structurally controlled intrusions in the host metasedimentary rock sequence. The syn to late tectonic emplacements of the Pan-African granitoids during the neoproterozoic period (600 Ma ± 150 Ma) has affected the evolution of the rocks. The granite intruded the folded metasediments in N-S direction and their emplacements reactivated the E-W fault zone in the country rocks with injection of magmatic materials into dilation zones in the metasediments and fault breccias within Igarra and environ.

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