GEOLOGIC MAPPING AND PETROGRAPHIC STUDY OF OGUDU AREA IN IFE-EAST LOCAL GOVERNMENT AREA OF OSUN STATE, SOUTH WESTERN NIGERIA

CHAPTER ONE

1.0      INTRODUCTION

Ogudu area is located in Ife-East Local Government Area of Osun State, Southwestern Nigeria, within latitude 7022.25’N and 7025’N, and longitude 4037.5’E and 4040.25’E covering a total area of 25 square kilometers. The terrain falls within the Ife-Ilesha schist belt, which is an integral part of the Nigerian Basement Complex. The Nigerian Basement Complex is part of the late Proterozoic to early Paleozoic mobile belt east of the West African craton. This basement complex comprises Archean and Proterozoic rocks and available geochronological data indicates that this basement is polycyclic and bears the imprint of three thermotectonic events; Liberian (ca. 2700 Ma), Eburnean (ca. 2000 Ma), and Pan-African (ca. 600Ma) orogenic events (Grant, 1970; Oversby,1975; Van Breemen et al., 1977; Fitches et al., 1985; Rahaman, 1988; Dada et al., 1994). The need for a detailed geology of this area forms the main objective of this field mapping. 
Lithologies were studied and observed structures were documented in this reported, geometrical analysis of structural fabrics in macro-, meso- and microscale are well documented. Field observations on the various rocks in the study area have shown that the degree of deformation is not equal and are characterized by varying fabrics, grain sizes, structural styles, mineralogy, etc. This independent mapping therefore aims at examining the outcrop scale structures, microstructural and mineralogical features of the various rocks in the study in order to gain understanding of the geology of the basement complex rock.        

1.1       AIM AND OBJECTIVES

The aim of this study is to produce the geological map of the study area with the following specific objectives: 
1.      To map all the lithological units; 
2.      to examine and report all the structural features and fabrics; 

1.2       LOCATION AND ACCESSIBILITY

Ogudu area is located in Ife East Local Government Area of Osun State within the Ife-Ilesha Schist belt in Southwestern Nigeria. Accessibility is poor, most of the routes (mostly footpath) shown on the available topographical map have been covered with vegetation due to abandonment of settlement and/or farmstead. 

1.3         TOPOGRAPHY

The topography of the study area is randomly an undulating feature. The eastern part of the study area has a higher elevation. The upper part of the study area has elevation between 1300 and 1995 feets above sea level. Generally the region is characterized by elevations between 1000 feets and 1400 feets above the sea levels. 

1.4         CLIMATE AND WEATHER CONDITION

The climate of the area fall under the equatorial climate belt of southwestern Nigeria and the weather condition has a comparatively high temperature throughout the year and high rainfall characteristic of a rain forest belt. 

1.5         DRAINAGE

The drainage system is dendritic. The stream channel are generally structurally and stratigraphically controlled with the rivers flowing southwards except in tributaries where they flow in W-E and E-W direction to join the main rivers flowing south.