CHAPTER ONE
1.1 GENERAL INTRODUCTION
Geological field mapping exercise is the preliminary study usually carried out to understand the geology of an area. A geological map identifies and shows the distribution of various rock types in area. Geological mapping is essential for both the economic, academic and financial growth of a nation. Geological field mapping is a very important exercise in the field of geology and geosciences generally, its an exercise carried out to collect information about the different rock lithologies in an area, structures exhibited in them, type of rock, mode of occurrence, texture, colour and mineralogy.
Samples are also analyzed to determine the petrology which helps to confirm the rock name and origin as well as general age of emplacement and metamorphism in the case of metamorphic rock. The research methodology used, materials employed, observations, results and conclusions are discussed in this report. This report also includes the list of different rocks found, their economic importance, mineralization and petrography. The field mapping and petrographic study of the rock sample was done to delineate the different rock type present in the area and to integrate the previous works on the geology of the area in order to delineate the mineralization zones.
1.2 AIM AND OBJECTIVES
The aim of this work is to thoroughly understand and establish the geologic history and events that led to the formation of the present geology of the area. The objectives of this study are;
1. To produce an accurate geological map of the area.
2. To carry out petrographic analysis of the rocks encountered.
3. To identify the different rock lithologies present in the study area.
4. To understand and establish the geologic history of the study area
5. To analyze structural data acquired and their relevance to the current geology of the study area.
6. To generally analyze the economic value of the rock lithologies found in the area.
1.3 LOCATION OF THE STUDY AREA
The study area covers Bolorunduro community and its environs. Plot 20B of the master sheet. Ife north local government Osun state , Nigeria. The area lies approximately between latitude 7015’n and 7012.5’N and longitude 4037.5’E and 40 40’E, covering an estimated area of 25km2. The study area is located in Atakumasa local government area of osun state n southwestern Nigeria. The important settlements are Bolorunduro, Egbejoda, baba Ibadan, Abusoro, kajola, Onikanga.
1.4 ACCESSIBILITY AND TOPOGRAPHY
Traversing the study area was fairly easy due to the presence of minor roads and footpaths and with the assistance of the villagers, who help to locate the existing outcrops in an initially inaccessible area, stream channels were also used as traverse, communities and hamlets are interconnected by footpaths. Accessibility by these footpaths is fair and further enhanced by the extensive cocoa plantations which have well worn footpaths. The topography of the study area is uneven and characterized by ridges, hills and valleys. The uneven topography is caused by the crystalline nature of the rocks found in the area which make them resistant to weathering
1.5 CLIMATE AND VEGETATION
The study area falls within the tropical humid climate region where the wet and dry seasons are noticed prominently in the area. Just like any other parts of the south western region of Nigeria. The dry season is between November and February while the wet season is mostly between April and October. The mean minimum temperature observed is 36.20c (Iloeje 1972).the mean annual rainfall is between 1100mm and 1500mm. The vegetation of the area is similar to that of the tropical rainforest where there are high trees and shrubs, the vegetation here is characterized by the presence of thick tropical evergreen forest.
