THE GEOLOGY OF IBODI AREA, ILESHA.
REPORT ON THE INDEPENDENCE GEOLOGICAL FIELD MAPPING AT ILESHA, OSUN STATE
SUBMITTED TO THE DEPARTMENT OF GEOLOGICAL SCIENCES, OSUN STATE UNIVERSITY, OSOGBO.
CHAPTER ONE: INTRODUCTION
1.1 LOCATION OF THE MAPPED AREA
The mapped area is located in Ilesha Atakunmosa local government area of Osun State, Nigeria. The area mapped lies approximately within latitudes 7° 34' and 7° 37' north and equally lies approximately within 4° 39' and 4° 42' west, and covers an area extent of about 30km².
1.2 ACCESSIBILITY AND NATURE OF EXPOSURE
The study area can be accessed through the old road from Osogbo and also through the new road from Osu or Ife, both roads and footpaths were used during the mapping exercise. Rocks were not well exposed, most of which were covered by either soil or vegetation. And are also affected by weathering
The exercise was done by 300 level students which were grouped into five groups with three students in each group to carry out the mapping exercise in different parts of Ilesha local government, Osun State, Nigeria. The field exercise is also one of the requirements to be fulfilled for the bachelor degree of science, in the department of geology of Osun State University, Nigeria. The field mapping exercise lasted for 14 days. At the end of the mapping exercise the geology of the study area should be known and an accurate geological map of the study area should be made.
FIG 1: BASE MAP OF THE STUDY AREA
1.4 METHODS OF INVESTIGATION
The mapping field exercise was done by road and footpath traverse using the topographical base map of the area which has a scale 1:25,000, the base map contains details of the study area and observations made during the mapping exercise were plotted on it. A global positioning system (GPS) was also for accurate location of outcrops on the base map. A geological hammer was used in collecting samples of every outcrop encountered and carried using a sack bag. Description of each rock encountered were written down in a field note book at each location also structures seen such as folds, joints, lineation, foliations were written down and also plotted on the map. A compass clinometer was used in measuring the strike and dip of planer fabric in rock and also measuring of lineation. 1.5 ACKNOWLEDGMENT
I would like to thank the Oba and Prince of ibodi village for the accommodation given throughout the field mapping exercise.
CHAPTER TWO: PHYSIOGRAPHY
The area has low relief. The study area is underlay by amphibolite, which is the basement rock. The other rock types which occurred in the study area are gneiss, and schist 2.2: DRAINGE
The study area has lots of stream, which occurred in a dendritic drainage pattern. Shown in fig 2 FIG 2 MAP SHOWING THE DRAINAGE PATTERN OF THE STUDY AREA
CHEAPTER THREE: REGIONAL GEOLOGY
3.1 BASEMENT COMPLEX GEOLOGY OF NIGERIA AND SOUTHWEST NIGERIA
The basement complex is one of the three major litho-petrological components that make up the geology of Nigeria. The Nigeria basement complex forms a part of the pan-african mobile belt and lies between the west African and congo cratons and south of the tuareg shield (Black 1980) it is intruded by the Mesozoic cal-alkaline ring complex (younger granites) of the jos plateau and is uncomformably over lain by cretaceous and younger sediments. The Nigeria basement was affected by the 600Ma Pan-African orogeny and it occupied the reactivated region which resulted from plate collision between the passive margin (Burke and Dewy, 1972; Dada 2006). (Shown in fig 3.1)
The Nigeria Basement complex can be divided into two provinces: 1) The western province approximately west of latitude 8°E is characterized by narrow, sediment dominated North – south trending low grade schist belts in a predominantly Migmatite-Gneiss “older” basement and the whole was intruded by Pan African Granitic...
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