We Rank the Best on Research Projects

GEOLOGY OF EKEREKUNTA AND ENVIRONS

Dept: GEOLOGY File: Word(doc) Chapters: 1-5 Views: 1

Abstract

We visited various locations during the time of our field exercise which include: Ekerekunta, Akpoha, Ogoubi, Okpoezi, AmaetaEnu. The present study area is bound within the latitude of 5055” N to 6° 0’ 0” N and longitude of 7055” E to 8° 1’ 0” E in the Southern Benue Trough within the Afikpo syncline and Abakaliki anticlinorium in south eastern Nigeria. The shale units underlie the bioturbated sandstones. Sedimentary structures were also observed in the study area, which include tabular cross stratification, beddings, herribone structures, asymmetrical ripples and trough cross beds. Asymmetrical ripples and trough cross beds indicates a high energy current. These bioturbated sandstones have high altitude (deeply steeping strikes and dips). This might be due to less period of exposure to erosion. The mapped area is drained by the streams of the Cross River system and Ebonyi River (Asu River). Compass/clinometers were used to obtain several measurements from outcrops within the study ar

INTRODUCTION

1.1 Background of the study

Geological and geophysical studies have enabled a  rather broad understanding of the geology of the Benue trough. Only in the latter part of the 20

th

 century that a more understandable picture of the structural framework within which the benue trough has been resolved.

Benkheli (1982) and Guiraud (1993) deduced that the benue trough is thought  to be as a collection of pull apart basins related to strike-slip movement along deep-seated basement shear zones of pan African origin reactivated as oceanic transform faults. Proof of this view can be deduced from field evidence in the northern benue trough where the climate and the nature of the sedimentary units allow for classic geologic study. The fine grained nature of most of the units and dense vegetation in the southern benue trough as a result of a wet tropical climate have hindered field studies and created a missing link in the proper explanation of the structural framework of the basin (Okonkwo,2014). Afikpo basin is located in the southern benue trough between the Abakaliki anticlinorium running north east. It forms part of the lower benue trough and the adjacent Anambra basin. The Ezeaku formation is believed to represent typical shallow water deposit consisting of grey to black shales and siltstones. Sedimentation took place in the Afikpobasin ranging in age from fromCretaceous to Mastrichian. The thickness of this formation varies and may be up to 100m thick and passes laterally into sandstone ridges at Amasirisandstone, calcareous rocks and sandy calcareous rocks.

1.2 Aims and objectives

To produce a geologic map showing detailed description of the lithologies as well as the structures present in the study area.

To identify mapable rock units and logging

To study the lithostratigraphy of Ekerekunta and its Environs

To deduce the geologic history and possibly geologic time sequence of the deposition

Description of the different lithologies (geologic details) encountered

1.3 Location of the Study Area

The present study area is bound within the bearings 5

0

55” N to 6° 0’ 0” N and 7

0

55” E to 8° 1’ 0” E in the Southern Benue Troughwithin the Afikpo syncline and Abakaliki anticlinorium in south eastern Nigeria. Various locations in the study area include:Ekerekunta, Akpoha, Ogoubi, Okpoezi, AmaetaEnu. Accessibility was by road and tracks and interconnected bush paths. The Abakaliki-Afikpohighway also provides a good accessibility into the study area and out.

 

Figure 1 : Accessibility map of the study area

 

1.4 Physiology and Topography

Afikpo is about 164 square kilometres in size with an undulating topography an elevation of 17m above mean sea level. The shale units underlie the bioturbated sandstones. These bioturbated sandstones have high altitude (deeply steeping strikes and dips). This might be due to less period of exposure to erosion.

 

 

 

Figure 2 : Topographical map of the study area

 

 

 

 

1.5 Drainage

The mapped area is drained by the streams of the Cross River system and Ebonyi River (Asu River). The drainage in the area consist of series of which emerge from the ridge and cleaned to the plain valley which widen at the foot of the ridge. The lithology of the area affects the development pattern and density of streams. The drainage pattern is mainly dendritic with a few rectangular or trellis patterns and the streams haven’t reached matured stage. These drainages serve as source of water supply to some of the villages and communities. Springs and seepages abound in the study area contributes to the drainage of the area.

Figure 3 : drainage map of the study area.

 

1.6 Vegetation

There are considerable disparity in vegetation between the shaley plains and the sandstone ridges. The ridges are generally covered with sparse vegetation while the plains have luxuriant vegetation. This is because the sandstone ridges are permeable and could not hold sufficient water to support luxuriant vegetation while the lowland plains of mud rocks are impermeable and thus retain water very well for crops.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

1.7 Weather and Climate

 

There are two marked seasons in the study area; the wet and dry season. The wet season begins in March and ends in October and the dry season begins from October through February. These two seasons are dependent on the two prevailing winds blowing over the country at different times of the year. The dry harmattan wind from the Sahara desert prevails in the dry season ranging from 20°c to 38°c and during the rainy season