THE GEOLOGY OF NANKA FORMATION AND ITS ENVIRONS OF ORUMBA NORTH AND AGUATA LOCAL GOVERNMENT AREA OF ANAMBRA STATE

Table of Contents
CHAPTER ONE
1.1 Introduction
1.2 Location and Accessibility
1.3 Objectives and Scope
CHAPTER TWO
2.0 Method of Investigation
2.1 Literature Review
2.2 Fieldwork and sample Collection
2.2.0 Outcrop Studies
2.2.1 Sample collection and Preservation
2.3 Instrumentation and Analysis
2.4 Mathematical and statistical method
CHAPTER THREE
3.0 Physiographic Features
3.1 Topography and Drainage
3.2 Climate and Vegetation
3.3 Temperature
3.4 Rainfall
CHAPTER FOUR
4.0 Geology/Geologic history and Regional Technoics
4.1 Local Geology
4.2 Nanka Formation
CHAPTER FIVE
5.0 Results and Discussions
5.1 Grain size analysis results
5.2 Atterberg limit test results
5.3 Hydrogeochemical results
5.3.1 Chemical Analysis
5.3.2 Physical Analysis
5.3.3 Biological Analysis
5.4 Discussions
CHAPTER SIX
6.0 Enivronmental Geology
6.1 Economic Geology
6.3 Structural Geology
6.3.1 Surface water Geology
6.3.2 Groundwater Geology
6.4 Engineering Geology
Summary
Conclusion
Recommendation
References





CHAPTER ONE
INTRODUCTION
1.1 Introduction
This project work is based on the study of Nanka and its environs. The towns involved are Nanka,Oko,Isuofia of Orumba North Local Government Area and Ekwulobia and Aguata of Aguata Local Government Area in Anambra State. Nanka formation is a regressive shallow marine deposit influenced by late Eocene technoics. The coefficient of curvature of Nanka sand is 2.6 and the coefficient of uniformity is 13.5 the soils are grey, brown, yellowish brown and predominantly reddish in colour.Alot of Gullies are concentrated in the studied area due to the friable nature of the unit and also its unconsolidated nature
1.2 Location and Extant Accessibility
Nanka is situated in Orumba North, Anambra, Nigeria. Its geographical coordinates are 6°3'0" North, 7°5'0" East and its original name (with diacritics) is Nanka. Nanka in Anambra State is located in Nigeria – about 340 km South of Abuja, the country's capital city. Cities, towns and places near Nanka include Ekwulobia, Oka, Agulezechuku and Aguata.
The area is accessible by major roads, but mostly by minor roads and footpaths. The major and minor roads lead to the outcrops of road-cut exposures while the footpath leads to outcrops of erosional exposures.
1.3 Climate and Vegetation
The study area has a tropical climate characterized by two main seasons; the rainy and dry seasons. The rainy season lasts between the months of April and October while the dry season lasts from the months of November to march.
Rainfall is generally high during the rainy season except sometime in the month of august when rainfall is reduced. The temperature of the study area varies in magnitude according to the period of the year. The hottest period is usually between February and April. The temperature is usually high all over the year with an average minimum to maximum temperature of 25 degree centigrade and 32 degree centigrade respectively. The dry season is characterized by the dusty dry hamatan wind. This lowers the temperature appreciably in the months of December to January. With associated features like excessive evaporation, low relative humidity (20%), low rainfall and general dryness (Egboka 1993). The daily mean humidity of the area varies between 40% to 92%, it is generally high during the early hours of the day.
The study area is located in the Awka–Orlu highlands of south eastern Nigeria. The landscape is undulating in some places and flat terrain in others. The topography of the study area is lower on the western half, rising between 150 to 450meters in places and punctuated by valleys and hills that determine the natural course of the Idemili River running from east to west.
1.4 Relief and Drainage
The study area is relieved by rivers streams and lake. While the tributaries of Idemili River drainage basin flow west of the divide, those of the Odo River drainage basin flow eastwards. The orientation of the tributaries and the rivers show that they are fracture/joint controlled. On the east and west of the cuesta, lakes such as Atama Lake and Agulu Lake occur respectively, exhibiting fracture-oriented characteristics from the aquifer system. The area receives torrential downpours of rain during the rainy season with a resultant rise in watertable and high groundwater flow rate. The watertable becomes shallower towards the water courses and at the edges of numerous water bodies with depth less than 8 m. During the dry season, watertable falls as a result of hydraulic head decay.
The sand/shale units are of high geotechnical interest because it is the layer through which several springs and seepage zones occur during the rainy season. These springs and seepage faces are widespread on the gully banks at Agulu, Oraukwu, Nanka, Ekwulobia etc.




1.5 Geomorphology of the Study area
The study area has an undulating topography ranging from gently sloping low lands to slightly steep highlands. These high lands area numerous e in the study area. The topography and geomorphology of a place often reflects the tectonic and geological events that occurred over a long period of time and tectonically continue to shape the geomorphic landscapes. The regional ggeomorphic feature that has shaped the landscape is the Awka-orlu highlands (Floyd, 1965) which slope gently into the floodplains of the river Niger west of the study area.
1.6 Climate and Vegetation of the Study Area
The study area has a tropical climate characterized by two main seasons; the rainy and dry seasons. The rainy season lasts between the months of April and October while the dry season lasts from the months of November to march.
Rainfall is generally high during the rainy season except sometime in the month of august when rainfall is reduced. The temperature of the study area varies in magnitude according to the period of the year. The hottest period is usually between February and April. The temperature is usually high all over the year with an average minimum to maximum temperature of 25 degree centigrade and 32 degree centigrade respectively. The dry season is characterized by the dusty dry hammatern wind. This lowers the temperature appreciably in the months of December to January. With associated features like excessive evaporation, low relative humidity (20%), low rainfall and general dryness (egboka 1993). The daily mean humidity of the area varies between 40% to 92%, it is generally high during the early hours of the day.
The study area is located in the Awka–Orlu highlands of south eastern Nigeria. The landscape is undulating in some places and flat trained in others. The topography of the study area is lower on the western half, rising between 150 to 450 meters in places and punctuated by valleys and hills that determine the natural course of the Idemili river running from east to west. The friable to loosed soil conditions combined with the steep slope of the valleys of River Idemmili has been responsible for the excessive and persistent soil erosion experienced in the sub region of the study area.
1.7 Objectives and Scope
The purpose of the study is to have a better understanding of the geology of the study area. This entailed;
1. producing a geologic map of the area with description of the mapped units
2. Evaluating the engineering properties of the soil in the study area.
3. interpreting depositional environment
4. Evaluating the sedimentologic and stratigraphic information on the area.

Tags: Geology Topics,

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