Field Geology of Kribi and its environs

ABSTRACT

The coastal town of Kribi lies on the Gulf of Guinea, in Océan Department, Province, at the mouth of the Kienké River.

The study was aimed at mapping geologic rocks and measuring wells physiochemical parameters and sieve analysis of some soil samples obtained.

Formations. In situ physicochemical parameters of 95 hand-dug wells weremeasured.

Field physicochemical parameters during the field mapping range as follows: temperatures, 28.8 to 34o C;pH, 4.27 to 6.95; EC, 80 to 3590 µS/cm; TDS, 53.6 to 2405.3 mg/L.

Chemical analysis revealed that chemical parameters of groundwater were not within WHO acceptable limits.

The main rocks types encountered in the field is mostly gneiss. Structures such as folds, veins, joints and Microfolds.

The joints have an average thickness of 7cm. the gneiss is made up of white and dark bands in which the white bands consist of quartz with a Pegmatititc texture.

Keywords: Kribi, Hydrogeology, Physiochemical parameter.

CHAPTER ONE

INTRODUCTION

1.0 General Overview

Water is one of the most important, abundant and most precious natural resources on earth which is vital in shaping the land and regulating the climate.

It is vital to man’s existence and without it, there would be no life on earth.

Yidanaet al. (2008) stated that sustainable socioeconomic development of every community depends much on having water of adequate quality as well as quantity. 

Unfortunately, in developing countries, inadequate water supply is still a major challenge with more than 18 million people dying each year from water-borne diseases (WHO, 2006).

This is evident in Cameroon like in most countries in Sub Saharan Africa where less than 50% of the population is connected to the national pipe-borne water network (Kuitchaet al., 2008).

Water quality guidelines can be used to identify constituents of concern in water, to determine the levels to which the constituents of water must be treated for drinking purposes (Raafat, 2013).

Although Cameroon is the second country in Africa in terms of quantity of available water resources estimated at 322 billion m³ (Akoet al., 2011; Mafany and Fantong, 2006),

it is unable to attain the second target of objective 7 of the Millenium Development Goals (Nkengfacket al., 2017) to reduce to the half, the percentage of the population that doesn’t have access to drinking water in a sustainable way in 2015.

Faced on these realities, the majority of households in villages and towns turn to non-conventional sources of water supply such as streams, groundwater like springs, wells and boreholes (MINEE, 2009) whose quality is often unknown and poorly managed (Wotchokoet al., 2016).

Groundwater is water held in the subsurface within the zone of saturation under hydrostatic pressure below water table (Ariyo and Banjo, 2008), and this water constitutes 21.5% (about 57 billion m³) of the country’s water source (Magha et al., 2015) which serves as an important source of drinking water for most Cameroonians (Teikeuet al., 2016).

Unfortunately, this resource which was once of excellent quality is now pruned to diverse sources of contamination.

The chemical composition of groundwater is controlled by many factors that include composition of precipitation, mineralogy of water head and aquifers (Jain et al., 2005), climate, topography as well as anthropogenic influence such as urban, industrial and agricultural activities (Magha et al., 2015), likewise, hygiene and sanitation of water sources (Edge et al., 2001., Davis and Hirji, 2003).

Once the groundwater is contaminated, its quality cannot be restored back easily and to device ways and means to protect it. 

According to WHO, about 80% of all diseases in human beings are caused by water (Devendraet al., 2014). 

Hydrogeology is the scientific study of the occurrence and flow of groundwater and its effects on earth materials.

An aquifer I defined by the American Geological Institute’s dictionary of Geological terms as a body of rock that is sufficiently permeable to conduct groundwater and to yield economically significant quantities of water to wells and springs. Aquifers may also be classed as confined, unconfined or leaky.

A confined aquifer is confined above and below by an impervious layer under pressure greater than atmospheric pressure.

An unconfined aquifer (phreatic) is one in which a water table (phreatic surface) serves as its upper boundary.

A phreatic aquifer is directly recharged from the ground surface above it.

1.1 Objectives

Main objectives of this field mapping project is for the award for the Bachelor of Science degree in Geology in the University of Buea and also  to fulfil the departmental requirement as the course GLY 498 carries a credit value of 12.

Specific Objectives

• To identify and describe the rock types in the study area.

• To take and record structural data of outcrops at the area.

• To produce a sketch geology map of the area.

• To analyse the field structural data using Stereo plots.

• To describe the metamorphic conditions of the rock types in the study area

1.2 Location and Biophysical Environment

The coastal town of Kribi lies on the Gulf of Guinea, in Océan Department, Province, at the mouth of the Kienké River. This location, lies approximately 150 kilometres (93 mi), by road, south of Douala, the largest city in Cameroon and the busiest seaport in the country(distancecalculator.globefeed.com2019.) The coordinates of Kribi are: 2° 56′ 6.00″N, 9° 54′ 36.00″E (Latitude: 2.9350; Longitude: 9.9100).