RELIEF OF NIGERIA

Relief refers to the surface features of the land above the sea level. Relief of Nigeria can be grouped into two main classes which are lowlands and highlands.

• Lowlands: Lowlands refer to the areas below 300m above the sea level.

 

Areas of Lowland in Nigeria and their Altitude or Height

1. The Sokoto plain in the North West (200 – 300m).
2. The Niger-Benue trough/valley (100 – 300m).
3. The Chad basin or Borno plain (100 – 300m).
4. The Niger Delta (0 – 100m).
5. The Cross River basin (120 – 180m).
6. The interior coastal lowland of Western Nigeria (100 – 300m).
7. The coastal plain (0 – 100m).

 

Rocks Associated with Lowlands

1. Coastal plain: Sedimentary rocks of alluvial deposits.
2. Niger-Benue trough: Sedimentary rocks of limestone, sandstone and shale.
3. Sokoto plain: Sand, clay, sandstone and limestone.
4. Chad basin: Made up of sand and clay. Rocks generally known to be associated with lowlands are the sedimentary rocks.

 

Importance of Lowlands

1. Plains, especially level ones are good for human habitation. Population and settlements are usually concentrated on plains.
2. Some plains are rich sources of minerals like petroleum and coal.
3. Plains, especially depositional plains have rich fertile soils which favour intensive agriculture.
4. Plains, generally favour communication as roads, railway, and airports are better built on levelled lands.
5. In areas of low rainfall, rearing of animals is carried out in plains as it favours the growth of pasture.
6. Rivers in plain provide water for drinking and transportation.
7. Rivers in plains (basins) provide jobs e.g. fishing.

 

Disadvantages of Plains

1. Some plains, especially in delta areas may be flooded with water and this reduces human activities.
2. Some may pose serious barrier to communication, especially in areas flooded by excess water either from river or after rain. It, therefore, increases the cost of developing these areas e.g. construction of flyovers.

 

• Highlands: Highlands refer to areas over 300m above the sea level.

 

Areas of highlands in Nigeria and their height or altitude

The highlands in Nigeria are grouped into four areas. These are:

1. The North-Central Highlands: It lies in the centre of Northern Nigeria around Kano, Kaduna, Bauchi, Jigawa and Plateau States. Jos Plateau (200 – 1500m) is found in this highland and is a great hydrological centre or watershed with radial pattern of drainage in which rivers like Hadeija, Kaduna, Sokoto, etc. take their sources. The highest point of Jos Plateau is Shere Hills (1650m).

 

2. The Western Highlands: The Western Highlands or upland is found in the western part of Nigeria around Ondo, Oyo, Kwara and Osun States. Important hills in this area include: Idanre hill (highest point) – 950m, Apata hill (400 – 700m), Epeme hill (350 – 600m). Three important rivers – rivers Ogun, Osun and Osse have their sources from these highlands.

 

3. The Eastern Highlands: These are found in the borders between Nigeria and Cameroun. They represent the highest zone in Nigeria. Among the mountains are: Mandara mountain (1200 – 1500m), Biu Plateau (800 – 1000), Adamawa mountain (1800 – 2400m), Alantika and Shebshi hills (1600 – 2000m), Obudu and Oban hills (1200m). The area has rivers like Rivers Gana, Ngoda and Yedseram which flow to Lake Chad.

 

 

4. The Eastern Scarpland: This is found within the eastern region of Nigeria, especially around Enugu and Nsukka. The major highland in this area is the Udi-Nsukka Plateau (300 – 600m). Rivers Anambra, Imo and Cross have their sources from this scarpland.

 

Major Rock types in Highlands

1. North central plateau, western highlands, Mandara Mountains, Shebsh, Alantika, Obudu and Oban hills are made up of basement complex rocks (combination of igneous and metamorphic rocks).
2. Jos Plateau is made up of volcanic rocks.
3. Udi Hills are made up of carboniferous sedimentary rocks.

 

Importance of Highlands

1. Some mountains are sources of some minerals like tin, gold, diamond, etc. which are useful to man.
2. High mountains aid the formation of rainfall (Orographic or relief rainfall), especially on the windward side of the mountain.
3. Some low mountains provide pasture which aid transhumance which is the practice whereby cattle move from the valley during rainy season to highlands where they feed on pasture till the end of the rainy season, after which they return to the valley.
4. Some mountains serve as climate barriers because; their two sides may have different climates.
5. Mountains are useful in times of inter-tribal wars for easy defense against enemies.
6. Some high mountains are centres for tourist attraction.
7. Mountains are the sources (the beginning) of many rivers and streams.
8. The nature of some rivers with their steep slopes, fast flowing and presence of rapids at the source aid the construction of H.E.P to generate electricity.
9. Some mountains, as a result of their location do serve as wind breaks.

 

Disadvantages of Mountains

1. Mountains are barriers to communication as they prevent road, railway and airport construction.
2. High mountains are known to be associated with cold weather which prevents good human and animal habitation.
3. Areas close to mountains are usually associated with soil erosion due to the speed to running water down the steep slopes of mountains.
4. Mountains at times do occupy good land that would have been used either for farming or settlement.
5. Mountainous areas are not good for agriculture as the soils are poor in nutrients and difficult to work on.