WEEK 2: RELIEF OF NIGERIA CONTENT Relief is the height above the sea level. Nigeria can be divided into lowlands and highlands. a. LOWLANDS The lowlands which are generally areas of sedimentary rocks refer to the areas below 300m above the sea level.

AREAS OF LOWLWNDS IN NIGERIA AND THEIR ALTITUDE The Sokoto plain in the north west (200-300m). The Niger-Benue trough or valley (100-300m). The Chad basin or Bornu plain (100-300m). The Niger Delta (0-100m). The Cross River basin (120-180m). The interior coastal lowland of Western Nigeria (100-300m). The coastal plain (0-100m). ROCKS ASSOCIATED WITH LOWLANDS Coastal plain- sedimentary rocks of alluvial deposits. Niger-Benue trough- sedimentary rocks of limestone, sandstone and shale. Sokoto plain- sand, clay, sandstone and limestone. Chad basin- made up of sand and clay. NB: Rocks generally known to be associated with lowlands are the sedimentary rocks. IMPORTANCE OF LOWLANDS Plains, especially level ones are good for human habitation. Population and settlements are usually concentrated on plains. Some plains are rich in minerals like petroleum and coal e.g. Niger delta plain. Depositional plains have rich fertile soils which favour intensive agriculture e.g. sokoto plain. Plains favour communication as roads, railways, airports are better built on levelled lands.

In areas of low rainfall, rearing of animals is carried out in plains as it favours the growth of pastures. Rivers in plains provide water for drinking and transportation. Rivers in plains (basins) provide jobs e.g. fishing and farming. DISADVANTAGES OF PLAINS Some plains including coastal plains, Niger-Benue trough and Cross River plains may be flooded with water and this reduces human activities. Some may pose serious barrier to communication, especially in areas flooded by excess water either from river or after rain. HIGHLANDS Highlands refer to areas over 300m above the sea level. The highest lands (areas above 900m) are found on the Jos plateau and on the eastern borderland with Chappai mountain having the highest height of 2419m above the sea level. AREAS OF HIGHLNDS IN NIGERIA AND THEIR HEIGHT The North-central highlands. It lies in the centre of Northern Nigeria around Kano, Kaduna, Bauchi, Jigawa and Plateau states.

Jos Plateau (200-1,500m) is found on this highland and is a great hydrological centre or watershed with radial pattern of drainage in which rivers like Hadejia, Kaduna, Gana, Sokoto e.t.c. take their sources The highest point of Jos Plateau is Shere Hills (1,650m). THE WESTERN HIGHLANDS. The western highland 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). The three important rivers include rivers Ogun, Osun and Osse having their sources from these highlands and flow into the Atlantic Ocean. Other rivers that flow north ward into river Niger include Avum and Monshi. THE EASTERN HIGHLANDS These are found in the borders between Nigeria and Cameroun. The represent the highest zone in Nigeria Among the mountains are : Mandara mountain (1,200-1,500m). Biu mountain (800-1,000m)

iii. Adamawa mountain (1,800-2,400m). iv. Alantika and Shebshi hills (1,600-2,000m). v. Obudu and Oban hills (1,200m). The area has rivers like rivers Ngoda, Cross, Yedseram which flow to lake Chad. THE EASTERN SCARPLAND This is found within the eastern region of Nigeria, especially around Enugu and Nsukka The major highland in the area is the Udi-Nsukka plateau (300-600m). Rivers Anambra and Imo have their sources from this scarpland. MAJOR ROCK TYPES IN HIGHLANDS North central plateau, western highland, Mandera mountain, Shebshi, Alantika, Obudu and Oban hills are made up of basement complex rocks (combination of igneous and metamorphic rocks). Jos plateau is made up of volcanic rocks. Udi hills are made up of carboniferous sedimentary rocks.

RELIEF MAP OF NIGERIA

ASSIGNMENT In your geography note book, discuss fully the advantages and disadvantages of highlands and lowlands in Nigeria. On a 20cm by 20cm cardboard paper, draw the outline map of Nigeria. In your outline, name and locate: North central highlands Western highlands. Eastern scarpland Eastern highland Sokoto plain Chad basin The Niger-Benue trough The coastal plain The Niger Delta Two rivers each that stream from the highlands enumerated above. 3. Identify the states and capitals of the numbers (1-37) in the map of Nigeria below.