Geological Features
Geological Features of Nigeria - Relief, Drainage and Soil

The geology of Nigeria could be described as Pre-Cambrian, Cretaceous, Tertiary, Quaternary and Volcanic. The pre-Cambrian rocks are made up of igneous and metamorphic rocks and cover almost fifty percent of the country. They are crystalline in nature and consist of granite, gneiss and schist and they are commonly referred to as the Basement Complex. When weathered, the older granites give rise to smooth-domed hills known as inselbergs. The Cretaceous rocks are relatively younger rock types than the Pre-Cambrian rock types. They consist of various sandstones that are basically classified as older sedimentary rocks. Cuesta relief forms are characteristic of these rocks; and coal, lignite and limestone are important minerals found in these rocks. These rocks occupy the basins of Niger, Benue, Gongola and Cross Rivers. The younger sedimentary rocks are the rocks of the Tertiary Age consisting mainly of sandstone but with some clay and lime- stone. They are found in the Chad Basin and in the South with its widest extent in the Lower Niger. The alternating layers of clay and sand, especially in the Chad Basin are a noteworthy characteristic of these rocks. The Quaternary rocks are comparatively recent depositions found along the coast and river deltas of the country. They are made up of sandy and muddy deposits. Volcanic rocks which are of the Tertiary Age are not wide- spread in Nigeria. They are mainly found in the centre and north-east of the country. The main areas are the Biu and Jos Plateau and the Kerrikerri area of the Benue valley. The acid and basic rocks of these places give rise to peculiar volcanic features.

The relief of Nigeria consists of plains in the north and south interrupted by plateaux and hills in the centre of the country. The Sokoto Plains lie in the northwestern corner of the country, while the Borno Plains in the northeastern corner extend as far as the Lake Chad basin. The Lake Chad basin and the coastal areas, including the Niger River delta and the western parts of the Sokoto region in the far northwest, are underlain by soft, geologically young sedimentary rocks. Gently undulating plains, which become waterlogged during the rainy season, are found in these areas. The characteristic landforms of the plateaus are high plains with broad, shallow valleys dotted with numerous hills or isolated mountains, called inselbergs; the underlying rocks are crystalline, although sandstones appear in river areas. The Jos Plateau rises almost in the centre of the country; it consists of extensive lava surfaces dotted with numerous extinct volcanoes. Other eroded surfaces, such as the Udi-Nsukka escarpment rise abruptly above the plains at elevations of at least 300 m. The most mountainous area is along the southeastern border with Cameroon, where the Cameroon Highlands rise to the highest points in the country, Chappal Waddi (2,419 m) in the Gotel Mountains and Mount Dimlang (2,042 m) in the Shebshi Mountains.

The major drainage areas in Nigeria are the Niger-Benue basin, the Lake Chad basin, and the Gulf of Guinea basin. The Niger River, from which the country’s name was derived, and the Benue, its largest tributary, are the principal rivers. The Niger has many rapids and waterfalls. The Benue is not interrupted by either rapids or waterfalls and is navigable throughout its length, except during the dry season. Rivers draining the area north of the Niger-Benue trough include the Sokoto, the Kaduna, the Gongola, and the rivers draining into Lake Chad. The coastal areas are drained by short rivers that flow into the Gulf of Guinea. River basin development projects have created many large man-made lakes, including Lake Kainji on the Niger and Lake Bakolori on the Rima River. The Niger delta is a vast low lying region through which the waters of the Niger River drain into the Gulf of Guinea. Characteristic landforms in this region include oxbow lakes, river meander belts (see meander), and prominent levees. Large freshwater swamps give way to brackish mangrove thickets near the seacoast.

Nigerian soils are usually of a poorer quality than those in other regions of the world and the major soil zones conform to geographic location. Loose sandy soils consisting of wind- borne deposits and riverine sands are found in the northern regions, although, in areas where there is a marked dry season, a dense surface layer of laterite develops, making these soils difficult to cultivate. The soils in the northern states of Kano and Sokoto, however, are not subject to leaching and are therefore easily farmed. South of Kano the mixed soils contain locally derived granite and loess (wind-borne deposits). The middle two- thirds of the country, the savanna regions, contain reddish, laterite soils; they are some- what less fertile than those of the north because they are not subject to as much seasonal drying, nor do they receive the greater rainfall that occurs in the more southerly regions. The forest soils represent the third zone. There the vegetation provides humus and protects it from erosion by heavy rainfall. Although these soils can readily be leached and lose their fertility, they are the most productive agriculturally. Hydromorphic and organic soils, confined largely to areas underlain by sedimentary rocks along the coast and river floodplains, are the youngest soil types.

Source: http://www.nigeria.gov.ng/

Search
SEARCH
Disclaimer
All content provided on this website is for informational purposes only. The owner of this website makes no representations as to the accuracy or completeness of any information on this site or found by following any link on this site.