What is the geology of West Africa?
Geology. West Africa is remarkable for its geological variety. Like most of Africa, the region is largely composed of ancient Precambrian rocks (at least 541 million years old; the oldest rocks may be about 3 billion years old), which have been folded and fractured over hundreds of millions of years.
What rock is used for dating the oldest craton in Africa?
The oldest rocks are of Archean age (i.e., about 4.6 to 2.5 billion years old) and are found in the so-called granite-gneiss-greenstone terrains of the Kaapvaal, Zimbabwe, and Congo cratons.
What is the geological structure of Africa?
The geological maps show that Africa is almost entirely made up of basement Precambrian rocks. The only exceptions are constituted by northwestern and southern parts of the continent where narrow Phanerozoic mountains belts are stacked against the Precambrian landmass.
How many cratons are in Africa?
Three major cratons identified in Africa are the West African, Congo and Kalahari Cratons (Fig. 1a), with the smaller Tanzanian Craton located east of Congo20.
Where are the cratons?
Cratons are generally found in the interiors of continents and are characteristically composed of ancient crystalline basement crust of lightweight felsic igneous rock such as granite. They have a thick crust and deep roots that extend into the mantle beneath to depths of 200 km.
What are the four main geographic regions of West Africa?
The West African region can be divided into four climatic sub-regions namely the Guinea Coast, Soudano-Sahel, Sahel (extending eastward to the Ethiopian border) and the Sahara, each with different climatic conditions.
What craton means?
craton, the stable interior portion of a continent characteristically composed of ancient crystalline basement rock. The term craton is used to distinguish such regions from mobile geosynclinal troughs, which are linear belts of sediment accumulations subject to subsidence (i.e., downwarping).
What do cratons do?
The term craton is used to distinguish the stable interior portion of the continental crust from such regions as mobile geosynclinal troughs, which are linear belts of sediment accumulations subject to subsidence, or downwarping.
How are cratons formed geology?
What is the West African Craton?
West African Craton. The West African Craton (WAC) is one of the five cratons of the Precambrian basement rock of Africa that make up the African Plate, the others being the Kalahari craton, Congo craton, Saharan Metacraton and Tanzania Craton.
What is the Precambrian geology of Africa?
Structurally, the Precambrian geology of Africa is grossly divided into cratons and mobile belts ( Petters, 1991 ). The two most important cratons are the West African craton and the Congo (Zaire) craton ( Fig. 1 (a,b)). Surrounding the cratons are the belts, which have been deformed or metamorphosed during the Early Palaeozoic Pan-African orogeny.
What resources are found in the West African Craton?
Within the West African Craton, there is a large amount of mining activity covering resources such as gold, copper, cobalt, silver, tin, and zinc. Artisanal mining activity in the craton dates back to the early 1960s which used quartz vein debris as a gold indicator.
What are the physical features of West Africa?
South of the mountains, the West African Craton is relatively flat, mostly desert or dry savanna apart from the areas near the Atlantic or Gulf of Guinea. However, below the surface there are ancient sedimentary basins such as the Taoudeni basin that may contain large reserves of oil and gas.