Sierra Leone

Geography

Sierra Leone is located on the west coast of Africa north of the equator. It is bordered by Guinea to the north and east, Liberia to the southeast and the North Atlantic Ocean to the southwest. The country has a total area of 71,740 km2, and comprises four distinct geographical regions: coastal Guinean mangroves, the wooded hill country, an upland plateau and the eastern mountains. Eastern Sierra Leone is an interior region of large plateaus (average 460-600 m above sea level) interspersed with high mountains, where Mount Bintumani, the highest point in the country, rises to 1,948 metres. Nearly all of the major rivers flow to the Atlantic from the eastern mountains. The centre of the country is a region of lowland plains, containing forests, bush and farmland, that occupies about 43% of Sierra Leone's land area. Sierra Leone's coast has numerous bays, estuaries, and mangrove swamps. It has the third largest natural harbour in the world. Rainfall along the coast can reach 495 cm a year, making it one of the wettest places along coastal, western Africa.

Geology

Sierra Leone is divisible into two major tectonostratigraphic units. The eastern division, known as the Kenema-Man Domain, is part of the Precambrian West African Craton and consists of crystalline basement comprising high-grade metamorphic rocks, granitic gneisses, greenstone belts and less frequent Banded Ironstone Formation lithologies. The western unit contains the various elements of an orogenic belt named the Rokelides that was deformed during the Pan-African tectonothermal event, about 550-560 Ma ago, and at least in part comprising reworked units of the Kenema-Man Domain. The two units are regionally separated by a major NW-SE east trending thrust fault zone. The 20-40 km wide coastal strip is made up of Pleistocene to Recent sediments.