GUINEA

Guinea, country of western Africa, located on the Atlantic coast. Three of western Africa’s major rivers—the Gambia, the Niger, and the Senegal—rise in Guinea. Natural resources are plentiful: in addition to its hydroelectric potential, Guinea possesses a large portion of the world’s bauxite reserves and significant amounts of iron, gold, and diamonds. Nonetheless, the economy is largely based on subsistence agriculture.

Guinea, under the name French Guinea, was a part of French West Africa until it achieved independence in 1958. It then was ruled successively by Sikou Tours (1958–84) and Lansana Conti (1984–2008), the latter of whom claimed power through a military coup. During the 1990s Guinea accommodated several hundred thousand war refugees from neighbouring Liberia and Sierra Leone, and conflicts between those countries and Guinea have continued to flare up over the refugee population. Following Conti’s death, a military junta took control of the country and suspended the constitution that had been adopted in 1991. The national capital of Conakry lies on Tombo (Tumbo) Island and spreads up the Camayenne (Kaloum) Peninsula; it is the country’s main port.

Guinea consists of four geographic regions: Lower Guinea, the Fouta Djallon, Upper Guinea, and the Forest Region, or Guinea Highlands. Lower Guinea includes the coast and coastal plain. The coast has undergone recent marine submergence and is marked by rias, or drowned river valleys, that form inlets and tidal estuaries. Numerous offshore islands are remnants of former hills.

Immediately inland the gently rolling coastal plain rises to the east, being broken by rocky spurs of the Fouta Djallon highlands in the north at Cape Verga and in the south at the Camayenne Peninsula. Between 30 and 50 miles (48 and 80 km) wide, the plain is wider in the south than the north. Its base rocks of granite and gneiss (coarse-grained rock containing bands of minerals) are covered with laterite (red soil with a high content of iron oxides and aluminum hydroxide) and sandstone gravel.

The Fouta Djallon highlands rise sharply from the coastal plain in a series of abrupt faults. More than 5,000 square miles (13,000 square km) of the highlands’ total extent of 30,000 square miles (78,000 square km) lie above 3,000 feet (900 metres). Basically an enormous sandstone block, the Fouta Djallon consists of level plateaus broken by deeply incised valleys and dotted with sills and dikes, or exposed structures of ancient volcanism resulting in resistant landforms of igneous rock. The Kakoulima Massif, for example, attains 3,273 feet (998 metres) northeast of Conakry. The highest point in the highlands, Mount Tamgui, rises to 5,046 feet (1,538 metres) near the town of Mali in the north.

Upper Guinea is composed of the Niger Plains, which slope northeastward toward the Sahara. The flat relief is broken by rounded granite hills and outliers of the Fouta Djallon. Composed of granite, gneiss, schist (crystalline rock), and quartzite, the region has an average elevation of about 1,000 feet (300 metres).

The climate of Guinea is tropical with two alternating seasons—a dry season (November through March) and a wet season (April through October). The arrival of the migratory intertropical convergence zone (ITCZ) in June brings the heaviest rainfall of the wet season. As the ITCZ shifts southward in November, the hot, dry wind known as the harmattan blows from the northeast off the Sahara.

On the coast a period of six months of dry weather is followed by six months of rain. The average rainfall at Conakry is about 170 inches (4,300 mm) a year, and the average annual temperatures are in the low 80s F (about 27 °C).

In the Fouta Djallon, January afternoon temperatures range from the mid-80s to the mid-90s F (about 30 to 35 °C), while evening temperatures dip into the high 40s and low 50s F (about 8 to 11 °C). Rainfall varies between 60 and 90 inches (1,500 and 2,300 mm) annually, and the average annual temperatures there are in the mid-70s F (about 25 °C).

In Upper Guinea rainfall drops to about 60 inches (1,500 mm) a year. During the dry season temperatures of more than 100 °F (38 °C) are common in the northeast.

In the Forest Region at Macenta there may be some 100 or more inches (2,540 mm) of rain annually. Only the months of December, January, and February are relatively dry, with possible rainfall of only 1 inch (25 mm). At low elevations, temperatures resemble those of the coastal areas.