Africa is an uplifted plateau which has an average height of approximately 2000 feet. During the process of uplift, which was accompanied by intense volcanic activity, a portion of the eastern section cracked and settled, forming the Rift Valley. The rift in Africa begins in the Sinai Peninsula and parallels the Red Sea coast until its major part enters Ethiopia in the Danakil Plains. From the extreme lowlands surrounding the Danakil Depression (380 feet below sea level) the floor of the Rift Valley rises to over 6000 feet in the area of Addis Ababa. In the southern part of Ethiopia the floor is only 2000 feet above sea level.
In the East African highlands there are two distinct branches to the rift -- the western and eastern. The valley floor of the Eastern Rift is 1300 feet above sea level at Lake Rudolf and rises to over 7000 feet near Naivasha, Kenya. From there it falls to 2000 feet at Lake Natron on the Tanzania border. In Kenya and northern Tanzania the rift is very noticeable, being 40-60 miles wide. It becomes less noticeable further south in Tanzania and ends near the coast in Mozambique. The most apparent portion of the Southern Rift is the Shire Valley. The Western Rift area is shared by Uganda, The Congo, Rwanda, Burundi, and Zambia. Mt. Ruwenzori lies directly in the rift line.
The major highland area of Africa is concentrated near the rift lines. The largest component section of these highlands is that of Ethiopia, where the bulk of the country is covered by two separate basaltic massifs which range in elevation from 8000 to 9000 feet. The greatest amount of volcanic activity on the continent occured in East Africa, forming the Ruwenzori and Aberdare ranges of mountains. Here are clustered the highest mountains in Africa -- Kilimanjaro, Kenya, and Ruwenzori.
The highlands of Africa not adjacent to the rift are scattered. In the north the Atlas chains separate the coastal plains from the desert. There are three main ranges to the Atlas -- the Great, or High, Atlas, the Tell Atlas, and the Saharan Atlas. The highest peaks are located in the Great Atlas. Lying in the heart of the Sahara are two large rocky headlands, the Ahaggar and Tibesti, with peaks over 9000 feet high.
There are only two major highlands in West Africa. The Fouta Jallon, concentrated mainly in Guinea, does not have extreme elevation. It is the source of the Niger, Senegal, and Gambia rivers. The Cameroon Highlands run northeastward from the coast. The coastal mountains, including Mt. Cameroon, are volcanic and represent the highest land in West Africa. This section blends into the Adamoua Massif, which covers the northern part of Cameroon at an elevation of 2500 to 4500 feet.
In the extreme south the Drakensberg range separates the high veld and semidesert lands from the coastal plain. This mountain chain, beginning near the Mozambique border, parallels the coast to the middle Cape region. These highlands, although in places above 10,000 feet, average approximately 5000 feet.
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Publication information: Book title: The History of Africa in Maps. Contributors: Harry A. Gailey Jr. - Author. Publisher: Denoyer-Geppert. Place of publication: Chicago. Publication year: 1971. Page number: 18.
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