Travel Reference
In-Depth Information
Environment & National Parks
At over 943,000 sq km (almost four times the size of the UK), Tanzania is East Africa's
largest country. It is bordered to the east by the Indian Ocean. To the west are the deep lakes
of the Western Rift Valley with mountains rising up from their shores. Much of central Tan-
zania is an arid highland plateau averaging 900m to 1800m in altitude and nestled between
the eastern and western branches of the Great Rift Valley.
About 6% (59,000 sq km) of mainland Tanzania is covered by inland
lakes. The deepest is Lake Tanganyika, while the largest (and one of the
shallowest) is Lake Victoria.
Tanzania's mountain ranges are grouped into a sharply rising northeastern section
(Eastern Arc), and an open, rolling central and southern section (the Southern Highlands or
Southern Arc). A range of volcanoes, the Crater Highlands, rises from the side of the Great
Rift Valley in northern Tanzania.
The largest river is the Rufiji, which drains the Southern Highlands en route to the coast.
THE GREAT RIFT VALLEY
The Great Rift Valley is part of the East African rift system - a massive geologic-
al fault stretching 6500km across the African continent, from the Dead Sea in the
north to Beira (Mozambique) in the south. The rift system was formed over 30
million years ago when the tectonic plates comprising the African and Eurasian
landmasses collided and then diverged. As the plates separated, large chunks of
the earth's crust dropped down between them, resulting over millennia in the es-
carpments, ravines, flatlands and lakes that characterise East Africa's topography
today.
The rift system is notable for its calderas and volcanoes (including Mt Kili-
manjaro, Mt Meru and the calderas of the Crater Highlands) and for its lakes,
which are often very deep, with floors well below sea level although their sur-
faces may be several hundred metres above sea level.
The Tanzanian Rift Valley consists of two branches formed where the main rift
system divides north of Kenya's Lake Turkana. The Western Rift Valley extends
past Lake Albert (Uganda) through Rwanda and Burundi to Lakes Tanganyika
and Nyasa, while the eastern branch (Eastern or Gregory Rift) runs south from
Lake Turkana, past Lakes Natron and Manyara, before joining again with the
Western Rift by Lake Nyasa. The lakes of the Eastern Rift are smaller than those
in the western branch, with some only waterless salt beds. The largest are Lakes
Natron and Manyara. Lake Eyasi is in a side branch off the main rift.
