Albertine Rift

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Coordinates: 9°S34°E / 9°S 34°E / -9; 34

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An artificial rendering of the Albertine Rift. Visible features include (from background to foreground, looking north): Lake Albert, Rwenzori Mountains, Lake Edward, Virunga Mountains, Lake Kivu, and northern Lake Tanganyika Albertine Rift, East African Rift (artificial rendering).jpg
An artificial rendering of the Albertine Rift. Visible features include (from background to foreground, looking north): Lake Albert, Rwenzori Mountains, Lake Edward, Virunga Mountains, Lake Kivu, and northern Lake Tanganyika

The Albertine Rift is the western branch of the East African Rift, covering parts of Uganda, the Democratic Republic of the Congo (DRC), Rwanda, Burundi and Tanzania. It extends from the northern end of Lake Albert to the southern end of Lake Tanganyika. The geographical term includes the valley and the surrounding mountains. [1]

Geology

Map of the region showing the Albertine Rift to the west Map of Great Rift Valley.svg
Map of the region showing the Albertine Rift to the west

The Albertine Rift and the mountains are the result of tectonic movements that are gradually splitting the Somali Plate away from the rest of the African continent. The mountains surrounding the rift are composed of uplifted Pre-Cambrian basement rocks, overlaid in parts by recent volcanic rocks.

Lakes and rivers

The northern part of the rift is crossed by two large mountain ranges, the Rwenzori Mountains between Lake Albert and Lake Rutanzige (formerly Lake Edward) and the Virunga Mountains between Lake Rutanziga and Lake Kivu. The Virungas form a barrier between the Nile Basin to the north and east and the Congo Basin to the west and south. Lake Rutenzige is fed by several large rivers, the Rutshuru River being one, and drains to the north through the Semliki River into Lake Albert. The Victoria Nile flows from Lake Victoria into the northern end of Lake Albert and exits as the White Nile from a point slightly to the west, flowing north to the Mediterranean. [2]

South of the Virungu, Lake Kivu drains to the south into Lake Tanganyika through the Ruzizi River. Lake Tanganyika then drains into the Congo River via the Lukuga River. [3] It seems likely that the present hydrological system was established quite recently when the Virunga volcanoes erupted and blocked the northward flow of water from Lake Kivu into Lake Edward, causing it instead to discharge southward into Lake Tanganyika. Before that Lake Tanganyika, or separate sub-basins in what is now the lake, may have had no outlet other than evaporation. [4] The Lukuga has formed relatively recently, providing a route through which aquatic species of the Congo Basin could colonize Lake Tanganyika, which formerly had distinct fauna. [5]

Mountains

Mount Stanley in the Rwenzori range. With an elevation of 5,109 m (16,763 ft), it is the tallest mountain in the Albertine Rift and the third tallest in Africa. Mount Stanley.jpg
Mount Stanley in the Rwenzori range. With an elevation of 5,109 m (16,763 ft), it is the tallest mountain in the Albertine Rift and the third tallest in Africa.

From north to south the mountains include the Lendu Plateau, Rwenzori Mountains, Virunga Mountains and Itombwe Mountains. [6] The Ruwenzori mountains have been identified with Ptolemy's "Mountains of the Moon". The range covers an area 120 kilometres (75 mi) long by 65 kilometres (40 mi) wide. This range includes Mount Stanley 5,119 metres (16,795 ft), Mount Speke 4,890 metres (16,040 ft) and Mount Baker 4,843 metres (15,889 ft). [7] The Virunga Massif along the border between Rwanda and the DRC consists of eight volcanoes. Two of these, Nyamuragira and Nyiragongo, are still highly active. [8]

Isolated mountain blocks further to the south include Mount Bururi in southern Burundi, the Kungwe-Mahale Mountains in western Tanzania, and Mount Kabobo and the Marungu Mountains in the DRC on the shores of Lake Tanganyika. [6] Most of the massifs rise to between 2,000 metres (6,600 ft) and 3,500 metres (11,500 ft). [9]

Ecology

The Albertine Rift montane forests are important eco-regions. [6] Transitional forests, intermediate between lowland and montane forest, are found at elevations from around 1,000 metres (3,300 ft) to 1,750 metres (5,740 ft). Montane forest covers the slopes from around 1,600 metres (5,200 ft) to 3,500 metres (11,500 ft). Above 2,400 metres (7,900 ft) there are areas of bamboo and elfin forest. Heather and grasses predominate above 3,500 metres (11,500 ft). The ecology is threatened by deforestation as a growing population seeks new farmland. Illegal timber extraction is another problem, and artisanal gold mining causes some local damage. [9]

See also

Related Research Articles

The Democratic Republic of the Congo (DRC) is the largest country of sub-Saharan Africa, occupying some 2,344,858 square kilometres (905,355 sq mi). Most of the country lies within the vast hollow of the Congo River basin. The vast, low-lying central area is a plateau-shaped basin sloping toward the west, covered by tropical rainforest and criss-crossed by rivers. The forest center is surrounded by mountainous terraces in the west, plateaus merging into savannas in the south and southwest. Dense grasslands extend beyond the Congo River in the north. High mountains of the Ruwenzori Range are found on the eastern borders with Rwanda and Uganda.

Geography of Rwanda

Rwanda is located in central Africa, to the east of the Democratic Republic of the Congo, at the co-ordinates 2°00′S30°0′E.

Virunga Mountains Chain of volcanoes in East Africa

The Virunga Mountains are a chain of volcanoes in East Africa, along the northern border of Rwanda, the Democratic Republic of the Congo (DRC), and Uganda. The mountain range is a branch of the Albertine Rift Mountains, which border the western branch of the East African Rift. They are located between Lake Edward and Lake Kivu. The name "Virunga" is an English version of the Kinyarwanda word ibirunga, which means "volcanoes".

Virunga National Park National park in the Democratic Republic of the Congo

Virunga National Park is a national park in the Albertine Rift Valley in the eastern part of the Democratic Republic of the Congo. It was created in 1925 and is among the first protected areas in Africa. In elevation, it ranges from 680 m (2,230 ft) in the Semliki River valley to 5,109 m (16,762 ft) in the Rwenzori Mountains. From north to south it extends about 300 km (190 mi), largely along the international borders with Uganda and Rwanda in the east. It covers an area of 8,090 km2 (3,120 sq mi).

Ruzizi River River in Central Africa

The Ruzizi is a river, 117 kilometres (73 mi) long, that flows from Lake Kivu to Lake Tanganyika in Central Africa, descending from about 1,500 metres (4,900 ft) to about 770 metres (2,530 ft) above sea level over its length. The steepest gradients occur over the first 40 kilometres (25 mi), where hydroelectric dams have been built. Further downstream, the Ruzizi Plain, the floor of the Western Rift Valley, has only gentle hills, and the river flows into Lake Tanganyika through a delta, with one or two small channels splitting off from the main channel.

Lukuga River

The Lukuga River is a tributary of the Lualaba River in the Democratic Republic of the Congo (DRC) that drains Lake Tanganyika. It is unusual in that its flow varies not just seasonally but also due to longer term climate fluctuations.

Rwenzori Mountains National Park

Rwenzori Mountains National Park is a Ugandan national park and UNESCO World Heritage Site located in the Rwenzori Mountains. Almost 1,000 km2 (386 sq mi) in size, the park has Africa's third highest mountain peak and many waterfalls, lakes, and glaciers. The park is known for its beautiful plant life.

Mgahinga Gorilla National Park

Mgahinga Gorilla National Park is a national park in southwestern Uganda. It was created in 1991 and covers an area of 33.9 km2 (13.1 sq mi).

Afromontane Subregion of the Afrotropical realm

The Afromontane regions are subregions of the Afrotropical realm, one of the Earth's eight biogeographic realms, covering the plant and animal species found in the mountains of Africa and the southern Arabian Peninsula. The Afromontane regions of Africa are discontinuous, separated from each other by lower-lying areas, and are sometimes referred to as the Afromontane archipelago, as their distribution is analogous to a series of sky islands.

Albertine Rift montane forests Ecoregion (WWF)

The Albertine Rift montane forests is a tropical moist broadleaf forest ecoregion in east-central Africa. The ecoregion covers the mountains of the northern Albertine Rift, and is home to distinct Afromontane forests with high biodiversity.

Semliki River

Semliki River is a major river, 140 kilometres (87 mi) long, in the Democratic Republic of the Congo (DRC) and Uganda in Central and East Africa. It flows north from Lake Edward to Lake Albert in the Albertine Rift west of the Rwenzori Mountains. Along its lower reaches, it forms part of the international border between the DRC and the western Ugandan district of Bundibugyo, near the Semuliki National Park. It empties into Lake Albert slightly west of the border in Orientale Province of the DRC.

Shelley's crimsonwingCryptospiza shelleyi is a vulnerable species of estrildid finch found in Burundi, eastern Democratic Republic of the Congo, Rwanda and western Uganda in Africa. It has shown population decline over the past few decades, with a current population estimate of 2,500–9,999. This is possibly related to uncontrolled deforestation.

The Albertine owlet is a small species of small owl in the family Strigidae, native to the Albertine Rift montane forests.

Rwenzori batis Species of bird

The Rwenzori batis is an endemic bird native to the Albertine Rift montane forests, where it inhabits altitudes of 1,340–3,300 m (4,400–10,830 ft).

Itombwe Mountains

The Itombwe Mountains are a range of mountains in the South Kivu province of the Democratic Republic of the Congo (DRC). They run along the west shore of the northern part of Lake Tanganyika. They contain a vast area of contiguous montane forest and are home to a rich diversity of wildlife.

Rutshuru River

The Rutshuru River is a river in the eastern Democratic Republic of the Congo that drains Lake Mutanda in the foothills of the Virunga Mountains in Uganda, flowing northward into Lake Rutanzige. For most of its length it runs through the Rutshuru Territory in North Kivu province.

Rwenzori–Virunga montane moorlands montane ecoregion in central Africa

The Ruwenzori-Virunga montane moorlands is a montane grasslands and shrublands ecoregion of central Africa.

Congo-Nile Divide

The Congo-Nile Divide is the continental divide that separates the drainage basins of the Nile and Congo rivers. It is about 2,000 kilometres (1,200 mi) long.

References

  1. Owiunji & Plumptre 2011, p. 164.
  2. Erfurt-Cooper & Cooper 2010, pp. 35–36.
  3. Erfurt-Cooper & Cooper 2010, p. 35-36.
  4. Clark 1969, p. 35.
  5. Hughes & Hughes 1992, p. 562.
  6. 1 2 3 "Albertine Rift montane forests". Terrestrial Ecoregions. World Wildlife Fund. Retrieved 2011-12-19.
  7. Erfurt-Cooper & Cooper 2010, p. 37.
  8. Erfurt-Cooper & Cooper 2010, p. 36.
  9. 1 2 Birdlife.

Sources