Great Rift Valley, Kenya

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Lake Bogoria LakeBogoria.jpg
Lake Bogoria
Mount Longonot Longolot.jpg
Mount Longonot
View of Uganda from Cherubei Village, Kenya Cherubei Villege, Mt. Elgon, Kenya.jpg
View of Uganda from Cherubei Village, Kenya

The Great Rift Valley is part of an intra-continental ridge system that runs through Kenya from north to south. It is part of the Gregory Rift, the eastern branch of the East African Rift, which starts in Tanzania to the south and continues northward into Ethiopia. [1] It was formed on the "Kenyan Dome", a geographical upwelling created by the interactions of three major tectonics: the Arabian, Nubian, and Somalian plates. [2] In the past, it was seen as part of a "Great Rift Valley" that ran from Madagascar to Syria. Most of the valley falls within the former Rift Valley Province.

Contents

The valley contains the Cherangani Hills and a chain of volcanoes, some of which are still active. The climate is mild, with temperatures usually below 28 °C (82 °F). Most rain falls during the March–June and October–November periods. [3] The Tugen Hills to the west of Lake Baringo contain fossils preserved in lava flows from the period 14 to 4 million years ago. The relics of many hominids, ancestors of humans, have been found here. [4]

In March 2018, a giant crack in the Earth, measuring 50 feet deep and 65 feet across, opened in the ground just west of Nairobi. [5] However, it is believed to be due to rain and erosion, and not of tectonic origin. [6]

Features

Main volcanoes and lakes in the rift valley Kenya Rift Valley volcanoes and lakes.svg
Main volcanoes and lakes in the rift valley

The valley is bordered by escarpments to the east and west. The floor is broken by volcanoes, some still active, and contains a series of lakes. Some of the soils are Andisols, fertile soils from relatively recent volcanic activity.

Lake Turkana occupies the northern end of the Great Rift Valley in Kenya. There are also volcanoes in Lake Turkana. The Suguta Valley, or Suguta Mud Flats, is an arid part of the Great Rift Valley directly south of Lake Turkana. The shield volcano Emuruangogolak straddles the valley to the south of Suguta, and further south Mount Silali and Paka rise from the valley floor. Paka is a shield volcano, with widespread geothermal activity. South of Paka are Mount Korosi, Lake Baringo and Lake Bogoria. Menengai is a massive shield volcano in the floor of the rift with a caldera that formed about 8,000 years ago. [7] It overlooks Lake Nakuru to the south. This region also includes Lake Elementaita, Mount Kipipiri and Lake Naivasha.

The Hell's Gate National Park lies south of Lake Naivasha. [8] In the early 1900s, Mount Longonot erupted, and ash can still be felt around Hell's Gate. [9] Mount Longonot is a dormant stratovolcano located southeast of Lake Naivasha. Mount Suswa is a shield volcano located between Narok and Nairobi. Lava flows from the most recent eruptions are still not covered by vegetation, and may be no more than one hundred years old. [10] Lake Magadi is the most southern rift valley lake in Kenya, although the northern end of Lake Natron in Tanzania reaches into Kenya.

The Elgeyo escarpment forms part of the western wall. The Kerio Valley lies between the Tugen Hills and the Elgeyo escarpment at an elevation of 1,000 metres (3,300 ft) There are large deposits of Fluorite in the Kerio Valley area. Further south the Mau Escarpment is a steep natural cliff approximately 1,000 m (3,300 ft) high, running along the western edge of the Great Rift Valley about Lake Naivasha. Yet further south the Nguruman Escarpment is around 50 kilometers long and elongated in N-W direction. Its northern edge is about 120 kilometres (75 mi) southwest of Nairobi, while the southern edge is near the Tanzanian border, at the northwestern corner of Lake Natron. The Aberdare Range forms a section of the eastern rim of the Great Rift Valley to the north of Nairobi. Mount Satima lies at the northern end of the Aberdares and is their highest point, and Mount Kinangop at the southern end is the second highest. The mountains form a ridge between these two peaks. Ngong Hills are peaks in a ridge along the east of the Great Rift Valley, located southwest near Nairobi.

Lakes

Kenya Lake System in the Great Rift Valley
UNESCO World Heritage Site
Lake bogoria.jpg
Lake Bogoria, one of the main lakes in the Great Rift Valley.
Location Rift Valley Province, Kenya
Includes
  1. Lake Elmentaita
  2. Lake Nakuru
  3. Lake Bogoria
Criteria Natural: (vii), (ix), (x)
Reference 1060rev
Inscription2011 (35th Session)
Area32,034 ha (79,160 acres)
Buffer zone3,581 ha (8,850 acres)
Coordinates 00°26′33″N36°14′24″E / 0.44250°N 36.24000°E / 0.44250; 36.24000
Official name Lake Turkana National Parks
Criteria Natural: viii, x
Reference 801bis
Inscription1997 (21st Session)
Extensions2001
Kenya relief location map.jpg
Red pog.svg
Location of Great Rift Valley, Kenya in Kenya

Kenya is home to 64 (9.50%) of the total lakes found within the continent of Africa. [11] Eight of these make up the main lakes in the Kenyan Rift Valley. From north to south, the names of these lakes are Lake Turkana, Lake Logipi, Lake Baringo, Lake Bogoria, Lake Nakuru, Lake Elmenteita, Lake Naivasha, and Lake Magadi. [3] Of those eight, only Lakes Baringo and Naivasha are fresh water. [12]

East African Rift Valley, Kenya ISS 2012 East African Rift Valley, Kenya ISS 2012.jpg
East African Rift Valley, Kenya ISS 2012

Lake Turkana, at the northern end of the rift, is 250 kilometres (160 mi) long, between 15 kilometres (9.3 mi) and 30 kilometres (19 mi) wide and is 125 metres (410 ft) at its greatest depth. [13] Most of the other lakes are shallow and poorly drained, and therefore have become alkaline. They have waters that are rich in blue-green algae, which feed insect larvae, small crustaceans and lesser flamingos. The larvae and crustaceans are food for fish and greater flamingos. [3] Massive flocks of these birds have been found to have an effect on the lakeside sediments also. Their numbers cause trampling of the silts in certain areas, while the feeding grounds are oxygenated due to probing beaks in the mud. Their nest mounds can also be preserved and cemented as the lake's water levels change. These form irregularities in the lakeside topography. [14]

Trona, an evaporative mineral, used for sodium carbonate production, has been mined at Lake Magadi for nearly 100 years. It produces about 250,000 metric tonnes per year. [15] Other precious minerals like rubies and pink sapphires have been found and mined from areas around Lake Baringo. In 2004, over 2 kilograms of Corundum were collected. [16]

Lake Bogoria is a caustic cauldron fringed by geysers and populated by over a million flamingos. Flickr - Rainbirder - Born of Fire.jpg
Lake Bogoria is a caustic cauldron fringed by geysers and populated by over a million flamingos.

Three shallow alkaline lakes and the surrounding lands make up the Kenya lake system: Lake Bogoria at 10,700 hectares (26,000 acres), Lake Nakuru at 18,800 hectares (46,000 acres) and Lake Elmenteita at 2,534 hectares (6,260 acres). This system has one of the most diverse populations of birds in the world, and is the home of thirteen globally threatened species of bird. It is an important nesting and breeding site for great white pelicans, and is the most important feeding area for lesser flamingos in the world. The system is home to globally important populations of black-necked grebe, African spoonbill, pied avocet, little grebe, yellow-billed stork, black-winged stilt, grey-headed gull and gull-billed tern. [17]

The Kenya lake system is a key location on the West Asian-East African Flyway, a route followed by huge numbers of birds in their annual migration from breeding grounds in the north to wintering places in Africa. The lands around the lakes include large populations of black rhino, Rothschild's giraffe, greater kudu, lion, cheetah and wild dogs. The Kenya lake system is surrounded by the steep escarpment of the Rift Valley, which provides a spectacular backdrop. [17]

Other lakes are Lake Chew Bahir, in the northeast extension. This lake lies mainly in Ethiopia but extends into Kenya in the rainy season. Lake Kamnarok is another small lake.

See also

Prehistory

Ethnic groups

Luhya children at Endebess, Kenya Luhya children.jpg
Luhya children at Endebess, Kenya

Economy

People

Related Research Articles

<span class="mw-page-title-main">Great Rift Valley</span> Continuous geographic trench from Asia to Southeast Africa

The Great Rift Valley is a series of contiguous geographic depressions, approximately 6000 or 7,000 kilometres (4,300 mi) in total length, the definition varying between sources, that runs from the southern Turkish Hatay Province in Asia, through the Red Sea, to Mozambique in Southeast Africa. While the name continues in some usages, it is rarely used in geology as it is considered an imprecise merging of separate though related rift and fault systems.

<span class="mw-page-title-main">Lake Baringo</span> Freshwater lake in Kenya

Lake Baringo is, after Lake Turkana, the most northern of the Kenyan Rift Valley lakes, with a surface area of 130 square kilometres (50 sq mi) and an elevation of 970 metres (3,180 ft). The lake is fed by several rivers: the Molo, Perkerra and Ol Arabel. It has no obvious outlet; the waters are assumed to seep through lake sediments into the faulted volcanic bedrock. It is one of the two freshwater lakes in the Rift Valley in Kenya, the other being Lake Naivasha.

<span class="mw-page-title-main">Rift Valley Province</span> Province of Kenya

Rift Valley Province of Kenya, bordering Uganda, was one of Kenya's eight provinces, before the 2013 Kenyan general election. Rift Valley Province was the largest and one of the most economically important provinces in Kenya. It was dominated by the Kenya Rift Valley which passes through it and gives the province its name. According to the 2009 Census, the former province covered an area of 182,505.1 square kilometres and would have had a population of 10,006,805, making it the largest and most populous province in the country. The bulk of the provincial population inhabited a strip between former Nairobi and Nyanza Province. The capital was the town of Nakuru.

<span class="mw-page-title-main">Rift Valley lakes</span> Group of lakes in the East African Rift

The Rift Valley lakes are a series of lakes in the East African Rift valley that runs through eastern Africa from Ethiopia in the north to Malawi in the south, and includes the African Great Lakes in the south. These include some of the world's oldest lakes, deepest lakes, largest lakes by area, and largest lakes by volume. Many are freshwater ecoregions of great biodiversity, while others are alkaline "soda lakes" supporting highly specialised organisms.

<span class="mw-page-title-main">Lake Bogoria</span> Meromictic lake in Kenya

Lake Bogoria is a saline, alkaline lake that lies in a volcanic region in a half-graben basin south of Lake Baringo, Kenya, a little north of the equator. Lake Bogoria, like Lake Nakuru, Lake Elementeita, and Lake Magadi further south in the Rift Valley, and Lake Logipi to the north, is periodically home to one of the world's largest populations of lesser flamingos. The lake is a Ramsar site and Lake Bogoria National Reserve has been a protected National Reserve since November 29, 1973.

<span class="mw-page-title-main">Tugen people</span> Tribe of Kenya

The Tugen are a sub tribe of the Kenyan Kalenjin people. They fall under the highland nilotes category. They occupy Baringo County and some parts of Nakuru County and Elgeyo Marakwet County in the former Rift Valley Province. Daniel Arap Moi, the second president of Kenya (1978–2002), came from this sub-tribe. The Tugen people speak the Tugen language. The Tugen population was 197,556 as of 2019.

<span class="mw-page-title-main">Nakuru</span> City in Nakuru County, Kenya

Nakuru is a city in the Rift Valley region of Kenya. It is the capital of Nakuru County, and is the third largest urban area in Kenya. As of 2019, Nakuru has an urban population of 570,674, making it the largest urban centre in the Rift Valley, succeeding Eldoret, Uasin Gishu County. The city lies along the Nairobi–Nakuru Highway, 160 kilometres (99 mi) from Nairobi.

<span class="mw-page-title-main">Nakuru County</span> County in Kenya

Nakuru County is a county in Kenya. It is county number 32 out of the 47 Kenyan counties. Nakuru County is a host to Kenya's Fourth City – Nakuru City. On 1 December 2021, President Uhuru Kenyatta awarded a City Charter status to Nakuru, ranking it with Nairobi, Mombasa, and Kisumu as the cities in Kenya. With a population of 2,162,202, it is the third most populous county in Kenya after Nairobi County and Kiambu County, in that order. With an area of 7,496.5 km2, it is Kenya's 19th largest county in size. Until 21 August 2010, it formed part of Rift Valley Province.

<span class="mw-page-title-main">Lake Nakuru</span> Alkaline lake in Rift valley

Lake Nakuru is one of the Rift Valley lakes, located at an elevation of 1,754 m (5,755 ft) above sea level. It lies to the south of Nakuru, in the rift valley of Kenya and is protected by Lake Nakuru National Park.

<span class="mw-page-title-main">Suguta Valley</span>

The Suguta Valley, also known as the Suguta Mud Flats, is an arid part of the Great Rift Valley in Kenya (Africa), directly south of Lake Turkana.

<span class="mw-page-title-main">Baringo County</span> County in Kenya

Baringo County is one of the 47 counties in Kenya. It is located in the former Rift Valley Province. Its headquarters and largest town is Kabarnet. The county is home to Lake Baringo, Lake Bogoria and Lake Kamnarok.

<span class="mw-page-title-main">Lake Elmenteita</span> Lake in Kenya

Lake Elmenteita is a soda lake, in the Great Rift Valley, about 120 km northwest of Nairobi, Kenya.

Mount Silali is a dormant volcano in the Gregory Rift Valley, near Kapedo, Kenya. Silali is south of the Suguta Valley, which reaches northward to Lake Turkana, and is about 70 kilometres (43 mi) north of Lake Baringo.

<span class="mw-page-title-main">Gregory Rift</span>

The Gregory Rift is the eastern branch of the East African Rift fracture system. The rift is being caused by the separation of the Somali Plate from the Nubian Plate, driven by a thermal plume. Although the term is sometimes used in the narrow sense of the Kenyan Rift, the larger definition of the Gregory Rift is the set of faults and grabens extending southward from the Gulf of Aden through Ethiopia and Kenya into Northern Tanzania, passing over the local uplifts of the Ethiopian and Kenyan domes. Ancient fossils of early hominins, the ancestors of humans, have been found in the southern part of the Gregory Rift.

The Suguta River is a seasonal river in the Great Rift Valley in Kenya (Africa), directly south of Lake Turkana. It flows northward through the Suguta Valley in the rainy season, forming the temporary Lake Alablad, a dry lake that combines with Lake Logipi at the northern end of the valley.

<span class="mw-page-title-main">Elgeyo-Marakwet County</span> County in Kenya

Elgeyo-Marakwet County is one of Kenya's 47 counties. Located in the former Rift Valley Province, its capital and largest town as Iten. Itborders the counties of West Pokot to the north, Baringo County to the east, southeast and south, Uasin Gishu to the southwest and west, and Trans Nzoia to the northwest.

Nakuru District was a district in the Rift Valley Province, Kenya. The district capital was Nakuru. With a population of 1,187,039, following the Nairobi region. Nakuru District had an area of 7,242 km².

Northern <i>Acacia</i>–<i>Commiphora</i> bushlands and thickets

The Northern Acacia–Commiphora bushlands and thickets are a tropical grasslands, savannas and shrublands ecoregion in eastern Africa. The ecoregion is mostly located in Kenya, extending north into southeastern South Sudan, northeastern Uganda and southwestern Ethiopia and south into Tanzania along the Kenya-Tanzania border.

The Southern Eastern Rift is a freshwater ecoregion in Kenya and Tanzania.

References

  1. ↑ Chorowicz, Jean (10 November 2005). "The East African Rift System". Journal of African Earth Sciences. 43 (1–3): 379–410. Bibcode:2005JAfES..43..379C. doi:10.1016/j.jafrearsci.2005.07.019.
  2. ↑ Corti, Giacomo (February 2012). "Evolution and characteristics of continental rifting: Analog modeling-inspired view and comparison with examples from the East African Rift System". Tectonophysics. 522: 1–33. Bibcode:2012Tectp.522....1C. doi:10.1016/j.tecto.2011.06.010.
  3. 1 2 3 Firestone 2009, p. 151.
  4. ↑ Firestone 2009, p. 23.
  5. ↑ "A giant crack in Kenya opens up, but what's causing it?". CBS News. April 3, 2018.
  6. ↑ "Africa is slowly splitting in two – but this 'crack' in Kenya has little to do with it". The Guardian. April 6, 2018.
  7. ↑ Menengai.
  8. ↑ Scoon, Roger N. (2018). Geology of National Parks of Central/Southern Kenya and Northern Tanzania: Geotourism of the Gregory Rift Valley, Active Volcanism and Regional Plateaus. Springer. p. 186. ISBN   9783319737850.
  9. ↑ Hell's Gate.
  10. ↑ Suswa.
  11. ↑ Singh 2006, p. 2.
  12. ↑ Britton & Harper 2006, p. 334.
  13. ↑ Anadón, Cabrera & Kelts 1991, p. 6.
  14. ↑ Scott, Jennifer J.; Robin W. Renaut; R. Bernhart Owen (15 November 2012). "Impacts of flamingos on saline lake margin and shallow lacustrine sediments in the Kenya Rift Valley". Sedimentary Geology. 277: 32–51. Bibcode:2012SedG..277...32S. doi:10.1016/j.sedgeo.2012.07.007.
  15. ↑ Warren, John K. (2006). Evaporites:Sediments, Resources and Hydrocarbons. New York: Springer Berlin Heidelberg. p. 861. ISBN   978-3-540-26011-0.
  16. ↑ Blauwet, Dudley; B. M. L. (1 June 2005). "New ruby and pink sapphire deposit in the Lake Baringo area, Kenya". Gems & Gemology. 41 (2): 177–178. Archived from the original on 3 March 2016.
  17. 1 2 UNESCO.

Sources

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