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The Great Rift Valley (Swahili: Bonde la ufa) is a series of contiguous geographic depressions, approximately 6,000 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 remains in some usages, it is rarely used in geology as it is considered an imprecise merging of rift and fault systems.
This valley extends southward from Western Asia into the eastern part of Africa, where several deep, elongated lakes, called ribbon lakes, exist on the rift valley floor, Lake Malawi and Lake Tanganyika being two such examples. The region has a unique ecosystem and contains a number of Africa's wildlife parks.
The term Great Rift Valley is most often used to refer to the valley of the East African Rift, the divergent plate boundary which extends from the Afar triple junction southward through eastern Africa, and is in the process of splitting the African plate into two new and separate plates. Geologists generally refer to these evolving plates as the Nubian plate and the Somali plate.
Theoretical extent
Today these rifts and faults are seen as distinct, although connected. Originally, the Great Rift Valley was thought to be a single feature that extended from Lebanon[dubious – discuss] in the north to Mozambique in the south, where it constitutes one of two distinct physiographic provinces of the East African mountains. It included what today is called the Lebanese section[dubious – discuss] of the Dead Sea Transform (Turkey to Straits of Tiran[dubious – discuss]), the Jordan Rift Valley (geographic term for section including entire course of the Jordan River, the Dead Sea, and the Arabah Valley), Red Sea Rift, and the East African Rift. These rifts and faults are considered to having been formed 35 million years ago.
Asia
The northernmost part of the Rift corresponds to the central[dubious – discuss] section of what is today called the Dead Sea Transform (DST) or Rift. This midsection of the DST forms the Beqaa Valley in Lebanon, separating the Mount Lebanon range from the Anti-Lebanon Mountains. Further south it is known as the Hula Valley separating the Galilee mountains and the Golan Heights.[failed verification][clarification needed]
The Jordan River begins here and flows southward through Lake Hula into the Sea of Galilee in Israel. The Rift then continues south through the Jordan Rift Valley into the Dead Sea, on the Israeli-Jordanian border. From the Dead Sea southwards, the Rift is occupied by the Wadi Arabah, then the Gulf of Aqaba, and then the Red Sea.
Off the southern tip of Sinai in the Red Sea, the Dead Sea Transform meets the Red Sea Rift which runs the length of the Red Sea. The Red Sea Rift comes ashore to meet the East African Rift and the Aden Ridge, in the Afar Depression of East Africa. The junction of these three rifts is called the Afar triple junction.
Africa
The East African Rift follows the Red Sea to the end before turning inland into the Ethiopian highlands, dividing the country into two large and adjacent but separate mountainous regions. In Kenya, Uganda, and the fringes of South Sudan, the Great Rift runs along two separate branches that are joined to each other only at their southern end, in Southern Tanzania along its border with Zambia. The two branches are called the Western Rift Valley and the Eastern Rift Valley.
The Western Rift, also called the Albertine Rift, is bordered by some of the highest mountains in Africa, including the Virunga Mountains, Mitumba Mountains, and Ruwenzori Range. It contains the Rift Valley lakes, which include some of the deepest lakes in the world (up to 1,470 metres (4,820 ft) deep at Lake Tanganyika).
Much of this area lies within the boundaries of national parks, such as Virunga National Park in the Democratic Republic of Congo, Rwenzori National Park and Queen Elizabeth National Park in Uganda, and Volcanoes National Park in Rwanda. Lake Victoria is considered to be part of the rift valley system although it actually lies between the two branches. All of the African Great Lakes were formed as the result of the rift, and most lie in territories within the rift.
In Kenya, the valley is deepest to the north of Nairobi. As the lakes in the Eastern Rift have no output to the sea and tend to be shallow, they have a high mineral content as the evaporation of water leaves the salts behind. For example, Lake Magadi has high concentrations of soda (sodium carbonate) and Lake Elmenteita, Lake Bogoria, and Lake Nakuru are all strongly alkaline, while the freshwater springs supplying Lake Naivasha are essential to support its current biological variety.
The southern section of the Rift Valley includes Lake Malawi, the third-deepest freshwater body in the world, which reaches 706 metres (2,316 ft) in depth and separates the Nyassa plateau of Northern Mozambique from Malawi. The rift extends southwards from Lake Malawi as the valley of the Shire River, which flows from the lake into the Zambezi River. The rift continues south of the Zambezi as the Urema Valley of central Mozambique.
See also
- Africa
- Great Rift Valley, Ethiopia
- Great Rift Valley, Kenya
- Rift Valley fever
- Rift Valley lakes
- Rift Valley Province
- Rift Valley Railways
- Rift Valley Technical Training Institute
- The Great Rift: Africa's Wild Heart, a BBC/Animal Planet production
- Major earthquakes
- 1837 Galilee earthquake
- 1995 Gulf of Aqaba earthquake
- 2005 Lake Tanganyika earthquake
- 2006 Mozambique earthquake
- 2008 Lake Kivu earthquake
References
- Benda, Petr; et al. (January 2006). "Bats (Mammalia: Chiroptera) of the Eastern Mediterranean. Part 4. Bat fauna of Syria: distribution, systematics, ecology". Acta Soc. Zool. Bohem. (70): 1–329 (9). ISSN 1211-376X. Retrieved 9 September 2024 – via ResearchGate.
- MERRIAM WEBSTER'S GEOGRAPHICAL DICTIONARY 3/E(H). Merriam-Webster. 1997. p. 444. ISBN 978-0-87779-546-9.
- Philip Briggs; Brian Blatt (15 July 2009). Ethiopia: the Bradt travel guide. Bradt Travel Guides. p. 450. ISBN 978-1-84162-284-2.
- G. Yirgu; C. J. (Cindy J.) Ebinger; P. K. H. Maguire (2006). The Afar Volcanic Province Within the East African Rift System: Special Publication No 259. Geological Society. pp. 306–307. ISBN 978-1-86239-196-3.
- Steinbruch, Franziska (2010). Geology and geomorphology of the Urema Graben with emphasis on the evolution of Lake Urema, Journal of African Earth Sciences, Volume 58, Issue 2, 2010, Pages 272-284. ISSN 1464-343X, https://doi.org/10.1016/j.jafrearsci.2010.03.007.
Further reading
- Africa's Great Rift Valley, 2001, ISBN 978-0-8109-0602-0
- Tribes of the Great Rift Valley, 2007, ISBN 978-0-8109-9411-9
- East African Rift Valley lakes, 2006, OCLC 76876862
- Photographic atlas of the Mid-Atlantic Ridge Rift Valley, 1977, ISBN 978-0-387-90247-0
- Rift Valley fever : an emerging human and animal problem, 1982, ISBN 978-92-4-170063-4
- Rift valley: definition and geologic significance, Giacomo Corti (National Research Council of Italy, Institute of Geosciences and Earth Resources) – The Ethiopian Rift Valley, 2013, [1]
- Big crack is evidence that East Africa could be splitting in two, by Lucia Perez Diaz, CNN. Updated April 5, 2018
External links
- Article on geology.com
- Geological Structure
- . New International Encyclopedia. 1905.
This article needs additional citations for verification Please help improve this article by adding citations to reliable sources Unsourced material may be challenged and removed Find sources Great Rift Valley news newspapers books scholar JSTOR June 2024 Learn how and when to remove this message The Great Rift Valley Swahili Bonde la ufa is a series of contiguous geographic depressions approximately 6 000 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 remains in some usages it is rarely used in geology as it is considered an imprecise merging of rift and fault systems Map of the Great Rift Valley This valley extends southward from Western Asia into the eastern part of Africa where several deep elongated lakes called ribbon lakes exist on the rift valley floor Lake Malawi and Lake Tanganyika being two such examples The region has a unique ecosystem and contains a number of Africa s wildlife parks The Great Rift Valley Location Uganda Map of the Great Rift Valley English version The background map and the locator map are raster images embedded into the SVG file The term Great Rift Valley is most often used to refer to the valley of the East African Rift the divergent plate boundary which extends from the Afar triple junction southward through eastern Africa and is in the process of splitting the African plate into two new and separate plates Geologists generally refer to these evolving plates as the Nubian plate and the Somali plate Theoretical extentDiagram of a rift valley s future evolution into a seaSatellite image of a graben in the Afar Depression Today these rifts and faults are seen as distinct although connected Originally the Great Rift Valley was thought to be a single feature that extended from Lebanon dubious discuss in the north to Mozambique in the south where it constitutes one of two distinct physiographic provinces of the East African mountains It included what today is called the Lebanese section dubious discuss of the Dead Sea Transform Turkey to Straits of Tiran dubious discuss the Jordan Rift Valley geographic term for section including entire course of the Jordan River the Dead Sea and the Arabah Valley Red Sea Rift and the East African Rift These rifts and faults are considered to having been formed 35 million years ago AsiaThe northernmost part of the Rift corresponds to the central dubious discuss section of what is today called the Dead Sea Transform DST or Rift This midsection of the DST forms the Beqaa Valley in Lebanon separating the Mount Lebanon range from the Anti Lebanon Mountains Further south it is known as the Hula Valley separating the Galilee mountains and the Golan Heights failed verification clarification needed The Jordan River begins here and flows southward through Lake Hula into the Sea of Galilee in Israel The Rift then continues south through the Jordan Rift Valley into the Dead Sea on the Israeli Jordanian border From the Dead Sea southwards the Rift is occupied by the Wadi Arabah then the Gulf of Aqaba and then the Red Sea Off the southern tip of Sinai in the Red Sea the Dead Sea Transform meets the Red Sea Rift which runs the length of the Red Sea The Red Sea Rift comes ashore to meet the East African Rift and the Aden Ridge in the Afar Depression of East Africa The junction of these three rifts is called the Afar triple junction AfricaEast African Rift ValleyEast Africa with active volcanoes red triangles and the Afar Triangle shaded center a triple junction where three plates are pulling away from one another This Envisat radar image captures volcanoes dotted across the landscape in Tanzania including the distinctive Ol Doinyo Lengai at lower left in the Great Rift Valley of East Africa The Gelai Volcano 2942 m is visible at the top and the Kitumbeine volcano The East African Rift follows the Red Sea to the end before turning inland into the Ethiopian highlands dividing the country into two large and adjacent but separate mountainous regions In Kenya Uganda and the fringes of South Sudan the Great Rift runs along two separate branches that are joined to each other only at their southern end in Southern Tanzania along its border with Zambia The two branches are called the Western Rift Valley and the Eastern Rift Valley The Western Rift also called the Albertine Rift is bordered by some of the highest mountains in Africa including the Virunga Mountains Mitumba Mountains and Ruwenzori Range It contains the Rift Valley lakes which include some of the deepest lakes in the world up to 1 470 metres 4 820 ft deep at Lake Tanganyika Much of this area lies within the boundaries of national parks such as Virunga National Park in the Democratic Republic of Congo Rwenzori National Park and Queen Elizabeth National Park in Uganda and Volcanoes National Park in Rwanda Lake Victoria is considered to be part of the rift valley system although it actually lies between the two branches All of the African Great Lakes were formed as the result of the rift and most lie in territories within the rift In Kenya the valley is deepest to the north of Nairobi As the lakes in the Eastern Rift have no output to the sea and tend to be shallow they have a high mineral content as the evaporation of water leaves the salts behind For example Lake Magadi has high concentrations of soda sodium carbonate and Lake Elmenteita Lake Bogoria and Lake Nakuru are all strongly alkaline while the freshwater springs supplying Lake Naivasha are essential to support its current biological variety The southern section of the Rift Valley includes Lake Malawi the third deepest freshwater body in the world which reaches 706 metres 2 316 ft in depth and separates the Nyassa plateau of Northern Mozambique from Malawi The rift extends southwards from Lake Malawi as the valley of the Shire River which flows from the lake into the Zambezi River The rift continues south of the Zambezi as the Urema Valley of central Mozambique See alsoAfricaGreat Rift Valley Ethiopia Great Rift Valley Kenya Rift Valley fever Rift Valley lakes Rift Valley Province Rift Valley Railways Rift Valley Technical Training Institute The Great Rift Africa s Wild Heart a BBC Animal Planet productionMajor earthquakes1837 Galilee earthquake 1995 Gulf of Aqaba earthquake 2005 Lake Tanganyika earthquake 2006 Mozambique earthquake 2008 Lake Kivu earthquakeReferencesBenda Petr et al January 2006 Bats Mammalia Chiroptera of the Eastern Mediterranean Part 4 Bat fauna of Syria distribution systematics ecology Acta Soc Zool Bohem 70 1 329 9 ISSN 1211 376X Retrieved 9 September 2024 via ResearchGate MERRIAM WEBSTER S GEOGRAPHICAL DICTIONARY 3 E H Merriam Webster 1997 p 444 ISBN 978 0 87779 546 9 Philip Briggs Brian Blatt 15 July 2009 Ethiopia the Bradt travel guide Bradt Travel Guides p 450 ISBN 978 1 84162 284 2 G Yirgu C J Cindy J Ebinger P K H Maguire 2006 The Afar Volcanic Province Within the East African Rift System Special Publication No 259 Geological Society pp 306 307 ISBN 978 1 86239 196 3 Steinbruch Franziska 2010 Geology and geomorphology of the Urema Graben with emphasis on the evolution of Lake Urema Journal of African Earth Sciences Volume 58 Issue 2 2010 Pages 272 284 ISSN 1464 343X https doi org 10 1016 j jafrearsci 2010 03 007 Further readingAfrica s Great Rift Valley 2001 ISBN 978 0 8109 0602 0 Tribes of the Great Rift Valley 2007 ISBN 978 0 8109 9411 9 East African Rift Valley lakes 2006 OCLC 76876862 Photographic atlas of the Mid Atlantic Ridge Rift Valley 1977 ISBN 978 0 387 90247 0 Rift Valley fever an emerging human and animal problem 1982 ISBN 978 92 4 170063 4 Rift valley definition and geologic significance Giacomo Corti National Research Council of Italy Institute of Geosciences and Earth Resources The Ethiopian Rift Valley 2013 1 Big crack is evidence that East Africa could be splitting in two by Lucia Perez Diaz CNN Updated April 5 2018External linksWikimedia Commons has media related to Great Rift Valley Article on geology com Geological Structure Great Rift Valley New International Encyclopedia 1905
