View source for Great Rift Valley

{{short description|Continuous geographic trench from Asia to Southeast Africa}}
{{other uses|Great Rift Valley (disambiguation)}}
{{more citations needed|date=June 2024}}
[[File:MapGreatRiftValley.png|thumb|Map of the Great Rift Valley]]

The '''Great Rift Valley''' ({{langx|sw|Bonde la ufa}}) is a series of contiguous geographic [[depression (geology)|depressions]], approximately 6,000 or {{convert|7000|km|mi|-2}} 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]].<ref name= Bat>{{cite journal |author= Benda, Petr |display-authors= et al. |title= Bats (Mammalia: Chiroptera) of the Eastern Mediterranean. Part 4. Bat fauna of Syria: distribution, systematics, ecology |date= January 2006 |journal= Acta Soc. Zool. Bohem. |issue= 70 |pages= 1–329 (9) |issn= 1211-376X |via= ResearchGate |url=https://www.researchgate.net/publication/235993996 |access-date= 9 September 2024}}</ref><ref name= webster1997>{{cite book|title=MERRIAM WEBSTER'S GEOGRAPHICAL DICTIONARY 3/E(H)|url=https://books.google.com/books?id=Co_VIPIJerIC&pg=PA444|year=1997|publisher=Merriam-Webster|isbn=978-0-87779-546-9|pages=444}}</ref> While the name remains in some usages, it is rarely used in [[geology]] where the term "'''Afro-Arabian Rift System'''" is preferred.<ref>{{Cite journal |last=Girdler |first=R. W. |date=1991-10-30 |title=The Afro-Arabian rift system—an overview |url=https://linkinghub.elsevier.com/retrieve/pii/004019519190038T |journal=Tectonophysics |volume=197 |issue=2 |pages=139–153 |doi=10.1016/0040-1951(91)90038-T |issn=0040-1951|url-access=subscription }}</ref>

This valley extends southward from [[Western Asia]] into the eastern part of Africa, where several deep, elongated lakes, called [[ribbon lake]]s, 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.

[[File:Great_rift_valley.jpg|220x124px|thumb|right|alt=The Great Rift Valley, Location: Uganda.|The Great Rift Valley, Location: Uganda.]] [[File:Great_Rift_Valley_map-en.svg|220x124px|thumb|right|alt=Map of the Great Rift Valley. English version. The background map and the locator map are raster images embedded into the SVG file.|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 boundary|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==
[[File:Ocean-birth.svg|thumb|Diagram of a rift valley's future evolution into a [[sea]]|left]]
[[File:Graben Afar ASTER 20020327.jpg|thumb|Satellite 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 |See talk-page: no, starting at the Marash triple junction in Hatay! |date= December 2024}} 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 |Same problem as previous dubious tag. |date= December 2024}} of the [[Dead Sea Transform]] (Turkey to [[Straits of Tiran]]{{dubious |Turkey to Sinai ain't Lebanon. |date= December 2024}}), 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]].<ref name= BriggsBlatt2009>{{cite book|author1=Philip Briggs|author2=Brian Blatt|title=Ethiopia: the Bradt travel guide|url=https://books.google.com/books?id=QFb6pacaczsC&pg=PA450|date=15 July 2009|publisher=Bradt Travel Guides|isbn=978-1-84162-284-2|page=450}}</ref> These rifts and faults are considered to having been formed 35 million years ago.

==Asia==
{{Further|Sinai Peninsula}}

The northernmost part of the Rift corresponds to the central{{dubious |Same problem as previous dubious tags. |date= December 2024}} 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|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]].<ref name="YirguEbinger2006">{{cite book|author1=G. Yirgu|author2=C. J. (Cindy J.) Ebinger|author3=P. K. H. Maguire|title=The Afar Volcanic Province Within the East African Rift System: Special Publication No 259|url=https://books.google.com/books?id=-NoKEx_AnUEC&pg=PA133|year=2006|publisher=Geological Society|isbn=978-1-86239-196-3|pages=306–307}}</ref>{{failed verification|date=September 2024}}{{clarify|Pls go to talk-page.|date=September 2024}}

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 [[Israel]]i-[[Jordan]]ian border. From the Dead Sea southwards, the Rift is occupied by the Wadi [[Arabah]], then the [[Gulf of Aqaba]], and then the [[Red Sea]].<ref name="YirguEbinger2006" />

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]].<ref name="YirguEbinger2006" />

==Africa==
{{Main|East African Rift}}
[[File:Great Rift Valley.png|thumb|East African Rift Valley]]
[[File:EAfrica.png|thumb|right|East Africa with active [[volcano]]es (red triangles) and the [[Afar Triangle]] (shaded, center)—a [[triple junction]] where three plates are pulling away from one another.|300x300px]] 
[[File:Cool_lava_in_Africa's_Great_Rift_Valley.jpg|440x248px|thumb|right|alt=date QS:P571,+2050-00-00T00:00:00Z/7,P1319,+2009-11-25T00:00:00Z/11,P1326,+2010-02-03T00:00:00Z/11|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|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 {{convert|1470|m}} 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 [[Great Lakes (Africa)|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 {{Convert|706|m|}} in depth and separates the [[Niassa Province|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.<ref>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.</ref>

==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==
{{Reflist}}

==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, [http://ethiopianrift.igg.cnr.it]
* [https://www.cnn.com/2018/04/05/africa/crack-africa-rift-valley-continent-splitting-two/index.html Big crack is evidence that East Africa could be splitting in two, by Lucia Perez Diaz, CNN. Updated April 5, 2018]

==External links==
{{Commons category}}
*[http://geology.com/articles/east-africa-rift.shtml Article on geology.com]
*[http://www.wysinfo.com/Dead_Sea/dead_sea_geo_structure.htm Geological Structure]
*{{Cite NIE|wstitle=Great Rift Valley|short=x}}

{{Kenya topics}}
{{Regions of the world|state=collapsed}}

{{Authority control}}

[[Category:Great Rift Valley| ]]
[[Category:Geography of Rift Valley Province|*]]
[[Category:Rifts and grabens]]
[[Category:Landforms of Israel]]
[[Category:Landforms of Syria]]
[[Category:Landforms of Egypt]]
[[Category:Landforms of Lebanon]]
[[Category:Landforms of Ethiopia]]
[[Category:Landforms of Kenya]]
[[Category:Landforms of Saudi Arabia]]
[[Category:Landforms of Yemen]]
[[Category:Landforms of Tanzania]]
[[Category:Landforms of the Democratic Republic of the Congo]]
[[Category:Landforms of Uganda]]
[[Category:Landforms of Burundi]]
[[Category:Geology of Israel]]
[[Category:Geology of Syria]]
[[Category:Geology of Egypt]]
[[Category:Geology of Lebanon]]
[[Category:Geology of Ethiopia]]
[[Category:Geology of Kenya]]
[[Category:Geology of Saudi Arabia]]
[[Category:Geology of Yemen]]
[[Category:Geology of Tanzania]]
[[Category:Geology of the Democratic Republic of the Congo]]
[[Category:Geology of Uganda]]
[[Category:Geology of Burundi]]
[[Category:Physiographic provinces]]
[[Category:Prehistoric Afar Triangle]]