Great Rift Valley For other uses, see Great Rift Valley (disambiguation). Rift Valley (African rift valley) The Great Rift Valley is a name given in the late 19th century by British explorer John Walter Gregory to the continuous geographic trench, approximately 6,000 kilo- metres (3,700 mi) in length, that runs from northern Jordan Rift Valley in Asia to Mozambique in South East- ern Africa.[1] The name continues in some usages, al- though it is today considered geologically imprecise as New Ocean Basin it combines features that are today regarded as separate, (Red Sea) although related, rift and fault systems. Today, the term is most often used to refer to the val- ley of the East African Rift, the divergent plate boundary which extends from the Afar Triple Junction southward across eastern Africa, and is in the process of splitting the African Plate into two new separate plates. Geolo- gists generally refer to these incipient plates as the Nubian Mature Ocean Plate and the Somali Plate. (Atlantic) Mid-Ocean Ridge Sediments Crust 1 Theoretical extent Mantle Diagram of a rift valley’s future evolution into a sea. 2 Asia Further information: Sinai peninsula The northernmost part of the Rift, today called the Dead Sea Transform or Rift, forms the Beqaa Valley in Lebanon separating the Lebanon Mountains and Anti- Lebanon Mountains. Further south it is known as the Hula Valley separating the Galilee mountains and the Golan Heights.[3] Satellite image of a graben in the Afar Depression. The River Jordan begins here and flows southward through Lake Hula into the Sea of Galilee in Israel. It The Great Rift Valley as originally described was thought then continues south through the Jordan Rift Valley into to extend from Lebanon in the north to Mozambique in the Dead Sea on the Israeli-Jordanian border. From the the south, and constitutes one of two distinct physio- Dead Sea southwards, the Rift is occupied by the Wadi graphic provinces of the East African mountains. It in- Arabah, then the Gulf of Aqaba, and then the Red Sea.[3] cluded the Jordan Rift Valley, Red Sea Rift and the East [2] Off the southern tip of Sinai in the Red Sea, the Dead African Rift. Sea Transform meets the Red Sea Rift which runs the Today these rifts and faults are seen as distinct, although length of the Red Sea. The Red Sea Rift comes ashore connected. to meet the East African Rift and the Aden Ridge in the 1 2 3 AFRICA The Sinai Peninsula at center and the Dead Sea and Jordan Val- ley above. 3 Africa East African Rift Valley. Main article: East African Rift The East African rift has two branches, the Western Rift Valley and the Eastern Rift Valley. The Western Rift, also called the Albertine Rift, is edged by some of the highest mountains in Africa, including the Virunga Mountains, Mitumba Mountains, and Ruwenzori The Rift Valley from space. Range. It contains the Rift Valley lakes, which include some of the deepest lakes in the world (up to 1,470 metres Afar Depression of East Africa. The junction of these (4,820 ft) deep at Lake Tanganyika). three rifts is called the Afar Triple Junction.[3] Much of this area lies within the boundaries of national 3 4 See also • The Great Rift: Africa’s Wild Heart, a BBC/Animal Planet production • Main earthquakes • 1837 Galilee earthquake • 2005 Lake Tanganyika earthquake • 2008 Lake Kivu earthquake 5 References [1] Merriam-Webster, Inc (1997). MERRIAM A map of East Africa showing some of the historically ac- WEBSTER'S GEOGRAPHICAL DICTIONARY 3/E(H). tive volcanoes (red triangles) and the Afar Triangle (shaded, Merriam-Webster. p. 444. ISBN 978-0-87779-546-9. center)—a triple junction where three plates are pulling away Retrieved 22 November 2012. from one another: the Arabian Plate, and the two parts of the [2] Philip Briggs; Brian Blatt (15 July 2009). Ethiopia: the African Plate (the Nubian and the Somali) splitting along the East Bradt travel guide. Bradt Travel Guides. p. 450. ISBN African Rift Zone (USGS). 978-1-84162-284-2. Retrieved 22 November 2012. [3] 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. Geolog- ical Society. pp. 306–307. ISBN 978-1-86239-196-3. Retrieved 22 November 2012. parks such as Virunga National Park in the Democratic 6 Further reading Republic of Congo, Rwenzori National Park and Queen Elizabeth National Park in Uganda, and Volcanoes Na- • tional Park in Rwanda. Lake Victoria is considered to be Africa’s Great Rift Valley, 2001, ISBN 0-8109- part of the rift valley system although it actually lies be- 0602-3 tween the two branches. All of the African Great Lakes • Tribes of the Great Rift Valley, 2007, ISBN 978-0- were formed as the result of the rift, and most lie within 8109-9411-9 its rift valley. • In Kenya, the valley is deepest to the north of Nairobi. East African Rift Valley lakes, 2006, OCLC As the lakes in the Eastern Rift have no outlet to the sea 76876862 and tend to be shallow, they have a high mineral content • Photographic atlas of the Mid-Atlantic Ridge Rift as the evaporation of water leaves the salts behind. For Valley, 1977, ISBN 0-387-90247-3 example, Lake Magadi has high concentrations of soda (sodium carbonate) and Lake Elmenteita, Lake Bogoria, • Rift Valley fever : an emerging human and animal and Lake Nakuru are all strongly alkaline, while the fresh- problem, 1982, ISBN 92-4-170063-7 water springs supplying Lake Naivasha are essential to • support its current biological variety. Rift valley: definition and geologic significance, Gia- como Corti (National Research Council of Italy, In- In Tanzania, the valley forms a triple junction just north stitute of Geosciences and Earth Resources) - The of Malawi and in Lake Nyasa. At this junction, the Great Ethiopian Rift Valley, 2013, East Africa valley diverges and forms another arm called the West arm, which extends to Democratic Republic of Congo and Uganda. The Western arm contains as many 7 External links lakes as the eastern arm including Lake Nyasa and world’s second deepest lake, Lake Tanganyika. The eastern arm, • on the other hand, has popular volcanoes like Mt Kili- Article on geology.com manjaro, Oldonyo Lengai and Mt Meru. The lakes found • Geological Structure of the Dead Sea on the eastern arm are not as deep or as voluminous like the ones on the western arm. Some of these lakes are • Birds Without Boundaries Lake Eyasi and Lake Natron. 4 8 TEXT AND IMAGE SOURCES, CONTRIBUTORS, AND LICENSES 8 Text and image sources, contributors, and licenses 8.1 Text • Great Rift Valley Source: http://en.wikipedia.org/wiki/Great%20Rift%20Valley?oldid=643809946 Contributors: AxelBoldt, Vicki Rosenzweig, Bryan Derksen, Tarquin, SimonP, Ktsquare, Heron, Hephaestos, Olivier, Menchi, Ixfd64, IZAK, Tregoweth, Ahoerstemeier, Stan Shebs, Pjamescowie, Angela, Kingturtle, Darkwind, Andrewa, Ijon, Raven in Orbit, Adam Bishop, David Newton, Steinsky, Drag- ons flight, Anupamsr, Joy, Wetman, Pollinator, UninvitedCompany, Robbot, Eman, RedWolf, Dittaeva, Academic Challenger, Rebrane, Hadal, Giftlite, Lee J Haywood, Tom Radulovich, Paul Pogonyshev, Bkonrad, Curps, Ssd, Gilgamesh, Guanaco, Dumbo1, Vidocq, Golbez, Gyrofrog, PeterC, Slowking Man, Antandrus, DragonflySixtyseven, GeoGreg, Mschlindwein, Avihu, Sonett72, Mike Rosoft, DanielCD, Discospinster, Guanabot, Oliver Lineham, Vsmith, Michael Zimmermann, ESkog, Doron, El C, Bletch, Kwamikagami, Shanes, Jojit fb, Nk, Darwinek, Nsaa, Siim, Alansohn, Riana, Super-Magician, BRW, Flit, Matthew Mattic, Deror avi, Oleg Alexandrov, Nuker, Rocastelo, Former user 2, Sengkang, Eras-mus, Prashanthns, Magister Mathematicae, Kbdank71, Dwaipayanc, Rjwilmsi, Erebus555, Jweiss11, Yuber, Tbone, Oo64eva, Margosbot, RexNL, Gurch, Chobot, Zyzzy, Sceptre, Wbfergus, Yyy, Johann Wolfgang, Igiffin, Searchme, Jwissick, Capi- talLetterBeginning, Tsunaminoai, The Yeti, Sardanaphalus, Veinor, SmackBot, Ashley thomas80, KnowledgeOfSelf, KingHezekiah, Jrock- ley, Edgar181, Gilliam, Hmains, Squiddy, Bluebot, Persian Poet Gal, Ian13, Ejg930, Hibernian, Baa, Q uant, Julius Sahara, Rolinator, Artie p, Yom, WoodyWerm, SashatoBot, Serein (renamed because of SUL), Goodnightmush, IronGargoyle, Drork, Chrisch, JHunterJ, Frokor, Slakr, Korovioff, Dblecros, Geologyguy, Istanbuljohnm, Politepunk, Joseph Solis in Australia, Michael Shade, Tmangray, Regiomontanus, Courcelles, Unionhawk, OMGsplosion, Karenjc, Oo7565, Ryan, Mattisse, Thijs!bot, Epbr123, Kablammo, Marek69, Dawnseeker2000, Mentifisto, Hmrox, AntiVandalBot, Neumannk, Danny lost, Baguala, Sluzzelin, Mikenorton, JAnDbot, Kaobear, IanOsgood, Owenozier, Igodard, PhilKnight, Acroterion, FaerieInGrey, Connormah, VoABot II, Sushant gupta, JamesBWatson, Jllm06, Twsx, Animum, Khalid Mahmood, Pere prlpz, MartinBot, CommonsDelinker, Artaxiad, J.delanoy, Icseaturtles, Samtheboy, Jamesc09, NewEnglandYankee, Ju- liancolton, ACBest, Vanished user 39948282, Treisijs, Idioma-bot, Wikieditor06, Egghead06, DSRH, Christophenstein, Jennavecia, Seat- tle Skier, Philip Trueman, TXiKiBoT, Caster23, FLELEE, Aymatth2, Naohiro19 revertvandal, Sintaku, Elphion, Martin451, Broadbot, ^demonBot2, Madhero88, SQL, Falcon8765, Temporaluser, Joelhowells, AlleborgoBot, EmxBot, Rontrigger, SieBot, Jaksap, Istota, Tri- wbe, Yintan, M.thoriyan, Flyer22, Jojalozzo, Mimihitam, Oxymoron83, Techman224, Rosiestep, Haimw, ClueBot, Dvl007, Transporter- Man, The Thing That Should Not Be, TheOldJacobite, Joao Xavier, Skäpperöd, Av0id3r, Darkest Days, Mr Accountable, Mindstorm- sKid, DragonBot, Excirial, Leonard^Bloom,