; fissure; cleft; chink. As the rift widens and thins, upwelling asthenosphere can melt to produce magmas that start to create new oceanic lithosphere and … [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. (modified from USGS). The most extensive rift valley is located along the crest of the mid-ocean ridge system and is the result of sea floor spreading. [14], 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 Elementaita at 2,534 hectares (6,260 acres). Most rain falls during the March–June and October–November periods. Both types of fault-caused extension commonly occur on a small scale, producing such features as sag ponds or landslides. The Afar region in Northern Ethiopia is the centre of a “Y” shaped rift system, where the continental lithosphere is being stretched and is splitting.. If they continue, continental rifts will eventually become oceanic rifts. 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. The valley is bordered by escarpments to the east and west. The mountains form a ridge between these two peaks. [10][11] Some natural satellites also have prominent rift valleys. There are large deposits of Fluorite in the Kerio Valley area. Other rift valleys are the result of bends or discontinuities in horizontally-moving (strike-slip) faults. 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. Ngong Hills are peaks in a ridge along the east of the Great Rift Valley, located southwest near Nairobi. 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. Which features result from constructive forces? Lake Turkana occupies the northern end of the Great Rift Valley in Kenya. What does that tell us about where they came from? Paka is a shield volcano, with widespread geothermal activity. Volcanoes have been constructed within the valley by rising magma. Two locations are marked within the rift valley of East Africa, and another location is marked within the Red Sea. Let's rewind it. The Tugen Hills to the west of Lake Baringo contain fossils preserved in lava flows from the period 14 to 4 million years ago. Menengai is a massive shield volcano in the floor of the rift with a caldera that formed about 8,000 years ago. That feature is the beginning of the rift valley, but as the process continues, the valley widens, until it becomes a large basin that fills with sediment from the rift walls and the surrounding area. Examples of this type of rift include the Mid-Atlantic Ridge and the East Pacific Rise. Yet further south the Nguruman Escarpment is around 50 kilometers long and elongated in N-W direction. Extraterrestrial rift valleys are also known to occur on other terrestrial planets and natural satellites. Sketch by John Walter Gregory from his expedition to East Africa in 1892-3. Right now, South America and Africa are moving away from each other, because of new plate material being created at the mid-Atlantic rift. When the tensional forces are strong enough to cause the plate to split apart, a center block drops between the two blocks at its flanks, forming a graben. Other lakes are Lake Chew Bahir, in the northeast extension. South of Paka are Mount Korosi, Lake Baringo and Lake Bogoria. It produces about 250,000 metric tonnes per year. Baikal is both the deepest lake in the world and, with 20% of all of the liquid freshwater on earth, has the greatest volume. There the plates have fully separated, and the central rift valley has dropped below sea level. Their nest mounds can also be preserved and cemented as the lake's water levels change. A rift valley is a lowland region that forms where Earth’s tectonic plates move apart, or rift.Rift valleys are found both on land and at the bottom of the ocean, where they are created by the process of seafloor spreading.Rift valleys differ from river valleys and glacial valleys in that they are created by tectonic activity and not the process of erosion. Charon's Nostromo Chasma is the first confirmed in the Pluto system, however large chasms up to 950 km wide observed on Charon have also been tentatively interpreted by some as giant rifts, and similar formations have also been noted on Pluto. The Aberdare Range forms a section of the eastern rim of the Great Rift Valley to the north of Nairobi. 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. A rift valley is a linear shaped lowland between several highlands or mountain ranges created by the action of a geologic rift or fault. There are also volcanoes in Lake Turkana. Many existing continental rift valleys are the result of a failed arm (aulacogen) of a triple junction, although there are two, the East African Rift and the Baikal Rift Zone, which are currently active, as well as a third which may be, the West Antarctic Rift System. The Elgeyo escarpment forms part of the western wall. 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. Lava flows from the most recent eruptions are still not covered by vegetation, and may be no more than one hundred years old. The lands around the lakes include large populations of black rhino, Rothschild's giraffe, greater kudu, lion, cheetah and wild dogs. [3] Of those eight, only Lakes Baringo and Naivasha are fresh water. They are often associated with a number of adjoining subsidiary or co-extensive valleys, which are typically considered part of the principal rift valley geologically. The 2,000 km long Ithaca Chasma on Tethys in the Saturn system is a prominent example. The 4,000 km long Valles Marineris on Mars is believed by planetary geologists to be a large rift system. [7][8] Some features of Venus, most notably, the 4,000 km Devana Chasma[9] and a part of the western Eistla, and possibly also Alta and Bell Regio have been interpreted by some planetary geologists as rift valleys. In 2004, over 2 kilograms of Corundum were collected. Another rift, the East African Rift Valley, is still in the phase where it forms a graben that is 'trying' to rip East-Africa apart from the rest of Africa. In the view of many geologists today, the Dead Sea lies in a rift which results from a leftward discontinuity in the left lateral-moving Dead Sea Transform fault. Most of the valley falls within the former Rift Valley Province. The Great Rift Valley is part of an intra-continental ridge system that runs through Kenya from north to south. [5] It overlooks Lake Nakuru to the south. The oldest continental rocks are billions of years old, so the continents have had a lot of time for things to happen to them. Lake Kamnarok is another small lake. When these bends or discontinuities are in the same direction as the relative motions along the fault, extension occurs. This scene is within the East African Rift where the crust is being pulled apart to form a large valley. [6] In the early 1900s, Mount Longonot erupted, and ash can still be felt around Hell's Gate. [7] Mount Longonot is a dormant stratovolcano located southeast of Lake Naivasha. The Kerio Valley lies between the Tugen Hills and the Elgeyo escarpment at an elevation of 1,000 metres (3,300 ft) [3] A rift valley is formed on a divergent plate boundary, a crustal extension or spreading apart of the surface, which is subsequently further deepened by the forces of erosion. In these instances, not only the crust but entire tectonic plates are in the process of breaking apart to create new plates. [6] Þingvallavatn, Iceland's largest natural lake, is also an example of a rift lake. Trough formation through super-isostasy, stress, sedimentation, and subsidence", "Venus tectonics: An overview of Magellan observations", "Birth of Uranus' provocative moon still puzzles scientists", "Voyager 2 in the Uranian System: Imaging Science Results", https://en.wikipedia.org/w/index.php?title=Rift_valley&oldid=997424115, Short description is different from Wikidata, Creative Commons Attribution-ShareAlike License, This page was last edited on 31 December 2020, at 12:44. One of the best known examples of this process is the East African Rift. The climate is mild, with temperatures usually below 28 °C (82 °F). The East African Rift (EAR) is a continental rift valley in Eastern Africa and is a unique type of divergent plate boundary in that it is 1) in its early stages of development and 2) primarily on land. [1] On Earth, rifts can occur at all elevations, from the sea floor to plateaus and mountain ranges in continental crust or in oceanic crust. [8] Lake Magadi is the most southern rift valley lake in Kenya, although the northern end of Lake Natron in Tanzania reaches into Kenya. The shield volcano Emuruangogolak straddles the valley to the south of Suguta, and further south Mount Silali and Paka rise from the valley floor. The Arabian Plate is rifting away from the African plate along an active divergent ridge system, to form the Red Sea and Gulf of Aden. The Suguta Valley, or Suguta Mud Flats, is an arid part of the Great Rift Valley directly south of Lake Turkana. Earth's rift valleys. [3] [9] Eight of these make up the main lakes in the Kenyan Rift Valley. This lake lies mainly in Ethiopia but extends into Kenya in the rainy season. [2] Lake Baikal in Siberia, a World Heritage Site,[3] lies in an active rift valley. Rift definition, an opening made by splitting, cleaving, etc. Visit the Interactive Plate Boundary Map to explore satellite images of divergent boundaries between continental plates. Ancient faults of the Reelfoot Rift have presumably been reactivated to form the complex fault structures seen in the distribution of earthquakes. See more. Many of the world's largest lakes are located in rift valleys. The most prominent example of a continental rift is the East-African Rift Valley and its continuations into the Red Sea and the Gulf of Aden. We know the direction they're moving in. Some of the soils are Andisols, fertile soils from relatively recent volcanic activity. 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. The most extensive rift valley is located along the crest of the mid-ocean ridge system and is the result of sea floor spreading.Examples of this type of rift include the Mid-Atlantic Ridge and the East Pacific Rise.. The relics of many hominids, ancestors of humans, have been found here.[4]. This region also includes Lake Elementaita, Mount Kipipiri and Lake Naivasha. The drop of the center creates the nearly parallel steeply dipping walls of a rift valley when it is new. 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. Continental Rifting - A new divergent plate boundary can form when continental lithosphere stretches, and thins to form a rift valley.