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29-669: The Mornos river erodes the Mornos rift valley , which crosses the trough between Parnassos and Pindus geotectonic zones. Those zones are simply mountain chains trending generally NW to SE. They were formed during the Hellenic orogeny , when the mountain zones of Greece were thrust upward in folds due to compression caused by the subduction of the African Plate under the Eurasian Plate . The old subduction zone remains as

58-545: A number of adjoining subsidiary or co-extensive valleys, which are typically considered part of the principal rift valley geologically. 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 . Many existing continental rift valleys are

87-413: A rift which results from a leftward discontinuity in the left lateral-moving Dead Sea Transform fault. Where a fault breaks into two strands, or two faults run close to each other, crustal extension may also occur between them, as a result of differences in their motions. Both types of fault-caused extension commonly occur on a small scale, producing such features as sag ponds or landslides . Many of

116-486: A river in Greece is a stub . You can help Misplaced Pages by expanding it . Rift valley A rift valley is a linear shaped lowland between several highlands or mountain ranges produced by the action of a geologic rift . Rifts are formed as a result of the pulling apart of the lithosphere due to extensional tectonics . The linear depression may subsequently be further deepened by the forces of erosion. More generally

145-1364: Is a local government area in the Scottish Highlands and Britain's largest local government area. Other highland or upland areas reaching 400 m or higher in the United Kingdom include the Southern Uplands in Scotland, the Pennines , North York Moors , Dartmoor and Exmoor in England , and the Cambrian Mountains in Wales . Many countries and regions also have areas referred to as highlands . These include parts of Afghanistan , Tibet , Ethiopia , Canada , Kenya , Eritrea , Yemen , Ghana , Nigeria , Papua New Guinea , Syria , Turkey and Cantabria . Similar terms used in other countries include high country , used in New Zealand , New South Wales , Victoria , Tasmania and Southern Queensland in Australia , and parts of

174-568: Is a prominent example. 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. A recent study suggests a complex system of ancient lunar rift valleys, including Vallis Rheita and Vallis Alpes . The Uranus system also has prominent examples, with large 'chasma' believed to be giant rift valley systems, most notably

203-460: Is believed by planetary geologists to be a large rift system. Some features of Venus, most notably, the 4,000 km Devana Chasma and a part of the western Eistla, and possibly also Alta and Bell Regio have been interpreted by some planetary geologists as rift valleys. Some natural satellites also have prominent rift valleys. The 2,000 km long Ithaca Chasma on Tethys in the Saturn system

232-670: Is one of the most intense on Earth. In addition to causing the main fault, the stress of extension relieved itself over a number of smaller approximately parallel subfaults within the Corinth Basin and to the north of it. One of these is the Amphissa-Arachova fault system, containing the Delphi fault, and creating the Pleistos rift valley. Further west is the Mornos fault, creating the Mornos rift valley, still separated from

261-613: Is the Central Highlands area, which covers most of the central-western parts of the state. Many of these areas are highly elevated alpine regions. The Ozarks cover nearly 120,000 square kilometres (46,000 sq mi), making it the most extensive highland region between the Appalachians and Rockies. This region contains some of the oldest rocks in North America. The spine of the mountains stretches across

290-640: Is usually reserved for ranges of low mountains . However, the two terms are interchangeable and also include regions that are transitional between hilly and mountainous terrain. Probably the best-known area officially or unofficially referred to as highlands in the Anglosphere is the Scottish Highlands in northern Scotland , the mountainous region north and west of the Highland Boundary Fault . The Highland council area

319-460: The Hellenic trench . The zones closest to the subduction are the outer Hellenides, where Hellenides is the geologic term for the mountains of Greece. The inner Hellenides are further east. Some compression continues today. However, in the Miocene (23-5 Ma) another geologic regime began, the extensional , as part of a process called back-arc extension . In this regime, not yet totally understood,

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348-655: The United States (notably Western North Carolina ), highveld , used in South Africa and Roof of the World , used for Tibet . The central Afghan highlands are in the center of Afghanistan , mostly located between 2,000 and 3,000 m above sea level. They have a very cold winter, and a short and cool summer. These highlands have mountain pastures during summer ( sardsīr ), watered by many small streams and rivers. There are also pastures available during winter in

377-443: The 1492 km long Messina Chasma on Titania, 622 km Kachina Chasmata on Ariel, Verona Rupes on Miranda, and Mommur Chasma on Oberon. Highland Highlands or uplands are areas of high elevation such as a mountainous region, elevated mountainous plateau or high hills . Generally, upland refers to a range of hills, typically from 300 m (980 ft) up to 600 m (2,000 ft), while highland

406-834: The compression zone, opened the Aegean Sea starting in the Miocene, and the Corinth rift along the Corinth fault, a normal one, starting less than 2 Ma in the Pleistocene (5-3 Ma). As a result of this "pull-apart" stress across the outer Hellenides, the Gulf of Corinth and its extension on the west, the Gulf of Patras, divided the Peloponnesus from the mainland and moved it south. The seismic zone created by all this deformation

435-540: The creation of the lake. The Mornos aqueduct is the sole conduit of water extending the entire distance from the reservoir to the processing stations of north Attica. That distance is 110 kilometres (68 mi), which is not exactly straight, but curves generally to the south and is positioned to take best advantage of the terrain. Because of the mountains, an aqueduct of this magnitude was impossible to ancient engineers, who constructed many effective aqueducts marvelous for their times. some of which stand partially yet. What

464-653: The endemic vertebrates are restricted to this ecoregion. The highlands of Iceland cover about 40% of the country and are mostly inhospitable to humans. They are generally considered to be any land above 500 m. The mountainous natural region of the Thai highlands is found in Northern Thailand. The Cameron Highlands is a highland area and hill station in Northern Malaysia. Shillong in India in

493-605: The island of New Guinea, forming the densely populated highlands of Papua New Guinea , and the Highland Papua , Indonesia . The Central Highlands of Sri Lanka are rain forests, where the elevation reaches 2,500 m (8,200 ft) above sea level. The Sri Lanka montane rain forests represent the montane and submontane moist forests above 1,000 m (3,300 ft) in the central highlands and in the Knuckles mountain range . Half of Sri Lanka's endemic flowering plants and 51 percent of

522-677: The largest freshwater lake by area, lies in the ancient and dormant Midcontinent Rift . The largest subglacial lake, Lake Vostok , may also lie in an ancient rift valley. Lake Nipissing and Lake Timiskaming in Ontario and Quebec , Canada lie inside a rift valley called the Ottawa-Bonnechere Graben . Þingvallavatn , Iceland's largest natural lake, is also an example of a rift lake. Rift valleys are also known to occur on other terrestrial planets and natural satellites. The 4,000 km long Valles Marineris on Mars

551-542: The moderns have that the ancients did not are the modern methods of tunneling. The aqueduct runs through 15 tunnels for a distance of 71 kilometres (44 mi). Due to modern tunneling machines and laser measurement devices no mountain is beyond the capability of the engineers. The method of transport is still gravity feed , the cheapest and most reliable in case of disaster. There is no need now for arched aerial structures porting water across valleys. Modern conduits go underground through steel and concrete structures far below

580-575: The neighboring warm lowlands ( garmsīr ), which makes the region ideal for seasonal transhumance . The highlands in Australia are often above the elevation of 500 m. These areas often receive snowfall in winter. Most of the highlands lead up to large alpine or sub-alpine mountainous regions such as the Australian Alps , Snowy Mountains , Great Dividing Range , Northern Tablelands and Blue Mountains . The most mountainous region of Tasmania

609-483: The overriding plate behind the arc raised by the subduction, termed the " back arc ," began to extend itself, pushing the arc, here the Hellenic arc , back over the subduction, causing what is known as "slab-rollback," in which the actual line of subduction moves in a direction opposite to the subduction even while the latter is still subducting and compressing. This extension in the back-arc region, causing normal faults , even while reverse faults are still collecting in

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638-695: The result of a failed arm ( aulacogen ) of a triple junction , although there are three, the East African Rift , Rio Grande rift and the Baikal Rift Zone , which are currently active, as well as a fourth which may be, the West Antarctic Rift System . In these instances, not only the crust but entire tectonic plates are in the process of breaking apart forming new plates. If they continue, continental rifts will eventually become oceanic rifts. Other rift valleys are

667-475: The result of bends or discontinuities in horizontally-moving (strike-slip) faults. When these bends or discontinuities are in the same direction as the relative motions along the fault, extension occurs. For example, for a right lateral-moving fault, a bend to the right will result in stretching and consequent subsidence in the area of the irregularity. In the view of many geologists today, the Dead Sea lies in

696-399: The soil is very compact. Monitored by GPS , the dam has a low rate of deformation and is considered one of the more stable in Greece. The fact that the dam is located in a region of high seismicity causes some concern and results in a higher level of monitoring. The lake has shrunk because of high temperatures and the lack of water, leading to the reemergence of Kallio , a village submerged by

725-535: The state of Meghalaya is a hill station that is surrounded by highlands. Officers of the British Raj referred to Shillong as "The Scotland of the East". Highland continents —or terrae —are areas of topographically unstable terrain , with high peaks and valleys. They resemble highlands on Earth , but the term is applied to much larger areas on other planets. They can be found on Mercury , Venus , Mars , and

754-403: The valley is likely to be filled with sedimentary deposits derived from the rift flanks and the surrounding areas. In many cases rift lakes are formed. One of the best known examples of this process is the East African Rift . On Earth, rifts can occur at all elevations, from the sea floor to plateaus and mountain ranges in continental crust or in oceanic crust . They are often associated with

783-589: The valley to the east by mountains of the outer Hellenides. Mornos Lake was created as a reservoir for the city of Athens , which is populated by about 3.1 million people, representing about 40% of the population of Greece. To create it, a simple earthen embankment was placed across the Mornos River in Central Greece at 38°31′37.1″N 22°07′14.7″E  /  38.526972°N 22.120750°E  / 38.526972; 22.120750 . Though of earth,

812-482: The valley. For example, the Mornos aqueduct crosses the Pleistos valley at Delphi, but none of it is observable to the visitor, as it is deep underground. It was thought more practical to place the tunnel below the karst imperfections near the surface, as their irregularities would place variable stresses on the structure, facilitating topical wear and tear and creating ruptures. [REDACTED] Media related to Mornos at Wikimedia Commons This article related to

841-611: The world's largest lakes are located in rift valleys. Lake Baikal in Siberia , a World Heritage Site , lies in an active rift valley. Baikal is both the deepest lake in the world and, with 20% of all of the liquid freshwater on earth, has the greatest volume. Lake Tanganyika , second by both measures, is in the Albertine Rift , the westernmost arm of the active East African Rift . Lake Superior in North America ,

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