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A dissected plateau is a
Catskill Center
in the United States, the Blue Mountains and Hornsby Plateau in
A dissected plateau is a plateau
In geology and physical geography, a plateau (; ; ), also called a high plain or a tableland, is an area of a highland consisting of flat terrain that is raised sharply above the surrounding area on at least one side. Often one or more sides ...
area that has been severely eroded such that the relief is sharp. Such an area may be referred to as mountainous, but dissected plateaus are distinguishable from orogenic mountain belts by the lack of folding, metamorphism, extensive faulting, or magma
Magma () is the molten or semi-molten natural material from which all igneous rocks are formed. Magma is found beneath the surface of the Earth, and evidence of magmatism has also been discovered on other terrestrial planets and some natura ...
tic activity that accompanies orogeny.
Formation
A dissected plateau may also be formed, or created, usually on a comparatively small scale, by the levelling of terrain by planing and deposition beneath an ice sheet or perhaps, an ice cap. Subsequently, during the same or a later glacial, the margins of theglacial till
image:Geschiebemergel.JPG, Closeup of glacial till. Note that the larger grains (pebbles and gravel) in the till are completely surrounded by the matrix of finer material (silt and sand), and this characteristic, known as ''matrix support'', is d ...
plain are removed by glacier
A glacier (; ) is a persistent body of dense ice that is constantly moving under its own weight. A glacier forms where the accumulation of snow exceeds its ablation over many years, often centuries. It acquires distinguishing features, such a ...
s, leaving the plateau into which erosion by water
Water (chemical formula ) is an inorganic, transparent, tasteless, odorless, and nearly colorless chemical substance, which is the main constituent of Earth's hydrosphere and the fluids of all known living organisms (in which it acts as ...
incises valleys. Such a plateau may be level or gently sloping but may be distinguished by the till caps on its hills. Glacial till is still widely known in Britain by the older name of boulder clay.
Dissected volcanic plateau
A volcanic plateau is a plateau produced by volcanic activity. There are two main types: lava plateaus and pyroclastic plateaus.
Lava plateau
Lava plateaus are formed by highly fluid basaltic lava during numerous successive eruptions thro ...
s include the Pajarito Plateau in New Mexico
)
, population_demonym = New Mexican ( es, Neomexicano, Neomejicano, Nuevo Mexicano)
, seat = Santa Fe, New Mexico, Santa Fe
, LargestCity = Albuquerque, New Mexico, Albuquerque
, LargestMetro = Albuquerque metropolitan area, Tiguex
, Offi ...
, on the skirt of the enormous Valles Caldera. Isolated portions of this plateau are known as mesas, and long, connected portions are known as potreros.
Distribution
The Allegheny Plateau, the Cumberland Plateau, theOzark Plateau
The Ozarks, also known as the Ozark Mountains, Ozark Highlands or Ozark Plateau, is a physiographic region in the U.S. states of Missouri, Arkansas, Oklahoma and the extreme southeastern corner of Kansas. The Ozarks cover a significant por ...
, and the Catskill Mountainsin the United States, the Blue Mountains and Hornsby Plateau in
Australia
Australia, officially the Commonwealth of Australia, is a sovereign country comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands. With an area of , Australia is the largest country by ...
and the Deccan Plateau
The large Deccan Plateau in southern India is located between the Western Ghats and the Eastern Ghats, and is loosely defined as the peninsular region between these ranges that is south of the Narmada river. To the north, it is bounded by th ...
in India
India, officially the Republic of India (Hindi: ), is a country in South Asia. It is the List of countries and dependencies by area, seventh-largest country by area, the List of countries and dependencies by population, second-most populous ...
are examples of dissected plateaus formed after regional uplift.
These older uplifts have been eroded by creeks and river
A river is a natural flowing watercourse, usually freshwater, flowing towards an ocean, sea, lake or another river. In some cases, a river flows into the ground and becomes dry at the end of its course without reaching another body of ...
s to develop steep relief not immediately distinguishable from mountain
A mountain is an elevated portion of the Earth's crust, generally with steep sides that show significant exposed bedrock. Although definitions vary, a mountain may differ from a plateau in having a limited summit area, and is usually higher ...
s.
Many areas of the Allegheny Plateau and the Cumberland Plateau, which are at the western edge of the Appalachian Mountains
The Appalachian Mountains, often called the Appalachians, (french: Appalaches), are a system of mountains in eastern to northeastern North America. The Appalachians first formed roughly 480 million years ago during the Ordovician Period. The ...
of eastern North America
North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and th ...
, are called "mountains" but are actually dissected plateaus. One can stand on the top of one of these high "mountains" and note that all the other tops are nearly the same height, which represents the original elevation profile of the plain
In geography, a plain is a flat expanse of land that generally does not change much in elevation, and is primarily treeless. Plains occur as lowlands along valleys or at the base of mountains, as coastal plains, and as plateaus or uplands ...
before uplift, and thereafter the subsequent weather erosion.
See also
* *, denudational uplands or dissected plateaus in Turkic toponymy ofRussia
Russia (, , ), or the Russian Federation, is a transcontinental country spanning Eastern Europe and Northern Asia. It is the largest country in the world, with its internationally recognised territory covering , and encompassing one-ei ...
and Central Asia
Central Asia, also known as Middle Asia, is a region of Asia that stretches from the Caspian Sea in the west to western China and Mongolia in the east, and from Afghanistan and Iran in the south to Russia in the north. It includes the fo ...
References
{{reflist Plateaus Erosion landforms