Dissected plateau

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View of the dissected plateau at Chapada Diamantina, Brazil. A melhor hora para visitar o morro e ao entardecer.JPG
View of the dissected plateau at Chapada Diamantina, Brazil.
Shaded relief map of Cumberland Plateau and Ridge and Valley Appalachians on the Virginia/West Virginia border WV plateau.jpg
Shaded relief map of Cumberland Plateau and Ridge and Valley Appalachians on the Virginia/West Virginia border

A dissected plateau is a plateau 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 magmatic activity that accompanies orogeny.

Contents

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.[ citation needed ]

Subsequently, during the same or a later glacial, the margins of the glacial till plain are removed by glaciers, leaving the plateau into which erosion by water 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.[ citation needed ]

Dissected volcanic plateaus include the Pajarito Plateau in New Mexico, on the skirt of the enormous Valles Caldera. [1] Isolated portions of this plateau are known as mesas, and long, connected portions are known as potreros.

Distribution

The Allegheny Plateau, [2] the Cumberland Plateau, [3] the Ozark Plateau, [4] and the Catskill Mountains [5] in the United States, the Blue Mountains and Hornsby Plateau in Australia and the Deccan Plateau in India are examples of dissected plateaus formed after regional uplift.[ citation needed ]

These older uplifts have been eroded by creeks and rivers to develop steep relief not immediately distinguishable from mountains.[ citation needed ]

Many areas of the Allegheny Plateau and the Cumberland Plateau, which are at the western edge of the Appalachian Mountains of eastern North America, 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 before uplift, and thereafter the subsequent weather erosion.[ citation needed ]

See also

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Intermontane Plateaus

In the context of physical geography, the Intermontane Plateaus is one of eight physiographic regions of the contiguous United States. The region consists mostly of plateaus and mountain ranges lying between the Rocky Mountains on the east and the Cascade and Sierra Nevada Mountains on the west. It is subdivided into three physiographic provinces: the Columbia Plateau in the north, the Basin and Range Province in the central and southwestern portions, and the Colorado Plateau in the southeast. In turn, each of these provinces are each subdivided into a number of physiographic sections.

Landforms are categorized by characteristic physical attributes such as their creating process, shape, elevation, slope, orientation, rock exposure, and soil type.

<span class="mw-page-title-main">Mesa</span> Elevated area of land with a flat top and sides that are usually steep cliffs

A mesa is an isolated, flat-topped elevation, ridge or hill, which is bounded from all sides by steep escarpments and stands distinctly above a surrounding plain. Mesas characteristically consist of flat-lying soft sedimentary rocks capped by a more resistant layer or layers of harder rock, e.g. shales overlain by sandstones. The resistant layer acts as a caprock that forms the flat summit of a mesa. The caprock can consist of either sedimentary rocks such as sandstone and limestone; dissected lava flows; or a deeply eroded duricrust. Unlike plateau, whose usage does not imply horizontal layers of bedrock, e.g. Tibetan Plateau, the term mesa applies exclusively to the landforms built of flat-lying strata. Instead, flat-topped plateaus are specifically known as tablelands.

Catskill Mountains Mountains in southeastern New York State, U.S.

The Catskill Mountains, also known as the Catskills, are a physiographic province of the larger Appalachian Mountains, located in southeastern New York. As a cultural and geographic region, the Catskills are generally defined as those areas close to or within the borders of the Catskill Park, a 700,000-acre (2,800 km2) forest preserve protected from many forms of development under New York state law.

Plateau Highland area, usually of relatively flat terrain

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 have deep hills or escarpments. Plateaus can be formed by a number of processes, including upwelling of volcanic magma, extrusion of lava, and erosion by water and glaciers. Plateaus are classified according to their surrounding environment as intermontane, piedmont, or continental. A few plateaus may have a small flat top while others have wide ones.

Geology of the United States National geology

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Cumberland Plateau Plateau in the United States

The Cumberland Plateau is the southern part of the Appalachian Plateau in the Appalachian Mountains of the United States. It includes much of eastern Kentucky and Tennessee, and portions of northern Alabama and northwest Georgia. The terms "Allegheny Plateau" and the "Cumberland Plateau" both refer to the dissected plateau lands lying west of the main Appalachian Mountains. The terms stem from historical usage rather than geological difference, so there is no strict dividing line between the two. Two major rivers share the names of the plateaus, with the Allegheny River rising in the Allegheny Plateau and the Cumberland River rising in the Cumberland Plateau in Harlan County, Kentucky.

Allegheny Plateau Dissected plateau in the eastern United States

The Allegheny Plateau, in the United States, is a large dissected plateau area of the Appalachian Mountains in western and central New York, northern and western Pennsylvania, northern and western West Virginia, and eastern Ohio. It is divided into the unglaciated Allegheny Plateau and the glaciated Allegheny Plateau.

Ridge-and-Valley Appalachians Physiographic province of the larger Appalachian division

The Ridge-and-Valley Appalachians, also called the Ridge and Valley Province or the Valley and Ridge Appalachians, are a physiographic province of the larger Appalachian division and are also a belt within the Appalachian Mountains extending from southeastern New York in the north through northwestern New Jersey, westward into Pennsylvania through the Lehigh Valley, and southward into Maryland, West Virginia, Virginia, Kentucky, Tennessee, Georgia, and Alabama. They form a broad arc between the Blue Ridge Mountains and the Appalachian Plateau physiographic province. They are characterized by long, even ridges, with long, continuous valleys in between.

<span class="mw-page-title-main">Glaciated Allegheny Plateau</span>

The Glaciated Allegheny Plateau is that portion of the Allegheny Plateau that lies within the area covered by the last glaciation. As a result, this area of the Allegheny Plateau has lower relief and gentler slopes than the relatively rugged Unglaciated Allegheny Plateau. In general, the glaciated lies to the north and west of the unglaciated, and forms an arc in northeastern to southeastern Ohio lying between the glacial till plains and the Unglaciated Allegheny Plateau. The Glaciated Allegheny Plateau extends into a belt of southern New York State and the central Susquehanna River basin.

Allegheny Front Major escarpment in the Allegheny Mountains

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Alleghanian orogeny Mountain-forming event that formed the Appalachian and Allegheny Mountains

The Alleghanian orogeny or Appalachian orogeny is one of the geological mountain-forming events that formed the Appalachian Mountains and Allegheny Mountains. The term and spelling Alleghany orogeny was originally proposed by H.P. Woodward in 1957.

Endless Mountains Mountainous region in northeast Pennsylvania

The Endless Mountains are a geographical, geological, and cultural region in Northeastern Pennsylvania. The Endless Mountains region includes Bradford, Sullivan, Susquehanna, and Wyoming counties. The highest peak in the region is the North Knob of Elk Mountain at 2693 feet.

Appalachian Plateau Series of rugged dissected plateaus in the eastern United States

The Appalachian Plateau is a series of rugged dissected plateaus located on the western side of the Appalachian Mountains. The Appalachian Mountains are a mountain range that run down the Eastern United States. The Appalachian Plateau is the northwestern part of the Appalachian Mountains, stretching from New York to Alabama. The plateau is a second level United States physiographic region, covering parts of the states of New York, Pennsylvania, Ohio, Maryland, West Virginia, Virginia, Kentucky, Tennessee, Alabama, and Georgia.

Geology of Pennsylvania Overview of the geology of the U.S. state of Pennsylvania

The Geology of Pennsylvania consists of six distinct physiographic provinces, three of which are subdivided into different sections. Each province has its own economic advantages and geologic hazards and plays an important role in shaping everyday life in the state. They are: the Atlantic Coastal Plain Province, the Piedmont Province, the New England Province, the Ridge and Valley Province, the Appalachian Plateau Province, and the Central Lowlands Province.

Scandinavian Mountains Mountain range in Finland, Norway and Sweden

The Scandinavian Mountains or the Scandes is a mountain range that runs through the Scandinavian Peninsula. The western sides of the mountains drop precipitously into the North Sea and Norwegian Sea, forming the fjords of Norway, whereas to the northeast they gradually curve towards Finland. To the north they form the border between Norway and Sweden, reaching 2,000 metres (6,600 ft) high at the Arctic Circle. The mountain range just touches northwesternmost Finland but are scarcely more than hills at their northernmost extension at the North Cape.

Paleic surface Erosion surface in Southern Norway

The paleic surface or palaeic surface is an erosion surface of gentle slopes that exist in South Norway. Parts of it are a continuation of the Sub-Cambrian peneplain and Muddus Plains found further east or equivalent to the strandflat coastal plains of Norway. Hardangervidda, a particularly flat and elevated part of the Paleic surface formed in the Miocene at sea level.

References

  1. Mathien, Frances Joan; Steen, Charlie R.; Allen, Craig D. (1993). The Pajarito Plateau: A bibliography (PDF). Professional Paper. Southwest Cultural Resources Center.
  2. Jones, Stephen B.1; Saviello, Thomas B A Field Guide to Site Quality for the Allegheny Hardwood Region Archived 2012-10-04 at the Wayback Machine Northern Journal of Applied Forestry, Volume 8, Number 1, 1 March 1991, pp. 3–8(6)
  3. PHYSIOGRAPHY Wayne L. Newell
  4. "The Ozarks Chronicle". Archived from the original on 2008-04-03. Retrieved 2007-12-19.
  5. Catskill Center Archived 2009-10-29 at the Wayback Machine