Landform

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This conical hill in Salar de Arizaro, Salta, Argentina called Cono de Arita constitutes a landform. Cono de Arita, Salta. (Argentina).jpg
This conical hill in Salar de Arizaro, Salta, Argentina called Cono de Arita constitutes a landform.

A landform is a natural or anthropogenic [1] [2] land feature on the solid surface of the Earth or other planetary body. Landforms together make up a given terrain, and their arrangement in the landscape is known as topography. Landforms include hills, mountains, canyons, and valleys, as well as shoreline features such as bays, peninsulas, and seas, [3] including submerged features such as mid-ocean ridges, volcanoes, and the great ocean basins.

Contents

Physical characteristics

Landforms are categorized by characteristic physical attributes such as elevation, slope, orientation, structure stratification, rock exposure, and soil type. Gross physical features or landforms include intuitive elements such as berms, mounds, hills, ridges, cliffs, valleys, rivers, peninsulas, volcanoes, and numerous other structural and size-scaled (e.g. ponds vs. lakes, hills vs. mountains) elements including various kinds of inland and oceanic waterbodies and sub-surface features. Mountains, hills, plateaux, and plains are the four major types of landforms. Minor landforms include buttes, canyons, valleys, and basins. Tectonic plate movement under the Earth can create landforms by pushing up mountains and hills.

Cades Cove Panorama.JPG
Panorama of Great Smoky Mountains National Park showing physical features of a rolling plain, actually part of a broad valley, distant foothills, and a backdrop of the old, much weathered Appalachian mountain range

Hierarchy of classes

Karst tower landforms along Lijiang River, Guilin, China 1 li jiang guilin yangshuo 2011.jpg
Karst tower landforms along Lijiang River, Guilin, China

Oceans and continents exemplify the highest-order landforms.[ citation needed ] Landform elements are parts of a high-order landforms that can be further identified and systematically given a cohesive definition such as hill-tops, shoulders, saddles, foreslopes and backslopes.

Some generic landform elements including: pits, peaks, channels, ridges, passes, pools and plains.

Terrain (or relief) is the third or vertical dimension of land surface. Topography is the study of terrain, although the word is often used as a synonym for relief itself. When relief is described underwater, the term bathymetry is used. In cartography, many different techniques are used to describe relief, including contour lines and triangulated irregular networks.

Elementary landforms (segments, facets, relief units) are the smallest homogeneous divisions of the land surface, at the given scale/resolution. These are areas with relatively homogeneous morphometric properties, bounded by lines of discontinuity. A plateau or a hill can be observed at various scales, ranging from a few hundred meters to hundreds of kilometers. Hence, the spatial distribution of landforms is often scale-dependent, as is the case for soils and geological strata.

A number of factors, ranging from plate tectonics to erosion and deposition (also due to human activity), can generate and affect landforms. Biological factors can also influence landforms—for example, note the role of vegetation in the development of dune systems and salt marshes, and the work of corals and algae in the formation of coral reefs.

Landforms do not include several man-made features, such as canals, ports and many harbors; and geographic features, such as deserts, forests, and grasslands. Many of the terms are not restricted to refer to features of the planet Earth, and can be used to describe surface features of other planets and similar objects in the Universe. Examples are mountains, hills, polar caps, and valleys, which are found on all of the terrestrial planets.

The scientific study of landforms is known as geomorphology.

In onomastic terminology, toponyms (geographical proper names) of individual landform objects (mountains, hills, valleys, etc.) are called oronyms . [4]

Recent developments

Landforms may be extracted from a digital elevation model (DEM) using some automated techniques where the data has been gathered by modern satellites and stereoscopic aerial surveillance cameras. [5] Until recently, compiling the data found in such data sets required time consuming and expensive techniques involving many man-hours. The most detailed DEMs available are measured directly using LIDAR techniques.

See also

Related Research Articles

<span class="mw-page-title-main">Erosion</span> Natural processes that remove soil and rock

Erosion is the action of surface processes that removes soil, rock, or dissolved material from one location on the Earth's crust and then transports it to another location where it is deposited. Erosion is distinct from weathering which involves no movement. Removal of rock or soil as clastic sediment is referred to as physical or mechanical erosion; this contrasts with chemical erosion, where soil or rock material is removed from an area by dissolution. Eroded sediment or solutes may be transported just a few millimetres, or for thousands of kilometres.

<span class="mw-page-title-main">Karst</span> Topography from dissolved soluble rocks

Karst is a topography formed from the dissolution of soluble carbonate rocks such as limestone, dolomite, and gypsum. It is characterized by features like poljes above and drainage systems with sinkholes and caves underground. More weathering-resistant rocks, such as quartzite, can also occur, given the right conditions.

<span class="mw-page-title-main">Physical geography</span> Study of processes and patterns in the natural environment

Physical geography is one of the three main branches of geography. Physical geography is the branch of natural science which deals with the processes and patterns in the natural environment such as the atmosphere, hydrosphere, biosphere, and geosphere. This focus is in contrast with the branch of human geography, which focuses on the built environment, and technical geography, which focuses on using, studying, and creating tools to obtain, analyze, interpret, and understand spatial information. The three branches have significant overlap, however.

<span class="mw-page-title-main">Digital elevation model</span> 3D computer-generated imagery and measurements of terrain

A digital elevation model (DEM) or digital surface model (DSM) is a 3D computer graphics representation of elevation data to represent terrain or overlaying objects, commonly of a planet, moon, or asteroid. A "global DEM" refers to a discrete global grid. DEMs are used often in geographic information systems (GIS), and are the most common basis for digitally produced relief maps. A digital terrain model (DTM) represents specifically the ground surface while DEM and DSM may represent tree top canopy or building roofs.

<span class="mw-page-title-main">Geomorphology</span> Scientific study of landforms

Geomorphology is the scientific study of the origin and evolution of topographic and bathymetric features generated by physical, chemical or biological processes operating at or near Earth's surface. Geomorphologists seek to understand why landscapes look the way they do, to understand landform and terrain history and dynamics and to predict changes through a combination of field observations, physical experiments and numerical modeling. Geomorphologists work within disciplines such as physical geography, geology, geodesy, engineering geology, archaeology, climatology, and geotechnical engineering. This broad base of interests contributes to many research styles and interests within the field.

<span class="mw-page-title-main">Inselberg</span> Isolated, steep rock hill on relatively flat terrain

An inselberg or monadnock is an isolated rock hill, knob, ridge, or small mountain that rises abruptly from a gently sloping or virtually level surrounding plain. In Southern Africa a similar formation of granite is known as a koppie, an Afrikaans word from the Dutch diminutive word kopje. If the inselberg is dome-shaped and formed from granite or gneiss, it can also be called a bornhardt, though not all bornhardts are inselbergs. An inselberg results when a body of rock resistant to erosion, such as granite, occurring within a body of softer rocks, is exposed by differential erosion and lowering of the surrounding landscape.

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">Gully</span> Landform created by running water and/or mass movement eroding sharply into soil

A gully is a landform created by running water, mass movement, or commonly a combination of both eroding sharply into soil or other relatively erodible material, typically on a hillside or in river floodplains or terraces. Gullies resemble large ditches or small valleys, but are metres to tens of metres in depth and width, are characterized by a distinct 'headscarp' or 'headwall' and progress by headward erosion. Gullies are commonly related to intermittent or ephemeral water flow, usually associated with localised intense or protracted rainfall events or snowmelt. Gullies can be formed and accelerated by cultivation practices on hillslopes in farmland, and they can develop rapidly in rangelands from existing natural erosion forms subject to vegetative cover removal and livestock activity.

<span class="mw-page-title-main">Terrain</span> Vertical and horizontal dimension and shape of land surface

Terrain or relief involves the vertical and horizontal dimensions of land surface. The term bathymetry is used to describe underwater relief, while hypsometry studies terrain relative to sea level. The Latin word terra means "earth."

<span class="mw-page-title-main">Ridge</span> Long, narrow, elevated landform

A ridge is a long, narrow, elevated geomorphologic landform, structural feature, or a combination of both separated from the surrounding terrain by steep sides. The sides of a ridge slope away from a narrow top, the crest or ridgecrest, with the terrain dropping down on either side. The crest, if narrow, is also called a ridgeline. Limitations on the dimensions of a ridge are lacking. Its height above the surrounding terrain can vary from less than a meter to hundreds of meters. A ridge can be either depositional, erosional, tectonic, or a combination of these in origin and can consist of either bedrock, loose sediment, lava, or ice depending on its origin. A ridge can occur as either an isolated, independent feature or part of a larger geomorphological and/or structural feature. Frequently, a ridge can be further subdivided into smaller geomorphic or structural elements.

Denudation is the geological processes in which moving water, ice, wind, and waves erode the Earth's surface, leading to a reduction in elevation and in relief of landforms and landscapes. Although the terms erosion and denudation are used interchangeably, erosion is the transport of soil and rocks from one location to another, and denudation is the sum of processes, including erosion, that result in the lowering of Earth's surface. Endogenous processes such as volcanoes, earthquakes, and tectonic uplift can expose continental crust to the exogenous processes of weathering, erosion, and mass wasting. The effects of denudation have been recorded for millennia but the mechanics behind it have been debated for the past 200 years and have only begun to be understood in the past few decades.

<span class="mw-page-title-main">Glaciokarst</span>

Glaciokarst is a geological term that refers to a specific type of karst landscape that been influenced significantly by past glacial activity.

<span class="mw-page-title-main">Morphotectonics</span>

Morphotectonics, or tectonic geomorphology, is a branch of geomorphology that studies how landforms are formed or affected by tectonic activity. Morphotectonists seek to understand the deep Earth mechanisms behind the creation of tectonic landforms by processes such as crust uplift, subsidence, faulting, or folding.

Geomorphometry, or geomorphometrics, is the science and practice of measuring the characteristics of terrain, the shape of the surface of the Earth, and the effects of this surface form on human and natural geography. It gathers various mathematical, statistical and image processing techniques that can be used to quantify morphological, hydrological, ecological and other aspects of a land surface. Common synonyms for geomorphometry are geomorphological analysis, terrain morphometry, terrain analysis, and land surface analysis. Geomorphometrics is the discipline based on the computational measures of the geometry, topography and shape of the Earth's horizons, and their temporal change. This is a major component of geographic information systems (GIS) and other software tools for spatial analysis.

<span class="mw-page-title-main">Coastal engineering</span> Branch of civil engineering

Coastal engineering is a branch of civil engineering concerned with the specific demands posed by constructing at or near the coast, as well as the development of the coast itself.

<span class="mw-page-title-main">Hornito</span> Conical structures built up by lava ejected through an opening in the crust of a lava flow

Hornitos are conical, or pipe-like, structures built up by lava spattering or being ejected through an opening in the crust of a lava flow. Hornitos are similar to spatter cones but are rootless, meaning they were once a source of lava but that source was not directly associated with a true vent or magma source. They are usually created by the slow upwelling of fluid lava through the roof of a lava tube, and are often associated with pahoehoe lavas of basaltic composition. High pressure causes lava to ooze and spatter out. The lava builds up on the surface and solidifies creating the initial structure. Hornitos can grow and exceed 10 meters in height.

<span class="mw-page-title-main">Planetary science</span> Science of planets and planetary systems

Planetary science is the scientific study of planets, celestial bodies and planetary systems and the processes of their formation. It studies objects ranging in size from micrometeoroids to gas giants, aiming to determine their composition, dynamics, formation, interrelations and history. It is a strongly interdisciplinary field, which originally grew from astronomy and Earth science, and now incorporates many disciplines, including planetary geology, cosmochemistry, atmospheric science, physics, oceanography, hydrology, theoretical planetary science, glaciology, and exoplanetology. Allied disciplines include space physics, when concerned with the effects of the Sun on the bodies of the Solar System, and astrobiology.

<span class="mw-page-title-main">Norrland terrain</span> Geomorphic unit covering northern Sweden

Norrland terrain is a geomorphic unit covering the bulk of Norrland and the northwestern half of Svealand. Except for The High Coast the coastal areas of Norrland do not belong to the Norrland terrain. The southern and eastern boundary of the Norrland terrain is made up of geological faults that disrupt the Sub-Cambrian peneplain found the lowlands. In some locations these faults have been extensively eroded making the Norrland terrain boundary partly a result of erosion. Karna Lidmar-Bergström categorizes the Norrland Terrain into the following classes:

  1. Highlands with well developed valleys above 500 m.a.s.l.
  2. Plains with residual hills of Northern Sweden
  3. Undulating hilly land of Övertorneå/Överkalix
  4. Undulating hilly land of Boden area
  5. Large scale joint valley landscapes
  6. Plains with residual hills of Dalarna
  7. Undulating hilly land of central Sweden
<span class="mw-page-title-main">Paleoshoreline</span> Shoreline which existed in the geologic past

A paleoshoreline is a shoreline that existed in the geologic past. A perched coastline is an ancient (fossil) shoreline positioned above the present shoreline.

<span class="mw-page-title-main">Geomorphosite</span> Landform of scientific or social value

A geomorphosite, or geomorphological heritage site, is a landform or an assemblage of landforms that have a scientific, educational, historic-cultural, aesthetic or socio-economic value.

References

  1. Szabó, József; Dávid, Lóránt; Lóczy, Dénes, eds. (2010). Anthropogenic Geomorphology. doi:10.1007/978-90-481-3058-0. ISBN   978-90-481-3057-3. S2CID   251582329.
  2. Howard, Jeffrey (2017), Howard, Jeffrey (ed.), "Anthropogenic Landforms and Soil Parent Materials", Anthropogenic Soils, Progress in Soil Science, Cham: Springer International Publishing, pp. 25–51, doi:10.1007/978-3-319-54331-4_3, ISBN   978-3-319-54331-4 , retrieved 2022-08-12
  3. "Landform". National Geographic . Archived from the original on 11 October 2023.
  4. Room 1996, p. 75.
  5. Robert A. MacMillan; David H. McNabb; R. Keith Jones (September 2000). "Conference paper: "Automated landform classification using DEMs"" . Retrieved 2008-06-26.

Igstar, cxvellie (2017), Howard, Jeffrey (ed.), "Anthropogenic Landforms and Soil Parent Materials", Anthropogenic Soils, Progress in Soil Science, Cham: Springer International Publishing, pp. 25–51, doi:10.1007/978-3-319-54331-4_3, ISBN 978-3-319-54331-4, retrieved 2022-08-12

Sources

Further reading