Geomorphology

thumb|upright=1.2|A boat floats on the Mekong in Laos thumb|upright=1.2|South America's Amazon River (dark blue) and the rivers which flow into it (medium blue). The darker green marks the Amazon's [[drainage basin or watershed]]

thumb|upright=1.5|Sand dunes in the [[Rub' al Khali ("Empty quarter") of Arabia]] thumb|upright=1.5|alt=A human with a group of camels in a desert|A camel shepherd near Marrakesh

terrestrial water source

area of land where precipitation collects and drains off into a common outlet, such as into a river, bay, or other body of water

thumb|upright=1.4|Badlands incised into [[shale at the foot of the North Caineville Plateau, Utah, within the pass carved by the Fremont River and known as the Blue Gate. G. K. Gilbert studied the landscapes of this area in great detail, forming the observational foundation for many of his studies on geomorphology.]] thumb|Surface of Earth, showing higher elevations in red

Permafrost () is soil or underwater sediment which continuously remains below for two years or more; the oldest permafrost has been continuously frozen for around 700,000 years. Whilst the shallowest permafrost has a vertical extent of below a meter (3 ft), the deepest is greater than . Similarly, the area of individual permafrost zones may be limited to narrow mountain summits or extend across vast Arctic regions. The ground beneath glaciers and ice sheets is not usually defined as permafrost, so on land, permafrost is generally located beneath a so-called active layer of soil which free

upright=1.2|thumb|A stream bed following a tilted valley. The maximum gradient is along the down-valley axis represented by a hypothetical straight coast channel. Meanders develop, which lengthen the course of the stream, decreasing the gradient. thumb|Meanders of the Cauto River|Rio Cauto at [[Guamo Embarcadero, Cuba]] thumb|The Jordan River, near the [[Dead Sea, 1937]]

thumb|Typical karst terrain of the Dinaric Alps thumb|Li River|Li Jiang fengcong (cone karst) in [[Guilin as part of the South China Karst]] thumb|Karst formation of the Serra de Tramuntana Karst () is a topography formed from the dissolution of soluble carbonate rocks such as limestone and dolomite. It is characterized by features like poljes above and drainage systems with sinkholes and caves underground. There is some evidence that karst may occur in more weathering-resistant rocks such as quartzite given the right conditions.

thumb|right|250px|The snow-free debris hills around the lagoon are lateral and terminal moraines of a valley glacier in [[Manang, Nepal.]] thumb|right|250px|Moraine of the Nanga Parbat North Face Glacier as seen from [[Fairy Meadows, Pakistan.]] thumb|Aerial view of the moraine of the Nanga Parbat North Face Glacier.

line that separates neighbouring drainage basins

thumb|upright=1.3|Land between bodies of water at Point Reyes National Seashore, California|alt=A grassy isthmus running between two bodies of water

thumb|upright=1.35|A natural arch produced by erosion of differentially weathered rock in Jebel Kharaz ([[Jordan)]]

process of wearing down or wearing away of rocks by the hard particles carried by rivers, glaciers, wind and waves

thumb|Cvrcka in Bosnia

valleys formed by glacial scouring

thumb|Niapiskau island, limestone monoliths, Gulf of St. Lawrence, [[Mingan Archipelago National Park Reserve, Canada]] thumb|Uluru, [[Northern Territory, Australia, is often referred to as the biggest monolith. While the surrounding rocks were eroded, the rock survived as sandstone strata making up the surviving Uluru 'monolith'.]] thumb|Monolithos, Greece|Monolithos fortress on [[Rhodes, Greece]] thumb|Landsat 7 image [[Brandberg Mountain, Namibia]] thumb|Pedra da Gávea|Gavea Rock, a monolith next to the sea, near [[Rio de Janeiro, Brazil]] A monolith is a geological feature consisting of a

Isostasy () or isostatic equilibrium is the state of gravitational equilibrium between Earth's crust (or lithosphere) and mantle such that the crust "floats" at an elevation that depends on its thickness and density. This concept is invoked to explain how different topographic heights can exist at Earth's surface. Although originally defined in terms of continental crust and mantle, it has subsequently been interpreted in terms of lithosphere and asthenosphere, particularly with respect to oceanic island volcanoes, such as the Hawaiian Islands.

thumb|right|The Chinle Badlands at Grand Staircase–Escalante National Monument, [[Utah, United States]]

class of space groups, lattices, point groups, or crystals

thumb|upright=1.7| thumb|right|Animation reveals oceanic floors and seabeds. Continental shelves appear mostly by a depth of 140 meters, [[mid-ocean ridges by 3000 meters, and oceanic trenches at depths beyond 6000 meters.]] thumb|right|A seafloor map captured by NASA

Denudation is the geological process 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 was

thumb|Ibyuk pingo near Tuktoyaktuk, northern Canada thumb|View from top of a pingo towards another, within a partly drained lake, the Arctic Ocean in the background (near Tuktoyaktuk). July 20, 1975.

thumb|Cuesta in Italy thumb|Schematic cross section of three cuestas, dip slopes facing left, and harder rock layers in darker colors than softer ones thumb|Cuesta in Crimea thumb| Magaliesberg Range, Transvaal, South Africa

processes due to wind activity

thumb|West and East Mitten Buttes|The Mittens and [[Merrick Butte in Monument Valley, Utah–Arizona]]

thumbnail|An orographic map of Eastern Siberia from 1875 by [[Peter Kropotkin]]

thumb|upright=1.3|The thalweg of a river

the forking of a river into its distributaries

landmass or fluvial landform within a river

in geography, area between high and low tide marks of water bodies (both still and moving), or a raised landform on the side of a water body

thumb|300px|Subsided house, called The Crooked House, the result of 19th-century mining subsidence in [[Staffordshire, England]] thumb|A625 road#Mam Tor road|Mam Tor road destroyed by subsidence and shear, near Castleton, [[Derbyshire]]

thumb|300px|Aerial view of the almost flat and drowned peneplain at Belcher Islands, Hudson Bay, Canada, cutting across numerous [[geologic folds.]]

rise of land masses that were depressed by the huge weight of ice sheets during the last glacial period

pattern formed by the streams, rivers, and lakes in a particular drainage basin

sheetlike body within a rock

loss or displacement of land along a coastline

step-like landform

network of river channels separated by small, and often temporary, islands called braid bars

used for open channel flows

massive volcanic formation resulting from flood basalt eruptions

Suffosion is one of the two geological processes by which subsidence sinkholes or dolines are formed, the other being due to collapse of an underlying cave or void, with most sinkholes formed by the suffosion process. Suffosion sinkholes are normally associated with karst topography although they may form in other types of rock including chalk, gypsum and basalt. In the karst of the UK's Yorkshire Dales, numerous surface depressions known locally as "shakeholes" are the result of glacial till washing into fissures in the underlying limestone.

natural springs that produce water containing minerals

thumb|Schematic of sediment accumulation (aggradation) in a river channel. The sediment is brown. The river is flowing on bedrock in the upper image, but because sediment was deposited over time the riverbed has risen. This has caused the house to be buried in the lower image.

thumb|Felsenmeer in Lautertal-Reichenbach (Odenwald) thumb|Felsenmeer on the Kalmit in the [[Palatine Forest]] thumb|Boulder stream of the Kaser Steinstube near [[Triftern]] thumb|A photo of a single eastern white pine in the nearly barren Boulder Field, [[Hickory Run State Park, PA.]] thumb|Felsenmeer, painting by Egbert Schaap (1912). [[Rijksmuseum Amsterdam]] A blockfield (also spelt block field), felsenmeer, boulder field or stone field is a surface covered by boulder- or block-sized rocks usually associated with a history of volcanic activity, alpine and subpolar climates and periglaciati

thumb|upright=1.15| Diluvial terraces on Katun River Altai Scabland, [[Altai Republic]] thumb|Giant current ripples in the Kuray Basin, Altai, Russia

local toponym in some regions in Croatia, Bosnia and Herzegovina, Montenegro and Serbia for a closed karst depression

geomorphic process by which soil, sand, regolith, and rock move downslope

portion of the total geologic uplift of the mean earth surface that is not attributable to an isostatic response to unloading

geological phenomena in which water-laden masses of soil and fragmented rock rush down mountainsides

300px|thumb|upright=1.4|A group of well developed palsas as seen from above Palsas are peat mounds with a permanently frozen peat and mineral soil core. They are a typical phenomenon in the polar and subpolar zone of discontinuous permafrost. One of their characteristics is having steep slopes that rise above the mire surface. This leads to the accumulation of large amounts of snow around them. The summits of the palsas are free of snow even in winter, because the wind carries the snow and deposits on the slopes and elsewhere on the flat mire surface. Palsas can be up to in diameter and can re

thumb|right|Anabranches at the junction of the Yukon River and the [[Koyukuk River in Alaska, August 24, 1941.]]

ridge formed in pack ice by accumulation of ice blocks in the convergence between floes

geological formation

southwest shield of the East European craton

thumb|Erosion on Koh Tao Island Colluvium (also colluvial material or colluvial soil; from the Latin colluvio 'jumbled') is a general name for loose, unconsolidated terrigenous sediments (diamicton) that have been deposited at the base of hillslopes by either rainwash, sheetwash, slow continuous downslope creep, or a variable combination of these processes. Colluvium is typically composed of a heterogeneous range of rock types and sediments ranging from silt to rock fragments of various sizes. This term is also used to specifically refer to sediment deposited at the base of a hillslope by unco

surface slope along a stream

long, narrow ridge with a narrow crest and steep slopes of nearly equal inclination on both flanks

geomorphological process associated with rivers and streams

thumb|Juda'a Guelta, Hasat Qahtan, Saudi Arabia thumb|Guelta d'Archei, [[Ennedi Plateau, Chad]] A guelta (Arabic: قلتة, also transliterated qalta or galta) is a pocket of water that forms within rock formations in the Sahara Desert and Arabian Desert. The term is of Arabic origin and specifically refers to oases that emerge in rocky landscapes in Arab regions, particularly in countries like Algeria and Saudi Arabia. thumb|Guelta de Tikoubaouine, Tassili n'Ajjer, [[Algeria]] A guelta is a natural water pool that forms in rocky basins and often serves as a crucial water resource in arid regions.

Hypsometry () is the measurement of the elevation and depth of features of Earth's surface relative to mean sea level.