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incised into
shale Shale is a fine-grained, clastic sedimentary rock, formed from mud that is a mix of flakes of clay minerals and tiny fragments (silt-sized particles) of other minerals, especially quartz and calcite.Blatt, Harvey and Robert J. Tracy (1996) ''Petr ...

shale
at the foot of the North Caineville Plateau, Utah, within the pass carved by the
Fremont River Fremont River is long river in southeastern Utah, United States that flows from the Johnson Valley Reservoir, which is located on the Wasatch Plateau near Fish Lake, southeast through Capitol Reef National Park to the Muddy Creek near Hanksville w ...

Fremont River
and known as the Blue Gate.
GK Gilbert
GK Gilbert
studied the landscapes of this area in great detail, forming the observational foundation for many of his studies on geomorphology. Geomorphology (from
Ancient Greek Ancient Greek includes the forms of the Greek language used in ancient Greece and the ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Dark Ages (), the Archaic period ...

Ancient Greek
:
γῆ
γῆ
, ''gê'', "earth";
μορφή
μορφή
, ''morphḗ'', "form"; and λόγος, ''
lógos
lógos
'', "study") is the scientific study of the origin and evolution of
topographic Topography is the study of the forms and features of land surfaces. The topography of an area could refer to the surface forms and features themselves, or a description (especially their depiction in maps). Topography is a field of geoscience ...

topographic
and
bathymetric Bathymetry (pronounced ) is the study of underwater depth of ocean floors or lake floors. In other words, bathymetry is the underwater equivalent to hypsometry or topography. The name comes from Greek βαθύς (''bathus''), "deep", and μέτρ ...

bathymetric
features created by physical, chemical or biological processes operating at or near the Earth's surface. Geomorphologists seek to understand why
landscape A landscape is the visible features of an area of land, its landforms, and how they integrate with natural or man-made features.''New Oxford American Dictionary''. A landscape includes the physical elements of geophysically defined landforms su ...

landscape
s look the way they do, to understand
landform A landform is a natural or artificial feature of 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 ...

landform
and
terrain Relief map of Sierra Nevada, Spain Terrain or relief (also topographical relief) involves the vertical and horizontal dimensions of land surface. The term bathymetry is used to describe underwater relief, while hypsometry studies terrain rel ...

terrain
history and dynamics and to predict changes through a combination of field observations, physical experiments and
numerical modeling
numerical modeling
. Geomorphologists work within disciplines such as
physical geography Physical geography (also known as physiography) is one of the two fields 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, hydrospher ...

physical geography
,
geology Geology (from the Ancient Greek γῆ, ''gē'' ("earth") and -λoγία, ''-logia'', ("study of", "discourse")) is an Earth science concerned with the solid Earth, the rocks of which it is composed, and the processes by which they change over t ...

geology
,
geodesy Geodesy () is the Earth science of accurately measuring and understanding Earth's geometric shape, orientation in space and gravitational field. The field also incorporates studies of how these properties change over time and equivalent measure ...

geodesy
,
engineering geology Engineering geology is the application of geology to engineering study for the purpose of assuring that the geological factors regarding the location, design, construction, operation and maintenance of engineering works are recognized and account ...

engineering geology
,
archaeology Archaeology or archeology is the study of human activity through the recovery and analysis of material culture. Archaeology is often considered a branch of socio-cultural anthropology, but archaeologists also draw from biological, geological, ...

archaeology
,
climatology Climatology (from Greek , ''klima'', "place, zone"; and , ''-logia'') or climate science is the scientific study of climate, scientifically defined as weather conditions averaged over a period of time. This modern field of study is regarded as a ...

climatology
and
geotechnical engineering#REDIRECT geotechnical engineering#REDIRECT geotechnical engineering {{Redirect category shell|1= {{R from other capitalisation ...
{{Redirect category shell|1= {{R from other capitalisation ...

geotechnical engineering
. This broad base of interests contributes to many research styles and interests within the field.


Overview

Earth Earth is the third planet from the Sun and the only astronomical object known to harbor life. About 29% of Earth's surface is land consisting of continents and islands. The remaining 71% is covered with water, mostly by oceans, seas, gulfs, an ...

Earth
's surface is modified by a combination of surface processes that shape landscapes, and geologic processes that cause
tectonic uplift Kupe's Sail at and [[subsidence
geologic u ...<br><br><img class =
and [[subsidence" >, and shape the [[coastal geography. Surface processes comprise the action of [[water, [[wind, [[ice, [[wildfire|fire, and living things on the surface of the Earth, along with chemical reactions that form [[soils and alter material properties, the stability and rate of change of
topography Topography is the study of the forms and features of land surfaces. The topography of an area could refer to the surface forms and features themselves, or a description (especially their depiction in maps). Topography is a field of geoscience ...

topography
under the force of
gravity Gravity (), or gravitation, is a natural phenomenon by which all things with mass or energy—including planets, stars, galaxies, and even light—are brought toward (or ''gravitate'' toward) one another. On Earth, gravity gives weight to p ...

gravity
, and other factors, such as (in the very recent past) human alteration of the landscape. Many of these factors are strongly mediated by
climate Climate is the long-term average of weather, typically averaged over a period of 30 years. More rigorously, it is the mean and variability of meteorological variables over a time spanning from months to millions of years. Some of the meteorologic ...

climate
. Geologic processes include the uplift of
mountain range#REDIRECT Mountain range#REDIRECT Mountain range {{Redirect category shell|1= {{R from other capitalisation ...
{{Redirect category shell|1= {{R from other capitalisation ...

mountain ranges, the growth of
volcano A volcano is a rupture in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface. On Earth, volcanoes are most often found where tectonic plates are d ...

volcano
es,
isostatic
isostatic
changes in land surface elevation (sometimes in response to surface processes), and the formation of deep
sedimentary basin Sedimentary basins are regions of the Earth where long-term subsidence creates accommodation space for accumulation of sediments. As the sediments are buried, they are subject to increasing pressure and begin the processes of compaction and lit ...

sedimentary basin
s where the surface of the Earth drops and is filled with material
eroded In earth science, erosion is the action of surface processes (such as water flow or wind) that removes soil, rock, or dissolved material from one location on the Earth's crust, and then transports it to another location. Erosion is distinct from ...

eroded
from other parts of the landscape. The Earth's surface and its topography therefore are an intersection of climatic,
hydrologic Hydrology (from Greek: ὕδωρ, "hýdōr" meaning "water" and λόγος, "lógos" meaning "study") is the scientific study of the movement, distribution, and management of water on Earth and other planets, including the water cycle, water reso ...

hydrologic
, and
biologic
biologic
action with geologic processes, or alternatively stated, the intersection of the Earth's
lithosphere A lithosphere ( grc|λίθος [] for "rocky", and [] for "sphere") is the rigid, outermost shell of a [[terrestrial planet|terrestrial-type planet or [[natural satellite. On [[Earth, it is composed of the [[crust (geology)|crust and the portio ...

lithosphere
with its
hydrosphere The hydrosphere (from Greek ὕδωρ ''hydōr'', "water" and σφαῖρα ''sphaira'', "sphere") is the combined mass of water found on, under, and above the surface of a planet, minor planet, or natural satellite. Although Earth's hydrosphere ha ...

hydrosphere
,
atmosphere An atmosphere (from the greek words ἀτμός ''(atmos)'', meaning 'vapour', and σφαῖρα ''(sphaira)'', meaning 'ball' or 'sphere') is a layer or a set of layers of gases surrounding a planet or other material body, that is held in pla ...

atmosphere
, and
biosphere The biosphere (from Greek βίος ''bíos'' "life" and σφαῖρα ''sphaira'' "sphere"), also known as the ecosphere (from Greek οἶκος ''oîkos'' "environment" and σφαῖρα), is the worldwide sum of all ecosystems. It can also be ...

biosphere
. The broad-scale topographies of the Earth illustrate this intersection of surface and subsurface action. Mountain belts are
uplifted
uplifted
due to geologic processes.
Denudation , Brazil: Cabo Frio Island and Itaúna Body. In geology, denudation involves the processes that cause the wearing away of the Earth's surface by moving water, by ice, by wind, and by waves, leading to a reduction in elevation and in relief of lan ...

Denudation
of these high uplifted regions produces
sediment Sediment is a naturally occurring material that is broken down by processes of weathering and erosion, and is subsequently transported by the action of wind, water, or ice or by the force of gravity acting on the particles. For example, sand and ...

sediment
that is transported and
deposited
deposited
elsewhere within the landscape or off the coast. On progressively smaller scales, similar ideas apply, where individual landforms evolve in response to the balance of additive processes (uplift and deposition) and subtractive processes (
subsidence Castleton,_[[Derbyshire.html" style="text-decoration: none;"class="mw-redirect" title="shear stress">shear, near [[Castleton, Derbyshire">Castleton, [[Derbyshire">shear stress">shear, near [[Castleton, Derbyshire">Castleton, [[Derbyshire Subside ...

subsidence
and [[erosion). Often, these processes directly affect each other: ice sheets, water, and sediment are all loads that change topography through [[flexural isostasy. Topography can modify the local climate, for example through
orographic precipitation Orography (from the Greek , hill, , to write) is the study of the topographic relief of mountains, and can more broadly include hills, and any part of a region's elevated terrain. Orography (also known as ''oreography'', ''orology'' or ''oreology'' ...

orographic precipitation
, which in turn modifies the topography by changing the hydrologic regime in which it evolves. Many geomorphologists are particularly interested in the potential for
feedbacks
feedbacks
between climate and
tectonics Tectonics (; ) are the processes that control the structure and properties of the Earth's crust and its evolution through time. These include the processes of mountain building, the growth and behavior of the strong, old cores of continents kn ...

tectonics
, mediated by geomorphic processes. In addition to these broad-scale questions, geomorphologists address issues that are more specific and/or more local. Glacial geomorphologists investigate glacial deposits such as
moraine A moraine is any accumulation of unconsolidated debris (regolith and rock), sometimes referred to as glacial till, that occurs in both currently and formerly glaciated regions, and that has been previously carried along by a glacier or ice shee ...

moraine
s,
esker An esker, eskar, eschar, or os, sometimes called an ''asar'', ''osar'', or ''serpent kame'', is a long, winding ridge of stratified sand and gravel, examples of which occur in glaciated and formerly glaciated regions of Europe and North Americ ...

esker
s, and proglacial [[lakes, as well as [[Erosion#Ice|glacial erosional features, to build chronologies of both small [[glaciers and large [[ice sheets and understand their motions and effects upon the landscape. [[Fluvial geomorphologists focus on [[rivers, how they [[sediment transport|transport sediment, [[River channel migration|migrate across the landscape, [[bedrock river|cut into bedrock, respond to environmental and tectonic changes, and interact with humans. Soils geomorphologists investigate soil profiles and chemistry to learn about the history of a particular landscape and understand how climate, biota, and rock interact. Other geomorphologists study how [[hillslopes form and change. Still others investigate the relationships between [[ecology and geomorphology. Because geomorphology is defined to comprise everything related to the surface of the Earth and its modification, it is a broad field with many facets. Geomorphologists use a wide range of techniques in their work. These may include fieldwork and field data collection, the interpretation of remotely sensed data, geochemical analyses, and the numerical modelling of the physics of landscapes. Geomorphologists may rely on [[geochronology, using dating methods to measure the rate of changes to the surface. Terrain measurement techniques are vital to quantitatively describe the form of the Earth's surface, and include [[differential GPS, remotely sensed [[digital terrain models and [[Lidar#Geology and soil science|laser scanning, to quantify, study, and to generate illustrations and maps. Practical applications of geomorphology include [[natural hazard|hazard assessment (such as [[landslide prediction and [[Landslide mitigation|mitigation), river control and [[stream restoration, and coastal protection. Planetary geomorphology studies landforms on other terrestrial planets such as Mars. Indications of effects of [[aeolian processes|wind, [[fluvial, [[glacial, [[mass wasting, [[Impact event|meteor impact, [[tectonics and [[Types of volcanic eruptions|volcanic processes are studied. This effort not only helps better understand the geologic and atmospheric history of those planets but also extends geomorphological study of the Earth. Planetary geomorphologists often use [[Terrestrial Analogue Sites|Earth analogues to aid in their study of surfaces of other planets.


History

[[File:Velke Hincovo pleso.jpg|Lake "Veľké Hincovo pleso" in [[High Tatras, [[Slovakia. The lake occupies an "[[overdeepening" carved by flowing ice that once occupied this glacial valley. Other than some notable exceptions in antiquity, geomorphology is a relatively young science, growing along with interest in other aspects of the [[earth sciences in the mid-19th century. This section provides a very brief outline of some of the major figures and events in its development.


Ancient geomorphology

The study of landforms and the evolution of the Earth's surface can be dated back to scholars of [[Classical Greece. [[Herodotus argued from observations of soils that the [[Nile delta was actively growing into the [[Mediterranean Sea, and estimated its age.Bierman, Paul R., and David R. Montgomery. Key concepts in geomorphology. Macmillan Higher Education, 2014. [[Aristotle speculated that due to [[sediment transport into the sea, eventually those seas would fill while the land lowered. He claimed that this would mean that land and water would eventually swap places, whereupon the process would begin again in an endless cycle. Another early theory of geomorphology was devised by the polymath [[History of China|Chinese scientist and statesman [[Shen Kuo (1031–1095). This was based on his observation of [[Ocean|marine [[fossil shells in a [[stratum|geological stratum of a mountain hundreds of miles from the [[Pacific Ocean. Noticing [[bivalvia|bivalve shells running in a horizontal span along the cut section of a cliffside, he theorized that the cliff was once the pre-historic location of a seashore that had shifted hundreds of miles over the centuries. He inferred that the land was reshaped and formed by [[soil erosion of the mountains and by deposition of [[silt, after observing strange natural erosions of the [[Taihang Mountains and the [[Yandangshan|Yandang Mountain near [[Wenzhou.Needham, Joseph. (1959). ''Science and Civilization in China: Volume 3, Mathematics and the Sciences of the Heavens and the Earth''. [[Cambridge University Press. pp. 603–618. Furthermore, he promoted the theory of gradual [[climate change (general concept)|climate change over centuries of time once ancient petrified [[bamboos were found to be preserved underground in the dry, northern climate zone of ''Yanzhou'', which is now modern day [[Yan'an, [[Shaanxi province.


Early modern geomorphology

The term geomorphology seems to have been first used by [[Laumann in an 1858 work written in German. Keith Tinkler has suggested that the word came into general use in English, German and French after [[John Wesley Powell and [[W. J. McGee used it during the International Geological Conference of 1891. [[John Edward Marr in his The Scientific Study of Scenery considered his book as, 'an Introductory Treatise on Geomorphology, a subject which has sprung from the union of Geology and Geography'. An early popular geomorphic model was the ''geographical cycle'' or ''[[cycle of erosion'' model of broad-scale landscape evolution developed by [[William Morris Davis between 1884 and 1899. It was an elaboration of the [[uniformitarianism (science)|uniformitarianism theory that had first been proposed by [[James Hutton (1726–1797).Oldroyd, David R. & Grapes, Rodney H. Contributions to the history of geomorphology and Quaternary geology: an introduction. In: Grapes, R. H., Oldroyd, D. & GrigelisR, A. (eds) ''History of Geomorphology and Quaternary Geology''. Geological Society, London, Special Publications, 301, 1–17. With regard to [[valley forms, for example, uniformitarianism posited a sequence in which a river runs through a flat terrain, gradually carving an increasingly deep valley, until the [[side valleys eventually erode, flattening the terrain again, though at a lower elevation. It was thought that
tectonic uplift Kupe's Sail at [[Palliser Bay in [[New Zealand">Palliser_Bay.html" style="text-decoration: none;"class="mw-redirect" title="Kupe's Sail at [[Palliser Bay">Kupe's Sail at [[Palliser Bay in [[New Zealand Tectonic uplift is the [[orogeny|geologic u ...

tectonic uplift
could then start the cycle over. In the decades following Davis's development of this idea, many of those studying geomorphology sought to fit their findings into this framework, known today as "Davisian". Davis's ideas are of historical importance, but have been largely superseded today, mainly due to their lack of predictive power and qualitative nature. In the 1920s, [[Walther Penck developed an alternative model to Davis's. Penck thought that landform evolution was better described as an alternation between ongoing processes of uplift and denudation, as opposed to Davis's model of a single uplift followed by decay.Ritter, Dale F., R. Craig Kochel, and Jerry R. Miller. ''Process geomorphology''. Boston: McGraw-Hill, 1995. He also emphasised that in many landscapes slope evolution occurs by backwearing of rocks, not by Davisian-style surface lowering, and his science tended to emphasise surface process over understanding in detail the surface history of a given locality. Penck was German, and during his lifetime his ideas were at times rejected vigorously by the English-speaking geomorphology community. His early death, Davis' dislike for his work, and his at-times-confusing writing style likely all contributed to this rejection.Simons, Martin (1962), "The morphological analysis of landforms: A new review of the work of Walther Penck (1888–1923)", Transactions and Papers (Institute of British Geographers) 31: 1–14. Both Davis and Penck were trying to place the study of the evolution of the Earth's surface on a more generalized, globally relevant footing than it had been previously. In the early 19th century, authors – especially in Europe – had tended to attribute the form of landscapes to local
climate Climate is the long-term average of weather, typically averaged over a period of 30 years. More rigorously, it is the mean and variability of meteorological variables over a time spanning from months to millions of years. Some of the meteorologic ...

climate
, and in particular to the specific effects of [[glaciation and [[periglacial processes. In contrast, both Davis and Penck were seeking to emphasize the importance of evolution of landscapes through time and the generality of the Earth's surface processes across different landscapes under different conditions. During the early 1900s, the study of regional-scale geomorphology was termed "physiography". Physiography later was considered to be a contraction of "''physi''cal" and "ge''ography''", and therefore synonymous with
physical geography Physical geography (also known as physiography) is one of the two fields 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, hydrospher ...

physical geography
, and the concept became embroiled in controversy surrounding the appropriate concerns of that discipline. Some geomorphologists held to a geological basis for physiography and emphasized a concept of [[physiographic regions of the world|physiographic regions while a conflicting trend among geographers was to equate physiography with "pure morphology", separated from its geological heritage. In the period following World War II, the emergence of process, climatic, and quantitative studies led to a preference by many earth scientists for the term "geomorphology" in order to suggest an analytical approach to landscapes rather than a descriptive one.


Climatic geomorphology

During the age of [[New Imperialism in the late 19th century European explorers and scientists traveled across the globe bringing descriptions of landscapes and landforms. As geographical knowledge increased over time these observations were systematized in a search for regional patterns. Climate emerged thus as prime factor for explaining landform distribution at a grand scale. The rise of climatic geomorphology was foreshadowed by the work of [[Wladimir Köppen, [[Vasily Dokuchaev and [[Andreas Franz Wilhelm Schimper|Andreas Schimper. [[William Morris Davis, the leading geomorphologist of his time, recognized the role of climate by complementing his "normal" temperate climate [[cycle of erosion with arid and glacial ones. Nevertheless, interest in climatic geomorphology was also a reaction ''against'' [[Cycle of erosion|Davisian geomorphology that was by the mid-20th century considered both un-innovative and dubious. Early climatic geomorphology developed primarily in [[continental Europe while in the English-speaking world the tendency was not explicit until L.C. Peltier's 1950 publication on a [[periglaciation|periglacial cycle of erosion. Climatic geomorphology was criticized in a 1969 [[review article by process geomorphologist [[David Stoddart (geographer)|D.R. Stoddart. The criticism by Stoddart proved "devastating" sparking a decline in the popularity of climatic geomorphology in the late 20th century. Stoddart criticized climatic geomorphology for applying supposedly "trivial" methodologies in establishing landform differences between morphoclimatic zones, being linked to [[Cycle of erosion|Davisian geomorphology and by allegedly neglecting the fact that physical laws governing processes are the same across the globe. In addition some conceptions of climatic geomorphology, like that which holds that chemical weathering is more rapid in tropical climates than in cold climates proved to not be straightforwardly true.


Quantitative and process geomorphology

Geomorphology was started to be put on a solid quantitative footing in the middle of the 20th century. Following the early work of [[Grove Karl Gilbert around the turn of the 20th century, a group of mainly American natural scientists, [[geologists and [[hydraulic engineers including [[William Walden Rubey, [[Ralph Alger Bagnold, [[Hans Albert Einstein, [[Frank Ahnert, [[John Tilton Hack|John Hack, [[Luna Leopold, [[Shields parameter|A. Shields, [[Thomas Maddock (scientist)|Thomas Maddock, [[Arthur Strahler, [[Stanley Schumm, and [[Ronald Shreve began to research the form of landscape elements such as [[rivers and [[mass wasting|hillslopes by taking systematic, direct, quantitative measurements of aspects of them and investigating the [[Scaling law|scaling of these measurements. These methods began to allow prediction of the past and future behavior of landscapes from present observations, and were later to develop into the modern trend of a highly quantitative approach to geomorphic problems. Many groundbreaking and widely cited early geomorphology studies appeared in the [[Bulletin of the Geological Society of America, and received only few citations prior to 2000 (they are examples of [[Paper with delayed recognition|"sleeping beauties") when a marked increase in quantitative geomorphology research occurred. Quantitative geomorphology can involve [[fluid dynamics and [[solid mechanics, [[geomorphometry, laboratory studies, field measurements, theoretical work, and full [[landscape evolution modeling. These approaches are used to understand [[weathering and [[pedogenesis|the formation of soils, [[sediment transport, landscape change, and the interactions between climate, tectonics, erosion, and deposition. In Sweden [[Filip Hjulström's doctoral thesis, "The River Fyris" (1935), contained one of the first quantitative studies of geomorphological processes ever published. His students followed in the same vein, making quantitative studies of mass transport ([[Anders Rapp), fluvial transport ([[Åke Sundborg), delta deposition ([[Valter Axelsson), and coastal processes ([[John O. Norrman). This developed into "the [[Uppsala University|Uppsala School of [[Physical Geography".


Contemporary geomorphology

Today, the field of geomorphology encompasses a very wide range of different approaches and interests. Modern researchers aim to draw out quantitative "laws" that govern Earth surface processes, but equally, recognize the uniqueness of each landscape and environment in which these processes operate. Particularly important realizations in contemporary geomorphology include: :1) that not all landscapes can be considered as either "stable" or "perturbed", where this perturbed state is a temporary displacement away from some ideal target form. Instead, dynamic changes of the landscape are now seen as an essential part of their nature. :2) that many geomorphic systems are best understood in terms of the [[stochastic process|stochasticity of the processes occurring in them, that is, the probability distributions of event magnitudes and return times. This in turn has indicated the importance of [[chaos theory|chaotic determinism to landscapes, and that landscape properties are best considered [[statistics|statistically. The same processes in the same landscapes do not always lead to the same end results. According to [[Karna Lidmar-Bergström, [[regional geography is since the 1990s no longer accepted by mainstream scholarship as a basis for geomorphological studies. Albeit having its importance diminished, [[climatic geomorphology continues to exist as field of study producing relevant research. More recently concerns over [[global warming have led to a renewed interest in the field. Despite considerable criticism, the [[cycle of erosion model has remained part of the science of geomorphology. The model or theory has never been proved wrong, but neither has it been proven. The inherent difficulties of the model have instead made geomorphological research to advance along other lines. In contrast to its disputed status in geomorphology, the cycle of erosion model is a common approach used to establish [[denudation chronology|denudation chronologies, and is thus an important concept in the science of [[historical geology. While acknowledging its shortcomings, modern geomorphologists [[Andrew Goudie (geographer)|Andrew Goudie and [[Karna Lidmar-Bergström have praised it for its elegance and pedagogical value respectively.


Processes

Geomorphically relevant processes generally fall into (1) the production of [[regolith by [[weathering and [[erosion, (2) the [[sediment transport|transport of that material, and (3) its eventual [[deposition (geology)|deposition. Primary surface processes responsible for most topographic features include [[wind, [[waves, [[weathering|chemical dissolution, [[mass wasting, [[groundwater movement, [[surface water flow, [[glacier|glacial action, [[tectonism, and [[volcanism. Other more exotic geomorphic processes might include [[periglacial (freeze-thaw) processes, salt-mediated action, changes to the seabed caused by marine currents, seepage of fluids through the seafloor or extraterrestrial impact.


Aeolian processes

[[Aeolian processes pertain to the activity of the [[winds and more specifically, to the winds' ability to shape the surface of the
Earth Earth is the third planet from the Sun and the only astronomical object known to harbor life. About 29% of Earth's surface is land consisting of continents and islands. The remaining 71% is covered with water, mostly by oceans, seas, gulfs, an ...

Earth
. Winds may erode, transport, and deposit materials, and are effective agents in regions with sparse [[vegetation and a large supply of fine, unconsolidated
sediment Sediment is a naturally occurring material that is broken down by processes of weathering and erosion, and is subsequently transported by the action of wind, water, or ice or by the force of gravity acting on the particles. For example, sand and ...

sediment
s. Although water and mass flow tend to mobilize more material than wind in most environments, aeolian processes are important in arid environments such as [[deserts.


Biological processes

The interaction of living organisms with landforms, or [[Biogeomorphology|biogeomorphologic processes, can be of many different forms, and is probably of profound importance for the terrestrial geomorphic system as a whole. Biology can influence very many geomorphic processes, ranging from [[biogeochemical processes controlling [[chemical weathering, to the influence of mechanical processes like [[burrowing and [[tree throw on soil development, to even controlling global erosion rates through modulation of climate through carbon dioxide balance. Terrestrial landscapes in which the role of biology in mediating surface processes can be definitively excluded are extremely rare, but may hold important information for understanding the geomorphology of other planets, such as [[Geography of Mars|Mars.


Fluvial processes

Rivers and streams are not only conduits of water, but also of
sediment Sediment is a naturally occurring material that is broken down by processes of weathering and erosion, and is subsequently transported by the action of wind, water, or ice or by the force of gravity acting on the particles. For example, sand and ...

sediment
. The water, as it flows over the channel bed, is able to mobilize sediment and transport it downstream, either as [[bed load, [[suspended load or [[dissolved load. The rate of sediment transport depends on the availability of sediment itself and on the river's [[discharge (hydrology)|discharge. Rivers are also capable of eroding into rock and creating new sediment, both from their own beds and also by coupling to the surrounding hillslopes. In this way, rivers are thought of as setting the base level for large-scale landscape evolution in nonglacial environments. Rivers are key links in the connectivity of different landscape elements. As rivers flow across the landscape, they generally increase in size, merging with other rivers. The network of rivers thus formed is a [[drainage system (geomorphology)|drainage system. These systems take on four general patterns: dendritic, radial, rectangular, and trellis. Dendritic happens to be the most common, occurring when the underlying stratum is stable (without faulting). Drainage systems have four primary components: drainage basin, alluvial valley, delta plain, and receiving basin. Some geomorphic examples of fluvial landforms are [[alluvial fans, [[oxbow lakes, and [[fluvial terraces.


Glacial processes

[[Glaciers, while geographically restricted, are effective agents of landscape change. The gradual movement of [[ice down a valley causes [[Abrasion (geology)|abrasion and [[Plucking (glaciation)|plucking of the underlying [[rock (geology)|rock. Abrasion produces fine sediment, termed [[glacial flour. The debris transported by the glacier, when the glacier recedes, is termed a
moraine A moraine is any accumulation of unconsolidated debris (regolith and rock), sometimes referred to as glacial till, that occurs in both currently and formerly glaciated regions, and that has been previously carried along by a glacier or ice shee ...

moraine
. Glacial erosion is responsible for U-shaped valleys, as opposed to the V-shaped valleys of fluvial origin. The way glacial processes interact with other landscape elements, particularly hillslope and fluvial processes, is an important aspect of [[Plio-Pleistocene landscape evolution and its sedimentary record in many high mountain environments. Environments that have been relatively recently glaciated but are no longer may still show elevated landscape change rates compared to those that have never been glaciated. Nonglacial geomorphic processes which nevertheless have been conditioned by past glaciation are termed [[paraglacial processes. This concept contrasts with [[periglacial processes, which are directly driven by formation or melting of ice or frost.


Hillslope processes

[[Image:Ferguson-slide.jpg|The [[Ferguson landslide|Ferguson Slide is an active [[landslide in the [[Merced River|Merced River canyon on [[California State Highway 140, a primary access road to [[Yosemite National Park. [[Soil, [[regolith, and [[rock (geology)|rock move downslope under the force of
gravity Gravity (), or gravitation, is a natural phenomenon by which all things with mass or energy—including planets, stars, galaxies, and even light—are brought toward (or ''gravitate'' toward) one another. On Earth, gravity gives weight to p ...

gravity
via [[Downhill creep|creep, [[Landslide|slides, flows, topples, and falls. Such [[mass wasting occurs on both terrestrial and submarine slopes, and has been observed on
Earth Earth is the third planet from the Sun and the only astronomical object known to harbor life. About 29% of Earth's surface is land consisting of continents and islands. The remaining 71% is covered with water, mostly by oceans, seas, gulfs, an ...

Earth
, [[Mars, [[Venus, [[Titan (moon)|Titan and [[Iapetus (moon)|Iapetus. Ongoing hillslope processes can change the topology of the hillslope surface, which in turn can change the rates of those processes. Hillslopes that steepen up to certain critical thresholds are capable of shedding extremely large volumes of material very quickly, making hillslope processes an extremely important element of landscapes in tectonically active areas. On the Earth, biological processes such as [[burrowing or [[tree throw may play important roles in setting the rates of some hillslope processes.


Igneous processes

Both [[volcanic (eruptive) and [[plutonic (intrusive) igneous processes can have important impacts on geomorphology. The action of volcanoes tends to rejuvenize landscapes, covering the old land surface with [[lava and [[tephra, releasing [[pyroclastic flow|pyroclastic material and forcing rivers through new paths. The cones built by eruptions also build substantial new topography, which can be acted upon by other surface processes. Plutonic rocks intruding then solidifying at depth can cause both uplift or subsidence of the surface, depending on whether the new material is denser or less dense than the rock it displaces.


Tectonic processes

[[Plate tectonics|Tectonic effects on geomorphology can range from scales of millions of years to minutes or less. The effects of tectonics on landscape are heavily dependent on the nature of the underlying [[bedrock fabric that more or less controls what kind of local morphology tectonics can shape. [[Earthquakes can, in terms of minutes, submerge large areas of land creating new wetlands. [[Isostatic rebound can account for significant changes over hundreds to thousands of years, and allows erosion of a mountain belt to promote further erosion as mass is removed from the chain and the belt uplifts. Long-term plate tectonic dynamics give rise to [[orogeny|orogenic belts, large mountain chains with typical lifetimes of many tens of millions of years, which form focal points for high rates of fluvial and hillslope processes and thus long-term sediment production. Features of deeper [[Mantle (geology)|mantle dynamics such as [[mantle plume|plumes and [[delamination (geology)|delamination of the lower lithosphere have also been hypothesised to play important roles in the long term (> million year), large scale (thousands of km) evolution of the Earth's topography (see [[dynamic topography). Both can promote surface uplift through isostasy as hotter, less dense, mantle rocks displace cooler, denser, mantle rocks at depth in the Earth.


Marine processes

Marine processes are those associated with the action of waves, marine currents and seepage of fluids through the seafloor. [[Mass wasting and submarine [[landslide|landsliding are also important processes for some aspects of marine geomorphology.Guilcher, A., 1958. Coastal and submarine morphology. Methuen. Because ocean basins are the ultimate sinks for a large fraction of terrestrial sediments, depositional processes and their related forms (e.g., sediment fans, [[deltas) are particularly important as elements of marine geomorphology.


Overlap with other fields

There is a considerable overlap between geomorphology and other fields. Deposition of material is extremely important in [[sedimentology. [[Weathering is the chemical and physical disruption of earth materials in place on exposure to atmospheric or near surface agents, and is typically studied by [[soil science|soil scientists and environmental [[chemistry|chemists, but is an essential component of geomorphology because it is what provides the material that can be moved in the first place. [[Civil engineering|Civil and [[Environmental engineering|environmental engineers are concerned with erosion and sediment transport, especially related to [[canals, [[slope stability (and [[natural hazards), [[water quality, coastal environmental management, transport of contaminants, and [[stream restoration. Glaciers can cause extensive erosion and deposition in a short period of time, making them extremely important entities in the high latitudes and meaning that they set the conditions in the headwaters of mountain-born streams; [[glaciology therefore is important in geomorphology.


See also

* [[Bioerosion * [[Biogeology * [[Biogeomorphology * [[Biorhexistasy * [[British Society for Geomorphology * [[Coastal biogeomorphology * [[Coastal erosion * [[Drainage system (geomorphology) * [[Erosion * [[Erosion prediction * [[Geologic modelling * [[Geomorphometry * [[Geotechnics * [[Hack's law * [[Hydrology|Hydrologic modeling, [[behavioral modeling in hydrology * [[Orogeny * [[Physiographic regions of the world * [[Sediment transport * [[Soil morphology * [[Soils retrogression and degradation * [[Stream capture * [[Thermochronology * [[Weathering * [[List of important publications in geology


References


Further reading

* * *
Ialenti, Vincent. "Envisioning Landscapes of Our Very Distant Future"
NPR Cosmos & Culture. 9/2014. * * * * * Anderson, R.S.; Anderson, S.P. ''Geomorphology: The Mechanics and Chemistry of Landscapes''. Cambridge: Cambridge University Press, 2011. . * Bierman, P.R.; Montgomery, D.R. ''Key Concepts in Geomorphology''. New York: W. H. Freeman, 2013. . * Ritter, D.F.; Kochel, R.C.; Miller, J.R.. ''Process Geomorphology''. London: Waveland Pr Inc, 2011. . *Hargitai H., Page D., Canon-Tapia E. and Rodrigue C.M..; ''Classification and Characterization of Planetary Landforms.'' in: Hargitai H, Kereszturi Á, eds, Encyclopedia of Planetary Landforms. Cham: Springer 2015


External links


The Geographical Cycle, or the Cycle of Erosion (1899)

Geomorphology from Space (NASA)

British Society for Geomorphology
{{Authority control [[Category:Geomorphology| [[Category:Earth sciences [[Category:Geology [[Category:Geological processes [[Category:Gravity [[Category:Physical geography [[Category:Planetary science [[Category:Seismology [[Category:Topography