Misplaced Pages

#419580

86-626: The peninsula has a rugged terrain with few level areas. The coastline of the peninsula suffers from extensive marine erosion , which resulted in the numerous natural stone pillars which project from the sea. Mount Shakotan (1,255 metres (4,117 ft)) forms the highest peak on the peninsula. The peninsula has numerous scenic capes and inlets , notably Cape Shakotan and Cape Kamui . The Shakotan Peninsula spans seven municipalities in Hokkaidō, all within Shiribeshi Subprefecture. The area

172-429: A glacial armor . Ice can not only erode mountains but also protect them from erosion. Depending on glacier regime, even steep alpine lands can be preserved through time with the help of ice. Scientists have proved this theory by sampling eight summits of northwestern Svalbard using Be10 and Al26, showing that northwestern Svalbard transformed from a glacier-erosion state under relatively mild glacial maxima temperature, to

258-426: A considerable depth. A gully is distinguished from a rill based on a critical cross-sectional area of at least one square foot, i.e. the size of a channel that can no longer be erased via normal tillage operations. Extreme gully erosion can progress to formation of badlands . These form under conditions of high relief on easily eroded bedrock in climates favorable to erosion. Conditions or disturbances that limit

344-408: A fall in sea level, can produce a distinctive landform called a raised beach . Chemical erosion is the loss of matter in a landscape in the form of solutes . Chemical erosion is usually calculated from the solutes found in streams. Anders Rapp pioneered the study of chemical erosion in his work about Kärkevagge published in 1960. Formation of sinkholes and other features of karst topography

430-409: A few millimetres, or for thousands of kilometres. Agents of erosion include rainfall ; bedrock wear in rivers ; coastal erosion by the sea and waves ; glacial plucking , abrasion , and scour; areal flooding; wind abrasion; groundwater processes; and mass movement processes in steep landscapes like landslides and debris flows . The rates at which such processes act control how fast

516-479: A glacier-armor state occupied by cold-based, protective ice during much colder glacial maxima temperatures as the Quaternary ice age progressed. These processes, combined with erosion and transport by the water network beneath the glacier, leave behind glacial landforms such as moraines , drumlins , ground moraine (till), glaciokarst , kames, kame deltas, moulins, and glacial erratics in their wake, typically at

602-464: A homogeneous bedrock erosion pattern, curved channel cross-section beneath the ice is created. Though the glacier continues to incise vertically, the shape of the channel beneath the ice eventually remain constant, reaching a U-shaped parabolic steady-state shape as we now see in glaciated valleys . Scientists also provide a numerical estimate of the time required for the ultimate formation of a steady-shaped U-shaped valley —approximately 100,000 years. In

688-423: A large river can remove enough sediments to produce a river anticline , as isostatic rebound raises rock beds unburdened by erosion of overlying beds. Shoreline erosion, which occurs on both exposed and sheltered coasts, primarily occurs through the action of currents and waves but sea level (tidal) change can also play a role. Hydraulic action takes place when the air in a joint is suddenly compressed by

774-586: A litter layer; water saturation > 30 consecutive days in most years or drained ; generally regarded as peat layer or organic limnic layer. O: Organic horizon or organotechnic layer, not forming part of a litter layer; water saturation ≤ 30 consecutive days in most years and not drained; generally regarded as non-peat and non-limnic horizon. A: Mineral horizon at the mineral soil surface or buried; contains organic matter that has at least partly been modified in-situ; soil structure and/or structural elements created by cultivation in ≥ 50% (by volume, related to

860-487: A mountain mass similar to the Himalaya into an almost-flat peneplain if there are no significant sea-level changes . Erosion of mountains massifs can create a pattern of equally high summits called summit accordance . It has been argued that extension during post-orogenic collapse is a more effective mechanism of lowering the height of orogenic mountains than erosion. Examples of heavily eroded mountain ranges include

946-410: A soil type. Some soils do not have a clear development of horizons. A soil horizon is a result of soil-forming processes ( pedogenesis ). Layers that have not undergone such processes may be simply called "layers". Many soils have an organic surface layer, which is denominated with a capital letter "O" (letters may differ depending on the system). The mineral soil usually starts with an A horizon. If

SECTION 10

#1732856039420

1032-432: A surface is eroded. Typically, physical erosion proceeds the fastest on steeply sloping surfaces, and rates may also be sensitive to some climatically controlled properties including amounts of water supplied (e.g., by rain), storminess, wind speed, wave fetch , or atmospheric temperature (especially for some ice-related processes). Feedbacks are also possible between rates of erosion and the amount of eroded material that

1118-501: A wave closing the entrance of the joint. This then cracks it. Wave pounding is when the sheer energy of the wave hitting the cliff or rock breaks pieces off. Abrasion or corrasion is caused by waves launching sea load at the cliff. It is the most effective and rapid form of shoreline erosion (not to be confused with corrosion ). Corrosion is the dissolving of rock by carbonic acid in sea water. Limestone cliffs are particularly vulnerable to this kind of erosion. Attrition

1204-412: A weak bedrock (containing material more erodible than the surrounding rocks) erosion pattern, on the contrary, the amount of over deepening is limited because ice velocities and erosion rates are reduced. Glaciers can also cause pieces of bedrock to crack off in the process of plucking. In ice thrusting, the glacier freezes to its bed, then as it surges forward, it moves large sheets of frozen sediment at

1290-406: A well-developed subsoil horizon as a result of soil formation exists, it is generally called a B horizon. An underlying loose, but poorly developed horizon is called a C horizon. Hard bedrock is mostly denominated R. Most individual systems defined more horizons and layers than just these five. In the following, the horizons and layers are listed more or less by their position from top to bottom within

1376-537: Is already carried by, for example, a river or glacier. The transport of eroded materials from their original location is followed by deposition, which is arrival and emplacement of material at a new location. While erosion is a natural process, human activities have increased by 10–40 times the rate at which soil erosion is occurring globally. At agriculture sites in the Appalachian Mountains , intensive farming practices have caused erosion at up to 100 times

1462-490: Is also more prone to mudslides, landslides, and other forms of gravitational erosion processes. Tectonic processes control rates and distributions of erosion at the Earth's surface. If the tectonic action causes part of the Earth's surface (e.g., a mountain range) to be raised or lowered relative to surrounding areas, this must necessarily change the gradient of the land surface. Because erosion rates are almost always sensitive to

1548-484: Is an example of extreme chemical erosion. Glaciers erode predominantly by three different processes: abrasion/scouring, plucking , and ice thrusting. In an abrasion process, debris in the basal ice scrapes along the bed, polishing and gouging the underlying rocks, similar to sandpaper on wood. Scientists have shown that, in addition to the role of temperature played in valley-deepening, other glaciological processes, such as erosion also control cross-valley variations. In

1634-472: Is defined by having a certain minimum content of soil organic carbon. In the WRB, this is 20% (by weight). The H horizon is formed from organic residues that are not incorporated into the mineral soil. The residues may be partially altered by decomposition. Contrary to the O horizons, the H horizons are saturated with water for prolonged periods, or were once saturated but are now drained artificially. In many H horizons,

1720-409: Is distinguished from changes on the bed of the watercourse, which is referred to as scour . Erosion and changes in the form of river banks may be measured by inserting metal rods into the bank and marking the position of the bank surface along the rods at different times. Thermal erosion is the result of melting and weakening permafrost due to moving water. It can occur both along rivers and at

1806-451: Is followed by the ρ. 4. If two suffixes belong to the same soil-forming process, they follow each other immediately; in the combination of t and n, the t is written first; rules 1, 2 and 3 have to be followed, if applicable. Examples: Btn, Bhs, Bsh, Bhsm, Bsmh. 5. If in a B horizon the characteristics of the suffixes g, h, k, l, o, q, s, t, v, or y are strongly expressed, the suffix w is not used, even if its characteristics are present; if

SECTION 20

#1732856039420

1892-631: Is mainly derived from iron oxides. Iron oxides and clay minerals accumulate as a result of weathering. In soil, where substances move down from the topsoil, this is the layer where they accumulate. The process of accumulation of clay minerals, iron, aluminum, and organic compounds, is referred to as illuviation . The B horizon has generally a soil structure. C) Substratum: Layer of non-indurated poorly weathered or unweathered rocks. This layer may accumulate more soluble compounds like CaCO 3 . Soils formed in situ from non-indurated material exhibit similarities to this C layer. R) Bedrock : R horizons denote

1978-511: Is not regarded to form part of a litter layer. The soil surface (0 cm) is by convention the surface of the soil after removing, if present, the litter layer and, if present, below a layer of living plants (e.g. living mosses). The mineral soil surface is the upper limit of the uppermost layer consisting of mineral material. A soil layer is a zone in the soil, approximately parallel to the soil surface, with properties different from layers above and/or below it. If at least one of these properties

2064-405: Is of two primary varieties: deflation , where the wind picks up and carries away loose particles; and abrasion , where surfaces are worn down as they are struck by airborne particles carried by wind. Deflation is divided into three categories: (1) surface creep , where larger, heavier particles slide or roll along the ground; (2) saltation , where particles are lifted a short height into

2150-416: Is pronounced, a lighter coloured E subsurface soil horizon is apparent at the base of the A horizon. The A horizon may also be the result of a combination of soil bioturbation and surface processes that winnow fine particles from biologically mounded topsoil . In this case, the A horizon is regarded as a "biomantle". B) Subsoil : This layer normally has less organic matter than the A horizon, so its colour

2236-404: Is sparse and soil is dry (and so is more erodible). Other climatic factors such as average temperature and temperature range may also affect erosion, via their effects on vegetation and soil properties. In general, given similar vegetation and ecosystems, areas with more precipitation (especially high-intensity rainfall), more wind, or more storms are expected to have more erosion. In some areas of

2322-457: Is the main climatic factor governing soil erosion by water. The relationship is particularly strong if heavy rainfall occurs at times when, or in locations where, the soil's surface is not well protected by vegetation . This might be during periods when agricultural activities leave the soil bare, or in semi-arid regions where vegetation is naturally sparse. Wind erosion requires strong winds, particularly during times of drought when vegetation

2408-527: Is the result of soil-forming processes, the layer is called a soil horizon . In the following, the term layer is used to indicate the possibility that soil-forming processes did not occur. The following layers are distinguished (see Chapter 3.3 of the WRB Manual): The designation consists of a capital letter (master symbol), which in most cases is followed by one or more lowercase letters (suffixes). H: Organic or organotechnic layer, not forming part of

2494-400: Is where particles/sea load carried by the waves are worn down as they hit each other and the cliffs. This then makes the material easier to wash away. The material ends up as shingle and sand. Another significant source of erosion, particularly on carbonate coastlines, is boring, scraping and grinding of organisms, a process termed bioerosion . Sediment is transported along the coast in

2580-468: 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

2666-658: The Great Plains , it is estimated that soil loss due to wind erosion can be as much as 6100 times greater in drought years than in wet years. Mass wasting or mass movement is the downward and outward movement of rock and sediments on a sloped surface, mainly due to the force of gravity . Mass wasting is an important part of the erosional process and is often the first stage in the breakdown and transport of weathered materials in mountainous areas. It moves material from higher elevations to lower elevations where other eroding agents such as streams and glaciers can then pick up

Shakotan Peninsula - Misplaced Pages Continue

2752-700: The Timanides of Northern Russia. Erosion of this orogen has produced sediments that are now found in the East European Platform , including the Cambrian Sablya Formation near Lake Ladoga . Studies of these sediments indicate that it is likely that the erosion of the orogen began in the Cambrian and then intensified in the Ordovician . If the erosion rate exceeds soil formation , erosion destroys

2838-416: The accumulation zone above the glacial equilibrium line altitude), which causes increased rates of erosion of the mountain, decreasing mass faster than isostatic rebound can add to the mountain. This provides a good example of a negative feedback loop . Ongoing research is showing that while glaciers tend to decrease mountain size, in some areas, glaciers can actually reduce the rate of erosion, acting as

2924-405: The impact of a falling raindrop creates a small crater in the soil , ejecting soil particles. The distance these soil particles travel can be as much as 0.6 m (2.0 ft) vertically and 1.5 m (4.9 ft) horizontally on level ground. If the soil is saturated , or if the rainfall rate is greater than the rate at which water can infiltrate into the soil, surface runoff occurs. If

3010-455: The lower crust and mantle . Because tectonic processes are driven by gradients in the stress field developed in the crust, this unloading can in turn cause tectonic or isostatic uplift in the region. In some cases, it has been hypothesised that these twin feedbacks can act to localize and enhance zones of very rapid exhumation of deep crustal rocks beneath places on the Earth's surface with extremely high erosion rates, for example, beneath

3096-407: The surface runoff which may result from rainfall, produces four main types of soil erosion : splash erosion , sheet erosion , rill erosion , and gully erosion . Splash erosion is generally seen as the first and least severe stage in the soil erosion process, which is followed by sheet erosion, then rill erosion and finally gully erosion (the most severe of the four). In splash erosion ,

3182-603: The "diagnostic horizons", for the definition; examples are the World Reference Base for Soil Resources (WRB), the USDA soil taxonomy and the Australian Soil Classification . Diagnostic horizons are usually indicated with names, e.g. the "cambic horizon" or the "spodic horizon". The WRB lists 40 diagnostic horizons. In addition to these diagnostic horizons, some other soil characteristics may be needed to define

3268-499: The 21st century, a strong link has been drawn between the increase in storm frequency with an increase in sediment load in rivers and reservoirs, highlighting the impacts climate change can have on erosion. Vegetation acts as an interface between the atmosphere and the soil. It increases the permeability of the soil to rainwater, thus decreasing runoff. It shelters the soil from winds, which results in decreased wind erosion, as well as advantageous changes in microclimate. The roots of

3354-423: The WRB, this is 20% (by weight). The O horizon is formed from organic residues that are not incorporated into the mineral soil. The residues may be partially altered by decomposition. Contrary to the H horizons, the O horizons are not saturated with water for prolonged periods and not drained artificially. In many O horizons, the residues are leaves, needles, twigs, moss, and lichens. Although these horizons form above

3440-433: The air, and bounce and saltate across the surface of the soil; and (3) suspension , where very small and light particles are lifted into the air by the wind, and are often carried for long distances. Saltation is responsible for the majority (50–70%) of wind erosion, followed by suspension (30–40%), and then surface creep (5–25%). Wind erosion is much more severe in arid areas and during times of drought. For example, in

3526-463: The base along with the glacier. This method produced some of the many thousands of lake basins that dot the edge of the Canadian Shield . Differences in the height of mountain ranges are not only being the result tectonic forces, such as rock uplift, but also local climate variations. Scientists use global analysis of topography to show that glacial erosion controls the maximum height of mountains, as

Shakotan Peninsula - Misplaced Pages Continue

3612-407: The characteristics of the mentioned suffixes are weakly expressed and the characteristics of the suffix w are present as well, the suffixes are combined. 6. In H and O layers, the i, e or a is written first. 7. The @, f and b are written last, if b occurs together with @ or f (only if other suffixes are present as well): @b, fb. 8. Besides that, combinations must be in the sequence of dominance,

3698-512: The coast. Rapid river channel migration observed in the Lena River of Siberia is due to thermal erosion, as these portions of the banks are composed of permafrost-cemented non-cohesive materials. Much of this erosion occurs as the weakened banks fail in large slumps. Thermal erosion also affects the Arctic coast , where wave action and near-shore temperatures combine to undercut permafrost bluffs along

3784-409: The coastline. Where there is a bend in the coastline, quite often a buildup of eroded material occurs forming a long narrow bank (a spit ). Armoured beaches and submerged offshore sandbanks may also protect parts of a coastline from erosion. Over the years, as the shoals gradually shift, the erosion may be redirected to attack different parts of the shore. Erosion of a coastal surface, followed by

3870-411: The direction of the prevailing current ( longshore drift ). When the upcurrent supply of sediment is less than the amount being carried away, erosion occurs. When the upcurrent amount of sediment is greater, sand or gravel banks will tend to form as a result of deposition . These banks may slowly migrate along the coast in the direction of the longshore drift, alternately protecting and exposing parts of

3956-466: The dominant one first. Examples: Btng, Btgb, Bkcyc. If the characteristics of two or more master layers are superimposed to each other, the master symbols are combined without anything in between, the dominant one first, each one followed by its suffixes. Examples: AhBw, BwAh, AhE, EAh, EBg, BgE, BwC, CBw, BsC, CBs. If the characteristics of two or more master layers occur in the same depth range, but occupy distinct parts clearly separated from each other,

4042-405: The extremely steep terrain of Nanga Parbat in the western Himalayas . Such a place has been called a " tectonic aneurysm ". Human land development, in forms including agricultural and urban development, is considered a significant factor in erosion and sediment transport , which aggravate food insecurity . In Taiwan, increases in sediment load in the northern, central, and southern regions of

4128-408: The fine earth), i.e. rock structure, if present, in < 50% (by volume). E: Mineral horizon; has lost by downward movement within the soil (vertically or laterally) one or more of the following: Fe, Al, and/or Mn species; clay minerals; organic matter. B: Mineral horizon that has (at least originally) formed below an A or E horizon; rock structure, if present, in < 50% (by volume, related to

4214-536: The fine earth); one or more of the following processes of soil formation : Nota bene: B horizons may show other accumulations as well. C: Mineral layer; unconsolidated (can be cut with a spade when moist), or consolidated and more fractured than the R layer; no soil formation, or soil formation that does not meet the criteria of the A, E, and B horizon. R: Consolidated rock; air-dry or drier specimens, when placed in water, will not slake within 24 hours; fractures, if present, occupy < 10% (by volume, related to

4300-575: The flood regions result from glacial Lake Missoula , which created the channeled scablands in the Columbia Basin region of eastern Washington . Wind erosion is a major geomorphological force, especially in arid and semi-arid regions. It is also a major source of land degradation, evaporation, desertification, harmful airborne dust, and crop damage—especially after being increased far above natural rates by human activities such as deforestation , urbanization , and agriculture . Wind erosion

4386-417: The growth of protective vegetation ( rhexistasy ) are a key element of badland formation. Valley or stream erosion occurs with continued water flow along a linear feature. The erosion is both downward , deepening the valley , and headward , extending the valley into the hillside, creating head cuts and steep banks. In the earliest stage of stream erosion, the erosive activity is dominantly vertical,

SECTION 50

#1732856039420

4472-411: The island can be tracked with the timeline of development for each region throughout the 20th century. The intentional removal of soil and rock by humans is a form of erosion that has been named lisasion . Mountain ranges take millions of years to erode to the degree they effectively cease to exist. Scholars Pitman and Golovchenko estimate that it takes probably more than 450 million years to erode

4558-579: The layer of partially weathered or unweathered bedrock at the base of the soil profile. Unlike the above layers, R horizons largely comprise of continuous masses (as opposed to boulders) of hard rock that cannot be excavated by hand. Soils formed in situ from bedrock will exhibit strong similarities to this bedrock layer. The designations are found in Chapter 10 of the World Reference Base for Soil Resources Manual , 4th edition (2022). The chapter starts with some general definitions : The fine earth comprises

4644-409: The local slope (see above), this will change the rates of erosion in the uplifted area. Active tectonics also brings fresh, unweathered rock towards the surface, where it is exposed to the action of erosion. However, erosion can also affect tectonic processes. The removal by erosion of large amounts of rock from a particular region, and its deposition elsewhere, can result in a lightening of the load on

4730-447: The master symbols are combined with the slash (/), the dominant one first, each one followed by its suffixes. Examples: Bt/E (interfingering of E material into a Bt horizon), C/Bt (Bt horizon forming lamellae within a C layer). W cannot be combined with other master symbols. H, O, I, and R can only be combined using the slash. The sequence of the layers is from top to down with a hyphen in between. If lithic discontinuities occur,

4816-418: The material and move it to even lower elevations. Mass-wasting processes are always occurring continuously on all slopes; some mass-wasting processes act very slowly; others occur very suddenly, often with disastrous results. Any perceptible down-slope movement of rock or sediment is often referred to in general terms as a landslide . However, landslides can be classified in a much more detailed way that reflects

4902-407: The material has begun to slide downhill. In some cases, the slump is caused by water beneath the slope weakening it. In many cases it is simply the result of poor engineering along highways where it is a regular occurrence. Surface creep is the slow movement of soil and rock debris by gravity which is usually not perceptible except through extended observation. However, the term can also describe

4988-438: The mechanisms responsible for the movement and the velocity at which the movement occurs. One of the visible topographical manifestations of a very slow form of such activity is a scree slope. Slumping happens on steep hillsides, occurring along distinct fracture zones, often within materials like clay that, once released, may move quite rapidly downhill. They will often show a spoon-shaped isostatic depression , in which

5074-484: The morphologic impact of glaciations on active orogens, by both influencing their height, and by altering the patterns of erosion during subsequent glacial periods via a link between rock uplift and valley cross-sectional shape. At extremely high flows, kolks , or vortices are formed by large volumes of rapidly rushing water. Kolks cause extreme local erosion, plucking bedrock and creating pothole-type geographical features called rock-cut basins . Examples can be seen in

5160-404: The most erosion occurs during times of flood when more and faster-moving water is available to carry a larger sediment load. In such processes, it is not the water alone that erodes: suspended abrasive particles, pebbles , and boulders can also act erosively as they traverse a surface, in a process known as traction . Bank erosion is the wearing away of the banks of a stream or river. This

5246-665: The most significant environmental problems . Often in the United States, farmers cultivating highly erodible land must comply with a conservation plan to be eligible for agricultural assistance. Soil horizon A soil horizon is a layer parallel to the soil surface whose physical, chemical and biological characteristics differ from the layers above and beneath. Horizons are defined in many cases by obvious physical features, mainly colour and texture. These may be described both in absolute terms (particle size distribution for texture, for instance) and in terms relative to

SECTION 60

#1732856039420

5332-531: The natural rate of erosion in the region. Excessive (or accelerated) erosion causes both "on-site" and "off-site" problems. On-site impacts include decreases in agricultural productivity and (on natural landscapes ) ecological collapse , both because of loss of the nutrient-rich upper soil layers . In some cases, this leads to desertification . Off-site effects include sedimentation of waterways and eutrophication of water bodies , as well as sediment-related damage to roads and houses. Water and wind erosion are

5418-434: The nutrient-rich upper soil layers . In some cases, the eventual result is desertification . Off-site effects include sedimentation of waterways and eutrophication of water bodies, as well as sediment-related damage to roads and houses. Water and wind erosion are the two primary causes of land degradation ; combined, they are responsible for about 84% of the global extent of degraded land , making excessive erosion one of

5504-440: The observed horizons. [REDACTED] A) Surface soil : Layer of mineral soil with most organic matter accumulation and soil life . Additionally, due to weathering , oxides (mainly iron oxides) and clay minerals are formed and accumulated. It has a pronounced soil structure. But in some soils, clay minerals, iron , aluminum , organic compounds, and other constituents are soluble and move downwards. When this eluviation

5590-411: The order of a few centimetres (about an inch) or less and along-channel slopes may be quite steep. This means that rills exhibit hydraulic physics very different from water flowing through the deeper, wider channels of streams and rivers. Gully erosion occurs when runoff water accumulates and rapidly flows in narrow channels during or immediately after heavy rains or melting snow, removing soil to

5676-556: The plants bind the soil together, and interweave with other roots, forming a more solid mass that is less susceptible to both water and wind erosion. The removal of vegetation increases the rate of surface erosion. The topography of the land determines the velocity at which surface runoff will flow, which in turn determines the erosivity of the runoff. Longer, steeper slopes (especially those without adequate vegetative cover) are more susceptible to very high rates of erosion during heavy rains than shorter, less steep slopes. Steeper terrain

5762-413: The relief between mountain peaks and the snow line are generally confined to altitudes less than 1500 m. The erosion caused by glaciers worldwide erodes mountains so effectively that the term glacial buzzsaw has become widely used, which describes the limiting effect of glaciers on the height of mountain ranges. As mountains grow higher, they generally allow for more glacial activity (especially in

5848-408: The residues are predominantly mosses. Although these horizons form above the mineral soil surface, they may be buried by mineral soil and therefore be found at greater depth. H horizons may be overlain by O horizons that especially form after drainage. O horizons or layers : These are layers of organic material. Organic material is defined by having a certain minimum content of soil organic carbon. In

5934-828: The rolling of dislodged soil particles 0.5 to 1.0 mm (0.02 to 0.04 in) in diameter by wind along the soil surface. On the continental slope , erosion of the ocean floor to create channels and submarine canyons can result from the rapid downslope flow of sediment gravity flows , bodies of sediment-laden water that move rapidly downslope as turbidity currents . Where erosion by turbidity currents creates oversteepened slopes it can also trigger underwater landslides and debris flows . Turbidity currents can erode channels and canyons into substrates ranging from recently deposited unconsolidated sediments to hard crystalline bedrock. Almost all continental slopes and deep ocean basins display such channels and canyons resulting from sediment gravity flows and submarine canyons act as conduits for

6020-515: The runoff has sufficient flow energy , it will transport loosened soil particles ( sediment ) down the slope. Sheet erosion is the transport of loosened soil particles by overland flow. Rill erosion refers to the development of small, ephemeral concentrated flow paths which function as both sediment source and sediment delivery systems for erosion on hillslopes. Generally, where water erosion rates on disturbed upland areas are greatest, rills are active. Flow depths in rills are typically of

6106-532: The shoreline and cause them to fail. Annual erosion rates along a 100-kilometre (62-mile) segment of the Beaufort Sea shoreline averaged 5.6 metres (18 feet) per year from 1955 to 2002. Most river erosion happens nearer to the mouth of a river. On a river bend, the longest least sharp side has slower moving water. Here deposits build up. On the narrowest sharpest side of the bend, there is faster moving water so this side tends to erode away mostly. Rapid erosion by

6192-429: The soil constituents ≤ 2 mm. The whole soil comprises fine earth, coarse fragments, artefacts, cemented parts, and dead plant residues of any size. A litter layer is a loose layer that contains > 90% (by volume, related to the fine earth plus all dead plant residues) recognizable dead plant tissues (e.g. undecomposed leaves). Dead plant material still connected to living plants (e.g. dead parts of Sphagnum mosses)

6278-421: The soil profile. Not all of them are present in every soil. Soils with a history of human interference, for instance through major earthworks or regular deep ploughing, may lack distinct horizons almost completely. When examining soils in the field, attention must be paid to the local geomorphology and the historical uses to which the land has been put, in order to ensure that the appropriate names are applied to

6364-593: The soil. Lower rates of erosion can prevent the formation of soil features that take time to develop. Inceptisols develop on eroded landscapes that, if stable, would have supported the formation of more developed Alfisols . While erosion of soils is a natural process, human activities have increased by 10-40 times the rate at which erosion occurs globally. Excessive (or accelerated) erosion causes both "on-site" and "off-site" problems. On-site impacts include decreases in agricultural productivity and (on natural landscapes ) ecological collapse , both because of loss of

6450-567: The strata are indicated by preceding figures, starting with the second stratum. I and W layers are not considered as strata. All layers of the respective stratum are indicated by the figure: Example: Oi-Oe-Ah-E-2Bt-2C-3R. If two or more layers with the same designation occur, the letters are followed by figures. The sequence of figures continues across different strata. Examples: Oi-Oe-Oa-Ah-Bw1-Bw2-2Bw3-3Ahb1-3Eb-3Btb-4Ahb2-4C, Oi-He-Ha-Cr1-2Heb-2Hab-2Cr2-3Crγ. Source: H horizons or layers : These are layers of organic material. Organic material

6536-431: The suffix that indicates the substance that forms the concretions or nodules; if this is true for more than one suffix, each one is followed by the c. 2. The m follows the suffix that indicates the substance that is the cementing agent; if this is true for more than one suffix, each one is followed by the m. 3. The ρ follows the suffix that indicates the relict features; if this is true for more than one suffix, each one

6622-404: The surrounding material, i.e. 'coarser' or 'sandier' than the horizons above and below. The identified horizons are indicated with symbols, which are mostly used in a hierarchical way. Master horizons (main horizons) are indicated by capital letters. Suffixes, in form of lowercase letters and figures, further differentiate the master horizons. There are many different systems of horizon symbols in

6708-433: The terminus or during glacier retreat . The best-developed glacial valley morphology appears to be restricted to landscapes with low rock uplift rates (less than or equal to 2mm per year) and high relief, leading to long-turnover times. Where rock uplift rates exceed 2mm per year, glacial valley morphology has generally been significantly modified in postglacial time. Interplay of glacial erosion and tectonic forcing governs

6794-409: The transfer of sediment from the continents and shallow marine environments to the deep sea. Turbidites , which are the sedimentary deposits resulting from turbidity currents, comprise some of the thickest and largest sedimentary sequences on Earth, indicating that the associated erosional processes must also have played a prominent role in Earth's history. The amount and intensity of precipitation

6880-563: The two primary causes of land degradation ; combined, they are responsible for about 84% of the global extent of degraded land, making excessive erosion one of the most significant environmental problems worldwide. Intensive agriculture , deforestation , roads , anthropogenic climate change and urban sprawl are amongst the most significant human activities in regard to their effect on stimulating erosion. However, there are many prevention and remediation practices that can curtail or limit erosion of vulnerable soils. Rainfall , and

6966-427: The valleys have a typical V-shaped cross-section and the stream gradient is relatively steep. When some base level is reached, the erosive activity switches to lateral erosion, which widens the valley floor and creates a narrow floodplain. The stream gradient becomes nearly flat, and lateral deposition of sediments becomes important as the stream meanders across the valley floor. In all stages of stream erosion, by far

7052-555: The whole soil); not resulting from the cementation of a soil horizon. I: ≥ 75% ice (by volume, related to the whole soil), permanent, below an H, O, A, E, B or C layer. W: Permanent water above the soil surface or between layers, may be seasonally frozen. This is the list of suffixes to the master symbols. In brackets is indicated to which master symbols the suffixes can be added. The suffixes e and i have different meanings for organic and mineral layers. I and W layers have no suffixes. Combination of suffixes: 1. The c follows

7138-550: The world (e.g. western Europe ), runoff and erosion result from relatively low intensities of stratiform rainfall falling onto the previously saturated soil. In such situations, rainfall amount rather than intensity is the main factor determining the severity of soil erosion by water. According to the climate change projections, erosivity will increase significantly in Europe and soil erosion may increase by 13–22.5% by 2050 In Taiwan , where typhoon frequency increased significantly in

7224-491: The world (e.g. the mid-western US ), rainfall intensity is the primary determinant of erosivity (for a definition of erosivity check, ) with higher intensity rainfall generally resulting in more soil erosion by water. The size and velocity of rain drops is also an important factor. Larger and higher-velocity rain drops have greater kinetic energy , and thus their impact will displace soil particles by larger distances than smaller, slower-moving rain drops. In other regions of

7310-439: The world. No one system is more correct—as artificial constructs, their utility lies in their ability to accurately describe local conditions in a consistent manner. Due to the different definitions of the horizon symbols, the systems cannot be mixed. In most soil classification systems, horizons are used to define soil types. The German system uses entire horizon sequences for definition. Other systems pick out certain horizons,

7396-515: Was once a thriving center of Pacific herring fishing, which was conducted from the villages of Furubira , Iwanai , and Yoichi . 43°20′01″N 140°20′46″E  /  43.333688°N 140.346214°E  / 43.333688; 140.346214 This Hokkaidō location article is a stub . You can help Misplaced Pages by expanding it . Erosion Erosion is the action of surface processes (such as water flow or wind ) that removes soil , rock , or dissolved material from one location on

#419580