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Cirques
A (; from the Latin word ) is an amphitheatre-like valley formed by glacial erosion. Alternative names for this landform are corrie (from , meaning a pot or cauldron) and ; ). A cirque may also be a similarly shaped landform arising from fluvial erosion. The concave shape of a glacial cirque is open on the downhill side, while the cupped section is generally steep. Cliff-like slopes, down which ice and glaciated debris combine and converge, form the three or more higher sides. The floor of the cirque ends up bowl-shaped, as it is the complex convergence zone of combining ice flows from multiple directions and their accompanying rock burdens. Hence, it experiences somewhat greater erosion forces and is most often overdeepened below the level of the cirque's low-side outlet (stage) and its down-slope (backstage) valley. If the cirque is subject to seasonal melting, the floor of the cirque most often forms a tarn (small lake) behind a dam, which marks the downstream limit of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pyramidal Peak
A pyramidal peak, sometimes called a glacial horn in extreme cases, is an angular, sharply pointed mountain peak which results from the cirque erosion due to multiple glaciers diverging from a central point. Pyramidal peaks are often examples of nunataks. Formation Glaciers, typically forming in drainages on the sides of a mountain, develop bowl-shaped depression (geology), basins called cirques (sometimes called 'corries' – from Scottish Gaelic [kʰəɾə] (a bowl) – or s). Cirque glaciers have rotational sliding that abrades the floor of the basin more than walls and that causes the bowl shape to form. As cirques are formed by glaciation in an alpine environment, the headwall and ridges between parallel glaciers called arêtes become more steep and defined. This occurs due to Frost wedging, freeze/thaw and mass wasting beneath the ice surface. It is widely held that a common cause for headwall steepening and extension headward is the crevasses known as bergschrund that ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glacial Tarn Formation EN
A glacier (; or ) is a persistent body of dense ice, a form of rock, that is constantly moving downhill under its own weight. A glacier forms where the accumulation of snow exceeds its Ablation#Glaciology, ablation over many years, often centuries. It acquires distinguishing features, such as crevasses and seracs, as it slowly flows and deforms under stresses induced by its weight. As it moves, it abrades rock and debris from its substrate to create landforms such as cirques, moraines, or fjords. Although a glacier may flow into a body of water, it forms only on land“Glacier, N., Pronunciation.” Oxford English Dictionary, Oxford University Press, Oxford UP, June 2024, https://doi.org/10.1093/OED/7553486115. Accessed 25 Jan. 2025. and is distinct from the much thinner sea ice and lake ice that form on the surface of bodies of water. On Earth, 99% of glacial ice is contained within vast ice sheets (also known as "continental glaciers") in the polar regions, but glaciers may ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glacier
A glacier (; or ) is a persistent body of dense ice, a form of rock, that is constantly moving downhill under its own weight. A glacier forms where the accumulation of snow exceeds its ablation over many years, often centuries. It acquires distinguishing features, such as crevasses and seracs, as it slowly flows and deforms under stresses induced by its weight. As it moves, it abrades rock and debris from its substrate to create landforms such as cirques, moraines, or fjords. Although a glacier may flow into a body of water, it forms only on land“Glacier, N., Pronunciation.” Oxford English Dictionary, Oxford UP, June 2024, https://doi.org/10.1093/OED/7553486115. Accessed 25 Jan. 2025. and is distinct from the much thinner sea ice and lake ice that form on the surface of bodies of water. On Earth, 99% of glacial ice is contained within vast ice sheets (also known as "continental glaciers") in the polar regions, but glaciers may be found in mountain ranges on ever ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Overdeepening
Overdeepening is a characteristic of Depression (geology), basins and valleys eroded by glaciers. An overdeepened valley profile is often eroded to depths which are hundreds of metres below the lowest continuous surface line (the thalweg) along a valley or watercourse. This phenomenon is observed under modern day glaciers, in salt-water fjords and fresh-water lakes remaining after glaciers melt, as well as in tunnel valleys which are partially or totally filled with sediment. When the Channel (geography), channel produced by a glacier is filled with debris, the subsurface Geomorphology, geomorphic structure is found to be erosionally cut into bedrock and subsequently filled by sediments. These overdeepened cuts into bedrock structures can reach a depth of several hundred metres below the valley floor. Overdeepened fjords and lakes have significant economic value as harbours and fisheries. Overdeepened basins and valleys filled with sediment (termed tunnel valleys) are of particular ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nivation
Nivation is the set of geomorphic processes associated with snow patches. The primary processes are mass wasting and the freeze-and-thaw cycle, in which fallen snow gets compacted into firn or névé. The importance of the processes covered by the term ''nivation'' with regard to the development of periglacial landscapes has been questioned by scholars, and the use of the term is discouraged. ''Nivation'' has come to include various subprocesses related to snow patches which may be immobile or semi-permanent. These sub-processes include erosion (if any) or initiation of erosion, weathering, and meltwater flow from beneath the snow patch. Weathered particles are moved downslope by creep, solifluction and rill wash. Over time, this leads to the formation of nivation hollows which, when enlarged, can be the beginnings of a cirque A (; from the Latin word ) is an amphitheatre-like valley formed by Glacier#Erosion, glacial erosion. Alternative names for this landform are corr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ice Segregation
Ice segregation is the geological phenomenon produced by the formation of ice lenses, which induce erosion when moisture, diffused within soil or rock, accumulates in a localized zone. The ice initially accumulates within small collocated pores or pre-existing cracks, and, as long as the conditions remain favorable, continues to collect in the ice layer or ice lens, wedging the soil or rock apart. Ice lenses grow parallel to the surface and several centimeters to several decimeters (inches to feet) deep in the soil or rock. Studies between 1990 and present have demonstrated that rock fracture by ice segregation (i.e., the fracture of intact rock by ice lenses that grow by drawing water from their surroundings during periods of sustained subfreezing temperatures) is a more effective weathering process than the freeze-thaw process which older texts proposed."Periglacial weathering and headwall erosion in cirque glacier bergschrunds"; Johnny W. Sanders, Kurt M. Cuffey, Jeffrey R. M ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Abrasion (geology)
Abrasion is a process of weathering that occurs when material being transported wears away at a surface over time, commonly occurring with ice and glaciers. The primary process of abrasion is physical weathering. Its the process of friction caused by scuffing, scratching, wearing down, marring, and rubbing away of materials. The intensity of abrasion depends on the hardness, concentration, velocity and mass of the moving particles. Abrasion generally occurs in four ways: glaciation slowly grinds rocks picked up by ice against rock surfaces; solid objects transported in river channels make abrasive surface contact with the bed with ppl in it and walls; objects transported in waves breaking on coastlines; and by wind transporting sand or small stones against surface rocks. Abrasion is the natural scratching of bedrock by a continuous movement of snow or glacier downhill. This is caused by a force, friction, vibration, or internal deformation of the ice, and by sliding over the rocks ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bergschrund
A bergschrund (from the German for ''mountain cleft''; sometimes abbreviated in English to "schrund") is a crevasse that forms where moving glacier ice separates from the stagnant ice or firn above. It is often a serious obstacle for mountaineering, mountaineers. Bergschrunds extend to the bedrock, and can have a depth of well over . A bergschrund is distinct from a randkluft, which is a crevasse with one side formed by rock. The randkluft arises in part from the melting of the ice due to the presence of the warmer rock face. However, a randkluft is sometimes called a bergschrund. The French word ''rimaye'' encompasses both randklufts and bergschrunds. In a corrie or cirque, the bergschrund is positioned at the rear, parallel to the back wall of the corrie. It is caused by the rotational movement of the glacier. In a longitudinal glacier, the bergschrund is at the top end of the glacier at a right angle to the flow of the glacier. It is caused by the downwards flow of the glacier ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bowl (vessel)
A bowl is a typically round dish or container generally used for preparing, serving, storing, or consuming food. The interior of a bowl is characteristically shaped like a spherical cap, with the edges and the bottom, forming a seamless curve. This makes bowls especially suited for holding liquids and loose food, as the contents of the bowl are naturally concentrated in its center by the force of gravity. The exterior of a bowl is most often round, but can be of any shape, including rectangular. The size of bowls varies from small bowls used to hold a single serving of food to large bowls, such as punch bowls or salad bowls, that are often used to hold or store more than one portion of food. There is some overlap between bowls, cups, and plates. Very small bowls, such as the tea bowl, are often called cups, while plates with especially deep wells are often called bowls. In many cultures, bowls are the most common kind of vessel used for serving and eating food. Historica ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plucking (glaciation)
Plucking, also referred to as ''quarrying'', is a Glacier, glacial phenomenon that is responsible for the weathering and erosion of pieces of bedrock, especially large "joint blocks". This occurs in a type of glacier called a "valley glacier". As a glacier moves down a valley, friction causes the basal sliding, basal ice of the glacier to melt and infiltrate joints (cracks) in the bedrock. The freezing and thawing action of the ice enlarges, widens, or causes further cracks in the bedrock as it changes volume across the ice/water phase transition (a form of hydraulic wedging), gradually loosening the rock between the joints. This produces large chunks of rock called joint blocks. Eventually these joint blocks come loose and become trapped in the glacier. In this way, plucking has been linked to regelation. Rocks of all sizes can become trapped in the bottom of the glacier. Joint blocks up to three meters have been "plucked" and transported. These entrained rock fragments can also ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
