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31-519: The Zastler Hut stands in the middle of the Feldberg Nature Reserve below an ice age cirque and below the summit of the Feldberg. Immediately next to a nature trail, it is a popular starting point and destination for walks in the Feldberg region. The Zastler cattle hut was formerly owned by the parish of Zastler, but was taken over by the state in the early 20th century along with the farms in

62-638: A pyramidal peak is created. In some cases, this peak will be made accessible by one or more arêtes. The Matterhorn in the European Alps is an example of such a peak. Where cirques form one behind the other, a cirque stairway results, as at the Zastler Loch in the Black Forest . As glaciers can only originate above the snowline, studying the location of present-day cirques provides information on past glaciation patterns and on climate change. Although

93-577: A larger leeward deposition zone, furthering the process of glaciation. Debris (or till) in the ice also may abrade the bed surface; should ice move down a slope it would have a 'sandpaper effect' on the bedrock beneath, on which it scrapes. Eventually, the hollow may become a large bowl shape in the side of the mountain, with the headwall being weathered by ice segregation, and as well as being eroded by plucking . The basin will become deeper as it continues to be eroded by ice segregation and abrasion. Should ice segregation, plucking and abrasion continue,

124-487: A less common usage, the term cirque is also used for amphitheatre-shaped, fluvial-erosion features. For example, an approximately 200 square kilometres (77 sq mi) anticlinal erosion cirque is at 30°35′N 34°45′E  /  30.583°N 34.750°E  / 30.583; 34.750  ( Negev anticlinal erosion cirque ) on the southern boundary of the Negev highlands . This erosional cirque or makhtesh

155-412: A mountainside near the firn line , they are typically partially surrounded on three sides by steep cliffs . The highest cliff is often called a headwall . The fourth side forms the lip , threshold or sill , the side at which the glacier flowed away from the cirque. Many glacial cirques contain tarns dammed by either till (debris) or a bedrock threshold. When enough snow accumulates, it can flow out

186-454: A short distance then settling again). If the upwards velocity is higher than the settling velocity, the sediment will be transported high in the flow as wash load . As there are generally a range of different particle sizes in the flow, it is common for material of different sizes to move through all areas of the flow for given stream conditions. Sediment motion can create self-organized structures such as ripples , dunes , or antidunes on

217-499: Is a terrain which includes erosion resistant upper structures overlying materials which are more easily eroded. Notes Citations Fluvial In geography and geology , fluvial sediment processes or fluvial sediment transport are associated with rivers and streams and the deposits and landforms created by sediments . It can result in the formation of ripples and dunes , in fractal -shaped patterns of erosion, in complex patterns of natural river systems, and in

248-668: Is available in a mattress room . The hut is only accessible on foot, the nearest car parks are on the Rinken (approach from Hinterzarten ), on the Feldberg, near the Erlenbacher Hut and the Stollenbacher Hut and in the valley head of the Zastlertal valley. 47°52′47″N 8°0′26.8″E  /  47.87972°N 8.007444°E  / 47.87972; 8.007444 Cirque A cirque ( French: [siʁk] ; from

279-666: Is enormous. It has been estimated that the Mississippi River annually carries 406 million tons of sediment to the sea, the Yellow River 796 million tons, and the Po River in Italy 67 million tons. The names of many rivers derive from the color that the transported matter gives the water. For example, the Yellow River (Huang He) in China is named after the hue of the sediment it carries, and

310-440: Is formed by intermittent river flow cutting through layers of limestone and chalk leaving sheer cliffs. A common feature for all fluvial -erosion cirques is a terrain which includes erosion resistant upper structures overlying materials which are more easily eroded. Glacial cirques are found amongst mountain ranges throughout the world; 'classic' cirques are typically about one kilometer long and one kilometer wide. Situated high on

341-479: 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 glacial overdeepening. The dam itself can be composed of moraine , glacial till , or a lip of the underlying bedrock . The fluvial cirque or makhtesh , found in karst landscapes,

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372-416: 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

403-411: Is transported as either bedload (the coarser fragments which move close to the bed) or suspended load (finer fragments carried in the water). There is also a component carried as dissolved material. For each grain size there is a specific flow velocity at which the grains start to move, called entrainment velocity . However the grains will continue to be transported even if the velocity falls below

434-463: The White Nile is named for the clay it carries. The main kinds of fluvial processes are: The major fluvial (river and stream) depositional environments include: Rivers and streams carry sediment in their flows. This sediment can be in a variety of locations within the flow, depending on the balance between the upwards velocity on the particle (drag and lift forces), and the settling velocity of

465-570: The Kirchzarten Forestry Office. The new, larger hut was opened on 12 June 1912. In February 1942 the cattle hut was partially collapsed by an avalanche and became increasingly dilapidated in the years that followed, until it was rebuilt in the early post-war period. In December 2011 the Zastler Hut was cut off from the outside world for six days by a rockslide . During the hut open season (mid May to end October) overnight accommodation

496-452: The Latin word circus ) is an amphitheatre -like valley formed by glacial erosion . Alternative names for this landform are corrie (from Scottish Gaelic : coire , meaning a pot or cauldron ) and cwm ( Welsh for 'valley'; pronounced [kʊm] ). A cirque may also be a similarly shaped landform arising from fluvial erosion. The concave shape of a glacial cirque

527-552: The Zastler valley. Since 1951 and 1962 it became once again the property of the then independent parish of Zastler which now belongs to the municipality of Oberried . Since 2001 the hut has been privately owned. In 1883 the herdsman's residence and cattle shed were demolished and a new, larger cattle hut with herdsman's quarters and farming rights was built. In the following years the hut was frequently visited by artists and naturalists from Freiburg, as well as walkers and skiers to whom it

558-407: The bed is composed of loose sediment which can be mobilized by such stresses, then the bed will be lowered purely by clearwater flow. In addition, if the river carries significant quantities of sediment , this material can act as tools to enhance wear of the bed ( abrasion ). At the same time the fragments themselves are ground down, becoming smaller and more rounded ( attrition ). Sediment in rivers

589-451: The bergschrund changes very little, however, studies have shown that ice segregation (frost shattering) may happen with only small changes in temperature. Water that flows into the bergschrund can be cooled to freezing temperatures by the surrounding ice, allowing freeze-thaw free mechanisms to occur. If two adjacent cirques erode toward one another, an arête , or steep sided ridge, forms. When three or more cirques erode toward one another,

620-419: The development of floodplains and the occurrence of flash floods . Sediment moved by water can be larger than sediment moved by air because water has both a higher density and viscosity . In typical rivers the largest carried sediment is of sand and gravel size, but larger floods can carry cobbles and even boulders . When the stream or rivers are associated with glaciers , ice sheets , or ice caps ,

651-406: The dimensions of the cirque will increase, but the proportion of the landform would remain roughly the same. A bergschrund forms when the movement of the glacier separates the moving ice from the stationary ice, forming a crevasse. The method of erosion of the headwall lying between the surface of the glacier and the cirque's floor has been attributed to freeze-thaw mechanisms. The temperature within

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682-470: The entrainment velocity due to the reduced (or removed) friction between the grains and the river bed. Eventually the velocity will fall low enough for the grains to be deposited. This is shown by the Hjulström curve . A river is continually picking up and dropping solid particles of rock and soil from its bed throughout its length. Where the river flow is fast, more particles are picked up than dropped. Where

713-524: The opening of the bowl and form valley glaciers which may be several kilometers long. Cirques form in conditions which are favorable; in the Northern Hemisphere the conditions include the north-east slope, where they are protected from the majority of the Sun's energy and from the prevailing winds. These areas are sheltered from heat, encouraging the accumulation of snow; if the accumulation of snow increases,

744-568: The particle. These relationships are shown in the following table for the Rouse number , which is a ratio of sediment settling velocity (fall velocity) to upwards velocity. Rouse = Settling velocity Upwards velocity from lift and drag = w s κ u ∗ {\displaystyle {\textbf {Rouse}}={\frac {\text{Settling velocity}}{\text{Upwards velocity from lift and drag}}}={\frac {w_{s}}{\kappa u_{*}}}} where If

775-408: The river flow is slow, more particles are dropped than picked up. Areas where more particles are dropped are called alluvial or flood plains, and the dropped particles are called alluvium . Even small streams make alluvial deposits, but it is in floodplains and deltas of large rivers that large, geologically-significant alluvial deposits are found. The amount of matter carried by a large river

806-472: The snow turns into glacial ice. The process of nivation follows, whereby a hollow in a slope may be enlarged by ice segregation weathering and glacial erosion. Ice segregation erodes the vertical rock face and causes it to disintegrate, which may result in an avalanche bringing down more snow and rock to add to the growing glacier. Eventually, this hollow may become large enough that glacial erosion intensifies. The enlarging of this open ended concavity creates

837-469: The tallest volcanic structure in the Indian Ocean . The island consists of an active shield-volcano ( Piton de la Fournaise ) and an extinct, deeply eroded volcano ( Piton des Neiges ). Three cirques have eroded there in a sequence of agglomerated, fragmented rock and volcanic breccia associated with pillow lavas overlain by more coherent, solid lavas. A common feature for all fluvial-erosion cirques

868-407: The term glaciofluvial or fluvioglacial is used, as in periglacial flows and glacial lake outburst floods . Fluvial sediment processes include the motion of sediment and erosion or deposition on the river bed . The movement of water across the stream bed exerts a shear stress directly onto the bed. If the cohesive strength of the substrate is lower than the shear exerted, or

899-404: The upwards velocity is approximately equal to the settling velocity, sediment will be transported downstream entirely as suspended load . If the upwards velocity is much less than the settling velocity, but still high enough for the sediment to move (see Initiation of motion ), it will move along the bed as bed load by rolling, sliding, and saltating (jumping up into the flow, being transported

930-587: Was formed by intermittent river flow in the Makhtesh Ramon cutting through layers of limestone and chalk, resulting in cirque walls with a sheer 200 metres (660 ft) drop. The Cirque du Bout du Monde is another such feature, created in karst terraine in the Burgundy region of the department of Côte-d'Or in France . Yet another type of fluvial erosion-formed cirque is found on Réunion island , which includes

961-567: Was rented in winter. The hut used to be supplied with water from the Zastlerbach . In 1954 three springs were impounded on the Osterrain in order to supply the nearby Freiburger Hut of the Ski-Club Freiburg and the Zastler Hut with drinking water, which was then connected in 1956. Since 1963 both huts have had electricity. After the cattle hut burned down on 12 February 1910, it was rebuilt by

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