Cirque

As Kar (English and French cirque, engl. / ( Scottish Gaelic ) corrie ), also Kahr, Kaar ( from Old High char " trough Jug" ) refers to cauldron-shaped depressions on mountain slopes below the summit and ridge lines, which of very short glaciers ( cirque glaciers ) have been carved out.

Formation

Kare are mainly from the fact itself downhill moving glacial ice and carried on the base of it rocks ( boulders ) carved out ( Exaration ). The Karrückwände be steepened mainly by frost shattering in bergschrund, which is not covered by ice seam between wall rock and glaciers. The here dissolved by moisture and frequent freeze-thaw cycles debris is then transported away from the glacier. Especially in its center, where the power and the movement of the ice are greatest, the reason is gouged; The result is the cirque hollow, terminating at the Karschwelle and merges into the surrounding relief. The Karschwelle often coincides with the end moraines Kargletschers. Kare therefore go back mainly on forming processes in the ablation area of a glacier.

Orographic context

Cirque glaciers form where more snow accumulates than locally in the area. In heavily in relief terrain Kare therefore are mainly found in sun facing away from slopes. For larger summit plateau itself Kare accumulate in the Leelagen where additionally to, loose snow can accumulate. To the north west wind zone, such as the Black Forest are the Kare predominantly north- to east oriented in the low mountain ranges. Exposures in other than the north-eastern directions are nevertheless not rare. Blending with the passage of time, the back walls of opposite Kare, created mountain ridges whose highest peaks are sharpened games like the Matterhorn, so-called Karl Inge.

Climatic context

The altitude of Karschwellen covers in our experience, almost to the height of the respective orographic snow line, so that it can be concluded with a larger number of ice-free today Karen in an area of previous lower snowline positions. To determine the exposure- independent (climatic ) snowline, are the Karhöhen opposite directions to submit. In the opposite case, when Kare are hidden under the ice of the glacier Nährgebiets larger, they are witnesses of Holocene glaciation phases with lower than today. In periods of very strong glaciation cirque glaciers, however, are rare and of minor importance for paleoclimatology. Glacier Vacant Kare belong to the subnivalen level or even lower altitude levels.

Characteristics typical Kare

Kare are characterized by steepened, lehnsesselförmige Karrückwände and a cirque hollow with verebnetem reason. In particularly striking trained Karen cliffs characterize the Karwand, and the cirque hollow is übertieft beck like. Except for permeable bedrock (loose material karstified rocks ) they are then filled by cirque lakes that may be, however, already zusedimentiert or vermoort. The downslope conclusion can be formed by a rocky Karschwelle ( Karriegel ) or by loose material of terminal moraines of the former Kargletschers. The outflows of cirque lakes with wondering Moränenwällen these walls sometimes cut a gorge or can even break through, after which the Karböden can be like dry completely (example: Nonnenmattweiher ).

The loamy ground moraine of the former glacier seals the base of the cirque from often, so also can occur in karst areas cirque lakes. Influenced by moisture are also many non übertiefte Karböden, firstly because there along the slope water flows, on the other hand, because the source horizons facilitate the formation of Karböden. In fine material rich Karkessel there are often good grazing ground and open water, which is why Kare are preferred Almstandorte, especially in low water content, such as karstic, environment.

The surrounding slopes are mostly covered below the rock walls of rubble and boulders. The reaching down into the boiler debris feet together in its lower part to a common surface debris. Here, the material remains mostly stable enough for the formation of a rubble base ( Syrosem ) with good conditions for wood species. In the deeper layers of the highlands are Kare, except rocky slopes and screes grobblockige, mostly wooded.

Similar landforms of other origin

Kare are fossil landforms after melting of the glacier forming. Subsequent rejuvenation by spillage under boulders or erosive fragmentation can blur the typical, the difference to funnel valleys making up the relief features. Their forms remain in low mountain ranges with their slightly lower shaping dynamics rather than get in the high mountains. Also karst, which removes the surface water erosive action underground, contributes to the maintenance of the molds.

In principle be distinguished from Karen are similar looking, but usually a larger boiler forms that arise further down the valley in the course of large glaciers, especially where the ice forms up to a glacier tongue, or where ice streams flow together. After melting of the glacier stay in a case striking Talschlüsse of trough valleys back or in the other case levels of the valley (called Konfluenzstufen ). In both cases, the combination thrust of ice from different directions creates a region of enhanced vertical erosion and glacier thickness.

Not always easy to distinguish from a sequence of smaller levels of the valley are multistage Kare. With them big Kare Kare have formed smaller during periods of glaciation lower in moderately inclined upper slopes. Transitional forms between Kar and valley glaciers can enter a sequence of karartigen wells produce so-called Treppenkare. They are due to changing dynamics and erosion performance of the ice, but not formed due to different thicknesses of juxtaposed glacier.

In rare cases, forms of glacial Aufschüttungsbereichs with Karen may be confused, such as Gletscherendseen at the foot of levels of the valley, kettle holes ( glacier Sackungsmulden over spilled residues) in slope or hollow shapes along the top of the landslide masses. There are also mixed forms with karst features such as sinkholes (example: Lai da Gonda Grossa on Lischanagletscher ) or with volcanic forms such as co- craters.

The karartig looking valley Fischunkel with periodic lake and the Röthbachfall

Origin of the name

Kar is probably akin to OHG char " vessel, dishes ". It is often in the Bavarian- Tyrolean area as Kår, diminutive of Charles. The word is also Tyrolean for " environment of the alpine hut ", but also " mountain peak ", towards the east in general for " alpine valley " in Carinthia generally for " pasture " or even " hunting ground " ( Koralpe ). Relationship is likely to Croatian Krš " thin soil" made ​​for Slovenian Kras word, from which the word karst is derived, but also with "swamp ", Scottish Kair, ker Icelandic, Danish kär, Kjaer, Norwegian kjerr, Swedish Kärr. Nevertheless, the importance mixed with an early pan-European root car, generally rock on which the terms of scree slopes, as well as the weathering form barrow back (usually dezimeterbreite, parallel grooves in the surfaces verkarstungsfähiger rocks ).

In Scotland and Ireland, the related corries found as a name, in Wales " CWMS " ( " kuhms "), in the north of England coombs for such boiler forms (whose glaciogenic origin 1849 John Ball recognized ).

In Sweden they are Botn (plural Botner " vessel ", related to Vat) called. In the Pyrenees cirques are called oules ( " Circus valleys ") in the High Tatras called the cirque lakes ( lakes ) Slovak tarn, or plesa ( Pl ), Polish oko or staw or stawy ( Pl ).

In particular, are related to the Karwendel Mountains ( where most of the top names of Karen derived including such as the Great Seekarspitze ), the Koralpe in South Tyrol or the Carezza (no Karsee ).

Examples

Kare are quite characteristic for high mountain ranges. But they also occur in low mountain ranges.

A large Kardichte are in plateau- rich northern Black Forest, whose most famous Karsee Mummelsee is similar to the higher of the southern Black Forest Feldsee. Especially deep cirque lakes are the Lac Blanc ( White Lake ) in the Vosges with 60 meters deep and the The Black Jezero ( Black Lake ) in the Bohemian Forest with 40 meters of depth. A very typical Kar in the northern uplands is the Steep Wall Kar in the resin.