Transfluence

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Gepatschferner from the south, in the center of the picture the transfluence to Langtauferer Ferner (front), the main stream of the Gepatschferner flows north

Transfluence (from Latin trans , '(towards) through', '(towards) over', + fluere , 'flow') is a term from glaciology and describes the overflow of glacial ice over a former glacier divide, whereby ice enters the Another glacier's nutrient zone .

Sometimes a distinction is made between transfluence and diffluence . Then Diffluenz describes the overflow of a glacier over a side valley slope into a neighboring valley, whereas transfluence is used when the ice already crosses a main watershed in the valley's origin. However, these two terms are often used synonymously.

geomorphology

The geomorphographic designation for pass crossings where there is or was a transfluence or diffluence is transfluence pass . Many higher mountain passes in the Alps were transfluence passes during the last glacial period . An example of this is the Simplon Pass , where during the last ice age maximum the ice coming from the Rhone Ice Dome - the counterpart of today's Rhone Glacier - "erupted" from the Rhone Valley near Brig and flowed south over the Simplon Pass into the northern Italian Alpine foothills. Such large-scale glacial tranfluences can be reconstructed using erratic blocks , among other things . As with a diffluence, glacial erosion can decrease on the bedrock of the main stream below a transfluence due to the reduced ice pressure and the slower flow velocity . After the glaciers have retreated, this can be the reason for the main valley to flatten at this point; it is even believed that a diffluence stage could form, a terrain stage opposite to the general slope of the valley.

Recent transfluences

The ice sheets in Greenland and Antarctica are also subject to major transfluences today. For example, ice from the East Antarctic Ice Sheet flows to the west at an altitude of 4000 meters over ice-covered gaps in the Transantarctic Mountains and thus reaches the Ross Ice Shelf .

Up until a few years ago there was a transfluence in the Ötztal Alps near the Gepatschferner , with ice flowing over parts of the Langtaufer ice walls via a mighty ice break to the Langtauferer Ferner in the south. The direct connection was broken at the beginning of the 21st century, there is still mass transfer through ice falls . The ice thus overcomes the Danube-Etsch watershed at this point .

However, it should be noted that some of the glacier connections that look like transfluences are actually firn saddles, as there is no ice transfer.

Individual evidence

  1. ↑ a b c Editing of the Swiss Lexicon, Glacier Commission of the Swiss Academy of Natural Sciences (ed.): Glaciers, snow and ice. Verlag Schweizer Lexikon Mengis + Ziehr, Horw / Luzern 1993, ISBN 3-9520144-2-7 , p.
  2. ↑ David Leslie Linton: The Forms of Glacial Erosion. In: Transactions and Papers (Institute of British Geographers). No. 33, 1963, pp. 1–28 ( abstract )
  3. ↑ a b Armin Dielford, Ralf Hetzel: The deglaciation history of the Simplon region (southern Swiss Alps) constrained by 10 Be exposure dating of ice-molded bedrock surfaces. In: Quaternary Science Reviews. Volume 84, 2014, pp. 26-38 ( doi : 10.1016 / j.quascirev.2013.11.008 )
  4. ↑ a b MJ Hambrey: Glacial Environments. UBC Press, Vancouver 1994, ISBN 0-7748-0510-2 , p. 91 ( online )
  5. ↑ Transfluenz at Spektrum.de
  6. ↑ Christoph Knoll, Hanns Kerschner: A glacier inventory for South Tyrol, Italy, based on airborne laser-scanner data. In: Annals of Glaciology. Volume 50, 2009, pp. 46–52 ( online ; PDF; 287 kB)