Fjord
A fjord ( Old Norse fjǫrðr , Norwegian fjord , spoken fjuur ) is an arm of the sea that extends far into the mainland and is created by a seaward migrating valley glacier. The German word Förde and the English Firth have the same etymological origin . However, while the Scottish Firths are actually real fjords, the fjords on the Baltic coast were created by tongues of a glacial ice sheet migrating inland , which means that fjords do not fall under the geological definition of a fjord.
Emergence
Fjords are created by valley glaciers that flow downwards from their area of origin, the Kar , through existing river valleys . The original valley shape is overprinted by the glacier, as the ice carries along rock ( detraction ) and this further erodes the rock. The original valley, for example a Kerbtal , becomes wider and deeper and receives its typical shape as a U-valley, also called a trough valley , with very steep slopes. The bottom of a fjord can be more than 1000 m below sea level. There is often a shoal in the mouth of the fjord that is related to the floating of the glacier tongue . With the retreat of the glaciers at the end of the Ice Age, the sea was able to flow into the deep valleys.
Most of the lakes at the edge of the Alps have the same Ice Age origins as fjords. The lake floors of five lakes on the southern edge of the Alps are even partially below sea level ( Lake Garda : -281 m slm , Lake Como : -228 m slm , Lake Maggiore : -180 m above sea level , Lake Iseo : -66 m slm , Lake Lugano : - 17 m slm ).
Fjord coasts are uplift coasts . Relieved by the melting of the glacial ice sheet, the land rises. There are fjords wherever mountains near the coast were or still are heavily iced. A fjord in a low mountain range is called fjärde in geomorphology .
Demarcation
Geologically
- In the intensive interlocking of land and sea that characterizes the west coast of Norway , the mountain ridge between two fjords can also continue as an island chain (which would represent mountain peaks at lower sea level). In addition to the “classic” fjords that are surrounded on three sides by the mainland, there are also those that are partially or completely bordered by chains of islands. In some cases, the islands are only separated from each other and from the mainland by very narrow channels . This form is also geologically real fjords, although the mountain ranges are not continuously visible.
- The fjords of Schleswig-Holstein and other similar estuaries East Jutland , in contrast to the fjords of landward glaciers of the Ice Age, the Baltic Sea covering ice sheet upslope been milled and flooded by raising sea levels. In Denmark they are called fjords because the Danish language does not distinguish between the two terms. Examples are Mariagerfjord , Limfjord and others. Such coastal waters are, however, to be classified as a fjord, lagoon or lagoon .
- As Ria flooded by rising sea river valleys are called, which have arisen without glacial action. Examples can be found in the northwest of the Iberian Peninsula .
Rias and fjords are thus forms on depression coasts .
Under international law
Under international law , narrow bulges in the sea are referred to as fjords or fjords, regardless of their geological origin. Therefore, not all geomorphological fjords are also such under international law, conversely, many legally so designated by no means geomorphologically such.
Occurrence
Norway in particular is known for its fjord coast in the west of the country , but also Scotland , where they are often called the Firth . Also, Iceland , the Faroe Islands, Greenland , Svalbard , Franz Josef Land , Novaya Zemlya , Alaska , British Columbia , Labrador , Newfoundland and Baffin Iceland are rich in fjords. In the southern hemisphere, fjords characterize the landscape on the South Island of New Zealand , Chilean Patagonia , Tierra del Fuego , Kerguelen , South Georgia and the Falkland Islands .
On the Antarctic Peninsula as well as on Greenland and Baffin Island, fjords are currently emerging or deepening due to the continuing glaciation and calving of the glaciers .
On the west coast of Newfoundland there are a number of former fjords whose direct connection to the sea has been lost in the past. Examples include Bakers Brook Pond , Ten Mile Pond , Trout River Big Pond, and Western Brook Pond - all located in Gros Morne National Park.
See also
- List of fjords , sorted by country, selected for some countries, Norway with map
Web links
Individual evidence
- ↑ Coastal elevation in Scotland ( Memento of the original dated November 6, 2007 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. (in English)
- ↑ George Schultz: Fjärdenküste. In: Georg Schultz: Lexicon for determining the landforms in maps (= Berlin geographic studies. 28). Institute for Geography of the Technical University of Berlin, Berlin 1989, ISBN 3-7983-1283-4 , pp. 85 ff., ( Online in the Google book search).
