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Geologically, a fjord ( or ) is a long, narrow inlet with steep sides, created in a valley carved by glacial activity.

Formation

Fjords are formed when a glacier cuts a v-shaped valley by abrasion of the surrounding bedrock. Many such valleys were formed during the recent ice age. Glacial melting is accompanied by rebound of Earth's crust as the ice load and eroded sediment is removed (also called isostasy or glacial rebound). In some cases this rebound is faster than sea level rise. Most fjords are deeper than the adjacent sea; Sognefjordmarker, Norwaymarker, reaches as much as below sea level. Fjords generally have a sill or rise at their mouth caused by the previous glacier's terminal moraine, in many cases causing extreme currents and large saltwater rapids (see skookumchuck). Saltstraumenmarker in Norway is often described as the worlds strongest tidal current. These characteristics distinguish fjords from rias (e.g. the Bay of Kotormarker), which are drowned valleys flooded by the rising sea.



Fjord features and variations

Coral reefs

As late as 2000, some of the world's largest coral reefs were discovered along the bottoms of the Norwegian fjords. These reefs were found in fjords from the north of Norway to the south. The marine life on the reefs is believed to be one of the most important reasons why the Norwegian coastline is such a generous fishing ground. Since this discovery is fairly new, little research has been done. The reefs are host to thousands of lifeforms such as plankton, coral, anemones, fish, several species of shark, and many more. Most are specially adapted to life under the greater pressure of the water column above it, and the total darkness of the deep sea.

New Zealand's fjords are also host to deep sea corals, but a surface layer of dark fresh water allows these corals to grow in much shallower water than usual. An underwater observatory in Milford Soundmarker allows tourists to view them without diving.

Skerries

In some places near the seaward margins of areas with fjords, the ice-scoured channels are so numerous and varied in direction that the rocky coast is divided into thousands of island blocks, some large and mountainous while others are merely rocky points or rock reefs, menacing navigation. These are called skerries. The term skerry is derived from the Old Norse sker, which means a rock in the sea.

Skerries are most commonly formed at the outlet of fjords where submerged glacially formed valleys perpendicular to the coast join with other cross valleys in a complex array. The island fringe of Norway is such a group of skerries (called a skjærgård); many of the cross fjords are so arranged that they parallel the coast and provide a protected channel behind an almost unbroken succession of mountainous islands and skerries. By this channel one can travel through a protected passage almost the entire route from Stavangermarker to North Cape, Norway. The Blindleia is a skerry-protected waterway that starts near Kristiansandmarker in southern Norway, and continues past Lillesandmarker. The Swedishmarker coast along Bohuslänmarker is likewise skerry guarded. The Inside Passage provides a similar route from Seattlemarker, Washingtonmarker and Vancouvermarker, British Columbiamarker to Skagwaymarker, Alaskamarker. Yet another such skerry protected passage extends from the Straits of Magellanmarker north for .

False fjords

The differences in usage between the English and the Scandinavian languages have contributed to confusion in the use of the term fjord. Bodies of water which are clearly fjords in Scandinavian languages are not considered fjords in English; similarly bodies of water which would clearly not be fjords in the Scandinavian sense have been named or suggested to be fjords. Examples of this confused usage follow.

The Bay of Kotormarker in Montenegromarker has been suggested by some to be a fjord, but is in fact a drowned river canyon or ria. Similarly the Limmarker bay in Istriamarker, Croatiamarker, is sometimes called "Lim fjord" although it is not actually a fjord carved by glacial erosion but instead a ria dug by the river Pazinčica. The Croats call it Limski kanal which does not transliterate precisely to the English equivalent either.

Limfjordmarker in the north of Denmarkmarker is a fjord in the Scandinavian sense, but is not a fjord in the English sense. In English it would be called a channel, since it separates the North Jutlandic Islandmarker (Vendsyssel-Thy) from the rest of Jutland.

While the long fjord-like bays of the New Englandmarker coast are sometimes referred to as "fiards", the only glacially-formed fjord-like feature in New England is Somes Soundmarker in Mainemarker.

The fjords in Finnmarkmarker (Norway), which are fjords in the Scandinavian sense of the term, are considered by some to be false fjords. Although glacially formed, most Finnmark fjords lack the classic hallmark steep-sided valleys of the more southerly Norwegian fjords since the glacial pack was deep enough to cover even the high grounds when they were formed.

In Acapulcomarker, Mexicomarker, the calanquesmarker—narrow, rocky inlets—on the western side of the city, where the famous cliff-divers perform daily, are described in the city's tourist literature as being fjords.

Freshwater fjords

Some Norwegian freshwater lakes which have formed in long glacially carved valleys with terminal moraines blocking the outlet follow the Norwegian naming convention; they are named fjords. Outside of Norway, the three western arms of New Zealandmarker's Lake Te Anaumarker are named North Fiord, Middle Fiord and South Fiord. Another freshwater "fjord" in a larger lake is Baie Fine, located on the northeastern coast of Georgian Baymarker of Lake Huronmarker in Ontariomarker. Western Brook Pondmarker, in Newfoundland'smarker Gros Morne National Parkmarker, is also often described as a fjord, but is actually a freshwater lake cut off from the sea, so is not a fjord in the English sense of the term. Such lakes are sometimes called "fjord lakes". Okanagan Lakemarker was the first North American lake to be so described, in 1962. The bedrock there has been eroded up to below sea level, which is below the surrounding regional topography. Fjord lakes are common on the inland lea of the Coast Mountainsmarker and Cascade Range; notable ones include Lake Chelanmarker, Seton Lakemarker, Chilko Lakemarker, and Atlin Lakemarker. Kootenay Lakemarker, Slocan Lake and others in the basin of the Columbia River are also fjord-like in nature, and created by glaciation in the same way. Along the British Columbia Coast, a notable fjord-lake is Owikeno Lakemarker, which is a freshwater extension of Rivers Inletmarker. Another area notable for fjord lakes is northern Italymarker and southern Switzerlandmarker - Lake Comomarker and its neighbours.

Etymology

Important fjords and lakes in Norway.
Note: The part of the map showing the northern fjords has a considerably smaller scale.
With Indo European origin (*prtús from *por- or *per) in the verb fara (travelling/ferrying), the Norse noun substantive fjǫrðr means a "lake-like" waterbody used for passage and ferrying.

The Scandinavian fjord, Proto-Scandinavian *ferþuz, is the origin for similar European words: Icelandic fjörður, Swedish fjärd (for Baltic waterbodies), Scottish firth. The Danish even use fjord for shallow lagoons as well as minor bodies of water cut into land. The Germans call the narrow long bays of Schleswig-Holsteinmarker Förde but the Norwegian bays Fjord. Perhaps the word is also related to English ford (which is in German Furt), Greek poros, Latin portus and the Dutch word voorde (for mudflat, cf. Vilvoorde).

As a loanword from Norwegian, it is one of the few words in the English language to start with the digraph fj.

Scandinavian usage

Use of the word fjord (including the eastern Scandinavian form fjärd) is more general in the Scandinavian languages than in English. In Scandinavia, fjord is used for a narrow inlet of the sea in Norway, Denmark and western Sweden, but this is not its only application. In Norway, the usage is closest to the Old Norse, with fjord used for both a firth and for a long, narrow inlet. In eastern Norway, the term is also applied to long narrow freshwater lakes (for instance Mjøsamarker [commonly referred to as fjorden], Randsfjordenmarker and Tyrifjordenmarker) and sometimes even to rivers (in local usage, for instance in Flåmarker in Hallingdalmarker, the Hallingdal river is referred to as fjorden). In east Sweden, the name fjärd is used in a synonymous manner for bays, bights and narrow inlets on the Swedish Baltic Seamarker coast, and in most Swedish lakes. This latter term is also used for bodies of water off the coast of Finland where Finland Swedish is spoken. In Danish, the word may even apply to shallow lagoons. In modern Icelandic, fjörður is still used with the broader meaning of firth or inlet. In the Finnish language, a word vuono is used although there is only one fjord in Finland.

The German use of the word Förde for long narrow bays on their Baltic Sea coastline, indicates a common Germanic origin of the word. The landscape consists mainly of moraine heaps. The "Förden" and some "fjords" on the east side of Denmark are also of glacial origin. But while the glaciers digging "real" fjords moved from the mountains to the sea, in Denmark and Germany they were tongues of a huge glacier covering the bassin of which is now the Baltic Sea. See Förden and East Jutland Fjorde.

Whereas fjordnames mostly describe bays (though not always geological fjords), straits in the same regions typically are named Sund, in Scandinavian languages as well as in German. The word is related to "to sunder" in the meaning of "to separate". So the use of Sound to name fjords in North America and New Zealand differs from the European meaning of that word.

The name of Wexfordmarker in Irelandmarker is originally derived from Veisafjǫrðr ("inlet of the mud flats") in Old Norse, as used by the Viking settlers — though the place does not have a fjord in the more narrow modern meaning.

Locations

The principal mountainous regions where fjords have formed are in the higher middle latitudes and the high latitudes reaching to 80°N (Svalbard, Greenland), where, during the glacial period, many valley glaciers descended to the then-lower sea level. The fjords develop best in mountain ranges against which the prevailing westerly marine winds are orographically lifted over the mountainous regions, resulting in abundant snowfall to feed the glaciers. Hence coasts having the most pronounced fjords include the west coast of Europe, the west coast of North America from Puget Soundmarker to Alaska, the west coast of New Zealand, and the west coast of South America and to south-western Tasmaniamarker. In Tasmania there are many small Fjords with mountains surrounding reaching 1000 m in southern districts, though these are not glaciated they are often covered in snow, sometimes in summer. These fjords have formed by past glaciers ripping through to the sea.

Principal glaciated regions

Magdalenafjord in the high arctic archipelago Svalbard




Other glaciated regions

Other regions have fjords, but many of these are less pronounced due to more limited exposure to westerly winds and less pronounced relief. Areas include:











Extreme fjords

The longest fjords in the world are:
  1. Scoresby Sundmarker in Greenland -
  2. Sognefjordmarker in Norway -
  3. Limfjordenmarker in Denmark -
  4. Hardangerfjordmarker in Norway -


Deep fjords include:
  1. Skelton Inlet in Antarctica -
  2. Sognefjord in Norway - (the mountains then rise to up to )
  3. Messier Channelmarker in Chile -


Even deeper is the Vanderford Valley ( ), carved by Antarctica's Vanderford Glaciermarker. This undersea valley lies offshore, however, and so is not a fjord.

References

  1. Institute of Marine Research: Coral reefs in Norway
  2. Paddy Ryan. Fiords - Underwater rock walls and basins, Te Ara - the Encyclopedia of New Zealand. Updated 21 September 2007. Accessed 2008-04-18.


External links




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