A glacier in eastern Greenland flowing through a fjord carved by the movement of iceIllustration of how a fjord is createdSørfjorden (Hardanger) withSandvinvatnet and Odda Valley can be clearly seen as continuation of the fjord.Odda sits on theisthmus.Folgefonna on the right hand.
A true fjord is formed when aglacier cuts aU-shaped valley byice segregation andabrasion of the surrounding bedrock.[6] According to the standard model, glaciers formed in pre-glacial valleys with a gently sloping valley floor. The work of the glacier then left anoverdeepened U-shaped valley that ends abruptly at a valley or trough end. Such valleys are fjords when flooded by the ocean. Thresholds above sea level create freshwater lakes.[7] Glacial melting is accompanied by the rebounding of Earth's crust as the ice load and eroded sediment is removed (also calledisostasy or glacial rebound). In some cases, this rebound is faster thansea level rise. Most fjords aredeeper than the adjacent sea;Sognefjord,Norway, reaches as much as 1,300 m (4,265 ft) belowsea level. Fjords generally have a sill or shoal (bedrock) at their mouth caused by the previous glacier's reduced erosion rate andterminal moraine.[8] In many cases this sill causes extreme currents and large saltwater rapids (seeskookumchuck).Saltstraumen in Norway is often described as the world's strongesttidal current. These characteristics distinguish fjords fromrias (such as theBay of Kotor), which are drowned valleys flooded by the rising sea.Drammensfjorden is cut almost in two by theSvelvik "ridge", a sandy moraine that was below sea level when it was covered by ice, but after the post-glacial rebound reaches 60 m (200 ft) above the fjord.[9]
In the 19th century,Jens Esmark introduced the theory that fjords are or have been created by glaciers and that large parts of Northern Europe had been covered by thick ice in prehistory.[10] Thresholds at the mouths and overdeepening of fjords compared to the ocean are the strongest evidence of glacial origin,[11] and these thresholds are mostly rocky. Thresholds are related to sounds and low land where the ice could spread out and therefore have less erosive force.John Walter Gregory argued that fjords are oftectonic origin and that glaciers had a negligible role in their formation. Gregory's views were rejected by subsequent research and publications. In the case of Hardangerfjord the fractures of theCaledonian fold has guided the erosion by glaciers, while there is no clear relation between the direction of Sognefjord and the fold pattern.[10] This relationship between fractures and direction of fjords is also observed inLyngen.[12] Preglacial,tertiary rivers presumably eroded the surface and created valleys that later guided the glacial flow and erosion of the bedrock. This may in particular have been the case in Western Norway where the tertiary uplift of the landmass amplified eroding forces of rivers.[10]
Confluence of tributary fjords led to excavation of the deepest fjord basins. Near the very coast, the typical West Norwegian glacier spread out (presumably through sounds and low valleys) and lost their concentration and reduced the glaciers' power to erode leaving bedrock thresholds.Bolstadfjorden is 160 m (520 ft) deep with a threshold of only 1.5 m (4 ft 11 in),[10][7] while the 1,300 m (4,300 ft) deep Sognefjorden has a threshold around 100 to 200 m (330 to 660 ft) deep.[13][14]Hardangerfjord is made up of several basins separated by thresholds: The deepest basin Samlafjorden between Jonaneset (Jondal) andÅlvik with a distinct threshold at Vikingneset inKvam Municipality.[10]
Muldalsfossen waterfall drops several hundred meters from the Muldalen hanging valley toTafjorden.
Hanging valleys are common along glaciated fjords andU-shaped valleys. A hanging valley is atributary valley that is higher than the main valley and was created by tributaryglacier flows into a glacier of larger volume. The shallower valley appears to be 'hanging' above the main valley or a fjord. Often,waterfalls form at or near the outlet of the upper valley.[15] Small waterfalls within these fjords are also used as freshwater resources. Hanging valleys also occur underwater in fjord systems. The branches ofSognefjord are for instance much shallower than the main fjord. The mouth ofFjærlandsfjord is about 400 m (1,300 ft) deep while the main fjord is 1,200 m (3,900 ft) nearby. The mouth of Ikjefjord is only 50 m (160 ft) deep while the main fjord is around 1,300 m (4,300 ft) at the same point.[11]
During the winter season, there is usually little inflow of water that is fresh. Surface water and deeper water (down to 100 m or 330 ft or more) are mixed during winter because of the steady cooling of the surface and wind. In the deep fjords, there is still fresh water from the summer with less density than the saltier water along the coast. Offshore wind, common in the fjord areas during winter, sets up a current on the surface from the inner to the outer parts. This current on the surface in turn pulls dense salt water from the coast across the fjord threshold and into the deepest parts of the fjord.[16] Bolstadfjorden has a threshold of only 1.5 m (4 ft 11 in) and strong inflow of freshwater fromVosso river creates a brackish surface that blocks circulation of the deep fjord. The deeper, salt layers of Bolstadfjorden are deprived of oxygen and the seabed is covered with organic material. The shallow threshold also creates a strong tidal current.[7]
During the summer season, there is usually a large inflow of river water in the inner areas. This freshwater gets mixed with saltwater creating a layer of brackish water with a slightly higher surface than the ocean which in turn sets up a current from the river mouths towards the ocean. This current is gradually more salty towards the coast and right under the surface current there is a reverse current of saltier water from the coast. In the deeper parts of the fjord the cold water remaining from winter is still and separated from the atmosphere by the brackish top layer. This deep water is ventilated by mixing with the upper layer causing it to warm and freshen over the summer.[17] In fjords with a shallow threshold or low levels of mixing this deep water is not replaced every year and low oxygen concentration makes the deep water unsuitable for fish and animals. In the most extreme cases, there is a constant barrier of freshwater on the surface and the fjord freezes over such that there is no oxygen below the surface.Drammensfjorden is one example.[16] The mixing in fjords predominantly results from the propagation of aninternal tide from the entrance sill or internal seiching.[18]
The Gaupnefjorden branch ofSognefjorden is strongly affected by freshwater as a glacial river flows in.Velfjorden has little inflow of freshwater.[19]
In 2000, somecoral reefs were discovered along the bottoms of the Norwegian fjords.[20] 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 asplankton,coral,anemones, fish, several species of shark, and many more. Most are specially adapted to life under the greater pressure of thewater column above it, and the total darkness of the deep sea.[21]
New Zealand's fjords are also host todeep-water corals, but a surface layer of dark fresh water allows these corals to grow in much shallower water than usual. An underwater observatory inMilford Sound allows tourists to view them without diving.[22]
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 rockreefs, menacing navigation. These are calledskerries.[21] The term skerry is derived from theOld Norsesker, which means a rock in the sea.[23]
Skerries 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 askjærgård); 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 1,601 km (995 mi) route fromStavanger toNorth Cape, Norway. TheBlindleia is a skerry-protected waterway that starts nearKristiansand in southern Norway and continues pastLillesand. TheSwedish coast alongBohuslän is likewise skerry guarded. TheInside Passage provides a similar route fromSeattle,Washington, andVancouver,British Columbia, toSkagway,Alaska. Yet another such skerry-protected passage extends from theStraits of Magellan north for 800 km (500 mi).
Fjords provide unique environmental conditions forphytoplankton communities. In polar fjords, glacier and ice sheet outflow add cold, fresh meltwater along with transported sediment into the body of water. Nutrients provided by this outflow can significantly enhance phytoplankton growth. For example, in some fjords of the West Antarctic Peninsula (WAP), nutrient enrichment from meltwater drivesdiatom blooms, a highly productive group of phytoplankton that enable such fjords to be valuable feeding grounds for other species.[24] It is possible that asclimate change reduces long-term meltwater output, nutrient dynamics within such fjords will shift to favor less productive species, destabilizing the food web ecology of fjord systems.
In addition to nutrient flux, sediment carried by flowing glaciers can become suspended in the water column, increasingturbidity and reducing light penetration into greater depths of the fjord. This effect can limit the available light forphotosynthesis in deeper areas of the water mass, reducing phytoplankton abundance beneath the surface.[25]
Overall, phytoplankton abundance and species composition within fjords is highly seasonal, varying as a result of seasonal light availability and water properties that depend on glacial melt and the formation of sea ice. The study of phytoplankton communities within fjords is an active area of research, supported by groups such as FjordPhyto, a citizen science initiative to study phytoplankton samples collected by local residents, tourists, and boaters of all backgrounds.
An epishelf lake forms when meltwater is trapped behind a floating ice shelf and the freshwater floats on the denser saltwater below. Its surface may freeze forming an isolated ecosystem.
Important fjords and lakes inNorway. Note: The part of the map showing the northern fjords has a considerably smaller scale. Blurred coastlines =skerries
The Norwegian word is inherited fromOld Norsefjǫrðr, a noun which refers to a 'lake-like' body of water used for passage and ferrying and is closely related to the nounferð "travelling, ferrying, journey".[26][27] Both words go back toIndo-European*pértus "crossing", from the root*per- "cross". The wordsfare andferry are of the same origin.[28][29]
The Scandinavianfjord,Proto-Scandinavian *ferþuz, is the origin for similarGermanic words:Icelandicfjörður,Faroesefjørður,Swedishfjärd (for Baltic waterbodies),Scotsfirth (for marine waterbodies, mainly in Scotland and northern England).[27][29] The Norse nounfjǫrðr was adopted in German asFörde, used for the narrow long bays ofSchleswig-Holstein, and in English asfirth "fjord, river mouth". The English wordford (compareGermanFurt,Low GermanFord orVörde, inDutch namesvoorde such as Vilvoorde,Ancient Greekπόρος,poros, andLatinportus) is assumed to originate from Germanic*ferþu- and Indo-European root *pertu- meaning "crossing point". Fjord/firth/Förde as well as ford/Furt/Vörde/voorde refer to a Germanic noun fora travel:North Germanicferd orfärd and of the verbto travel, Dutchvaren, Germanfahren; Englishto fare.[30]
As aloanword from Norwegian,[26] it is one of the few words in the English language to start with the sequencefj.[31] The word was for a long time normally spelledfiord,[32] a spelling preserved in place names such asGrise Fiord. Thefiord spelling mostly remains only inNew Zealand English, as in the place nameFiordland.[33]
The use of the word fjord in Norwegian, Danish and Swedish is more general than in English and in international scientific terminology. 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 and Iceland, 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 (Randsfjorden andTyrifjorden) and sometimes even to rivers (for instance inFlå Municipality inHallingdal, theHallingdal river is referred to asfjorden). In southeast Sweden, the namefjardfjärd is a subdivision of the term 'fjord' used for bays,bights and narrow inlets on the SwedishBaltic Sea coast, and in most Swedish lakes. This latter term is also used for bodies of water off the coast of Finland whereFinland Swedish is spoken. In Danish, the word may even apply to shallowlagoons. In modern Icelandic,fjörður is still used with the broader meaning of firth or inlet. InFaroesefjørður is used both about inlets and about broader sounds, whereas a narrower sound is calledsund. In theFinnish language, a wordvuono is used although there is only one fjord in Finland.
In old Norsegenitive wasfjarðar whereasdative wasfirði. The dative form has become common place names like Førde (for instanceFørde), Fyrde or Førre (for instanceFørre).[34]
The German use of the wordFöhrde for long narrow bays on their Baltic Sea coastline, indicates a commonGermanic origin of the word. The landscape consists mainly of moraine heaps. TheFöhrden and some "fjords" on the east side of Jutland, 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 basin of which is now the Baltic Sea. SeeFörden and East Jutland Fjorde.
Whereas fjord names mostly describe bays (though not always geological fjords),straits in the same regions typically are namedSund, in Scandinavian languages as well as in German. The word is related to "to sunder" in the meaning of "to separate". So the use ofSound to name fjords in North America and New Zealand differs from the European meaning of that word.
The name ofWexford inIreland is originally derived fromVeisafjǫrðr ("inlet of the mud flats") in Old Norse, as used by theViking settlers—though the inlet at that place in modern terms is anestuary, not a fjord. Similarly the name ofMilford (now Milford Haven) inWales is derived fromMelrfjǫrðr ("sandbank fjord/inlet"),[35] though theinlet on which it is located is actually a ria.
Before or in the early phase ofOld Norseangr was anothercommon noun for fjords and other inlets of the ocean. This word has survived only as a suffix in names of some Scandinavian fjords and has in same cases also been transferred to adjacent settlements or surrounding areas for instanceHardanger,Stavanger, andGeiranger.[36][37]
TheLim bay in Croatia is commonly called a fjord but is scientifically aria.
The differences in usage between theEnglish and theScandinavian languages have contributed to confusion in the use of the term fjord. Bodies of water that are clearly fjords in Scandinavian languages are not considered fjords in English; similarly bodies of water that would clearly not be fjords in the Scandinavian sense have been named or suggested to be fjords. Examples of this confused usage follow.
In theDanish language some inlets are called a fjord, but are, according to the English language definition, technically not a fjord, such asRoskilde Fjord.Limfjord in English terminology is asound, since it separates theNorth Jutlandic Island (Vendsyssel-Thy) from the rest ofJutland. However, the Limfjord once was a fjord until the sea broke through from the west.Ringkøbing Fjord on the western coast of Jutland is alagoon. The long narrow fjords of Denmark'sBaltic Sea coast like the GermanFörden were dug by ice moving from the sea upon land, while fjords in the geological sense were dug by ice moving from the mountains down to the sea. However, some definitions of a fjord is: "A long narrow inlet consisting of only one inlet created by glacial activity". Examples of Danish fjords are:Kolding Fjord,Vejle Fjord andMariager Fjord.
The fjords inFinnmark in Norway, which are fjords in theScandinavian sense of the term, are not universally considered to be fjords by the scientific community,[38] because although glacially formed, most Finnmark fjords lack the steep-sided valleys of the more southerly Norwegian fjords. The glacial pack was deep enough to cover even the high grounds when they were formed. TheOslofjord, on the other hand, is arift valley, and not glacially formed.
The indigenousMāori people ofNew Zealand see a fjord as a kind of sea (Māori:tai) that runs by abluff (matapari, altogethertai matapari "bluff sea").[39]
The term "fjord" is sometimes applied to steep-sided inlets which were not created by glaciers. Most such inlets are drowned river canyons orrias. Examples include:
InAcapulco,Mexico, thecalanques (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.
theLim bay inIstria,Croatia, is sometimes called "Lim fjord" although it is aria dug by the river Pazinčica. TheCroats call itLimski kanal, which does not translate precisely to the English equivalent either.
Eidfjord village beneath the high terrace, the original ice-age delta. The river has carved a gorge through the terrace.
Some Norwegian freshwater lakes that have formed in long glacially carved valleys with sill thresholds, ice front deltas or terminalmoraines blocking the outlet follow the Norwegian naming convention; they are frequently named fjords. Ice front deltas developed when the ice front was relatively stable for long time during the melting of the ice shield. The resulting landform is anisthmus between the lake and the saltwater fjord, in Norwegian called "eid" as in placenameEidfjord orNordfjordeid. The post-glacial rebound changed these deltas into terraces up to the level of the original sea level. In Eidfjord,Eio has dug through the original delta and left a 110 m (360 ft) terrace while lake is only 19 m (62 ft) above sea level.[45][46] Such deposits are valuable sources of high-quality building materials (sand and gravel) for houses and infrastructure.[47] Eidfjord village sits on theeid or isthmus betweenEidfjordvatnet lake and Eidfjorden branch of Hardangerfjord.[48] Nordfjordeid is the isthmus with a village between Hornindalsvatnet lake andNordfjord.[49][50] Such lakes are also denotedfjord valley lakes by geologists.[51]
One of Norway's largest isTyrifjorden at 63 m (207 ft) above sea level and an average depth at 97 m (318 ft) most of the lake is under sea level. Norway's largest lake,Mjøsa, is also referred to as "the fjord" by locals.[46] Another example is the freshwater fjordMovatnet (Mo lake) that until 1743 was separated fromRomarheimsfjorden by an isthmus and connected by a short river. During a flood in November 1743, the river bed eroded and sea water could flow into the lake at high tide. Eventually, Movatnet became a saltwater fjord and renamed Mofjorden (Mofjorden [no]).[52] Like fjords, freshwater lakes are often deep. For instanceHornindalsvatnet is at least 500 m (1,600 ft) deep and water takes an average of 16 years to flow through the lake.[53] Such lakes created by glacial action are also called fjord lakes ormoraine-dammed lakes.[54]
Some of these lakes were salt after the ice age but later cut off from the ocean during thepost-glacial rebound.[19] At the end of theice age Eastern Norway was about 200 m (660 ft) lower (the marine limit). When the ice cap receded and allowed the ocean to fill valleys and lowlands, and lakes like Mjøsa and Tyrifjorden were part of the ocean while Drammen valley was a narrow fjord. At the time of theVikingsDrammensfjord was still four or five m (13 or 16 ft) higher than today and reached the town ofHokksund, while parts of what is now the city ofDrammen was under water.[55] After the ice age the ocean was about 150 m (490 ft) atNotodden. The ocean stretched like a fjord throughHeddalsvatnet all the way toHjartdal.Post-glacial rebound eventually separated Heddalsvatnet from the ocean and turned it into a freshwater lake.[56][57] InNeolithic times Heddalsvatnet was still a saltwater fjord connected to the ocean, and was cut off from the ocean around 1500 BC.[58]
Some freshwater fjords such asSlidrefjord are above the marine limit.
Like freshwater fjords, the continuation of fjords on land are in the same way denoted asfjord-valleys. For instanceFlåmsdal (Flåm valley) andMåbødalen.[10][59][60]
Årdalstangen village on the small isthmus between Årdalsvatnet lake (behind) and Årdalsfjorden branch of Sognefjorden (front)
Outside of Norway, the three western arms ofNew Zealand'sLake Te Anau are named North Fiord, Middle Fiord and South Fiord. Another freshwater "fjord" in a larger lake isWestern Brook Pond, inNewfoundland'sGros Morne National Park; it 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. Locally they refer to it as a "landlocked fjord". Such lakes are sometimes called "fjord lakes".Okanagan Lake was the first North American lake to be so described, in 1962.[61] The bedrock there has been eroded up to 650 m (2,133 ft)below sea level, which is 2,000 m (6,562 ft) below the surrounding regional topography.[62] Fjord lakes are common on the inland lea of theCoast Mountains andCascade Range; notable ones includeLake Chelan,Seton Lake,Chilko Lake, andAtlin Lake.Kootenay Lake,Slocan Lake and others in the basin of theColumbia River are also fjord-like in nature, and created by glaciation in the same way. Along theBritish Columbia Coast, a notable fjord-lake isOwikeno Lake, which is a freshwater extension ofRivers Inlet.Quesnel Lake, located in central British Columbia, is claimed to be the deepest fjord formed lake on Earth.
A family of freshwater fjords are the embayments of the North American Great Lakes. Baie Fine is located on the northwestern coast ofGeorgian Bay ofLake Huron inOntario, andHuron Bay is located on the southern shore ofLake Superior inMichigan.
The principal mountainous regions where fjords have formed are in the highermiddle 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 prevailingwesterly marine winds areorographically 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 Norway, the west coast of North America fromPuget Sound to Alaska, the southwest coast of New Zealand, and the west and to south-western coasts ofSouth America, chiefly inChile.
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:
Sognefjord in Norway—1,308 m (4,291 ft)[71][69] (the mountains then rise to up to 1,500 m (4,921 ft) and more,Hurrungane reaches 2,400 m (7,874 ft))[72]
Norway has several heritage fjords, including UNESCO World Heritage Sites and other notable fjords, these will require visiting ships to be low-emission by 2026 and zero-emission by 2032[75]
^Syvitsky, James P. M.; Burrell, David C.; Skei, Jens M. (1987).Fjords: Processes and Products. New York:Springer. pp. 46–49.ISBN0-387-96342-1.The NE coast, from Victoria Fjord to the Scoresby Sund fjord complex ..., has approximately 78660 major fjords, some of them the world's largest and deepest. ... The SE coast, from Scoresby Sund to Kap Farvel ..., has approximately 100 fjords.
^Randall, B. A. O. (1961). On the relationship of valley and fjord directions to the fracture pattern of Lyngen, Troms N. Norway.Geografiska Annaler, 43(3/4), 336–338.
^abSkreslet, Stig (1980).Fjordene og kyststrømmen. Åndalsnes; Rauma/Ulvåa på vektskåla: Møre og Romsdal naturvern. pp. 48–54.
^Simpson, J.H.; Rippeth, T.P. (1993). "The Clyde Sea – a model of seasonal stratification and mixing".Estuarine, Coastal and Shelf Science (37):129–144.doi:10.1006/ecss.1993.1047.
^Arneborg, L., Janzen, C., Liljebladh, B., Rippeth, T., Simpson, J. H. & Stigebrandt, A. (2004). Spatial variability of diapycnal mixing and turbulent dissipation rates in a stagnant fjord basin. Journal of Physical Oceanography, 34(7), 1679–1691
^ab"Fjord". Norwegian Biodiversity Information Centre. Archived fromthe original on 3 February 2016. Retrieved30 January 2016.
^abNesje, A. (2009). Fjords of Norway: Complex Origin of a Scenic Landscape. InGeomorphological Landscapes of the World (pp. 223–234). Springer, Dordrecht.
^abcLilleøren, Karianne (2021)."fjord".Store norske leksikon. Retrieved11 December 2021.
^Norge sett fra luften. Oslo: Det Beste. 1980.ISBN8270100935.
^Mikkelsen, Egil (1989).Fra jeger til bonde: utviklingen av jordbrukssamfunn i Telemark i steinalder og bronsealder. Oslo: Universitetets oldsaksamling.ISBN8271810790.
^Hansen, L., Eilertsen, R. S., Solberg, I. L., Sveian, H., & Rokoengen, K. (2007). Facies characteristics, morphology and depositional models of clay-slide deposits in terraced fjord valleys, Norway.Sedimentary Geology, 202(4), 710–729.
^Lidmar-Bergström, K., Ollier, C. D., & Sulebak, J. R. (2000). Landforms and uplift history of southern Norway. Global and Planetary Change, 24(3), 211–231.
^Nasmith, Hugh (1962).Late glacial history and surficial deposits of the Okanagan Valley, British Columbia. Victoria, BC, Canada: BC Ministry of Energy, Mines and Petroleum Resources.
^abØi, Ørnulf (1987).Norges sjøatlas : fra svenskegrensen til Sognefjorden. Oslo: Nautisk forlag i samarbeid med Statens kartverk, Norges sjøkartverk. pp. 225, 244.ISBN8290335024.
^Alexander P. Lisitzin,Sea-Ice and Iceberg Sedimentation in the Ocean: Recent and Past, p. 449.
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