A glacier is a persistent body of dense ice, moving under its own weight. Glaciers deform and flow due to stresses induced by their weight, creating crevasses and other distinguishing features, they abrade rock and debris from their substrate to create landforms such as cirques and moraines. Glaciers form only on land and are distinct from the much thinner sea ice and lake ice that form on the surface of bodies of water. On Earth, 99% of glacial ice is contained within vast ice sheets in the polar regions, but glaciers may be found in mountain ranges on every continent including Oceania's high-latitude oceanic island countries such as New Zealand and Papua New Guinea. Between 35°N and 35°S, glaciers occur only in the Himalayas, Rocky Mountains, a few high mountains in East Africa, New Guinea and on Zard Kuh in Iran. Glaciers cover about 10 percent of Earth's land surface. Continental glaciers cover nearly 13 million km2 or about 98 percent of Antarctica's 13.2 million km2, with an average thickness of 2,100 m.
Greenland and Patagonia have huge expanses of continental glaciers. Glacial ice is the largest reservoir of fresh water on Earth. Many glaciers from temperate and seasonal polar climates store water as ice during the colder seasons and release it in the form of meltwater as warmer summer temperatures cause the glacier to melt, creating a water source, important for plants and human uses when other sources may be scant. Within high-altitude and Antarctic environments, the seasonal temperature difference is not sufficient to release meltwater. Since glacial mass is affected by long-term climatic changes, e.g. precipitation, mean temperature, cloud cover, glacial mass changes are considered among the most sensitive indicators of climate change and are a major source of variations in sea level. A large piece of compressed ice, or a glacier, appears blue, as large quantities of water appear blue; this is. The other reason for the blue color of glaciers is the lack of air bubbles. Air bubbles, which give a white color to ice, are squeezed out by pressure increasing the density of the created ice.
The word glacier is a loanword from French and goes back, via Franco-Provençal, to the Vulgar Latin glaciārium, derived from the Late Latin glacia, Latin glaciēs, meaning "ice". The processes and features caused by or related to glaciers are referred to as glacial; the process of glacier establishment and flow is called glaciation. The corresponding area of study is called glaciology. Glaciers are important components of the global cryosphere. Glaciers are categorized by their morphology, thermal characteristics, behavior. Cirque glaciers form on the slopes of mountains. A glacier that fills a valley is called a valley glacier, or alternatively an alpine glacier or mountain glacier. A large body of glacial ice astride a mountain, mountain range, or volcano is termed an ice cap or ice field. Ice caps have an area less than 50,000 km2 by definition. Glacial bodies larger than 50,000 km2 are called continental glaciers. Several kilometers deep, they obscure the underlying topography. Only nunataks protrude from their surfaces.
The only extant ice sheets are the two that cover most of Greenland. They contain vast quantities of fresh water, enough that if both melted, global sea levels would rise by over 70 m. Portions of an ice sheet or cap that extend into water are called ice shelves. Narrow, fast-moving sections of an ice sheet are called ice streams. In Antarctica, many ice streams drain into large ice shelves; some drain directly into the sea with an ice tongue, like Mertz Glacier. Tidewater glaciers are glaciers that terminate in the sea, including most glaciers flowing from Greenland, Antarctica and Ellesmere Islands in Canada, Southeast Alaska, the Northern and Southern Patagonian Ice Fields; as the ice reaches the sea, pieces break off, or calve. Most tidewater glaciers calve above sea level, which results in a tremendous impact as the iceberg strikes the water. Tidewater glaciers undergo centuries-long cycles of advance and retreat that are much less affected by the climate change than those of other glaciers.
Thermally, a temperate glacier is at melting point throughout the year, from its surface to its base. The ice of a polar glacier is always below the freezing point from the surface to its base, although the surface snowpack may experience seasonal melting. A sub-polar glacier includes both temperate and polar ice, depending on depth beneath the surface and position along the length of the glacier. In a similar way, the thermal regime of a glacier is described by its basal temperature. A cold-based glacier is below freezing at the ice-ground interface, is thus frozen to the underlying substrate. A warm-based glacier is above or at freezing at the interface, is able to slide at this contact; this contrast is thought to a large extent to govern the ability of a glacier to erode its bed, as sliding ice promotes plucking at rock from the surface below. Glaciers which are cold-based and warm-based are known as polythermal. Glaciers form where the accumulation of ice exceeds ablation. A glacier originates from a landform called'cirque' – a armchair-shaped geological feature (such as a depressio
Vatnajökull known as Water Glacier in English, is the largest and most voluminous ice cap in Iceland, one of the largest in area in Europe. It is the second largest glacier in area after Austfonna on Svalbard in Norway but larger by volume, it is in the south-east of the island, covering 8% of the country. With an area of 7,900 km², Vatnajökull is the largest ice cap in Europe by volume and the second-largest in area. On 7 June 2008, it became a part of the Vatnajökull National Park; the average thickness of the ice is 380 m, with a maximum thickness of 950 m. Iceland's highest peak, Hvannadalshnúkur, is in the southern periphery of Vatnajökull, near Skaftafell National Park. Under the ice cap, as under many of the glaciers of Iceland, there are several volcanoes. Eruptions from these volcanoes have led to the development of large pockets of water beneath the ice, which may burst the weakened ice and cause a jökulhlaup. During the last ice age, numerous volcanic eruptions occurred under Vatnajökull, creating many subglacial eruptions.
In more modern times, the volcanoes continue to erupt beneath the glaciers, resulting in many documented floods. One jökulhlaup in 1934 caused the release of 15 km3 of water over the course of several days; the volcanic lake Grímsvötn was the source of a large jökulhlaup in 1996. There was a considerable but short-lived eruption of the volcano under these lakes at the beginning of November 2004. On 21 May 2011 a volcanic eruption started in Grímsvötn in Vatnajökull National Park at around 7 p.m. The plume reached as up to 17 kilometres; the glacier was used as the setting for the opening sequence of the 1985 James Bond film A View to a Kill, in which Bond eliminated a host of armed villains before escaping in a submarine to Alaska. Several other films, including another in the Bond franchise, have been filmed on or using Jökulsárlón, the terminal lake of the Breiðamerkurjökull outlet from Vatnajökull. Westlife's official music video for their twenty-fifth single top 10 and #2 UK hit in 2009 "What About Now" is the last film of Vatnajökull Glacier before the subsequent volcanic eruption.
In November 2011, the glacier was used as a shooting location for the second season of the HBO fantasy TV series Game of Thrones. In 1950, a Douglas DC-4 operated by the private airline Loftleiðir crash-landed on the Vatnajökull glacier. Vatnajökull has around 30 outlet glaciers flowing from the ice cap; the Icelandic term for glacier is "jökull", so is the term for outlet glacier. Given below is a list of outlet glaciers flowing from Vatnajökull, sorted by the four administrative territories of Vatnajökull National Park; this is not a complete list. Southern territory Breiðamerkurjökull Brókarjökull Falljökull Fjallsjökull Fláajökull Heinabergsjökull Hoffellsjökull Hólárjökull Hrútárjökull Kvíárjökull Lambatungnajökull Morsárjökull Skaftafellsjökull Skálafellsjökull Skeiðarárjökull Stigárjökull Svínafellsjökull Viðborðsjökull VirkisjökullEastern territory Brúarjökull Eyjabakkajökull KverkjökullNorthern territory DyngjujökullWestern territory Köldukvíslarjökull Síðujökull Skaftárjökull Sylgjujökull Tungnaárjökul Geography of Iceland Iceland plume Vatnajökull National Park News about Vatnajokull National park Search engine and map of Iceland Viewfinder Panoramas
Firn is compacted névé, a type of snow, left over from past seasons and has been recrystallized into a substance denser than névé. It is ice, at an intermediate stage between snow and glacial ice. Firn has the appearance of wet sugar, but has a hardness that makes it resistant to shovelling, its density ranges from 0.4 g/cm³ to 0.83 g/cm³, it can be found underneath the snow that accumulates at the head of a glacier. Snowflakes are compressed under the weight of the overlying snowpack. Individual crystals near the melting point are semiliquid and slick, allowing them to glide along other crystal planes and to fill in the spaces between them, increasing the ice's density. Where the crystals touch they bond together, squeezing the air between them to the surface or into bubbles. In the summer months, the crystal metamorphosis can occur more because of water percolation between the crystals. By summer's end, the result is firn; the minimum altitude that firn accumulates on a glacier is called the firn limit, firn line or snowline.
In colloquial and technical language,'firn' is used to describe certain forms of old snow or harsch: Old snowfields or névé if the snow is not yet one year old the more recent snow layers of a glacier the uppermost, soft layer of snow, frozen overnight and, as a result of spring sunshine and high air temperatures, forms on an area of old snow or harsch "Firn". Encyclopædia Britannica. "Fundamentals of Physical Geography". Physicalgeography.net."Greenland Meltwater Storage in Firn Limited". Nature.com. "USGS Glossary of Selected Glacier and Related Terminology". Ulcan.wr.usgs.gov. Fern
Quebec is one of the thirteen provinces and territories of Canada. It is bordered to the west by the province of Ontario and the bodies of water James Bay and Hudson Bay. S. states of Maine, New Hampshire and New York. It shares maritime borders with Nunavut, Prince Edward Island, Nova Scotia. Quebec is Canada's largest province by its second-largest administrative division, it is and politically considered to be part of Central Canada. Quebec is the second-most populous province of Canada, after Ontario, it is the only one to have a predominantly French-speaking population, with French as the sole provincial official language. Most inhabitants live in urban areas near the Saint Lawrence River between Montreal and Quebec City, the capital. Half of Quebec residents live in the Greater Montreal Area, including the Island of Montreal. English-speaking communities and English-language institutions are concentrated in the west of the island of Montreal but are significantly present in the Outaouais, Eastern Townships, Gaspé regions.
The Nord-du-Québec region, occupying the northern half of the province, is sparsely populated and inhabited by Aboriginal peoples. The climate around the major cities is four-seasons continental with cold and snowy winters combined with warm to hot humid summers, but farther north long winter seasons dominate and as a result the northern areas of the province are marked by tundra conditions. In central Quebec, at comparatively southerly latitudes, winters are severe in inland areas. Quebec independence debates have played a large role in the politics of the province. Parti Québécois governments held referendums on sovereignty in 1980 and 1995. Although neither passed, the 1995 referendum saw the highest voter turnout in Quebec history, at over 93%, only failed by less than 1%. In 2006, the House of Commons of Canada passed a symbolic motion recognizing the "Québécois as a nation within a united Canada". While the province's substantial natural resources have long been the mainstay of its economy, sectors of the knowledge economy such as aerospace and communication technologies and the pharmaceutical industry play leading roles.
These many industries have all contributed to helping Quebec become an economically influential province within Canada, second only to Ontario in economic output. The name "Québec", which comes from the Algonquin word kébec meaning "where the river narrows" referred to the area around Quebec City where the Saint Lawrence River narrows to a cliff-lined gap. Early variations in the spelling of the name included Kébec. French explorer Samuel de Champlain chose the name Québec in 1608 for the colonial outpost he would use as the administrative seat for the French colony of New France; the province is sometimes referred to as "La belle province". The Province of Quebec was founded in the Royal Proclamation of 1763 after the Treaty of Paris formally transferred the French colony of Canada to Britain after the Seven Years' War; the proclamation restricted the province to an area along the banks of the Saint Lawrence River. The Quebec Act of 1774 expanded the territory of the province to include the Great Lakes and the Ohio River Valley and south of Rupert's Land, more or less restoring the borders existing under French rule before the Conquest of 1760.
The Treaty of Paris ceded territories south of the Great Lakes to the United States. After the Constitutional Act of 1791, the territory was divided between Lower Canada and Upper Canada, with each being granted an elected legislative assembly. In 1840, these become Canada East and Canada West after the British Parliament unified Upper and Lower Canada into the Province of Canada; this territory was redivided into the Provinces of Quebec and Ontario at Confederation in 1867. Each became one of the first four provinces. In 1870, Canada purchased Rupert's Land from the Hudson's Bay Company and over the next few decades the Parliament of Canada transferred to Quebec portions of this territory that would more than triple the size of the province. In 1898, the Canadian Parliament passed the first Quebec Boundary Extension Act that expanded the provincial boundaries northward to include the lands of the local aboriginal peoples; this was followed by the addition of the District of Ungava through the Quebec Boundaries Extension Act of 1912 that added the northernmost lands of the Inuit to create the modern Province of Quebec.
In 1927, the border between Quebec and Newfoundland and Labrador was established by the British Judicial Committee of the Privy Council. Quebec disputes this boundary. Located in the eastern part of Canada, part of Central Canada, Quebec occupies a territory nearly three times the size of France or Texas, most of, sparsely populated, its topography is different from one region to another due to the varying composition of the ground, the climate, the proximity to water. The Saint Lawrence Lowland and the Appalachians are the two main topographic regions in southern Quebec, while the Canadian Shield occupies most of central and northern Quebec. Quebec has one of the world's largest reserves of fresh water, occupying 12% of its surface, it has 3 % of the world's renewable fresh water. Mor
Geothermal gradient is the rate of increasing temperature with respect to increasing depth in the Earth's interior. Away from tectonic plate boundaries, it is about 25–30 °C/km of depth near the surface in most of the world. Speaking, geo-thermal refers to the Earth but the concept may be applied to other planets; the Earth's internal heat comes from a combination of residual heat from planetary accretion, heat produced through radioactive decay, latent heat from core crystallization, heat from other sources. The major heat-producing isotopes in the Earth are potassium-40, uranium-238, uranium-235, thorium-232. At the center of the planet, the temperature may be up to 7,000 K and the pressure could reach 360 GPa; because much of the heat is provided by radioactive decay, scientists believe that early in Earth history, before isotopes with short half-lives had been depleted, Earth's heat production would have been much higher. Heat production was twice that of present-day at 3 billion years ago, resulting in larger temperature gradients within the Earth, larger rates of mantle convection and plate tectonics, allowing the production of igneous rocks such as komatiites that are no longer formed.
Temperature within the Earth increases with depth. Viscous or molten rock at temperatures between 650 to 1,200 °C are found at the margins of tectonic plates, increasing the geothermal gradient in the vicinity, but only the outer core is postulated to exist in a molten or fluid state, the temperature at the Earth's inner core/outer core boundary, around 3,500 kilometres deep, is estimated to be 5650 ± 600 Kelvin; the heat content of the Earth is 1031 joules. Much of the heat is created by decay of radioactive elements. An estimated 45 to 90 percent of the heat escaping from the Earth originates from radioactive decay of elements located in the mantle. Gravitational potential energy released during the accretion of the Earth. Heat released during differentiation. Latent heat released as the liquid outer core crystallizes at the inner core boundary. Heat may be generated by tidal forces on the Earth; the resulting earth tides dissipate energy in Earth's interior as heat. There is no reputable science to suggest that any significant heat may be created by the Earth's magnetic field, as suggested by some contemporary folk theories.
In Earth's continental crust, the decay of natural radioactive isotopes makes a significant contribution to geothermal heat production. The continental crust is abundant in lower density minerals but contains significant concentrations of heavier lithophilic minerals such as uranium; because of this, it holds the most concentrated global reservoir of radioactive elements found in the Earth. In layers closer to Earth's surface occurring isotopes are enriched in the granite and basaltic rocks; these high levels of radioactive elements are excluded from the Earth's mantle due to their inability to substitute in mantle minerals and consequent enrichment in melts during mantle melting processes. The mantle is made up of high density minerals with higher concentrations of elements that have small atomic radii such as magnesium and calcium; the geothermal gradient is steeper in the lithosphere than in the mantle because the mantle transports heat by convection, leading to a geothermal gradient, determined by the mantle adiabat, rather than by the conductive heat transfer processes that predominate in the lithosphere, which acts as a thermal boundary layer of the convecting mantle.
Heat flows from its sources within the Earth to the surface. Total heat loss from the Earth is estimated at 44.2 TW. Mean heat flow is 101 mW/m2 over oceanic crust; this is 0.087 watt/square meter on average, but is much more concentrated in areas where the lithosphere is thin, such as along mid-ocean ridges and near mantle plumes. The Earth's crust acts as a thick insulating blanket which must be pierced by fluid conduits in order to release the heat underneath. More of the heat in the Earth is lost through plate tectonics, by mantle upwelling associated with mid-ocean ridges; the final major mode of heat loss is by conduction through the lithosphere, the majority of which occurs in the oceans due to the crust there being much thinner and younger than under the continents. The heat of the Earth is replenished by radioactive decay at a rate of 30 TW; the global geothermal flow rates are more than twice the rate of human energy consumption from all primary sources. Heat from Earth's interior can be used as an energy source, known as geothermal energy.
The geothermal gradient has been used for space heating and bathing since ancient Roman times, more for generating electricity. As the human population continues to grow, so does energy use and the correlating environmental impacts that are consistent with global primary sources of energy; this has caused a growing interest in finding sources of energy that are renewable and have reduced greenhouse gas emissions. In areas of high geothermal energy density, current technology allows for the generation of electrical power because of the corresponding high temperatures. Generating electrical power from geothermal resources requires no fuel while providing true baseload energy at a reliability rate that exceeds 90%. In order to extract geothermal energy, it is necessary to efficiently transfer heat from a
In earth science, erosion is the action of surface processes that removes soil, rock, or dissolved material from one location on the Earth's crust, transports it to another location. This natural process is caused by the dynamic activity of erosive agents, that is, ice, air, plants and humans. In accordance with these agents, erosion is sometimes divided into water erosion, glacial erosion, snow erosion, wind erosion, zoogenic erosion, anthropogenic erosion; the particulate breakdown of rock or soil into clastic sediment is referred to as physical or mechanical erosion. Eroded sediment or solutes may be transported just a few millimetres, or for thousands of kilometres. Natural rates of erosion are controlled by the action of geological weathering geomorphic drivers, such as rainfall; the rates at which such processes act control. Physical erosion proceeds fastest on steeply sloping surfaces, rates may be sensitive to some climatically-controlled properties including amounts of water supplied, wind speed, wave fetch, or atmospheric temperature.
Feedbacks are possible between rates of erosion and the amount of eroded material, carried by, for example, a river or glacier. Processes of erosion that produce sediment or solutes from a place contrast with those of deposition, which control the arrival and emplacement of material at a new location. While erosion is a natural process, human activities have increased by 10-40 times the rate at which erosion is occurring globally. At well-known agriculture sites such as the Appalachian Mountains, intensive farming practices have caused erosion up to 100x the speed of the natural rate of erosion in the region. Excessive erosion causes both "on-site" and "off-site" problems. On-site impacts include decreases in agricultural productivity and ecological collapse, both because of loss of the nutrient-rich upper soil layers. In some cases, the eventual end result is desertification. Off-site effects include sedimentation of waterways and eutrophication of water bodies, as well as sediment-related damage to roads and houses.
Water and wind erosion are the two primary causes of land degradation. Intensive agriculture, roads, anthropogenic climate change and urban sprawl are amongst the most significant human activities in regard to their effect on stimulating erosion. However, there are many prevention and remediation practices that can curtail or limit erosion of vulnerable soils. Rainfall, the surface runoff which may result from rainfall, produces four main types of soil erosion: splash erosion, sheet erosion, rill erosion, gully erosion. Splash erosion is seen as the first and least severe stage in the soil erosion process, followed by sheet erosion rill erosion and gully erosion. In splash erosion, the impact of a falling raindrop creates a small crater in the soil, ejecting soil particles; the distance these soil particles travel can be as much as 0.6 m vertically and 1.5 m horizontally on level ground. If the soil is saturated, or if the rainfall rate is greater than the rate at which water can infiltrate into the soil, surface runoff occurs.
If the runoff has sufficient flow energy, it will transport loosened soil particles down the slope. Sheet erosion is the transport of loosened soil particles by overland flow. Rill erosion refers to the development of small, ephemeral concentrated flow paths which function as both sediment source and sediment delivery systems for erosion on hillslopes. Where water erosion rates on disturbed upland areas are greatest, rills are active. Flow depths in rills are of the order of a few centimetres or less and along-channel slopes may be quite steep; this means that rills exhibit hydraulic physics different from water flowing through the deeper, wider channels of streams and rivers. Gully erosion occurs when runoff water accumulates and flows in narrow channels during or after heavy rains or melting snow, removing soil to a considerable depth. Valley or stream erosion occurs with continued water flow along a linear feature; the erosion is both downward, deepening the valley, headward, extending the valley into the hillside, creating head cuts and steep banks.
In the earliest stage of stream erosion, the erosive activity is dominantly vertical, the valleys have a typical V cross-section and the stream gradient is steep. When some base level is reached, the erosive activity switches to lateral erosion, which widens the valley floor and creates a narrow floodplain; the stream gradient becomes nearly flat, lateral deposition of sediments becomes important as the stream meanders across the valley floor. In all stages of stream erosion, by far the most erosion occurs during times of flood when more and faster-moving water is available to carry a larger sediment load. In such processes, it is not the water alone
In geography, a plain is a flat, sweeping landmass that does not change much in elevation. Plains occur as lowlands along the bottoms of valleys or on the doorsteps of mountains, as coastal plains, as plateaus or uplands. In a valley, a plain is enclosed on two sides, but in other cases a plain may be delineated by a complete or partial ring of hills, by mountains, or by cliffs. Where a geological region contains more than one plain, they may be connected by a pass. Coastal plains would rise from sea level until they run into elevated features such as mountains or plateaus. Plains are one of the major landforms on earth, where they are present on all continents, would cover more than one-third of the world’s land area. Plains may have been formed from flowing lava, deposited by water, wind, or formed by erosion by these agents from hills and mountains. Plains would be under the grassland, savannah or tundra biomes. In a few instances and rainforests can be plains. Plains in many areas are important for agriculture because where the soils were deposited as sediments they may be deep and fertile, the flatness facilitates mechanization of crop production.
Depositional plains formed by the deposition of materials brought by various agents of transportation such as glaciers, rivers and wind. Their fertility and economic relevance depend on the types of sediments that are laid down; the types of depositional plains include: Abyssal plains, flat or gently sloping areas of the deep ocean basin. Planitia, the Latin word for plain, is used in the naming of plains on extraterrestrial objects, such as Hellas Planitia on Mars or Sedna Planitia on Venus. Alluvial plains, which are formed by rivers and which may be one of these overlapping types: Alluvial plains, formed over a long period of time by a river depositing sediment on their flood plains or beds, which become alluvial soil; the difference between a flood plain and an alluvial plain is: a flood plain represents areas experiencing flooding regularly in the present or whereas an alluvial plain includes areas where a flood plain is now and used to be, or areas which only experience flooding a few times a century.
Flood plain, adjacent to a lake, stream, or wetland that experiences occasional or periodic flooding. Scroll plain, a plain through which a river meanders with a low gradient. Glacial plains, formed by the movement of glaciers under the force of gravity: Outwash plain, a glacial out-wash plain formed of sediments deposited by melt-water at the terminus of a glacier. Sandar consist of stratified gravel and sand. Till plains, plain of glacial till that form when a sheet of ice becomes detached from the main body of a glacier and melts in place depositing the sediments it carries. Till plains are composed of unsorted material of all sizes. Lacustrine plains, plains that formed in a lacustrine environment, that is, as the bed of a lake. Lava plains, formed by sheets of flowing lava. Erosional plains have been leveled by various agents of denudation such as running water, rivers and glacier which wear out the rugged surface and smoothens them. Plain resulting from the action of these agents of denudation are called peneplains while plains formed from wind action are called pediplains.
Structural plains are undisturbed horizontal surfaces of the Earth. They are structurally depressed areas of the world that make up some of the most extensive natural lowlands on the Earth's surface. Altiplano Altiplano Cundiboyacense Caroni Plain Chilean Central Valley Gran Chaco Los Llanos Venezuelan Llanos Argentine Pampas Atlantic coastal plain Carrizo Plain Great Plains Gulf Coastal Plain Interior Plains Lake Superior Lowland Laramie Plains Mississippi Alluvial Plain Oxnard Plain Snake River Plain Chianan Plain Depsang Plains Kantō Plain Kedu Plain Kewu Plain Mallig Plains Nōbi Plain North China Plain Osaka Plain Pingtung Plain Sarobetsu plain West Siberian Plain Yilan Plain Bhuikhel Depsang Plains Dooars Eastern coastal plains Indo-Gangetic Plains More plains North Bengal plains Punjab Plains Terai Utkal Plains Western coastal plains Al-Ghab Plain Aleppo plateau Ararat plain Israeli coastal plain Khuzestan Plain Mugan plain Nineveh Plains Shiraki Plain Limagne North German Plain Ochsenfeld Pannonian Basin Parndorf Plain Westphalian Lowland Bărăgan Plain Danubian Plain Dnieper Lowland East European Plain European Plain Great Hungarian Plain Kosovo field Little Hungarian Plain Pannonian Steppe Polesian Lowland Upper Thracian Plain Wallachian Plain Cheshire Plain Hardangervidda Kaffiøyra Muddus plains North