Volcanic cones are among the simplest volcanic landforms. They are built by ejecta from a volcanic vent, piling up around the vent in the shape of a cone with a central crater. Volcanic cones are of different types, depending upon the nature and size of the fragments ejected during the eruption. Types of volcanic cones include stratocones, spatter cones, tuff cones, cinder cones. Stratocones are large cone-shaped volcanoes made up of lava flows, explosively erupted pyroclastic rocks, igneous intrusives that are centered around a cylindrical vent. Unlike shield volcanoes, they are characterized by a steep profile and periodic alternating, explosive eruptions and effusive eruptions; some have collapsed. The central core of a stratocone is dominated by a central core of intrusive rocks that range from around 500 meters to over several kilometers in diameter; this central core is surrounded by multiple generations of lava flows, many of which are brecciated, a wide range of pyroclastic rocks and reworked volcanic debris.
The typical stratocone is an andesitic to dacitic volcano, associated with subduction zones. They are known as either stratified volcano, composite cone, bedded volcano, cone of mixed type or Vesuvian-type volcano. A spatter cone is a low, steep-sided hill or mound that consists of welded lava fragments, called spatter, which has formed around a lava fountain issuing from a central vent. Spatter cones are about 3–5 meters high. In case of a linear fissure, lava fountaining will create broad embankments of spatter, called spatter ramparts, along both sides of the fissure. Spatter cones are more circular and cone shaped, while spatter ramparts are linear wall-like features. Spatter cones and spatter ramparts are formed by lava fountaining associated with mafic fluid lavas, such as those erupted in the Hawaiian Islands; as blobs of molten lava, are erupted into the air by a lava fountain, they can lack the time needed to cool before hitting the ground. The spatter are not solid, like taffy, as they land and they bind to the underlying spatter as both slowly ooze down the side of the cone.
As a result, the spatter builds up a cone, composed of spatter either agglutinated or welded to each other. A tuff cone, sometimes called an ash cone, is a small monogenetic volcanic cone produced by phreatic explosions directly associated with magma brought to the surface through a conduit from a deep-seated magma reservoir, they are characterized by high rims that have a maximum relief of 100–800 meters above the crater floor and steep slopes that are greater than 25 degrees. They have a rim to rim diameter of 300–5,000 meters. A tuff cone consists of thick-bedded pyroclastic flow and surge deposits created by eruption-fed density currents and bomb-scoria beds derived from fallout from its eruption column; the tuffs composing a tuff cone have been altered, palagonitized, by either its interaction with groundwater or when it was deposited warm and wet. The pyroclastic deposits of tuff cones differ from the pyroclastic deposits of spatter cones by their lack or paucity of lava spatter, smaller grain-size, excellent bedding.
But not always, tuff cones lack associated lava flows. A tuff ring is a related type of small monogenetic volcano, produced by phreatic explosions directly associated with magma brought to the surface through a conduit from a deep-seated magma reservoir.. They are characterized by rims that have a low, broad topographic profiles and gentle topographic slopes that are 25 degrees or less; the maximum thickness of the pyroclastic debris comprising the rim of a typical tuff ring is thin, less than 50 meters to 100 meters thick. The pyroclastic materials that comprise their rim consist of fresh and unaltered and thin-bedded volcanic surge and air fall deposits, their rims can contain variable amounts of local country rock blasted out of their crater. In contrast to tuff cones, the crater of a tuff ring has been excavated below the existing ground surface; as a result, water fills a tuff ring's crater to form a lake once eruptions cease. Both tuff cones and their associated tuff rings were created by explosive eruptions from a vent where the magma is interacting with either groundwater or a shallow body of water as found within a lake or sea.
The interaction between the magma, expanding steam, volcanic gases resulted in the production and ejection of fine-grained pyroclastic debris called ash with the consistency of flour. The volcanic ash comprising a tuff cone accumulated either as fallout from eruption columns, from low-density volcanic surges and pyroclastic flows, or combination of these. Tuff cones are associated with volcanic eruptions within shallow bodies of water and tuff rings are associated with eruptions within either water saturated sediments and bedrock or permafrostNext to spatter cones, tuff cones and their associated tuff rings are among the most common types of volcanoes on Earth. An example of a tuff cone is Diamond Head at Waikīkī in Hawaiʻi. Clusters of pitted cones observed in the Nephentes/Amenthes region of Mars at the southern margin of the ancient Utopia impact basin are interpreted as being tuff cones and rings. Cinder cones known as scoria cones and less scoria mounds, are small, steep-sided volcanic cones built of loose pyroclastic fragments, such as either volcanic clinkers, volcanic ash, or scoria.
They consist of loose pyroclastic debris formed by explosive eruptions or lava fountains from a single, typi
A mountain range or hill range is a series of mountains or hills ranged in a line and connected by high ground. A mountain system or mountain belt is a group of mountain ranges with similarity in form and alignment that have arisen from the same cause an orogeny. Mountain ranges are formed by a variety of geological processes, but most of the significant ones on Earth are the result of plate tectonics. Mountain ranges are found on many planetary mass objects in the Solar System and are a feature of most terrestrial planets. Mountain ranges are segmented by highlands or mountain passes and valleys. Individual mountains within the same mountain range do not have the same geologic structure or petrology, they may be a mix of different orogenic expressions and terranes, for example thrust sheets, uplifted blocks, fold mountains, volcanic landforms resulting in a variety of rock types. Most geologically young mountain ranges on the Earth's land surface are associated with either the Pacific Ring of Fire or the Alpide Belt.
The Pacific Ring of Fire includes the Andes of South America, extends through the North American Cordillera along the Pacific Coast, the Aleutian Range, on through Kamchatka, Taiwan, the Philippines, Papua New Guinea, to New Zealand. The Andes is 7,000 kilometres long and is considered the world's longest mountain system; the Alpide belt includes Indonesia and Southeast Asia, through the Himalaya, Caucasus Mountains, Balkan Mountains fold mountain range, the Alps, ends in the Spanish mountains and the Atlas Mountains. The belt includes other European and Asian mountain ranges; the Himalayas contain the highest mountains in the world, including Mount Everest, 8,848 metres high and traverses the border between China and Nepal. Mountain ranges outside these two systems include the Arctic Cordillera, the Urals, the Appalachians, the Scandinavian Mountains, the Great Dividing Range, the Altai Mountains and the Hijaz Mountains. If the definition of a mountain range is stretched to include underwater mountains the Ocean Ridges form the longest continuous mountain system on Earth, with a length of 65,000 kilometres.
The mountain systems of the earth are characterized by a tree structure, where mountain ranges can contain sub-ranges. The sub-range relationship is expressed as a parent-child relationship. For example, the White Mountains of New Hampshire and the Blue Ridge Mountains are sub-ranges of the Appalachian Mountains. Equivalently, the Appalachians are the parent of the White Mountains and Blue Ridge Mountains, the White Mountains and the Blue Ridge Mountains are children of the Appalachians; the parent-child expression extends to the sub-ranges themselves: the Sandwich Range and the Presidential Range are children of the White Mountains, while the Presidential Range is parent to the Northern Presidential Range and Southern Presidential Range. The position of mountains influences climate, such as snow; when air masses move up and over mountains, the air cools producing orographic precipitation. As the air descends on the leeward side, it warms again and is drier, having been stripped of much of its moisture.
A rain shadow will affect the leeward side of a range. Mountain ranges are subjected to erosional forces which work to tear them down; the basins adjacent to an eroding mountain range are filled with sediments which are buried and turned into sedimentary rock. Erosion is at work while the mountains are being uplifted until the mountains are reduced to low hills and plains; the early Cenozoic uplift of the Rocky Mountains of Colorado provides an example. As the uplift was occurring some 10,000 feet of Mesozoic sedimentary strata were removed by erosion over the core of the mountain range and spread as sand and clays across the Great Plains to the east; this mass of rock was removed as the range was undergoing uplift. The removal of such a mass from the core of the range most caused further uplift as the region adjusted isostatically in response to the removed weight. Rivers are traditionally believed to be the principal cause of mountain range erosion, by cutting into bedrock and transporting sediment.
Computer simulation has shown that as mountain belts change from tectonically active to inactive, the rate of erosion drops because there are fewer abrasive particles in the water and fewer landslides. Mountains on other planets and natural satellites of the Solar System are isolated and formed by processes such as impacts, though there are examples of mountain ranges somewhat similar to those on Earth. Saturn's moon Titan and Pluto, in particular exhibit large mountain ranges in chains composed of ices rather than rock. Examples include the Mithrim Montes and Doom Mons on Titan, Tenzing Montes and Hillary Montes on Pluto; some terrestrial planets other than Earth exhibit rocky mountain ranges, such as Maxwell Montes on Venus taller than any on Earth and Tartarus Montes on Mars, Jupiter's moon Io has mountain ranges formed from tectonic processes including Boösaule Montes, Dorian Montes, Hi'iaka Montes and Euboea Montes. Peakbagger Ranges Home Page Bivouac.com
A volcanic field is an area of the Earth's crust, prone to localized volcanic activity. They contain 10 to 100 volcanoes such as cinder cones and are in clusters. Lava flows may occur, they may occur as a polygenetic volcanic field. Atlin Volcanic Field, British Columbia Desolation Lava Field, British Columbia Garibaldi Lake volcanic field, British Columbia Mount Cayley volcanic field, British Columbia Tuya Volcanic Field, British Columbia Wells Gray-Clearwater volcanic field, British Columbia Wrangell Volcanic Field, Yukon Territory Boring Lava Field, Oregon Central Colorado volcanic field, Colorado Clear Lake Volcanic Field, California Coso Volcanic Field, California Indian Heaven, Washington Marysvale Volcanic Field, Utah Raton-Clayton volcanic field, New Mexico San Bernardino Volcanic Field, Arizona San Francisco volcanic field, Arizona San Juan volcanic field, Colorado Taos Plateau volcanic field, Taos County, New Mexico Trans-Pecos Volcanic Field, Texas Wrangell Volcanic Field, Alaska San Quintín Volcanic Field, Baja California Durango volcanic field, Durango Auckland volcanic field, North Island, New Zealand Bayuda Volcanic Field, Sudan Bombalai Hill, Malaysia Central Skåne Volcanic Province, Sweden Chaîne des Puys, France Cu-Lao Re Group, Vietnam Haruj, Libya In Teria volcanic field, Algeria Laguna Volcanic Field, Philippines Manzaz volcanic field, Algeria Meidob Volcanic Field, Sudan Nemours-Nedroma, Algeria Oujda volcanic field, Morocco Oulmés volcanic field, Morocco Rekkame volcanic field, Morocco Todra volcanic field, Niger Vulkan Eifel, Germany Volcanic arc – A chain of volcanoes formed above a subducting plate Volcanic belt – A large volcanically active region
A conical hill is a landform with a distinctly conical shape. It is isolated or rises above other surrounding foothills, is but not always, of volcanic origin. Conical hills or mountains occur in different shapes and are not geometrically-shaped cones. However, they have a circular base and smooth sides with a gradient of up to 30°; such conical mountains are found in all volcanically-formed areas of the world such as the Bohemian Central Uplands in the Czech Republic, the Rhön in Germany or the Massif Central in France. The conical hill as a geomorphological term first appeared in the German language, as Kegelberg, coined by Goethe and geologists of his era. From their natural appearance these were basaltic or phonolitic landforms in the shape of a mathematical cone, hence why the term came to be used in the early geological literature; the first systematic geological mapping of the Kingdom of Saxony and started by Abraham Gottlob Werner, describes, in his works, numerous mountains and hills of volcanic or subvolcanic origin as Kegel or Kegelberg.
The term was introduced more definitively by Carl Friedrich Naumann in Notes to Section VII of the Geognostic Charter of the Kingdom of Saxony and its Adjacent Territories thus: "The ordinary form of basalt and phonolitic hills is so wonderfully uniform that you can recognize them from a distance. They are cones. Of course, this typical form has many variations. Flat ridges are arranged in rows, out of which rise only a isolated basalt or phonolite cones."In this work, published by Naumann and revised by Bernhard Cotta, the most important hills are described in the relevant map sheets, for example: 33. The Mittenberg, a conical hill in the centre between Tollenstein, Schönfeld and Neuhütte. Today the descriptors "cone", "conical hill" or "conical mountain" are used as morphological terms in geography for a steep-sided, isolated hill or mountain, because they are not always seen or described in connexion with volcanic processes. All stratovolcanoes and shield volcanoes have a tendency to form a cone at the surface.
However, stratovolcanoes are able to form steeper sides whilst shield volcanoes only form flat cones. The reason for this is that stratovolcanoes are composed of solid, eruptive material, whereas shield volcanoes are built up by fluid lava flows. Over the course of time, after several eruptions, a cone of debris forms from the eruptive material; the natural conical shape so formed is a result of the fact that the amount of ejected material decreases with the radially distance from the crater. The layer of debris deposited is greater near the volcano than further away, so the volcano grows more close to the crater itself; the slope gradient of the resulting volcano is dependent both on the angle of repose as well as the speed at which the volcano is weathered. The angle of repose is, in turn, dependent on the composition of the lava, its viscosity and rate of solidification, the amount of ejected loose rock. Many volcanoes tend to produce subsidiary craters or adventive cones; these are new openings formed on the sides of the volcano through which new material is ejected sometimes only on one side.
As a result, these mountains lose their ideal conical shape. The formation of an perfect conical mountain or hill is only possible where there is a stable, central crater. Many volcanoes are therefore only conical from one direction of view. Conical hills may form in such terrain being known as kegelkarst. A typical example of non-volcanic conical hills are the Chocolate Hills in Bohol on the Philippines. In all mountain regions of the world, conical peaks may be formed by erosion processes, but they are not isolated landforms, they arise through the formation of ordinary riverine meanders. But they can result from the action of an entrenched river that has cut into a plateau; the resulting cutoff meander spur may be cone-shaped. The artificially created hills or mounds associated, for example, with mining tend to be cone-shaped; these artificial hills are free-standing and, once tipping has finished, they may become conical hills overgrown with vegetation. However, as artificial features they are classed as spoil tips rather than natural hills.
Geomorphology Inliers and outliers Spoil tip Table hill Volcanic cone Carl Friedrich Naumann, Bernhard Cotta: Erläuterungen zu Section VII der geognostischen Charte des Königreiches Sachsen und der angränzenden Länderabtheilungen oder: Geognostische Skizze der gegenden zwischen Schandau, Kratzau, Gabel, Böhmisch-Leipe, Wernstadtel und Tetschen. Dresden und Leipzig, 1840
Mesa is the American English term for tableland, an elevated area of land with a flat top and sides that are steep cliffs. It takes its name from its characteristic table-top shape, it may be called a table hill, table-topped hill or table mountain. It is larger than a butte, it is a characteristic landform of arid environments the Western and Southwestern United States in badlands and mountainous regions ranging from Washington and California to the Dakotas, Utah and Texas. Examples are found in many other nations including Spain, Sardinia and South Africa, Arabia and Australia. Grand Mesa is a large mesa located in western Colorado in the Southwest United States. Cerro Negro is a mesa in Argentina. Mesas form by weathering and erosion of horizontally layered rocks that have been uplifted by tectonic activity. Variations in the ability of different types of rock to resist weathering and erosion cause the weaker types of rocks to be eroded away, leaving the more resistant types of rocks topographically higher than their surroundings.
This process is called differential erosion. The most resistant rock types include sandstone, quartzite, chert, lava flows and sills. Lava flows and sills, in particular, are resistant to weathering and erosion, form the flat top, or caprock, of a mesa; the less resistant rock layers are made up of shale, a softer rock that weathers and erodes more easily. The differences in strength of various rock layers is. Less resistant rocks are eroded away on the surface into valleys, where they collect water drainage from the surrounding area, while the more resistant layers are left standing out. A large area of resistant rock, such as a sill may shield the layers below it from erosion while the softer rock surrounding it is eroded into valleys, thus forming a caprock. Differences in rock type reflect on the sides of a mesa, as instead of smooth slopes, the sides are broken into a staircase pattern called "cliff-and-bench topography"; the more resistant layers form the cliffs, or stairsteps, while the less resistant layers form gentle slopes, or benches, between the cliffs.
Cliffs retreat and are cut off from the main cliff, or plateau, by basal sapping. When the cliff edge does not retreat uniformly, but instead is indented by headward eroding streams, a section can be cut off from the main cliff, forming a mesa. Basal sapping occurs as water flowing around the rock layers of the mesa erodes the underlying soft shale layers, either as surface runoff from the mesa top or from groundwater moving through permeable overlying layers, which leads to slumping and flowage of the shale; as the underlying shale erodes away, it can no longer support the overlying cliff layers, which collapse and retreat. When the caprock has caved away to the point where only a little remains, it is known as a butte. A transitional zone on Mars, known as the fretted terrain, lies between cratered highlands and less cratered lowlands; the younger lowland knobs. The mesa and knobs are separated by flat lying lowlands, they are thought to form from ice-facilitated mass wasting processes from ground or atmospheric sources.
The mesas and knobs decrease in size with increasing distance from the highland escarpment. The relief of the mesas range from nearly 2 km to 100m depending on the distance they are from the escarpment
Intrusive rock is formed when magma crystallizes and solidifies underground to form intrusions, for example plutons, dikes, sills and volcanic necks. Intrusive rock forms within Earth's crust from the crystallization of magma. Many mountain ranges, such as the Sierra Nevada in California, are formed from large granite intrusions. Intrusions are one of the two ways igneous rock. Technically an intrusion is any formation of intrusive igneous rock. In contrast, an extrusion consists of extrusive rock. Large bodies of magma that solidify underground before they reach the surface of the crust are called plutons. Plutonic rocks form 7% of the Earth's current land surface. Coarse-grained intrusive igneous rocks that form at depth within the earth are called abyssal while those that form near the surface are called subvolcanic or hypabyssal. Intrusive structures are classified according to whether or not they are parallel to the bedding planes or foliation of the country rock: if the intrusion is parallel the body is concordant, otherwise it is discordant.
An intrusive suite is a group of plutons related in time and space.. Intrusions vary from mountain-range-sized batholiths to thin veinlike fracture fillings of aplite or pegmatite. Intrusions can be classified according to the shape and size of the intrusive body and its relation to the other formations into which it intrudes: Batholith: a large irregular discordant intrusion Chonolith: an irregularly-shaped intrusion with a demonstrable base Cupola: a dome-shaped projection from the top of a large subterranean intrusion Dike: a narrow tabular discordant body nearly vertical Laccolith: concordant body with flat base and convex top with a feeder pipe below Lopolith: concordant body with flat top and a shallow convex base, may have a feeder dike or pipe below Phacolith: a concordant lens-shaped pluton that occupies the crest of an anticline or trough of a syncline Volcanic pipe or volcanic neck: tubular vertical body that may have been a feeder vent for a volcano Sill: a thin tabular concordant body intruded along bedding planes Stock: a smaller irregular discordant intrusive Boss: a small stock A body of intrusive igneous rock which crystallizes from magma cooling underneath the surface of the Earth is called a pluton.
If the pluton is large, it may be called a stock. Intrusive rocks are characterized by large crystal sizes, as the individual crystals are visible, the rock is called phaneritic; this is as the magma cools underground, while cooling may be fast or slow, cooling is slower than on the surface, so larger crystals grow. If it runs parallel to rock layers, it is called a sill. If an intrusion makes rocks above rise to form a dome, it is called a laccolith. How deep-seated intrusions burst through the overlying strata causes intrusive rock to be recognized: Veins spread out into branches, or branchlike parts result from filled cracks, the high temperature is evident in how they alter country rock; as heat dissipation is slow, as the rock is under pressure, crystals form, no vitreous chilled matter is present. The intrusions did not flow. Contained gases could not escape through the thick strata, thus form cavities, which can be observed; because their crystals are of the rough equal size, these rocks are said to be equigranular.
There is no distinction between a first generation of large well-shaped crystals and a fine-grained ground-mass. The minerals of each have formed in a definite order, each has had a period of crystallization that may be distinct or may have coincided with or overlapped the period of formation of some of the other ingredients. Earlier crystals originated at a time when most of the rock was still liquid and are more or less perfect. Crystals are less regular in shape because they were compelled to occupy the spaces left between the already-formed crystals; the former case is said to be idiomorphic. There are many other characteristics that serve to distinguish the members of these two groups. For example, orthoclase is feldspar from granite, while its modifications occur in lavas of similar composition; the same distinction holds for nepheline varieties. Leucite is common in lavas but rare in plutonic rocks. Muscovite is confined to intrusions; these differences show the influence of the physical conditions under which consolidation takes place.
Intrusive rocks formed at greater depths are called abyssal. Some intrusive rocks solidified in fissures as dikes and intrusive sills at shallow depth and are called subvolcanic or hypabyssal, they show structures intermediate between those of plutonic rocks. They are commonly porphyritic and sometimes vesicular. In fact, many of them are petrologically indistinguishable from lavas of similar composition. Ellicott City Granodiorite Guilford Quartz Monzonite Methods of pluton emplacement Norbeck Intrusive Suite Volcanic rock Woodstock Quartz Monzonite
A fell is a high and barren landscape feature, such as a mountain range or moor-covered hills. The term is most employed in Fennoscandia, the Isle of Man, parts of Northern England, Scotland. Bekkr -'stream' » beck dalr -'valley' » dale fors -'waterfall' » force/foss fjallr -'mountain' » fell gil -'ravine' » gill/ghyll haugr -'hill' » howe pic -'peak' » pike sætr -'shieling' » side/seat tjorn -'small lake' » tarn þveit -'clearing' » thwaite The English word fell comes from Old Norse fell and fjall, it is cognate with Danish fjeld, Faroese fjall and fjøll, Icelandic fjall and fell, Norwegian fjell with dialects fjøll, fjødd, fjedl, fjill and fel, Swedish fjäll, all referring to mountains rising above the alpine tree line. In Northern England in the Lake District and in the Pennine Dales, the word "fell" referred to an area of uncultivated high ground used as common grazing on common land and above the timberline. Today "fell" refers to the mountains and hills of the Lake District and the Pennine Dales.
Names that referred to grazing areas have been applied to these hilltops. This is the case with Seathwaite Fell, for example, which would be the common grazing land used by the farmers of Seathwaite; the fellgate marks the road from a settlement onto the fell, as is the case with the Seathwaite Fell. In other cases the reverse is true; the word "fell" is used in the names of various breeds of livestock, bred for life on the uplands, such as Rough Fell sheep, Fell Terriers and Fell ponies. It is found in many place names across the North of England attached to the name of a community. In northern England, there is a Lord of the Fells – this ancient aristocratic title being associated with the Lords of Bowland. Groups of cairns are a common feature on many fells marking the summit – there are fine examples on Wild Boar Fell in Mallerstang Dale, on Nine Standards Rigg just outside Kirkby Stephen, Cumbria; as the most mountainous region of England, the Lake District is the area most associated with the sport of fell running, which takes its name from the fells of the district.
"Fellwalking" is the term used locally for the activity known in the rest of Great Britain as hillwalking. The word "fell" enjoys limited use in Scotland, with for example the Campsie Fells in Central Scotland, to the North East of Glasgow. One of the most famous examples of the use of the word "fell" in Scotland is Goat Fell, the highest point on the Isle of Arran. Criffel and the nearby Long Fell in Galloway may be seen from the northern Lake District of England. Peel Fell in the Kielder Forest is situated on the border between the Scottish Borders to the North and the English county of Northumberland to the South. In Norway, fjell, in common usage, is interpreted as a summit of greater altitude than a hill, which leads to a great deal of local variation in what is defined as a'fjell'. Professor of geography at the University of Bergen, Anders Lundeberg, has summed up the problem by stating that "There is no fixed and unambiguous definition of'fjell'." Ivar Aasen defined fjell as a "tall berg" referring to a berg that reaches an altitude where trees don't grow, lower berg are referred to as "berg", "ås" or "hei".
The fixed expression til fjells refers to mountains as a collective rather than a specific location or specific summit. According to Ivar Aasen berg refers to cliffs and notable elevations of the surface underpinned by bedrock. For all practical purposes,'fjell' can be translated as'mountain' and the Norwegian language has no other used word for mountain. In Sweden, "fjäll" refers to any mountain or upland high enough that forest will not survive at the top, in effect a mountain tundra.'Fjäll' is used to describe mountains in the Nordic countries, but more to describe mountains shaped by massive ice sheets in Arctic and subarctic regions. In Finnish, the mountains characteristic of the region of Lapland are called tunturi. In Finnish, the geographical term vuori is used for mountains uplifted and with jagged terrain featuring permanent glaciers, while tunturi refers to the old eroded shaped terrain without glaciers, as found in Finland, they are round inselbergs rising from the otherwise flat surroundings.
The mountains in Finnish Lapland reach heights of up to 400 and 800 metres, where the upper reaches are above the tree line. Those that do not reach the tree line, on the other hand, are referred to as vaara; the mountains in Finnish Lapland form vestiges of the Karelides mountains, formed two billion years ago. The term tunturi a word limited to Far-Northern dialects of Finnish and Karelian, is a loan from Sami, compare Proto-Sami *tuontër, South Sami doedtere, Northern Sami duottar, Inari Sami tuodâr "uplands, tundra", Kildin Sami tūndâr, which means "uplands, treeless mountain tract" and is cognate with Finnish tanner "hard ground". From this Sami word, the word tundra is borrowed, as well, through the Russian language; the term förfjäll is used in Sweden and Finland to denote moun