128-447: The Coalman Glacier (also Coleman Glacier ) is a glacier located on the upper slopes of Mount Hood in the U.S. state of Oregon . It is the mountain's highest glacier ranging from about 11,200 to 10,500 ft (3,400 to 3,200 m), located within the crater rim, southwest of the peak. It was named for Elija Coalman (variously spelled Elijah Coleman ), an early mountain guide who climbed Mount Hood 586 times. Coalman Glacier
256-424: A cirque landform (alternatively known as a corrie or as a cwm ) – a typically armchair-shaped geological feature (such as a depression between mountains enclosed by arêtes ) – which collects and compresses through gravity the snow that falls into it. This snow accumulates and the weight of the snow falling above compacts it, forming névé (granular snow). Further crushing of the individual snowflakes and squeezing
384-574: A fight, and the western section was not of any strategic value to either side, so they did not battle there. The Japanese invaded the north shore of the Australia territories and were aiming to move south and take the southern shore too. The highlands, northern and eastern parts of the island became key battlefields in the South West Pacific Theatre of World War II . Notable battles were for Port Moresby (the naval battle
512-778: A floristic region that extends from the Malay Peninsula across Indonesia to New Guinea and the East Melanesian Islands . The flora of New Guinea is a mixture of many tropical rainforest species with origins in Asia, together with typically Australasian flora. Typical Southern Hemisphere flora include the conifers Podocarpus and the rainforest emergents Araucaria and Agathis , as well as tree ferns and several species of Eucalyptus . New Guinea has 284 species and six orders of mammals: monotremes , three orders of marsupials , rodents and bats ; 195 of
640-522: A glacier is usually assessed by determining the glacier mass balance or observing terminus behavior. Healthy glaciers have large accumulation zones, more than 60% of their area is snow-covered at the end of the melt season, and they have a terminus with a vigorous flow. Following the Little Ice Age 's end around 1850, glaciers around the Earth have retreated substantially . A slight cooling led to
768-601: A glacier may flow into a body of water, it forms only on land and is 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 (also known as "continental glaciers") in the polar regions , but glaciers may be found in mountain ranges on every continent other than the Australian mainland, including Oceania's high-latitude oceanic island countries such as New Zealand . Between latitudes 35°N and 35°S, glaciers occur only in
896-411: A glacier via moulins . Streams within or beneath a glacier flow in englacial or sub-glacial tunnels. These tunnels sometimes reemerge at the glacier's surface. Most of the important processes controlling glacial motion occur in the ice-bed contact—even though it is only a few meters thick. The bed's temperature, roughness and softness define basal shear stress, which in turn defines whether movement of
1024-408: A kilometer per year. Eventually, the ice will be surging fast enough that it begins to thin, as accumulation cannot keep up with the transport. This thinning will increase the conductive heat loss, slowing the glacier and causing freezing. This freezing will slow the glacier further, often until it is stationary, whence the cycle can begin again. The flow of water under the glacial surface can have
1152-404: A large effect on the motion of the glacier itself. Subglacial lakes contain significant amounts of water, which can move fast: cubic kilometers can be transported between lakes over the course of a couple of years. This motion is thought to occur in two main modes: pipe flow involves liquid water moving through pipe-like conduits, like a sub-glacial river; sheet flow involves motion of water in
1280-460: A lower heat conductance, meaning that the basal temperature is also likely to be higher. Bed temperature tends to vary in a cyclic fashion. A cool bed has a high strength, reducing the speed of the glacier. This increases the rate of accumulation, since newly fallen snow is not transported away. Consequently, the glacier thickens, with three consequences: firstly, the bed is better insulated, allowing greater retention of geothermal heat. Secondly,
1408-537: A near-equivalent number of separate languages, which makes New Guinea the most linguistically diverse area in the world. Ethnologue 's 14th edition lists 826 languages of Papua New Guinea and 257 languages of Western New Guinea , total 1073 languages, with 12 languages overlapping. They can be divided into two groups, the Austronesian languages , and all the others placed in the catch-all category of Papuan languages , most of which are unrelated. The separation
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#17327878819241536-638: A new name because of the negative association of Papua . Frans Kaisiepo , the committee leader, suggested the name from Mansren Koreri myths, Iri-an from the Biak language of Biak Island , meaning "hot land" (referring to the climate), but also from Iryan which means heated process as a metaphor for a land that is entering a new era. In Serui Iri-an ( lit. "land-nation") means "pillar of nation", while in Merauke Iri-an ( lit. "placed higher-nation") means "rising spirit" or "to rise". The name
1664-489: A part of Indonesia and is organized as the provinces of Papua , Central Papua , Highland Papua , South Papua , Southwest Papua , and West Papua . The two major cities on the island are Port Moresby and Jayapura . The island has been known by various names: The name Papua was used to refer to parts of the island before contact with the West. Its etymology is unclear; one theory states that it derived from Tidore ,
1792-488: A thin layer. A switch between the two flow conditions may be associated with surging behavior. Indeed, the loss of sub-glacial water supply has been linked with the shut-down of ice movement in the Kamb ice stream. The subglacial motion of water is expressed in the surface topography of ice sheets, which slump down into vacated subglacial lakes. The speed of glacial displacement is partly determined by friction . Friction makes
1920-410: 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 climate change than other glaciers. Thermally, a temperate glacier is at a melting point throughout the year, from its surface to its base. The ice of a polar glacier is always below the freezing threshold from the surface to its base, although
2048-429: Is divided politically into roughly equal halves across a north–south line: The current population of the island of New Guinea is about fifteen million. Archaeological evidence indicates that humans may have inhabited the island continuously since 50,000 BCE, and first settlement possibly dating back to 60,000 years ago has been proposed. The island is presently populated by almost a thousand different tribal groups and
2176-468: Is a persistent body of dense ice that is constantly moving downhill under its own weight. A glacier forms where the accumulation of snow exceeds its ablation over many years, often centuries . It acquires distinguishing features, such as crevasses and seracs , as it slowly flows and deforms under stresses induced by its weight. As it moves, it abrades rock and debris from its substrate to create landforms such as cirques , moraines , or fjords . Although
2304-456: Is above or at freezing at the interface and is able to slide at this contact. This contrast is thought to a large extent to govern the ability of a glacier to effectively erode its bed , as sliding ice promotes plucking at rock from the surface below. Glaciers which are partly cold-based and partly warm-based are known as polythermal . Glaciers form where the accumulation of snow and ice exceeds ablation . A glacier usually originates from
2432-407: Is affected by factors such as slope, ice thickness, snowfall, longitudinal confinement, basal temperature, meltwater production, and bed hardness. A few glaciers have periods of very rapid advancement called surges . These glaciers exhibit normal movement until suddenly they accelerate, then return to their previous movement state. These surges may be caused by the failure of the underlying bedrock,
2560-437: Is around 4,000 m (13,100 ft) elevation, and the tallest peaks contain equatorial glaciers —which have been retreating since at least 1936 . Various other smaller mountain ranges occur both north and west of the central ranges. Except in high elevations, most areas possess a warm humid climate throughout the year, with some seasonal variation associated with the northeast monsoon season. Another major habitat feature
2688-411: Is because these peaks are located near or in the hyperarid Atacama Desert . Glaciers erode terrain through two principal processes: plucking and abrasion . As glaciers flow over bedrock, they soften and lift blocks of rock into the ice. This process, called plucking, is caused by subglacial water that penetrates fractures in the bedrock and subsequently freezes and expands. This expansion causes
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#17327878819242816-410: Is bounded on the north and east by the summit, on the northwest by the rocky crater wall known as Castle Crags (also Hawkins Cliffs ), on the west by Hot Rocks , and on southeast by the back side of Steel Cliff . Hawkins Ridge lies on the upper western edge of Coalman Glacier. There is no weather station, but this climate table contains interpolated data. This article about a glacier in
2944-406: Is by basal sliding, where meltwater forms between the ice and the bed itself. Whether a bed is hard or soft depends on the porosity and pore pressure; higher porosity decreases the sediment strength (thus increases the shear stress τ B ). Porosity may vary through a range of methods. Bed softness may vary in space or time, and changes dramatically from glacier to glacier. An important factor
3072-434: Is called glaciology . Glaciers are important components of the global cryosphere . Glaciers are categorized by their morphology, thermal characteristics, and behavior. Alpine glaciers form on the crests and 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
3200-416: Is called rock flour and is made up of rock grains between 0.002 and 0.00625 mm in size. Abrasion leads to steeper valley walls and mountain slopes in alpine settings, which can cause avalanches and rock slides, which add even more material to the glacier. Glacial abrasion is commonly characterized by glacial striations . Glaciers produce these when they contain large boulders that carve long scratches in
3328-647: Is higher, and the mountains above 5,000 m (16,400 ft) usually have permanent snow. Even at high latitudes, glacier formation is not inevitable. Areas of the Arctic , such as Banks Island , and the McMurdo Dry Valleys in Antarctica are considered polar deserts where glaciers cannot form because they receive little snowfall despite the bitter cold. Cold air, unlike warm air, is unable to transport much water vapor. Even during glacial periods of
3456-722: Is home to an estimated 44 uncontacted tribal groups . With some 786,000 km of tropical land—less than one-half of one percent (0.5%) of the Earth's surface—New Guinea has an immense biodiversity , containing between 5 and 10 percent of the total species on the planet. This percentage is about the same amount as that found in the United States or Australia. A high percentage of New Guinea's species are endemic , and thousands are still unknown to science: probably well over 200,000 species of insect, between 11,000 and 20,000 plant species, and over 650 resident bird species. Most of these species are shared, at least in their origin, with
3584-703: Is known as the Battle of the Coral Sea ), Milne Bay and for the Kokoda track . Papuans often gave vital assistance to the Allies , fighting alongside Australian troops, and carrying equipment and injured men across New Guinea. Approximately 216,000 Japanese, Australian and U.S. soldiers, sailors and airmen died during the New Guinea Campaign. Following the return to civil administration after World War II,
3712-529: Is most often used for a wider region that includes lands, such as New Zealand , which are not on the same continental shelf. In the early 1970s, they introduced the term Greater Australia for the Pleistocene continent. Then, at a 1975 conference and consequent publication, they extended the name Sahul from its previous use for just the Sahul Shelf to cover the continent. The island of New Guinea
3840-451: Is not merely linguistic; warfare among societies was a factor in the evolution of the men's house : separate housing for groups of adult men, away from the single-family houses of women and children. Pig-based trade between groups and pig-based feasts form a common tradition with the other peoples of southeast Asia and Oceania. Most Papuan societies practice agriculture, supplemented by hunting and gathering. Current evidence indicates that
3968-897: Is termed an ice cap or ice field . Ice caps have an area less than 50,000 km (19,000 sq mi) by definition. Glacial bodies larger than 50,000 km (19,000 sq mi) are called ice sheets or 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 Antarctica and Greenland. They contain vast quantities of freshwater, enough that if both melted, global sea levels would rise by over 70 m (230 ft). Portions of an ice sheet or cap that extend into water are called ice shelves ; they tend to be thin with limited slopes and reduced velocities. 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
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4096-531: Is the world's second-largest island , with an area of 785,753 km (303,381 sq mi). Located in Melanesia in the southwestern Pacific Ocean , the island is separated from Australia by the 150-kilometre (81-nautical-mile; 93-mile) wide Torres Strait , though both landmasses lie on the same continental shelf , and were united during episodes of low sea level in the Pleistocene glaciations as
4224-413: Is the region where there is a net loss in glacier mass. The upper part of a glacier, where accumulation exceeds ablation, is called the accumulation zone . The equilibrium line separates the ablation zone and the accumulation zone; it is the contour where the amount of new snow gained by accumulation is equal to the amount of ice lost through ablation. In general, the accumulation zone accounts for 60–70% of
4352-549: Is the second most frequently visited glacier on the mountain because it is part of the popular South Climbing route from Timberline Lodge . It lies entirely within Mount Hood Wilderness . The most well known feature of Coalman is the Hogsback : a snow ridge running southwest to northeast from Crater Rock toward the summit ridge. The Bergschrund is another widely known feature where the glacier pulls away from
4480-402: Is the underlying geology; glacial speeds tend to differ more when they change bedrock than when the gradient changes. Further, bed roughness can also act to slow glacial motion. The roughness of the bed is a measure of how many boulders and obstacles protrude into the overlying ice. Ice flows around these obstacles by melting under the high pressure on their stoss side ; the resultant meltwater
4608-478: Is the vast southern and northern lowlands. Stretching for hundreds of kilometres, these include lowland rainforests, extensive wetlands, savanna grasslands, and some of the largest expanses of mangrove forest in the world. The southern lowlands are the site of Lorentz National Park , a UNESCO World Heritage Site . The northern lowlands are drained principally by the Mamberamo River and its tributaries on
4736-552: Is then forced into the cavity arising in their lee side , where it re-freezes. As well as affecting the sediment stress, fluid pressure (p w ) can affect the friction between the glacier and the bed. High fluid pressure provides a buoyancy force upwards on the glacier, reducing the friction at its base. The fluid pressure is compared to the ice overburden pressure, p i , given by ρgh. Under fast-flowing ice streams, these two pressures will be approximately equal, with an effective pressure (p i – p w ) of 30 kPa; i.e. all of
4864-993: The Andes , the Himalayas , the Rocky Mountains , the Caucasus , Scandinavian Mountains , and the Alps . Snezhnika glacier in Pirin Mountain, Bulgaria with a latitude of 41°46′09″ N is the southernmost glacial mass in Europe. Mainland Australia currently contains no glaciers, although a small glacier on Mount Kosciuszko was present in the last glacial period . In New Guinea, small, rapidly diminishing, glaciers are located on Puncak Jaya . Africa has glaciers on Mount Kilimanjaro in Tanzania, on Mount Kenya , and in
4992-553: The Biak phrase sup i babwa , which means "the land below [the sunset]", and refers to the Raja Ampat Islands . When Portuguese and Spanish explorers arrived via the Spice Islands , they also used the name Papua . However, Westerners, beginning with Spanish explorer Yñigo Ortiz de Retez in 1545, used the name New Guinea , due to the resemblance between the indigenous peoples of the island and Africans of
5120-644: The Faroe and Crozet Islands were completely glaciated. The permanent snow cover necessary for glacier formation is affected by factors such as the degree of slope on the land, amount of snowfall and the winds. Glaciers can be found in all latitudes except from 20° to 27° north and south of the equator where the presence of the descending limb of the Hadley circulation lowers precipitation so much that with high insolation snow lines reach above 6,500 m (21,330 ft). Between 19˚N and 19˚S, however, precipitation
5248-580: The Grand Valley of the Baliem River, which had 50,000 yet-undiscovered Stone Age farmers living in orderly villages. The people, known as the Dani , were the last society of its size to make first contact with the rest of the world. A 1930 expedition led by the prospector Michael Lehay also encountered an indigenous group in the highlands. The inhabitants, believing themselves to be the only people in
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5376-579: The Guinea region . The name is one of several toponyms sharing similar etymologies , ultimately meaning "land of the blacks" or similar meanings. The Dutch, who arrived later under Jacob Le Maire and Willem Schouten , called it Schouten island . They later used this name only to refer to islands off the north coast of Papua proper, the Schouten Islands or Biak Island. When the Dutch colonized
5504-598: The Gulf of Papua form a single delta complex. The rivers of the island are extremely rich in water due to the annual rainfall of 2,000–10,000 mm. According to a modest calculation, the New Guinea River carries about 1,500 km /a (48,000 m /s) of water into the sea. Fly alone carries more water 238 km /a (7,500 m /s) than all the rivers in Australia combined. The island of New Guinea lies to
5632-760: The Himalayas , Andes , and a few high mountains in East Africa, Mexico, New Guinea and on Zard-Kuh in Iran. With more than 7,000 known glaciers, Pakistan has more glacial ice than any other country outside the polar regions. Glaciers cover about 10% of Earth's land surface. Continental glaciers cover nearly 13 million km (5 million sq mi) or about 98% of Antarctica 's 13.2 million km (5.1 million sq mi), with an average thickness of ice 2,100 m (7,000 ft). Greenland and Patagonia also have huge expanses of continental glaciers. The volume of glaciers, not including
5760-599: The Indonesian archipelago , it lies north of Australia's Top End , the Gulf of Carpentaria and Cape York Peninsula , and west of the Bismarck Archipelago and the Solomon Islands archipelago . Politically, the western half of the island comprises six provinces of Indonesia : Papua , Central Papua , Highland Papua , South Papua , West Papua and Southwest Papua . The eastern half forms
5888-583: The Mamberamo River , near which he landed on 20 June, naming the island 'Nueva Guinea'. The first known map of the island was made by F. Hoeiu in 1600 and shows it as 'Nova Guinea'. In 1606, Luís Vaz de Torres explored the southern coast of New Guinea from Milne Bay to the Gulf of Papua including Orangerie Bay , which he named Bahía de San Lorenzo . His expedition also discovered Basilaki Island naming it Tierra de San Buenaventura , which he claimed for Spain in July 1606. On 18 October, his expedition reached
6016-623: The Papuan Peninsula ). A spine of east–west mountains, the New Guinea Highlands , dominates the geography of New Guinea, stretching over 1,600 km (1,000 mi) across the island, with many mountains over 4,000 m (13,100 ft). The western half of the island contains the highest mountains in Oceania , with its highest point, Puncak Jaya , reaching an elevation of 4,884 m (16,023 ft). The tree line
6144-562: The Quaternary , Manchuria , lowland Siberia , and central and northern Alaska , though extraordinarily cold, had such light snowfall that glaciers could not form. In addition to the dry, unglaciated polar regions, some mountains and volcanoes in Bolivia, Chile and Argentina are high (4,500 to 6,900 m or 14,800 to 22,600 ft) and cold, but the relative lack of precipitation prevents snow from accumulating into glaciers. This
6272-535: The Rwenzori Mountains . Oceanic islands with glaciers include Iceland, several of the islands off the coast of Norway including Svalbard and Jan Mayen to the far north, New Zealand and the subantarctic islands of Marion , Heard , Grande Terre (Kerguelen) and Bouvet . During glacial periods of the Quaternary, Taiwan , Hawaii on Mauna Kea and Tenerife also had large alpine glaciers, while
6400-583: The Territory of New Guinea , to be administered by Australia under a League of Nations mandate . The territories under Australian administration became collectively known as The Territories of Papua and New Guinea (until February 1942). Before about 1930, European maps showed the highlands as uninhabited forests. When first flown over by aircraft, numerous settlements with agricultural terraces and stockades were observed. The most startling discovery took place on 4 August 1938, when Richard Archbold discovered
6528-505: The United States is a stub . You can help Misplaced Pages by expanding it . This Clackamas County , Oregon state location article is a stub . You can help Misplaced Pages by expanding it . This Hood River County , Oregon state location article is a stub . You can help Misplaced Pages by expanding it . Glacier A glacier ( US : / ˈ ɡ l eɪ ʃ ər / ; UK : / ˈ ɡ l æ s i ər , ˈ ɡ l eɪ s i ər / )
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#17327878819246656-448: The 1990s and 2000s. In a study using data from January 1993 through October 2005, more events were detected every year since 2002, and twice as many events were recorded in 2005 as there were in any other year. Ogives or Forbes bands are alternating wave crests and valleys that appear as dark and light bands of ice on glacier surfaces. They are linked to seasonal motion of glaciers; the width of one dark and one light band generally equals
6784-610: The Australian section was known as the Territory of Papua-New Guinea from 1945 to 1949 and then as Territory of Papua and New Guinea . Although the rest of the Dutch East Indies achieved independence as Indonesia on 27 December 1949, the Netherlands regained control of western New Guinea. During the 1950s, the Dutch government began to prepare Netherlands New Guinea for full independence and allowed elections in 1959;
6912-474: The Dutch promoted Tidore as suzerain of Papua. By 1849, Tidore's borders had been extended to the proximity of the current international border between Indonesia and Papua New Guinea , as it formed extensive trade pact and custom of Uli-Siwa ( federation of nine ). In 1883, following a short-lived French annexation of New Ireland , the British colony of Queensland annexed south-eastern New Guinea. However,
7040-563: The Indonesian portion of New Guinea and the Maluku Islands is estimated to have 9,518 species of vascular plants, of which 4,380 are endemic. In 2020, an international study conducted by a team of 99 experts cataloged 13,634 species representing 1,742 genera and 264 families of vascular plants for New Guinea and its associated islands ( Aru Islands , Bismarck Archipelago , D'Entrecasteaux Islands , Louisiade Archipelago ), making it
7168-545: The Morning Star flag) and via the formation of the Organisasi Papua Merdeka (OPM, or Free Papua Movement) in 1965. Amnesty International has estimated more than 100,000 Papuans, one-sixth of the population, have died as a result of government-sponsored violence against West Papuans. Reports published by TRT World and De Gruyter Oldenbourg have put the number of killed Papuans since the start of
7296-606: The Papuans (who constitute the majority of the island's peoples) are descended from the earliest human inhabitants of New Guinea. These original inhabitants first arrived in New Guinea at a time around the Last Glacial Maximum (c. 21,000 years ago) when the island was connected to the Australian continent via a land bridge , forming the landmass of Sahul . These peoples had made the (shortened) sea-crossing from
7424-522: The Queensland government's superiors in the United Kingdom revoked the claim, and (formally) assumed direct responsibility in 1884, when Germany claimed north-eastern New Guinea as the protectorate of German New Guinea (also called Kaiser-Wilhelmsland ). The first Dutch government posts were established in 1898 and in 1902: Manokwari on the north coast, Fak-Fak in the west and Merauke in
7552-412: The advance of many alpine glaciers between 1950 and 1985, but since 1985 glacier retreat and mass loss has become larger and increasingly ubiquitous. Glaciers move downhill by the force of gravity and the internal deformation of ice. At the molecular level, ice consists of stacked layers of molecules with relatively weak bonds between layers. When the amount of strain (deformation) is proportional to
7680-520: The air from the snow turns it into "glacial ice". This glacial ice will fill the cirque until it "overflows" through a geological weakness or vacancy, such as a gap between two mountains. When the mass of snow and ice reaches sufficient thickness, it begins to move by a combination of surface slope, gravity, and pressure. On steeper slopes, this can occur with as little as 15 m (49 ft) of snow-ice. In temperate glaciers, snow repeatedly freezes and thaws, changing into granular ice called firn . Under
7808-430: The amount of melting at surface of the glacier, the faster the ice will flow. Basal sliding is dominant in temperate or warm-based glaciers. The presence of basal meltwater depends on both bed temperature and other factors. For instance, the melting point of water decreases under pressure, meaning that water melts at a lower temperature under thicker glaciers. This acts as a "double whammy", because thicker glaciers have
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#17327878819247936-713: The annual movement of the glacier. Ogives are formed when ice from an icefall is severely broken up, increasing ablation surface area during summer. This creates a swale and space for snow accumulation in the winter, which in turn creates a ridge. Sometimes ogives consist only of undulations or color bands and are described as wave ogives or band ogives. Glaciers are present on every continent and in approximately fifty countries, excluding those (Australia, South Africa) that have glaciers only on distant subantarctic island territories. Extensive glaciers are found in Antarctica, Argentina, Chile, Canada, Pakistan, Alaska, Greenland and Iceland. Mountain glaciers are widespread, especially in
8064-506: The area now known as the Torres Strait flooded after the end of the last glacial period . Anthropologically, New Guinea is considered part of Melanesia . New Guinea is differentiated from its drier, flatter, and less fertile southern counterpart, Australia, by its much higher rainfall and its active volcanic geology. Yet the two land masses share a similar animal fauna, with marsupials , including wallabies and possums , and
8192-432: The bedrock has frequent fractures on the surface, glacial erosion rates tend to increase as plucking is the main erosive force on the surface; when the bedrock has wide gaps between sporadic fractures, however, abrasion tends to be the dominant erosive form and glacial erosion rates become slow. Glaciers in lower latitudes tend to be much more erosive than glaciers in higher latitudes, because they have more meltwater reaching
8320-445: The bedrock. By mapping the direction of the striations, researchers can determine the direction of the glacier's movement. Similar to striations are chatter marks , lines of crescent-shape depressions in the rock underlying a glacier. They are formed by abrasion when boulders in the glacier are repeatedly caught and released as they are dragged along the bedrock. The rate of glacier erosion varies. Six factors control erosion rate: When
8448-403: The coastal areas and islands of New Guinea. They also introduced pigs and dogs . These Austronesian migrants are considered the ancestors of most people in insular Southeast Asia, from Sumatra and Java to Borneo and Sulawesi , as well as coastal new Guinea. The western part of the island was in contact with kingdoms in other parts of modern-day Indonesia. The Negarakertagama mentioned
8576-507: The coastal fringes of the main island in places. Human habitation of New Guinea over tens of thousands of years has led to a great deal of diversity, which was further increased by the later arrival of the Austronesians and the more recent history of European and Asian settlement through events like transmigration . Large areas of New Guinea are yet to be explored by scientists and anthropologists. The Indonesian province of West Papua
8704-513: The combined landmass of Sahul . Numerous smaller islands are located to the west and east. The island's name was given by Spanish explorer Yñigo Ortiz de Retez during his maritime expedition of 1545 due to the resemblance of the indigenous peoples of the island to those in the African region of Guinea . The eastern half of the island is the major land mass of the nation of Papua New Guinea . The western half, known as Western New Guinea , forms
8832-442: The conflict at roughly 500,000. From 1971, the name Papua New Guinea was used for the Australian territory. On 16 September 1975, Australia granted full independence to Papua New Guinea. In 2000, Irian Jaya was formally renamed "The Province of Papua" and a Law on Special Autonomy was passed in 2001. The Law established a Papuan People's Assembly (MRP) with representatives of the different indigenous cultures of Papua. The MRP
8960-571: The continent of Australia, which was until fairly recent geological times part of the same landmass (see Australia-New Guinea for an overview). The island is so large that it is considered 'nearly a continent' in terms of its biological distinctiveness. In the period from 1998 to 2008, conservationists identified 1,060 new species in New Guinea, including 218 plants, 43 reptiles, 12 mammals, 580 invertebrates, 134 amphibians, 2 birds and 71 fish. Between 2011 and 2017, researchers described 465 previously undocumented plant species in New Guinea. As of 2019,
9088-571: The created ice's density. 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 , and ultimately Latin glaciēs , meaning "ice". The processes and features caused by or related to glaciers are referred to as glacial. The process of glacier establishment, growth and flow is called glaciation . The corresponding area of study
9216-467: The deep profile of fjords , which can reach a kilometer in depth as ice is topographically steered into them. The extension of fjords inland increases the rate of ice sheet thinning since they are the principal conduits for draining ice sheets. It also makes the ice sheets more sensitive to changes in climate and the ocean. Although evidence in favor of glacial flow was known by the early 19th century, other theories of glacial motion were advanced, such as
9344-483: The deformation to become a plastic flow rather than elastic. Then, the glacier will begin to deform under its own weight and flow across the landscape. According to the Glen–Nye flow law , the relationship between stress and strain, and thus the rate of internal flow, can be modeled as follows: where: The lowest velocities are near the base of the glacier and along valley sides where friction acts against flow, causing
9472-524: The east of the Malay Archipelago , with which it is sometimes included as part of a greater Indo-Australian Archipelago. Geologically it is a part of the same tectonic plate as Australia. When world sea levels were low, the two shared shorelines (which now lie 100 to 140 metres below sea level), and combined with lands now inundated into the tectonic continent of Sahul , also known as Greater Australia. The two landmasses became separated when
9600-474: The egg-laying monotreme , the echidna . Other than bats and some two dozen indigenous rodent genera, there are no pre-human indigenous placental mammals . Pigs, several additional species of rats, and the ancestor of the New Guinea singing dog were introduced with human colonization. Prior to the 1970s, archaeologists called the single Pleistocene landmass by the name Australasia , although this word
9728-418: The essentially correct explanation in the 1840s, although it was several decades before it was fully accepted. The top 50 m (160 ft) of a glacier are rigid because they are under low pressure . This upper section is known as the fracture zone and moves mostly as a single unit over the plastic-flowing lower section. When a glacier moves through irregular terrain, cracks called crevasses develop in
9856-438: The estuary, making it the longest river in New Guinea. The winding, muddy, sluggish river can be navigated for 500 km. Ramu is a 650 km long river. Its lower section is navigable, but its upper flow is high-falling, fast-flowing. The energy of the river is used by a power plant near the city of Kainantu . On the south side, the most significant rivers are Pulau , Digul, Fly, Kikori and Purari . The largest river in
9984-475: The fracture zone. Crevasses form because of differences in glacier velocity. If two rigid sections of a glacier move at different speeds or directions, shear forces cause them to break apart, opening a crevasse. Crevasses are seldom more than 46 m (150 ft) deep but, in some cases, can be at least 300 m (1,000 ft) deep. Beneath this point, the plasticity of the ice prevents the formation of cracks. Intersecting crevasses can create isolated peaks in
10112-448: The glacial base and facilitate sediment production and transport under the same moving speed and amount of ice. Material that becomes incorporated in a glacier is typically carried as far as the zone of ablation before being deposited. Glacial deposits are of two distinct types: New Guinea New Guinea ( Tok Pisin : Niugini ; Hiri Motu : Niu Gini ; Indonesian : Papua , fossilized Nugini , or historically Irian )
10240-453: The glacier to melt, creating a water source that is especially important for plants, animals and human uses when other sources may be scant. However, within high-altitude and Antarctic environments, the seasonal temperature difference is often not sufficient to release meltwater. Since glacial mass is affected by long-term climatic changes, e.g., precipitation , mean temperature , and cloud cover , glacial mass changes are considered among
10368-428: The glacier will be accommodated by motion in the sediments, or if it'll be able to slide. A soft bed, with high porosity and low pore fluid pressure, allows the glacier to move by sediment sliding: the base of the glacier may even remain frozen to the bed, where the underlying sediment slips underneath it like a tube of toothpaste. A hard bed cannot deform in this way; therefore the only way for hard-based glaciers to move
10496-510: The glacier's surface area, more if the glacier calves icebergs. Ice in the accumulation zone is deep enough to exert a downward force that erodes underlying rock. After a glacier melts, it often leaves behind a bowl- or amphitheater-shaped depression that ranges in size from large basins like the Great Lakes to smaller mountain depressions known as cirques . The accumulation zone can be subdivided based on its melt conditions. The health of
10624-589: The highlands were an early and independent center of agriculture, with evidence of irrigation going back at least 10,000 years. Sugarcane was cultivated in New Guinea around 6000 BCE. The gardens of the New Guinea Highlands are ancient, intensive permacultures , adapted to high population densities, very high rainfalls (as high as 10,000 mm per year (400 in/yr)), earthquakes, hilly land, and occasional frost. Complex mulches, crop rotations and tillages are used in rotation on terraces with complex irrigation systems. Western agronomists still do not understand all of
10752-619: The ice at the bottom of the glacier move more slowly than ice at the top. In alpine glaciers, friction is also generated at the valley's sidewalls, which slows the edges relative to the center. Mean glacial speed varies greatly but is typically around 1 m (3 ft) per day. There may be no motion in stagnant areas; for example, in parts of Alaska, trees can establish themselves on surface sediment deposits. In other cases, glaciers can move as fast as 20–30 m (70–100 ft) per day, such as in Greenland's Jakobshavn Isbræ . Glacial speed
10880-420: The ice sheets of Antarctica and Greenland, has been estimated at 170,000 km . Glacial ice is the largest reservoir of fresh water on Earth, holding with ice sheets about 69 percent of the world's freshwater. Many glaciers from temperate , alpine and seasonal polar climates store water as ice during the colder seasons and release it later in the form of meltwater as warmer summer temperatures cause
11008-556: The ice to act as a lever that loosens the rock by lifting it. Thus, sediments of all sizes become part of the glacier's load. If a retreating glacier gains enough debris, it may become a rock glacier , like the Timpanogos Glacier in Utah. Abrasion occurs when the ice and its load of rock fragments slide over bedrock and function as sandpaper, smoothing and polishing the bedrock below. The pulverized rock this process produces
11136-488: The ice, called seracs . Crevasses can form in several different ways. Transverse crevasses are transverse to flow and form where steeper slopes cause a glacier to accelerate. Longitudinal crevasses form semi-parallel to flow where a glacier expands laterally. Marginal crevasses form near the edge of the glacier, caused by the reduction in speed caused by friction of the valley walls. Marginal crevasses are largely transverse to flow. Moving glacier ice can sometimes separate from
11264-411: The idea that meltwater, refreezing inside glaciers, caused the glacier to dilate and extend its length. As it became clear that glaciers behaved to some degree as if the ice were a viscous fluid, it was argued that "regelation", or the melting and refreezing of ice at a temperature lowered by the pressure on the ice inside the glacier, was what allowed the ice to deform and flow. James Forbes came up with
11392-418: The increased pressure can facilitate melting. Most importantly, τ D is increased. These factors will combine to accelerate the glacier. As friction increases with the square of velocity, faster motion will greatly increase frictional heating, with ensuing melting – which causes a positive feedback, increasing ice speed to a faster flow rate still: west Antarctic glaciers are known to reach velocities of up to
11520-423: The infrared OH stretching mode of the water molecule. (Liquid water appears blue for the same reason. The blue of glacier ice is sometimes misattributed to Rayleigh scattering of bubbles in the ice.) A glacier originates at a location called its glacier head and terminates at its glacier foot, snout, or terminus . Glaciers are broken into zones based on surface snowpack and melt conditions. The ablation zone
11648-583: The island and the province. The name Irian , which was originally favored by natives, is now considered to be a name imposed by the authority of Jakarta . New Guinea is an island to the north of the Australian mainland , south of the equator. It is isolated by the Arafura Sea to the west, and the Torres Strait and Coral Sea to the east. Sometimes considered to be the easternmost island of
11776-543: The islands of Wallacea and Sundaland (the present Malay Archipelago ) by at least 40,000 years ago. The ancestral Austronesian peoples are believed to have arrived considerably later, approximately 3,500 years ago, as part of a gradual seafaring migration from Southeast Asia , possibly originating in Taiwan. Austronesian-speaking peoples colonized many of the offshore islands to the north and east of New Guinea, such as New Ireland and New Britain , with settlements also on
11904-657: The language used by the Sultanate of Tidore . An expedition by the Sultan of Tidore , together with Sahmardan, the Sangaji of Patani , and the Papuan Gurabesi , managed to conquer some areas in New Guinea, which was then reorganised to form Korano Ngaruha ("Four Kings") or Raja Ampat , Papoua Gam Sio ( lit. "The Papua Nine Negeri "), and Mafor Soa Raha ( lit. The Mafor "Four Soa "). The name comes from
12032-435: The main exports of the island during this period were resins, spices, slaves and the highly priced feathers of the bird-of-paradise . In a period of constant conflict called 'hongi wars', in which rival villages or kingdoms would invoke the name of Tidore Sultan, rightly, for punitive expeditions for not fulfilling their tributary obligations, or opportunitively for competitions over resources and prestige. Sultan Nuku , one of
12160-548: The main island as part of the Dutch East Indies , they called it Nieuw Guinea . The name Irian was used in the Indonesian language to refer to the island and Indonesian province, as Irian Barat (West Irian) Province and later Irian Jaya Province. The name Irian was suggested during a tribal committee meeting in Tobati, Jayapura, formed by Soegoro Atmoprasodjo under governor JP van Eechoed, to decide on
12288-594: The mainland of the country of Papua New Guinea . The shape of New Guinea is often compared to that of a bird-of-paradise (indigenous to the island), and this results in the usual names for the two extremes of the island: the Bird's Head Peninsula in the northwest ( Vogelkop in Dutch, Kepala Burung in Indonesian; also known as the Doberai Peninsula), and the Bird's Tail Peninsula in the southeast (also known as
12416-472: The mammal species (69%) are endemic. New Guinea has 578 species of breeding birds, of which 324 species are endemic. The island's frogs are one of the most poorly known vertebrate groups, totalling 282 species, but this number is expected to double or even triple when all species have been documented. New Guinea has a rich diversity of coral life and 1,200 species of fish have been found. Also about 600 species of reef-building coral—the latter equal to 75 percent of
12544-679: The most deformation. Velocity increases inward toward the center line and upward, as the amount of deformation decreases. The highest flow velocities are found at the surface, representing the sum of the velocities of all the layers below. Because ice can flow faster where it is thicker, the rate of glacier-induced erosion is directly proportional to the thickness of overlying ice. Consequently, pre-glacial low hollows will be deepened and pre-existing topography will be amplified by glacial action, while nunataks , which protrude above ice sheets, barely erode at all – erosion has been estimated as 5 m per 1.2 million years. This explains, for example,
12672-539: The most famous Tidore sultans who rebelled against Dutch colonization, called himself "Sultan of Tidore and Papua", during his revolt in 1780s. He commanded loyalty from both Moluccan and Papuan chiefs, especially those of Raja Ampat Islands, from his base in Gebe . Following Tidore's subjugation as Dutch tributary, much of the territory it claimed in western part of New Guinea came under Dutch rule as part of Dutch East Indies. The first known European contact with New Guinea
12800-445: 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 , because water molecules absorb other colors more efficiently than blue. 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
12928-553: The mouth of the river in 1845. The total length of the river is 1,050 km. Smaller boats can sail 900 km on the river. The estuary section, which decomposes into islands, is 70 km wide. The tide of the sea can have an effect of up to 300 kilometers. Strickland , a tributary of the Fly, reaches the Papuan Plain through wild gorges. Fly and Strickland together form the largest river in New Guinea. The many rivers flowing into
13056-561: The partial elected New Guinea Council took office on 5 April 1961. The Council decided on the name of West Papua ( Papua Barat ) for the territory, along with an emblem, flag , and anthem to complement those of the Netherlands. On 1 October 1962, after some military interventions and negotiations, the Dutch handed over the territory to the United Nations Temporary Executive Authority , until 1 May 1963, when Indonesia took control. The territory
13184-674: The pooling of meltwater at the base of the glacier — perhaps delivered from a supraglacial lake — or the simple accumulation of mass beyond a critical "tipping point". Temporary rates up to 90 m (300 ft) per day have occurred when increased temperature or overlying pressure caused bottom ice to melt and water to accumulate beneath a glacier. In glaciated areas where the glacier moves faster than one km per year, glacial earthquakes occur. These are large scale earthquakes that have seismic magnitudes as high as 6.1. The number of glacial earthquakes in Greenland peaks every year in July, August, and September and increased rapidly in
13312-480: The practices, and it has been noted that native gardeners are as, or even more, successful than most scientific farmers in raising certain crops. There is evidence that New Guinea gardeners invented crop rotation well before western Europeans. A unique feature of New Guinea permaculture is the silviculture of Casuarina oligodon , a tall, sturdy native ironwood tree, suited to use for timber and fuel, with root nodules that fix nitrogen. Pollen studies show that it
13440-410: The pressure of the layers of ice and snow above it, this granular ice fuses into denser firn. Over a period of years, layers of firn undergo further compaction and become glacial ice. Glacier ice is slightly more dense than ice formed from frozen water because glacier ice contains fewer trapped air bubbles. Glacial ice has a distinctive blue tint because it absorbs some red light due to an overtone of
13568-627: The region of Wanin and Sran, in eastern Nusantara as part of Majapahit 's tributary. This 'Wanin' has been identified with the Onin Peninsula, part of the Bomberai Peninsula near the city of Fakfak . while ' Sran ' had been identified as region of Kowiai , just south of Onin peninsula. The sultans of Tidore , in the Maluku Islands , claimed sovereignty over various coastal parts of the island. During Tidore's rule,
13696-544: The richest coral reefs on the planet. The entire length of the New Guinea Highlands system passes through New Guinea as a vast watershed. The northern rivers flow into the Pacific Ocean , the southern rivers into the Arafura Sea and the Gulf of Papua . On the north side, the largest rivers are the Mamberamo, Sepik and Ramu. Mamberamo was born from the confluence of two large inland rivers. Tariku comes from
13824-567: The sea, often with an ice tongue , like Mertz Glacier . Tidewater glaciers are glaciers that terminate in the sea, including most glaciers flowing from Greenland, Antarctica, Baffin , Devon , and Ellesmere Islands in Canada, Southeast Alaska , and the Northern and Southern Patagonian Ice Fields . As the ice reaches the sea, pieces break off or calve, forming icebergs . Most tidewater glaciers calve above sea level, which often results in
13952-471: The seas bordering New Guinea: The first inhabitants Indigenous people of New Guinea , from whom the Papuan people are probably descended, adapted to the range of ecologies and, in time, developed one of the earliest known agricultures. Remains of this agricultural system, in the form of ancient irrigation systems in the highlands of Papua New Guinea, are being studied by archaeologists. Research indicates that
14080-568: The south at the border with British New Guinea . The German, Dutch and British colonial administrators each attempted to suppress the still-widespread practices of inter-village warfare and headhunting within their respective territories. In 1905, the British government transferred some administrative responsibility over southeast New Guinea to Australia (which renamed the area " Territory of Papua "); and, in 1906, transferred all remaining responsibility to Australia. During World War I , Australian forces seized German New Guinea, which in 1920 became
14208-409: The stagnant ice above, forming a bergschrund . Bergschrunds resemble crevasses but are singular features at a glacier's margins. Crevasses make travel over glaciers hazardous, especially when they are hidden by fragile snow bridges . Below the equilibrium line, glacial meltwater is concentrated in stream channels. Meltwater can pool in proglacial lakes on top of a glacier or descend into the depths of
14336-429: The stagnant ice leaving a large crevasse . In 2007, it had become large enough to cause most climbers to use another route. The glacier is a remnant of the massive glaciers that formed during the last ice age . It is historically known to change configuration dramatically, at times a gradual, smooth surface to Hot Rocks; at other times the same place has a 40 ft (12 m) ice cliff. The glacier flows southwest, and
14464-423: The stress being applied, ice will act as an elastic solid. Ice needs to be at least 30 m (98 ft) thick to even start flowing, but once its thickness exceeds about 50 m (160 ft) (160 ft), stress on the layer above will exceeds the inter-layer binding strength, and then it'll move faster than the layer below. This means that small amounts of stress can result in a large amount of strain, causing
14592-438: The surface snowpack may experience seasonal melting. A subpolar glacier includes both temperate and polar ice, depending on the depth beneath the surface and position along the length of the glacier. In a similar way, the thermal regime of a glacier is often described by its basal temperature. A cold-based glacier is below freezing at the ice-ground interface and is thus frozen to the underlying substrate. A warm-based glacier
14720-417: The weight of the ice is supported by the underlying water, and the glacier is afloat. Glaciers may also move by basal sliding , where the base of the glacier is lubricated by the presence of liquid water, reducing basal shear stress and allowing the glacier to slide over the terrain on which it sits. Meltwater may be produced by pressure-induced melting, friction or geothermal heat . The more variable
14848-555: The west to the east and Taritatu from the east. These rivers meander through swamps with huge internal descents and then merge. The Mamberamo thus formed reaches the ocean by breaking through the Coastal Mountains. Mamberamo River is navigable to Marine Falls. The Sepik is a much more important river. Similarly, it collects water from a spacious pool. It is 1,100 kilometers from the Victor Emanuel Range to
14976-519: The western part of the island in present-day Indonesia, and also claimed the territory for the King of Spain. A successive European claim occurred in 1828, when the Netherlands formally claimed the western half of the island as Netherlands New Guinea . Dutch colonial authority built Fort Du Bus an administrative and trading post established near Lobo, Triton Bay, but by 1835 had been abandoned. Considering that New Guinea had little economic value for them,
15104-622: The western part of the island is Digul . It originates from the Star Mountains , which rise to an altitude of 4,700 m. The coastal plain is bordered by a swamp world hundreds of kilometers wide. Digul is the main transport route to the fertile hills and mountains within the island. The river Fly is born near the eastern branches of the Digul. It is named after one of the ships of the English Royal Fleet, which first sailed into
15232-687: The western side, and by the Sepik on the eastern side. The more extensive southern lowlands are drained by a larger number of rivers, principally the Digul in the west and the Fly in the east. The largest island offshore, Dolak , lies near the Digul estuary, separated by a strait so narrow it has been named a "creek". New Guinea contains many of the world's ecosystem types: glacial, alpine tundra , savanna , montane and lowland rainforest, mangroves , wetlands , lake and river ecosystems , seagrasses , and some of
15360-498: The words papo ("to unite") and ua (negation), which means "not united", i.e. an outlying possession of Tidore. Anton Ploeg reports that the word papua is often said to be derived from the Malay word papua or pua-pua , meaning "frizzly-haired", referring to the very curly hair of the island's inhabitants. However Sollewijn Gelpke in 1993 considered this unlikely as it had been used earlier, and he instead derived it from
15488-459: The world and, having never seen Europeans before, initially believed the explorers to be spirits of the dead due to the local belief that a person's skin turned white when they died and crossed into the land of the dead. Netherlands New Guinea and the Australian territories (the eastern half ) were invaded in 1942 by the Japanese . The Netherlands were defeated by that stage and did not put up
15616-669: The world's known total. The entire coral area covers 18 million hectares off a peninsula in northwest New Guinea. As of 2020, the Western portion of New Guinea, Papua and West Papua, accounts for 54% of the island's primary forest and about 51% of the island's total tree cover, according to satellite data. According to the WWF , New Guinea can be divided into twelve terrestrial ecoregions : The WWF and Nature Conservancy divide New Guinea into five freshwater ecoregions : The WWF and Nature Conservancy identify several marine ecoregions in
15744-534: The world's most floristically diverse island, surpassing Madagascar (11,488), Borneo (11,165), Java (4,598), and the Philippines (9,432). Biogeographically , New Guinea is part of Australasia rather than the Indomalayan realm, although New Guinea's flora has many more affinities with Asia than its fauna, which is overwhelmingly Australian. Botanically, New Guinea is considered part of Malesia ,
15872-535: Was adopted during an ancient period of extreme deforestation. In more recent millennia, another wave of people arrived on the shores of New Guinea. These were the Austronesian people , who had spread down from Taiwan , through the South-east Asian archipelago , colonising many of the islands on the way. The Austronesian people had technology and skills extremely well adapted to ocean voyaging and Austronesian language speaking people are present along much of
16000-456: Was by Portuguese and Spanish sailors in the 16th century. In 1526–27, Portuguese explorer Jorge de Meneses saw the western tip of New Guinea and named it ilhas dos Papuas . In 1528, the Spanish navigator Álvaro de Saavedra also recorded its sighting when trying to return from Tidore to New Spain . In 1545, Spaniard Íñigo Ortíz de Retes sailed along the north coast of New Guinea as far as
16128-505: Was empowered to protect the rights of Papuans, raise the status of women in Papua, and to ease religious tensions in Papua; block grants were given for the implementation of the Law as much as $ 266 million in 2004. The Indonesian courts ' enforcement of the Law on Special Autonomy blocked further creation of subdivisions of Papua: although President Megawati Sukarnoputri was able to create
16256-456: Was promoted in 1945 by Marcus Kaisiepo, brother of Frans Kaisiepo . The name was politicized later by Corinus Krey, Marthen Indey , Silas Papare , and others with the Indonesian backronym Ikut Republik Indonesia Anti Nederland ("Join the Republic of Indonesia Oppose the Netherlands"). Irian was used somewhat in 1972. The name was used until 2001, when Papua was again used for
16384-469: Was renamed West Irian ( Irian Barat ) and then Irian Jaya. In 1969, Indonesia, under the 1962 New York Agreement , organised a referendum named the Act of Free Choice , in which the military hand picked Papuan tribal elders to vote for integration with Indonesia. There has been significant reported resistance to Indonesian integration and occupation, both through civil disobedience (such as publicly raising
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