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Donjek Glacier
Donjek Glacier (''Southern Tutchone'': ''Dän Zhǘr is located in Kluane National Park and Reserve, Kluane National Park, in Yukon, Canada, on the eastern side of the Saint Elias Mountains. Donjek Glacier is about long and extends into the Donyek River Valley to its terminus.http://pubs.aina.ucalgary.ca/arctic/Arctic25-4-302.pdf Centuries ago Donjek Glacier formed a dam, creating Donjek Lake which is estimated to have been 230 x 106 m3. In 1970 a study was performed at the terminus of the glacier to determine its position during the Holocene climatic optimum but the study found no evidence in the valley that the glacier had retreated from the Donyek River Valley. However there is evidence that the glacier had retreated before it advanced during the neoglaciation. Near the river bed there is also an area of high mounds whose surfaces have been worn by the river. Inside the mounds there is a large amount of groundmass, which indicates the mounds may have been formed of till ori ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Yukon
Yukon (; ; formerly called Yukon Territory and also referred to as the Yukon) is the smallest and westernmost of Canada's three territories. It also is the second-least populated province or territory in Canada, with a population of 43,964 as of March 2022. Whitehorse, the territorial capital, is the largest settlement in any of the three territories. Yukon was split from the North-West Territories in 1898 as the Yukon Territory. The federal government's ''Yukon Act'', which received royal assent on March 27, 2002, established Yukon as the territory's official name, though ''Yukon Territory'' is also still popular in usage and Canada Post continues to use the territory's internationally approved postal abbreviation of ''YT''. In 2021, territorial government policy was changed so that “''The'' Yukon” would be recommended for use in official territorial government materials. Though officially bilingual (English and French), the Yukon government also recognizes First Natio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Southern Tutchone
The Southern Tutchone are a First Nations people of the Athabaskan-speaking ethnolinguistic group living mainly in the southern Yukon in Canada. The Southern Tutchone language, traditionally spoken by the Southern Tutchone people, is a variety of the Tutchone language, part of the Athabaskan language family. Some linguists suggest that Northern and Southern Tutchone are distinct and separate languages. Southern Tutchone First Nations governments and communities include: *Champagne and Aishihik First Nations (Haines Junction, Champagne, and Aishihik in Yukon) Many Champagne and Aishihik members also live in Whitehorse. * Ta'an Kwach'an Council (Whitehorse, Yukon and Lake Laberge) (Ta’an Kwäch’än - ″People of Lake Laberge″, because they called it ''Tàa'an Män'') *Kluane First Nation (Burwash Landing, Yukon) (Lù’àn Män Ku Dän or Lù’àn Mun Ku Dän - ″Kluane Lake People″, referring to their territory around Kluane Lake). Many citizens of the Kwanlin Dün Fi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kluane National Park And Reserve
Kluane National Park and Reserve (; french: Parc national et réserve de parc national de Kluane) are two protected areas in the southwest corner of the territory of Yukon. The National Park Reserve was set aside in 1972 to become a national park, pending settlement of First Nations land claims. It covered an area of . When agreement was reached with the Champagne and Aishihik First Nations over an eastern portion of the Reserve, that part—about —became a national park in 1993, and is a unit of the national park system administered co-operatively with Parks Canada. The larger western section remains a Reserve, awaiting a final land claim settlement with the Kluane First Nation. The park borders B.C. to the south, while the Reserve borders both B.C. to the south, and the United States (Alaska) to the south and west. The Reserve includes the highest mountain in Canada, Mount Logan () of the Saint Elias Mountains. Mountains and glaciers, including Donjek Glacier, dominate t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Canada
Canada is a country in North America. Its ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, covering over , making it the world's second-largest country by total area. Its southern and western border with the United States, stretching , is the world's longest binational land border. Canada's capital is Ottawa, and its three largest metropolitan areas are Toronto, Montreal, and Vancouver. Indigenous peoples have continuously inhabited what is now Canada for thousands of years. Beginning in the 16th century, British and French expeditions explored and later settled along the Atlantic coast. As a consequence of various armed conflicts, France ceded nearly all of its colonies in North America in 1763. In 1867, with the union of three British North American colonies through Confederation, Canada was formed as a federal dominion of four provinces. This began an accretion of provinces an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Holocene Climatic Optimum
The Holocene Climate Optimum (HCO) was a warm period that occurred in the interval roughly 9,000 to 5,000 years ago BP, with a thermal maximum around 8000 years BP. It has also been known by many other names, such as Altithermal, Climatic Optimum, Holocene Megathermal, Holocene Optimum, Holocene Thermal Maximum, Hypsithermal, and Mid-Holocene Warm Period. The warm period was followed by a gradual decline, of about 0.1 to 0.3 °C per millennium, until about two centuries ago (when this trend was rapidly reversed due to human-produced greenhouse gas emissions). However, on a sub-millennial scale, there were regional warm periods superimposed on this decline. * For other temperature fluctuations, see temperature record. * For other past climate fluctuation, see paleoclimatology. * For the pollen zone and Blytt–Sernander period, associated with the climate optimum, see Atlantic (period). Global effects The Holocene Climate Optimum warm event consisted of increases of up t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neoglaciation
The neoglaciation ("renewed glaciation") describes the documented cooling trend in the Earth's climate during the Holocene, following the retreat of the Wisconsin glaciation, the most recent glacial period. Neoglaciation has followed the hypsithermal or Holocene Climatic Optimum, the warmest point in the Earth's climate during the current interglacial stage, excluding the global warming-induced temperature increase starting in the 20th century. The neoglaciation has no well-marked universal beginning: local conditions and ecological inertia affected the onset of detectably cooler (and wetter) conditions. Driven inexorably by the Milankovitch cycle, cooler summers in higher latitudes of North America, which would cease to completely melt the annual snowfall, were masked at first by the presence of the slowly disappearing continental ice sheets, which persisted long after the astronomically calculated moment of maximum summer warmth: "the neoglaciation can be said to have begun wh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stream Bed
A stream bed or streambed is the bottom of a stream or river (bathymetry) or the physical confine of the normal water flow (Channel (geography), channel). The lateral confines or channel margins are known as the stream Bank (geography), banks or river banks, during all but flood stage. Under certain conditions a river can branch from one stream bed to multiple stream beds. A flood occurs when a stream overflows its banks and flows onto its flood plain. As a general rule, the bed is the part of the stream channel, channel up to the normal water line, and the banks are that part above the normal water line. However, because water flow varies, this differentiation is subject to local interpretation. Usually, the bed is kept clear of terrestrial vegetation, whereas the banks are subjected to water flow only during unusual or perhaps infrequent high water stages and therefore might support vegetation some or much of the time. The nature of any stream bed is always a function of th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Matrix (geology)
The matrix or groundmass of a rock is the finer-grained mass of material in which larger grains, crystals, or clasts are embedded. The matrix of an igneous rock consists of finer-grained, often microscopic, crystals in which larger crystals, called phenocrysts, are embedded. This porphyritic texture is indicative of multi-stage cooling of magma. For example, porphyritic andesite will have large phenocrysts of plagioclase in a fine-grained matrix. Also in South Africa, diamonds are often mined from a matrix of weathered clay-like rock (kimberlite) called "yellow ground". The matrix of sedimentary rocks is finer-grained sedimentary material, such as clay or silt, in which larger grains or clasts are embedded. It is also used to describe the rock material in which a fossil is embedded. Cementation All sediments are at first in an incoherent condition (e.g. sands, clays and gravels, beds of shells), and they may remain in this state for an indefinite period. Millions of years have ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Till
image:Geschiebemergel.JPG, Closeup of glacial till. Note that the larger grains (pebbles and gravel) in the till are completely surrounded by the matrix of finer material (silt and sand), and this characteristic, known as ''matrix support'', is diagnostic of till. image:Glacial till exposed in roadcut-750px.jpg, Glacial till with tufts of grass Till or glacial till is unsorted glacier, glacial sediment. Till is derived from the erosion and entrainment of material by the moving ice of a glacier. It is deposited some distance down-ice to form terminal, lateral, medial and ground moraines. Till is classified into primary deposits, laid down directly by glaciers, and secondary deposits, reworked by fluvial transport and other processes. Description Till is a form of '' glacial drift'', which is rock material transported by a glacier and deposited directly from the ice or from running water emerging from the ice. It is distinguished from other forms of drift in that it is depos ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Erosion
Erosion is the action of surface processes (such as water flow or wind) that removes soil, rock, or dissolved material from one location on the Earth's crust, and then transports it to another location where it is deposited. Erosion is distinct from weathering which involves no movement. Removal of rock or soil as clastic sediment is referred to as ''physical'' or ''mechanical'' erosion; this contrasts with ''chemical'' erosion, where soil or rock material is removed from an area by dissolution. Eroded sediment or solutes may be transported just a few millimetres, or for thousands of kilometres. Agents of erosion include rainfall; bedrock wear in rivers; coastal erosion by the sea and waves; glacial plucking, abrasion, and scour; areal flooding; wind abrasion; groundwater processes; and mass movement processes in steep landscapes like landslides and debris flows. The rates at which such processes act control how fast a surface is eroded. Typically, physical erosion procee ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Surge (glacier)
Glacial surges are short-lived events where a glacier can advance substantially, moving at velocities up to 100 times faster than normal. Surging glaciers cluster around a few areas. High concentrations of surging glaciers occur in the Karakoram, Pamir Mountains, Svalbard, the Canadian Arctic islands, Alaska and Iceland, although overall it is estimated that only one percent of all the world's glaciers ever surge. In some glaciers, surges can occur in fairly regular cycles, with 15 to 100 or more surge events per year. In other glaciers, surging remains unpredictable. In some glaciers, however, the period of stagnation and build-up between two surges typically lasts 10 to 200 years and is called the quiescent phase. Dowdeswell, J. A., B. Unwin, A. M. Nuttall and D. J. Wingham. 1999. Velocity structure, flow instability and mass flux on a large Arctic ice cap from satellite radar interferometry. Elsevier Science B.V. During this period the velocities of the glacier are significantly ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
