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Dead-ice
Dead ice is ice which, though part of a glacier or ice sheet, is no longer moving. When this melts it does so in situ, leaving behind a hummocky terrain known as dead-ice moraine which is produced by the deposition of glacio-fluvial sediments and ablation till. Such features include kettle holes. Landscapes forming Veiki moraine A Veiki moraine (Swedish: Veikimorän) is a type of moraine found in northern Sweden, Troms og Finnmark in Norway, and parts of Canada. This moraine is characterized by forming a hummocky landscape of irregular moraine plateaus with elevated rim ...s in northern Sweden and Canada have been attributed to the ablation of extensive bodies of till-covered dead ice. References Glaciology {{glaciology-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kettle Hole
A kettle (also known as a kettle lake, kettle hole, or pothole) is a depression/hole in an outwash plain formed by retreating glaciers or draining floodwaters. The kettles are formed as a result of blocks of dead ice left behind by retreating glaciers, which become surrounded by sediment deposited by meltwater streams as there is increased friction. The ice becomes buried in the sediment and when the ice melts, a depression is left called a kettle hole, creating a dimpled appearance on the outwash plain. Lakes often fill these kettles; these are called kettle hole lakes. Another source is the sudden drainage of an ice-dammed lake. When the block melts, the hole it leaves behind is a kettle. As the ice melts, ramparts can form around the edge of the kettle hole. The lakes that fill these holes are seldom more than deep and eventually fill with sediment. In acid conditions, a kettle bog may form but in alkaline conditions, it will be kettle peatland. Overview Kettles are fluviog ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glacier
A glacier (; ) is a persistent body of dense ice that is constantly moving under its own weight. A glacier forms where the accumulation of snow exceeds its Ablation#Glaciology, ablation over many years, often Century, centuries. It acquires distinguishing features, such as Crevasse, crevasses and Serac, 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 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 lati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ice Sheet
In glaciology, an ice sheet, also known as a continental glacier, is a mass of glacial ice that covers surrounding terrain and is greater than . The only current ice sheets are in Antarctica and Greenland; during the Last Glacial Period at Last Glacial Maximum, the Laurentide Ice Sheet covered much of North America, the Weichselian ice sheet covered Northern Europe and the Patagonian Ice Sheet covered southern South America. Ice sheets are bigger than ice shelves or alpine glaciers. Masses of ice covering less than 50,000 km2 are termed an ice cap. An ice cap will typically feed a series of glaciers around its periphery. Although the surface is cold, the base of an ice sheet is generally warmer due to geothermal heat. In places, melting occurs and the melt-water lubricates the ice sheet so that it flows more rapidly. This process produces fast-flowing channels in the ice sheet — these are ice streams. The present-day polar ice sheets are relatively young in geol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glacio-fluvial
In geography and geology, fluvial processes are associated with rivers and streams and the Deposition (geology), deposits and landforms created by them. When the stream or rivers are associated with glaciers, ice sheets, or ice caps, the term glaciofluvial or fluvioglacial is used. Fluvial processes Fluvial processes include the sediment transport, motion of sediment and erosion or deposition (geology), deposition on the river bed. The movement of water across the stream bed exerts a shear stress directly onto the bed. If the Cohesion (geology), cohesive strength of the substrate is lower than the shear exerted, or the bed is composed of loose sediment which can be mobilized by such stresses, then the bed will be lowered purely by clearwater flow. In addition, if the river carries significant quantities of sediment, this material can act as tools to enhance wear of the bed (abrasion (geology), abrasion). At the same time the fragments themselves are ground down, becoming smaller ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ablation Till
A glacier (; ) is a persistent body of dense ice that is constantly moving 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 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Veiki Moraine
A Veiki moraine (Swedish: Veikimorän) is a type of moraine found in northern Sweden, Troms og Finnmark in Norway, and parts of Canada. This moraine is characterized by forming a hummocky landscape of irregular moraine plateaus with elevated rims that are intercalated with ponds. Gunnar Hoppe was the first to define the Veiki moraine concept in 1952, naming it after a locality consisting of two farms located about 10 kilometers north of Gällivare and Malmberget. To the east in Finnish Lapland, a moraine type similar to Veiki moraine but smaller is known as Pulju moraine since 1967. The disposition of the Veiki moraines reflects the last glacier movements before an ice sheet retreats, and their final form is given by the melting of dead-ice and the development and sedimentation of glacial lagoons between dead-ice cored rims during interstadial periods. In the case of the Veiki moraines of Sweden, the interstadial during which the lagoons sedimented is believed to have occurred ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
