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Protalus Rampart
A protalus rampart (or pronival rampart) is a depositional landform of periglacial origin. It forms as rock debris falls onto a steep snow slope from a cliff above and slides down the snow surface to come to a rest at the foot of the slope. Over a long period of time, sufficient material can accumulate in this way to produce a distinct bank of stony material which, long after the snowbed has melted away, remains as a rampart (a bank or mound similar to a manmade rampart). The debris may also accumulate through avalanching or landslide. Protalus ramparts may be distinguished from glacial moraines by their lack of rock fragments with glacial abrasion or striations. The morphology of the site may also suggest it being unfavourable for the development of a glacier, but suitable for this mechanism. Protalus ramparts are recorded in the Cairngorms and northwest Highlands of Scotland. An especially large example on the north side of Baosbheinn measures 1 km in length and reaches ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Depositional Landform
Glacial landforms are landforms created by the action of glaciers. Most of today's glacial landforms were created by the movement of large ice sheets during the Quaternary glaciations. Some areas, like Fennoscandia and the southern Andes, have extensive occurrences of glacial landforms; other areas, such as the Sahara, display rare and very old fossil glacial landforms. Erosional landforms As the glaciers expand, due to their accumulating weight of snow and ice they crush and abrade and scour surfaces such as rocks and bedrock. The resulting erosional landforms include striations, cirques, glacial horns, arêtes, trim lines, U-shaped valleys, roches moutonnées, overdeepenings and hanging valleys. * Cirque: Starting location for mountain glaciers * Cirque stairway: a sequence of cirques * U-shaped, or trough, valley: U-shaped valleys are created by mountain glaciers. When filled with ocean water so as to create an inlet, these valleys are called fjords. * Arête: spiky high ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Periglaciation
Periglaciation (adjective: "periglacial", also referring to places at the edges of glacier, glacial areas) describes Geomorphology, geomorphic processes that result from seasonal thawing of snow in areas of permafrost, the runoff from which refreezes in ice wedges and other structures. "Periglacial" suggests an environment located on the margin of past glaciers. However, freeze and thaw cycles influence landscapes outside areas of past glaciation. Therefore, periglacial environments are anywhere that freezing and thawing modify the landscape in a significant manner. Tundra is a common Biocoenosis, ecological community in periglacial areas. History Periglaciation became a distinct subject within the study of geology after Walery Łoziński, a Polish geologist, introduced the term in 1909. Łoziński drew upon the early work of Johan Gunnar Andersson. According to Alfred Jahn, his introduction of his work at the 1910 International Geological Congress held in Stockholm caused signifi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rampart (fortification)
In fortification architecture, a bank or rampart is a length of embankment or wall forming part of the defensive boundary of a castle, hillfort, settlement or other fortified site. It is usually broad-topped and made of excavated earth and/or masonry.Darvill, Timothy (2008). ''Oxford Concise Dictionary of Archaeology'', 2nd ed., Oxford University Press, Oxford and New York, p. 376. . Early fortifications Many types of early fortification, from prehistory through to the Early Middle Ages, employed earth ramparts usually in combination with external ditches to defend the outer perimeter of a fortified site or settlement. Hillforts, ringforts or "raths" and ringworks all made use of ditch and rampart defences, and they are the characteristic feature of circular ramparts. The ramparts could be reinforced and raised in height by the use of palisades. This type of arrangement was a feature of the motte and bailey castle of northern Europe in the early medieval period. Types of ram ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Avalanche
An avalanche is a rapid flow of snow down a slope, such as a hill or mountain. Avalanches can be set off spontaneously, by such factors as increased precipitation or snowpack weakening, or by external means such as humans, animals, and earthquakes. Primarily composed of flowing snow and air, large avalanches have the capability to capture and move ice, rocks, and trees. Avalanches occur in two general forms, or combinations thereof: slab avalanches made of tightly packed snow, triggered by a collapse of an underlying weak snow layer, and loose snow avalanches made of looser snow. After being set off, avalanches usually accelerate rapidly and grow in mass and volume as they capture more snow. If an avalanche moves fast enough, some of the snow may mix with the air, forming a powder snow avalanche. Though they appear to share similarities, avalanches are distinct from slush flows, mudslides, rock slides, and serac collapses. They are also different from large scale movement ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Landslide
Landslides, also known as landslips, are several forms of mass wasting that may include a wide range of ground movements, such as rockfalls, deep-seated grade (slope), slope failures, mudflows, and debris flows. Landslides occur in a variety of environments, characterized by either steep or gentle slope gradients, from mountain ranges to coastal cliffs or even underwater, in which case they are called submarine landslides. Gravity is the primary driving force for a landslide to occur, but there are other factors affecting slope stability that produce specific conditions that make a slope prone to failure. In many cases, the landslide is triggered by a specific event (such as a heavy rainfall, an earthquake, a slope cut to build a road, and many others), although this is not always identifiable. Causes Landslides occur when the slope (or a portion of it) undergoes some processes that change its condition from stable to unstable. This is essentially due to a decrease in the She ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Moraine
A moraine is any accumulation of unconsolidated debris (regolith and rock), sometimes referred to as glacial till, that occurs in both currently and formerly glaciated regions, and that has been previously carried along by a glacier or ice sheet. It may consist of partly rounded particles ranging in size from boulders (in which case it is often referred to as boulder clay) down to gravel and sand, in a groundmass of finely-divided clayey material sometimes called glacial flour. Lateral moraines are those formed at the side of the ice flow, and terminal moraines were formed at the foot, marking the maximum advance of the glacier. Other types of moraine include ground moraines (till-covered areas forming sheets on flat or irregular topography) and medial moraines (moraines formed where two glaciers meet). Etymology The word ''moraine'' is borrowed from French , which in turn is derived from the Savoyard Italian ("mound of earth"). ''Morena'' in this case was derived from Proven ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glacial Striations
Glacial striations or striae are scratches or gouges cut into bedrock by glacial abrasion. These scratches and gouges were first recognized as the result of a moving glacier in the late 18th century when Swiss alpinists first associated them with moving glaciers. They also noted that if they were visible today that the glaciers must also be receding. Glacial striations are usually multiple, straight, and parallel, representing the movement of the glacier using rock fragments and sand grains, embedded in the base of the glacier, as cutting tools. Large amounts of coarse gravel and boulders carried along underneath the glacier provide the abrasive power to cut trough-like ''glacial grooves''. Finer sediments also in the base of the moving glacier further scour and polish the bedrock surface, forming a ''glacial pavement''. Ice itself is not a hard enough material to change the shape of rock but because the ice has rock embedded in the basal surface it can effectively abrade the ... [...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] |
Cairngorms
The Cairngorms ( gd, Am Monadh Ruadh) are a mountain range in the eastern Highlands of Scotland closely associated with the mountain Cairn Gorm. The Cairngorms became part of Scotland's second national park (the Cairngorms National Park) on 1 September 2003. Although the Cairngorms give their name to, and are at the heart of, the Cairngorms National Park, they only form one part of the national park, alongside other hill ranges such as the Angus Glens and the Monadhliath, and lower areas like Strathspey. The Cairngorms consists of high plateaux at about above sea level, above which domed summits (the eroded stumps of once much higher mountains ) rise to around . Many of the summits have tors, free-standing rock outcrops that stand on top of the boulder-strewn landscape. In places, the edges of the plateau form steep cliffs of granite and they are excellent for skiing, rock climbing and ice climbing. The Cairngorms form an arctic-alpine mountain environment, with tundra-like ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Northwest Highlands
The Northwest Highlands are located in the northern third of Scotland that is separated from the Grampian Mountains by the Great Glen (Glen More). The region comprises Wester Ross, Assynt, Sutherland and part of Caithness. The Caledonian Canal, which extends from Loch Linnhe in the south-west, via Loch Ness to the Moray Firth in the north-east splits this area from the rest of the country. The city of Inverness and the town of Fort William serve as gateways to the region from the south. Geology The geology of the Highlands is complex. Along the western coastal margin it is characterised by Lewisian gneiss, the oldest rock in Scotland. Liathach, Beinn Alligin, Suilven, Cùl Mòr, Cùl Beag, and Quinag are just some of the impressive rock islands of the significantly younger rich brown-coloured Torridonian sandstone which rests on the gneiss. Some of the peaks, such as Beinn Eighe and Canisp, are topped with later light grey or white Cambrian quartzite. Cambro-Ordovician li ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scotland
Scotland (, ) is a country that is part of the United Kingdom. Covering the northern third of the island of Great Britain, mainland Scotland has a border with England to the southeast and is otherwise surrounded by the Atlantic Ocean to the north and west, the North Sea to the northeast and east, and the Irish Sea to the south. It also contains more than 790 islands, principally in the archipelagos of the Hebrides and the Northern Isles. Most of the population, including the capital Edinburgh, is concentrated in the Central Belt—the plain between the Scottish Highlands and the Southern Uplands—in the Scottish Lowlands. Scotland is divided into 32 administrative subdivisions or local authorities, known as council areas. Glasgow City is the largest council area in terms of population, with Highland being the largest in terms of area. Limited self-governing power, covering matters such as education, social services and roads and transportation, is devolved from the Scott ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Baosbheinn
Baosbheinn is a Scottish mountain situated in the Torridon area of the Northwest Highlands. It stands in a remote area within the Flowerdale deer forest some 39 km NNE of Kyle of Lochalsh. Overview Baosbheinn which is made up of Torridon Sandstone reaches a height of making it the 56th highest Corbett Walking Highlands. Gives list of Corbetts in height order. and the 277th highest Marilyn.The Relative Hills Of Britain. Gives list of Marilyns in height order. It is a long elongated mountain with a NW-SE orientation, its summit ridge is impressive, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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