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34 Cards in this Set
- Front
- Back
pleistocene epoch
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from two million to 11 thousand years ago; extensive glaciation of the northern hemisphere; the time of human evolution
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ice sheets
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A permanent layer of ice covering an extensive tract of land, esp. a polar region.
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nunatasks
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An isolated peak of rock projecting above a surface of inland ice or snow.
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cirque galciers
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is formed in a [cirque], bowl-shaped depressions on the side of or near mountains.
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valley glaciers
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which provide drainage for icefields, are also constrained by underlying topography. These glaciers form up in mountain ranges as gathering snow turns to ice.
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piedmont glaciers
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a type of glaciation characteristic of Alaska; large valley glaciers meet to form an almost stagnant sheet of ice.
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accumulation zone
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is the area above the firn line, where snowfall accumulates and exceeds the losses from ablation, (melting, evaporation, and sublimation). The accumulation zone is also defined as the part of a glacier’s surface, usually at higher elevations, on which there is net accumulation of snow, which subsequently turns into firn and then glacier ice.
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ablation zone
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efers to the low-altitude area of a glacier or ice sheet below firn with a net loss in ice mass due to melting, sublimation, evaporation, ice calving, aeolian processes like blowing snow, avalanche, and any other ablation.
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firn
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Crystalline or granular snow, esp. on the upper part of a glacier, where it has not yet been compressed into ice.
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equilibrium line
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is the boundary between the accumulation area and the ablation area..
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glacial surge
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The swift and dramatic movement of a glacier.
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plucking
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A process of glacial erosion which involves the penetration of ice or rock wedges into subglacial niches, crevices, and joints.
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abrasion
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The process of scraping or wearing away.
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striations
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any of a number of tiny parallel grooves such as: the scratches left by a glacier on rocks
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drift
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is the name for all material of glacial origin found anywhere on land or at sea, including sediment and large rocks (glacial erratic)
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stratified drift
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Fluvioglacial drift composed of material deposited by a meltwater stream.
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glacial erratics
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is a piece of rock that differs from the size and type of rock native to the area in which it rests.
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meltwater
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Water formed by the melting of snow and ice.
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roche moutonnee
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(or sheepback) is a rock formation created by the passing of a glacier
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till plain
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An extensive, relatively flat area overlying a till
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kettles
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A depression left in a mass of glacial drift, formed by the melting of an isolated block of glacial ice
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drumlin
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A low oval mound or small hill, typically one of a group, consisting of compacted glacial till shaped by past glacial action.
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moraine
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A mass of rocks and sediment deposited by a glacier, typically as ridges at its edges or extremity.
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esker
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A long ridge of gravel and other sediment, typically winding, deposited by meltwater from a retreating glacier or ice sheet
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outwash plain
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is a plain formed of glacial sediments deposited by meltwater outwash at the terminus of a glacier
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kame
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A low, long, steep-sided mound of glacial drift, commonly stratified sand and gravel, deposited.
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arete
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is a thin, almost knife-like, ridge of rock which is typically formed when two glaciers erode parallel U-shaped valleys
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col
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A high, sharp-edged pass occurring in a mountain ridge, usually produced by the headward erosion of opposing cirques
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horn
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a sharp peak formed where the ridges separating three or more cirques intersect
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tarn
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A small mountain lake, especially one set in a glaciated steep-walled amphitheatre known as a cirque.
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glacial trough
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A deep U-shaped valley with steep sides that leads down from a cirque a.
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hanging valley
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A tributary valley that joins a main valley where the latter has been deepened
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paternoster lakes
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is one of a series of glacial lakes connected by a single stream or a braided stream system
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Holocene Epoch
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based on that past evidence, can be considered an interglacial in the current ice age.
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