Glaciation 0.0 / 5 ? GeographyGlacial landscapes and processesGCSEAQA Created by: Emily ForresterCreated on: 28-01-15 20:11 What is an ice age? Long period of time where global temperature is very cold and large areas were covered with sheets of ice 1 of 23 What is an inter glacial period? A short term period of warmer temperatures within an ice age. (current one is called the Pliestocene ice age) 2 of 23 What are ice sheets? Large areas of solid ice which completely cover continents. E.g. Antarctica 3 of 23 What are valley glaciers? Tongues of ice that 'flow' down valleys. Short valley glaciers are called corries or cirques 4 of 23 How do glaciers begin? Snow compaction on sheltered valley turns into Neve and eventually into ice. Eventually due to accumulation, they begin to flow downhill. 5 of 23 What is the glacial budget? Balance between accumulation (snow & avalanches) and ablation (melting) of a glacier. 6 of 23 What happens when accumulation and ablation are not balanced? More accumulation- glacier will advance. More ablation- glacier will retreat 7 of 23 Name the erosional processes that operate in glacial environments Glacial erosion, abrasion, plucking 8 of 23 What is glacial erosion? Angular weathered rock fragments under ice act like sand paper and grind away valley floor and sides. Leaving smooth surface 9 of 23 What is abrasion? Erosion involving wearing away of glaciers and the shoreline (coastal zones) 10 of 23 What is plucking? Erosion where individual rocks are plucked from valley floor as water freezes the, to the glacier. 11 of 23 How does a glacier move? Melting at bottom of ice sheet produces meltwater which lubricates the ice, allowing it to slide. 12 of 23 How do glaciers move in a cirque? Ice moves in rotational slip (circular direction). In winter, much less melting but weight of glacier causes slow movement by internal deformation. 13 of 23 What is moraine? General term to describe debris carried by a glacier. When angular rocks form thick layer, it's known as till or boulder clay. 14 of 23 What is ground moraine? Material dragged underneath glacier which is left behind when ice melts. 15 of 23 What is lateral moraine? Forms at edge of glaciers. Mostly scree fallen of valley sides. 16 of 23 What is medial moraine? When tributary glacier joins main glacier lateral moraines join to produce one single line of sediment in the center of the main glacier. 17 of 23 What is terminal moraine? Big amounts of material pile up at snout of glacier. Meltwater often erodes away moraine features, leaving only fragments. 18 of 23 What is the G.I.S? Geologiacl information systems- digital data in form of tables or maps which helps people understand patterns. Eg. flooding or shopping patterns 19 of 23 What are the causes of avalanches? Heavy snowfall; Steep slopes; Deforestation; Temperature rise; Heavy rainfall; Human facors (eg. off piste skiing) 20 of 23 What is an avalanche? Rapid downhill movement of mass of snow, ice and rocks usually in mountainous environments. 21 of 23 What are the two types of avalanches? Loose snow avalanches (powdery avalanche) & Slab avalanches (large-scale when slab of ice and snow breaks away from main ice pack. 22 of 23 State a case study of a recent avalanche Kashmir Feb 2008- heavy snowfall & killed 30. Europe 2006-irregular weather patterns, 49 killed off piste. 23 of 23
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