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29 Cards in this Set
- Front
- Back
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What is a glacier? |
large. slow moving river of ice |
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Glacier ice is the largest reservoir of __________ on ___________ |
1. Fresh water 2. earth |
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Glaciers are formed from compacted layers of ________, that slowly deforms and flows in response to _____________ |
1. snow 2. gravity |
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The snow which forms temperate glaciers is subject to repeated freezing and thawing, which changes it into a form of granular snow called ________ |
neve |
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Under the pressure of the layers of ice and snow above it, granular ice fuses into denser ___________ |
firn |
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over a period of years, layers of firn undergo further compaction and become __________ |
glacial ice |
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The melting runoff, evaporation or sublimation of the ice, resulting in a thinning of the ice if it is not replenished by some other process is called |
ablation |
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What is sublimation? |
Transformation from solid to gaseous state |
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True or false: The lower layers of glacial ice flow and deform plastically under pressure, allowing the glacier as a whole to move slowly like a viscous fluid. (glacier movement due to plastic flow) |
True |
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The uppermost levels of glacier that follows britlle behaviour and allows ice to form in crevasses is called the ___________ |
rigid zone |
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What is the zone of plastic flow? |
Below brittle-plastic transition zone in which ice is able to flow or deform plastically |
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What type of glaciers form in mountainous regions and occur at all latitudes (but at much higher altitudes closer to the equator)? |
Alpine Glaciers (mountain glaciers) |
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Lens shaped (thickest in middle) that flow out in all directions are called |
Continental glaciers (ice sheets) |
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What is larger: valley glaciers or Continental glaciers ( ice sheets) |
Continental Glaciers |
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What type of Glacier is found in Greenland and Antartica |
Continental Glaciers |
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During the Pleistocene (1.8 Ma) , glaciers retreated (interglacial) because of __________ temperatures and advanced because of ____________ temperatures (glacial) |
1. Mild 2. Cold |
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What is the name of the most recent interglacial that began about 10,000 years ago and is still going on? |
Holocene Epoch |
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What is the name of the most recent North American glaciation where ice sheets extended to about 45 degrees north latitude? |
Wisconsin glaciation |
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Interlayerd glacial deposits and soil layers are known as |
Surficial deposits |
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Cold water marine microfossils are evidence from the Kansan glacial and the ___________ interglacial |
Aftonian interglacial |
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Warm water marine microfossils are evidence from the Kansan glacial and the ____________ interglacial |
Yarmouth |
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The Northern hemisphere glaciation was during the last ______________ |
ice age |
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The accumulation of 3 to 4 km thick _____________ caused a sea level _______________ of about 120 m |
1. ice sheets 2. lowering |
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What places were covered by glaciers as a result of the sea level lowering? (2 answers) |
Alps Himalayas |
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Occurs when the ice and the load of rock fragments slide over the bedrock and function as sandpaper that smooths and polished the surface situated below ? a)moraine b) abrasion c) striation d) Drumlin e) Erratic |
Abrasion |
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Exceptionally large rocks carried long distances by glaciers. a) moraine b) abrasion c) striation d) Drumlin e) Erratics |
Erratics |
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A elongated whale-shaped hill formed by glacial action. Often found in drumlin fields. Blunter end faces into glacial movement. a) moraine b) abrasion c) striation d) Drumlin e) Erratics |
Drumlin |
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Scratches left behind as a result of glacier abrasion a) moraine b) abrasion c) striation d) Drumlin e) Erratic |
Striations |
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Linear mounds of till a ,non- sorted mixture of rock, gravel and boulders within a matrix of a fine powdery material. The till is deposited directly by the glacier as it erodes rocks that it passes over. a) moraine b) abrasion c) striation d) Drumlin e) Erratic |
Moraine |
