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34 Cards in this Set
- Front
- Back
Where would you find these areas? Give 4 specific areas |
North Scandanavia, Alaska and Canada, Siberia |
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In general where about would you find this area? |
Around the fringes of glacier. Tundra Areas |
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Name all 4 types of processes |
Active layer Frost Heave Nivation Solifluction |
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Name all 5 Landforms |
Solifluction lobes Pingos Patterned Ground Nivation Hollows Ice Wedge |
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Describe what happens in the Active Layer (5) |
1.As summer temperatures rise above freezing, 2.the surface layer begins to thaw downwards to form the active layer, 3.extending to sometimes 4 meters, 4.when the ice melts a large volume of water is released, 5.the water is unable to drain through the permafrost layer so it produces a wet surface. |
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How far can the active layer get? |
4 meters |
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At what temperature does it have to be in order for the active layer to happen |
Above freezing |
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Describe the process of Frost Heave (4) |
1.The cold penetrates from the surface into stones faster than the surrounding material, 2.As active layer starts to re freeze ice crystals develop, 3.this increases the volume of soil and the expansion of the soil surface, 4.this pushes stones to the surface which eventually roll down the side forming a patterned ground, |
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What and where is frost heave most significant? |
Fined grained materials as it causes them to be small domes on surface. Fluctuating temperatures between 0'C to -4'C |
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What is another word for Solifluction? |
Flowing Soil |
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What is another word for "flowing soil" |
Solifluction |
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What happens in Solifluction? (3) |
1.As the active layer thaws, water is released mixing with soil particles (soil flow), 2.It occurs on shallow (2') downslopes, 3.Forms Solifluction Lobes which are tongue like semi-mixed surface deposits. |
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What is needed in order for Solifluction to occur? |
Downslope, Shallow 2' |
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What is soil flow and which process does it occur in? |
Where water is mixed with soil particles Solifluction |
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Where does nivation occur? |
Under snow patches |
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What type of weathering occur in Nivation? |
Freeze-thaw and chemical |
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Describe the process of Nivation (3) |
1.Freeze-thaw and chemical weathering occur under snow, 2.causing underlying rock to dis-intergrate, 3.As the snow melts, the weathered particles move downslope by meltwater and solifluction, 3.Forming nivation hollows which leads to a corrie. |
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During Nivation, what other processes move the weathered particles down slope? |
Solifluction and meltwater |
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Describe Nivation Hollows (3) |
small/shallow depression, occur under snow patches, north-east facing |
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Describe Ice Wedges |
Downward, narrowing mass of ice. At least 1 meter deep and 2-3 meters wide |
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How are Ice Wedges formed? (4) |
1.As active layer re-freezes, the soil contracts which form cracks on the surface, 2.As the ice melts in the summer, cracks open again and fill with meltwater, 3.the meltwater contains fine sediment, which also fills cracks, 4.This is repeated forming an ice-wedge. |
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Describe a Pingo |
Ice covered dome-like hills, rising up to 50 meters |
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How is a Pingo formed? (4) |
1.When the permafrost is thin, 2.water seeps into the upper layers of the ground and freezes, 3.the expansion of ice causes overlying sediments to heave upwards, 4.creating a dome shape feature-pingos. |
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Describe solifluction lobes |
rounded, tongue-like features |
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What do solifluction lobes form? |
Terraces on sides of valley |
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What two types of patterned ground are there? |
Stone polygons Stone strips |
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On what slopes do the different types of stone ground occur on? |
Stone polygons- Gentle Stone strips- Steep |
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What does the permafrost have to be in order for pings to form? |
Thin |
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how high do pingos get? |
50 meters |
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What three types of permafrost are there? |
Continuous Discontinuous Sporadic |
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Give 2 characteristics about permafrost? |
1. Subsoil temperatures remain below 0' for at least 2 years 2. Covers 1/4 of the Earths surface |
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Give 3 characteristics of continuous permafrost? |
1. Coldest regions 2. Deep into the surface layer 3. Hardly any melting of uppermost layer |
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Give 2 characteristics of discontinuous permafrost |
1. Slightly warmer than continuous permafrost 2. on average, frozen area will extend 20-30 meters below the ground surface |
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Give 2 characteristics of sporadic permafrost |
1. Temperatures are just below freezing point 2. Occurs in isolated spots |