Periglacial Landscape Flashcards

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1
Q

What is a periglacial landscape?

A

Landscape that is exposed to cold conditions, with intense frost action and development of permanently frozen ground.

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2
Q

Examples of Periglacial Landscape?

A

Alaska, North Canada

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3
Q

Characteristics?

A

Temps between -15 and -1
Annual Rainfall 120-1400mm
Short summers, long winters

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4
Q

Vegetation in the Tundra?

A

Pioneer species (low shrubs etc)
Difficult to grow due to harsh conditions
Ground hugging - to avoid harsh katabatibc winds
Shallow roots and waxy leaves to retain moisture
Example - Labradora Tea

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5
Q

Characteristics of Tundra soil?

A

waterlogged in summer, permafrost layer generally grey from iron (grey mud)

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6
Q

Characteristics of permafrost?

A

Permanently frozen ground.
Temperatures below 0 for 2 or more years
either continuous, discontinuous or sporadic

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7
Q

Landforms?

A
Ice Wedge
Solifluction Lobe 
Pingo 
Thermokarst 
Terracette 
Patterned Ground
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8
Q

What is an Ice Wedge?

A

Relatively narrow cracks formed by ground contractions in upper layers of ground full with ice.

  • seasonal
  • cracks widens and deepens by expansion of ice
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9
Q

What Is a Solifluction Lobe?

A

Formed on a gradient, tongue shaped appearance that extends downslope.

  • 50m wide
  • 5m high
  • small terrace can form on them
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10
Q

What is a Closed Pingo?

A

In areas of continuous permafrost. Develop beneath a lake bed, the permafrost lay of the lake bed remains frozen, rest may thaw. This means the lake may drain and water freezes. Expanding of ice forms a dome shape from the ice core.
Example - North Canada

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11
Q

What is an open Pingo?

A

In areas of discontinuous permafrost.
Valley bottom, water seeps to upper layers due to artesian pressure, water will freeze and the ice core will expand to form a bingo shape.
Example - Alaska

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12
Q

What is a Thermokarst?

A

Depressions in the ground surface from ice melting within permafrost, this can cause subsidence.

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13
Q

What is a Terracette?

A

Pathways running horizontally along a slope. Formed by Frost Action and Soil Creep

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14
Q

What is Patterned Ground?

A

Ice lens grows in autumn as active layer freezes and thaws daily. Ice lens grows, pushing sediment above it, creating stone rings as larger sediment falls to edges.

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15
Q

Processes?

A

Nivation
Solifluction
Frost Heave
Frost Creep

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