10 Glaciation Flashcards

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1
Q

Epoch

A

Subdivision of a geological period ranging from 1-10mil years

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2
Q

Cold periods of temp variations were called…

A

Glacials

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3
Q

Warm periods of temp variations were called…

A

Interglacials

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4
Q

Nunatak definition

A

Part of the landscape protruding above ice cover

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5
Q

Terminal Moraine definition

A

Material deposited in front of the ice sheets when the ice had reached its maximum advance

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6
Q

Glacial ice formation:
Ice advance-ice retreat

A

snow accumulates
weight compresses air from underlying layers into
1.granular ice
2.firn
3.glacial ice.
Low air concentration=bluer ice

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7
Q

Where can valley glaciers b found

A

The Alps

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8
Q

Where can ice sheets be found

A

Greenland

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9
Q

What is glacier mass balance

A

Difference between the amount of ice a glacier gains in winter and loses in summer

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10
Q

Explaine positive mass balance

A

Glacier gains more ice in winter than it loses in summer = advancing

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11
Q

Explain negative mass balance

A

Glacier loses more ice and is retreating

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12
Q

What dors it mean when a glacier is labeled as “stationary”

A

When loss and gain of ice are balanced

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13
Q

What are the two zones glaciers have called?

A

Accumulation zone
Ablation zone

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14
Q

What is the accumulation zone of a glacier?

A

Snow falls and remains all year here

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15
Q

What is the ablation zone of a glacier?

A

Winter snow melts during the summer here

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16
Q

What divides the accumulation and ablation zones of a glacier

A

Snowline

17
Q

Define ablation

A

Loss of ice and snow from a glacier by melting,runoff and evaporation

18
Q

Name three ice flow processes

A

1.Basal Sliding
2.Plastic Flow/Internal Flow
3.Rate of flow

19
Q

Explain 1.Basal Sliding

A

At base of glacier friction from heavy ice on bedrock causes melting.
Meltwater acts as lubricant and causes glacier to move downhill
Rate of this will depend on steepness of glacier and rate of ice accumulation

20
Q

Explain 2.Plastic flow/Internal flow

A

2 zones WITHIN a glacier
Upper zone:Ice brittle. breaks easily to form crevasses
Lower zone: ice under steady pressure=stronger wnd able to bend without breaking

21
Q

Explain 3.Rate of flow

A

Friction with bedrock and valley sides means rate of flow at base and sides is much slower than at surface(middle)
In middle surface glacier ice flows faster

22
Q

name 3 forms of glacial erosion

A

1.Plucking
2.Abrasion
3.Freeze-thaw action

23
Q

Explain 1.Plucking

A

Plucking is when glacier ice melts and seeps around a rock, refreezes and carries the rock with the glacier as the glacier moves

24
Q

Explain 2.Abrasion

A

The rock particles on the base of the glacier abrade the rock underneath the glacier leaving marks called STRIAE on the rock.

25
Q

Explain 3.Freeze thaw action

A

When water seeps into cracks in the rock and refreezes it expands and can break off rock around the crack called scree

26
Q

Name the two types of glaciation

A

1.Upland Glaciation (alpine)

2.Lowland Glaciation (continental)

27
Q

What is Upland Glaciation

A

Mountainous regions
Carried out by glaciers
Mostly landforms of erosion
Alps/Himalayas/Kerry

28
Q

What is Lowland Glaciation

A

Carried out by ice sheets
Mostly landforms of deposition
Greenland/Kildare/Offaly

29
Q

What is the rate of glacial erosion influenced by

A

Presence/absence of well jointed bedrock
Gradient (steeper=faster erosion overall)
Shape Size and amount of Basal Debris

30
Q

Describe a cirque

A

Armchair shaped depression that forms on slopes of upland areas

31
Q

Describe an Arête

A

2cirques form back to back creating a narrow ridge in the middle called an arete

32
Q

Describe a pyramidal peak

A

Angular pointed mountain peak

33
Q

describe a U shaped valley

A

Valley with steep sides and a broad flat floor

34
Q

Describe pater noster lakes

A

Series of glacial lakes connected by streams