Glaciated Landscapes SG6

Question 1

Define Periglacial

Answer 1

Areas with permafrost mainly in high latitude locations with temperatures fluctuating around 0 degrees C

Question 2

What % of Alaska is periglacial?

Answer 2

90%

Question 3

What % of the earth’s surface is periglacial?

Answer 3

25%

Question 4

Define Permafrost

Answer 4

Ground that remains frozen for at least two consecutive years overlain by an active layer

Question 5

Define Active Layer

Answer 5

Thawed permafrost when temperatures exceed 0 degrees C

Question 6

Define Talik

Answer 6

Unfrozen ground, normal/loose soil

Question 7

What are the three types of permafrost?

Answer 7

Continuous, Discontinuous, Sporadic

Question 8

What is the depths of the three types of permafrost?

Answer 8

Continuous - 396m
Discontinuous - 45m
Sporadic - 12m

Question 9

What is the depths of the active layers above the three types of permafrost?

Answer 9

Continuous - 0.5m
Discontinuous - 1-1.5m
Sporadic - 1.5-3m

Question 10

Define Solifluction

Answer 10

The upper layer of soil in the active layer undergoes seasonal thawing. Water can’t drain away due to the impermeable permafrost below so active layer may begin to move downslope when saturated

Question 11

What angle are the slopes at on which solifluction takes place?

Answer 11

2 degrees

Question 12

Explain the process of freeze-thaw weathering?

Answer 12

Water enters cracks in the rock. When temps are below 0 degrees C the water freezes and expands by 9% putting pressure on the rock causing it to crack further. It then thaws when temps increase slightly

Question 13

What are the five geomorphic processes in periglacial landscapes?

Answer 13

Solifluction, Weathering, Nivation, Ground Ice, Frost Heave

Question 14

Define Nivation

Answer 14

A collection of geomorphic processes which can occur under a permanent snow patch high up in the mountain

Question 15

Define Ground Ice

Answer 15

A generic term which includes ice lenses and ice needles

Question 16

Define Ice Lens

Answer 16

An accumulation of ice beneath the surface which forms a lens shape parallel to the ground surface and the thickening of the ice at its centre causes the ground to heave upwards

Question 17

Define Ice Needles

Answer 17

A needle-like column ice column which lifts or pushes away small soil particles

Question 18

Are ice lenses or needles more likely to form in areas which experience lower temperatures for longer periods of time?

Answer 18

Ice Lenses

Question 19

Define Frost Heave

Answer 19

A subsurface process that leads to vertical sorting of material in the active layer

Question 20

Define Specific Heat Capacity

Answer 20

The amount of heat required to raise the temperature of a given mass of a substance by one degree C

Question 21

A substance with a low heat capacity will…

Answer 21

Heat and cool quickly

Question 22

A substance with a high heat capacity will…

Answer 22

Heat and cool slowly

Question 23

Define Patterned Ground

Answer 23

The collective term for a number of fairly small scale features of periglacial landscapes including stone polygons and stone stripes

Question 24

What angle are the slopes which stone polygons form on?

Answer 24

Less than 6 degrees

Question 25

What angle are the slopes which stone stripes form on?

Answer 25

More than 6 degrees

Question 26

Define Pingos

Answer 26

Rounded ice cored hills that can be as much as 90m in height and 800m in diameter

Question 27

At what rate do pingos grow?

Answer 27

A couple of cm/year

Question 28

What are the two types of pingo?

Answer 28

Open system and closed system

Question 29

Define Artesian Pressure

Answer 29

When groundwater is put under enough pressure it can be lifted up to a higher level than the surface of the ground

Question 30

Define Ognip

Answer 30

The remains of a collapsed pingo forming a depression surrounded by circular earth ramparts

Question 31

Define Thermokarst

Answer 31

Used to refer to areas of hummocky, irregular ground interposed by waterlogged depressions created as ground ice thaws. Depressions fill with water to form shallow lakes less than 5m deep and 1-km wide

Question 32

Define Ice Wedge Polygon

Answer 32

A crack in the ground formed by a narrow or thin piece of ice that measures up to 3-4m in length at ground level and extends downwards into the ground up to several meters

Question 33

How long is the Trans-Alaskan Pipeline (TAPs)?

Answer 33

800 miles log

Question 34

What are four reasons the oil industry is important to Alaska?

Answer 34

Resource availability, Demand for oil, US energy security, Benefits for Alaska

Question 35

What is the depth of the continuous permafrost at Prudhoe Bay?

Answer 35

660m

Question 36

What is the depth of the active layer at Prudhoe Bay?

Answer 36

0.5m

Question 37

What are four consequences of changes on the landscape?

Answer 37

Increased solifluction, Development of thermokarst landscapes, Formation of Alases, Degradation of Ice Wedge Polygons

Question 38

Define Alas

Answer 38

A flat floored, steep sided depression ranging from 5-50m in depth and 100m-15km in length