Geography 2290

Question 1

What is a glacier?

Answer 1

a mass of ice on land that formed by the accumulation of snow

Question 2

Where does a glacier form?

Answer 2

Glaciers form at high elevations and high latitudes

Question 3

How does a glacier form?

Answer 3

When snow remains year round, and the accumulation starts to transform into ice. New layers of snow bury and compress the previous layers. This new layer forces the snow to recrystallize.

Question 4

What are the physical properties of glacial ice that make it so unique? (3)

Answer 4

• While it is solid, it is very close to becoming a liquid.
• It forms at 0 degrees celsius and more or less remains there.
• It will melt when you add pressure.

Question 5

How does glacial ice move and how does the velocity of the ice vary within a glacier?

Answer 5

the presence or absence of meltwater will affect how fast and how far a glacier will move

Question 6

What is regelation?

Answer 6

the way that a glacier moves around an obstacle by melting and refreezing

Question 7

How does a roche moutonnee form?

Answer 7

When meltwater is on the lee-side of the obstacle, it refreezes due to lower pressure. The bedrock is physically weathered creating more angular rock fragments. This ends in the formation of a roche moutonnee.

Question 8

What is a cold-based glacier and how does velocity vary with depth within this ice?

Answer 8

the ice is frozen to the underlying bedrock, the glacier deforms as it moves, the bottom is slow and the top is fast, the average ice velocity is slow

Question 9

What is warm-based glacier and how does velocity vary with depth within this ice?

Answer 9

the ice is not frozen to the bedrock beneath it and the glacier does not deform internally, instead it slides along at a faster velocity as a single block of ice on a layer of meltwater.

Question 10

How does sediment form at the base of a glacier as it forms and how does it move?

Answer 10

When sediment contacts the underlying bedrock, there is weathering and erosion. During this contact zone, the sediment abrades against the bed rock creating the fine sediment. It is done by frost action and abrasion. Once abrasion occurs, this results in finer sediment to form as the fragment scrapes the bedrock beneath it as the glacier moves.

Question 11

What is a striation, how does it form and what is it used for?

Answer 11

they are straight, long shallow engravings or scratches in the bedrock caused by the passage of a rock embedded in the base of a glacier, they are very good at indicating ice flow.

Question 12

What is a friction crack, also called a chattermark, and how does it form?

Answer 12

A friction crack is broken bedrock. It forms when the bedrock has been physically weathered by the ice when it doesn’t want to go around/erode the rock fragment.

Question 13

What is lodgement till and how does it form?

Answer 13

It is till that is deposited in and around the irregularities in the bedrock. It forms when a glacier cannot move a high concentration of sediment so the ice will detach from it resulting in living it behind.

Question 14

What is ablation till and how does it form?

Answer 14

As the ice at the edge of the glacier slows down, it is pushed by the faster ice behind it and this causes the ice and sediment to move and away from the bedrock. The sediment carried on the ice, in the ice and beneath the ice is now concentrated at the edge of the glacier.

Question 15

What is supraglacial, englacial and subglacial?

Answer 15

on the ice, in the ice and beneath the ice

Question 16

How do you tell the difference between lodgement and ablation till?

Answer 16

Ablation till is not compacted and is often reworked by meltwater or gravity.
Lodgement till is beneath the ice, and internal structures are formed because of the pressure exerted by the glacier.
Overall, ablation till is not dense nor hard like lodgement till and finer grain sizes have been removed.

Question 17

What is a till plain and why does it often have a hummocky topography?

Answer 17

A large area covered by till that can often have a hummocky topography because the sediment was deposited unevenly/kettles were formed.

Question 18

What are the sources of liquid water in a glacial environment? What does liquid water have that solid ice does not? How does liquid water affect the behaviour of glacial ice and sediment it carries?

Answer 18

• Sources of liquid water: rain, melting snow, melting caused by pressure within glacier or geothermal gradient
• Meltwater has heat and mobility, which introduces more melting
• Liquid water at the base of glacier results in a warm-based glacier, where as no water results in cold-based glacier. If there is enough meltwater, an esker could form.

Question 19

What happens to a glacier once it reaches an ocean?

Answer 19

Upon reaching the ocean, the ice will begin to float and melt, this ice will begin to break apart ice-bergs. The rise and fall of the sea level with tides will help break the ice. More sediment may be released at the base of the glacier while some may be carried away by ice-bergs.

Question 20

How is the front of a glacier that is advancing different from the front of a glacier that is retreating?

Answer 20

In an advancing ice sheet, the ice is steep and thick and is also less affected by bedrock topography.
In a retreating ice sheet, the ice is gently sloped and thin and is more affected by bedrock topography.

Question 21

What is an esker and how does it form?

Answer 21

it is a long linear ridge of sediment that is deposited by meltwater in a tunnel at the base of the glacier. The water that is flowing through has a high velocity and whenever velocity decreases, sediment is deposited.

Question 22

What is a drumlin and how does it form?

Answer 22

a asymmetrical hill composed of till deposited beneath a glacier as the ice advanced

Question 23

What is a kame and how does it form?

Answer 23

a mixture of sediment deposited at the margin of an ice sheet where meltwater and gravity have concentrated the sediment, the sediment is often poorly sorted because it is quickly deposited

Question 24

Briefly describe the formation of glacial lake deposits

Answer 24

During the summer, water and sediment enter the lake and only the coarser sediment (silt) settles to the bottom. Silt is in suspension, in which it settles to the bottom. More fine sediment is not deposited because the lake is still circulating.
During the winder, the lake is covered in ice. The water in the lake is isolated and circulates very little. The finer sediment is carried in suspension which then are deposited creating a fine-grain, dark coloured winter layer.
Pieces of glacial ice with sediment in it may melt resulting in large coarse grains to be deposited at the bottom as well. The presence of large drop stones in the summer and winter layers are called VARVES.

Question 25

What is a paraglacial environment?

Answer 25

A cold environment that persist after a glacier is gone.

Question 26

What is a periglacial environment?

Answer 26

A cold environment that does not always experience freezing conditions.

Question 27

What is nivation hollow and how does it form?

Answer 27

in the northern hemisphere, a north facing slope will be colder as it gets less sunlight. As a result, more snow will accumulate and persist longer on the slope. At the base of the snow bank, there is repeated freeze/thaw cycles which physically weathers the rock by frost action. Gravity and some meltwater will then erode and transport this sediment to create a shallow depression on the hillside which is a nivation hollow.

Question 28

What is permafrost and why is it so important to Canada?

Answer 28

Permafrost is ground that has been frozen for at least two years. It is so important to Canada because it is a major process/feature that occurs on the Canadian landscape.

Question 29

What is a patterned ground and how does it form?

Answer 29

A very regular arrangement of different sediment sizes, often in the form of very defined circles. These patterns often consist of an elevated ridge of coarse sediment surrounding an area of finer sediment. It is thought to be the result of he mixing in the form of convection currents results in repeated expansion and contraction caused by freeze-thaw cycles. The mixing of the sediment to some depth that moves the larger rock fragments further to the outsides while leaving finer sediments closer to the centre.

Question 30

What is a pingo and what are the two ways it can form?

Answer 30

A large ice cored hill that forms in open and closed systems.

Question 31

How are pingos formed in an open system?

Answer 31

In a layer of sediment, ice forms at some point underground. Once the ice forms, more water is drawn to it. This additional water, sometimes in the form of water vapour freezes to the ice and the original ice grows in size. As the ice grows, it pushes up the ground above it creating a pingo. As it forms, the ice excludes the sediment, pushing it away and maximizing uplift.

Question 32

How are pingos formed in a closed system?

Answer 32

Permafrost beneath a lake occurs at greater depth because of the heat holding the capacity of water. Once the lake is drained, the exposed ground beneath the lake freezes- the surface of the permafrost rises. The water between the lake bottom and the surface of the permafrost is trapped. The water eventually freezes to form ice that pushes the ground up.

Question 33

What is a rock glacier and what are two ways it can form?

Answer 33

A glacier that has more sediment than ice, they form at high latitudes/high elevations where snow accumulates, and they flow.
It forms when:
- a typical glacier accumulates more and more sediment until it is mostly rock fragments
- a deposit of rock fragments becomes mixed with snow and ice such that pores begin to fill and it starts to flow.

Question 34

Briefly describe the geomorphology of the deep ocean basins.

Answer 34

there is very little sediment because the rate of deposition is slow. It is fine grained that is layered in the form of thin horizontal beds.

Question 35

How are wind generated waves created on the ocean?

Answer 35

by storms; the mass of water beneath storm waves radicate outward in all directions.

Question 36

What are the three factors that control the formation of a wave?

Answer 36

Wind Speed
Wind Duration
Fetch

Question 37

What is fetch?

Answer 37

the body of water the wind blows over

Question 38

What is wave interference? Briefly explain it using one example.

Answer 38

When different wave patterns meet and combine; when two waves are in phase, it results in the crest and the trough being twice as big (positive interference). If two waves combine to cancel each other out, it is negative interference.

Question 39

What is wave reflection?

Answer 39

When a wave bounces off an object, the only thing that is changed is the wave direction.

Question 40

What is wave refraction?

Answer 40

When a wave bends around an object, at the centre of the object, the waves slow down and bunch up. At the sides of the object, the waves move on without a change.

Question 41

Briefly explain how a wave becomes more parallel to a shoreline as it approaches the shoreline.

Answer 41

As waves are reaching the shoreline, there is a drop in water energy because turbulence increases. As the part of the inner wave enters shallow water, it makes contact with the bottom and slows down. As a result, the entire wave bends in a way that is becomes parallel to the coast.

Question 42

Briefly explain how a long shore current is generated by waves at a shoreline.

Answer 42

When waves strike the shoreline at an angle as it breaks, the water rushes up on shore and goes to zero velocity. The water returns straight back offshore by gravity. The returning water is redirected back on shore by the next incoming wave and the water returns back offshore again. This process repeats itself and it results in a longshore current.

Question 43

What is a long shore current?

Answer 43

the flow of water parallel to the shoreline

Question 44

Briefly explain the process of wave breaking at a shoreline.

Answer 44

As the wave moves towards the shoreline into shallower water, the orbits touch the bottom which results in the wave to slow down and begin breaking. The waves bunch up and the wavelength decreases while the wave height increases as the water is forced upward. The wave orbits fallen out as the wave runs out of room. Instead of the orbit motion, there is a distinct back and forth motion to the water beneath the wave. The wave than reaches a height and speed where it is no longer stable and it falls over. The final wave energy is expanded as the water rushes up the swash zone, and the water finally reaches zero velocity to the point where it stops. The water then infiltrates into the shoreline or it returns back offshore as a bottom current.

Question 45

What is a beach?

Answer 45

A sedimentary deposit at a coast line created by waves.

Question 46

Describe the landforms that form in the breaker zone.

Answer 46

Ripple bedding forms as there is an abundant of sand moving as bedload. The water is very turbulent and moves in two directions (back and forth) which results in ripple bedding as the water becomes more shallow.

Question 47

Describe the landforms that form in the swash zone.

Answer 47

Horizontal bedding forms (tilted towards the ocean)
and it is formed by the thin layer of fast moving water created by the final breaking of the wave.
Beach Cusp
Beach step

Question 48

Describe the landforms that form in the dune areas.

Answer 48

Berms form from increased deposition and incoming waves. The dunes are piles of sand that result by wind action.

Question 49

What is the difference between a winter beach profile and summer beach profile?

Answer 49

In the winter, there are larger waves that carry sediment on shore and they are strong enough to keep it moving and carry it back offshore. In the summer, the waves are smaller and the return flow is weaker which results in sediment to not be carried back offshores.

Question 50

How do multiple bars form in the breaker zone?

Answer 50

Offshore bars are deposited by the action of breaking waves. When waves break at different places and times, it is because they are different sizes and they can produce more than one bar. On gently sloping shorelines, the same wave can break more than once as it breaks, reforms and breaks again resulting in multiple bars to be formed.

Question 51

What is an edge wave and how does it form?

Answer 51

A wave that travels parallel to the shoreline. They are wind generated and they travel parallel to the coast because that was the direction the wind was blowing or by wave refraction.

Question 52

What is a beach cusp and how does it form?

Answer 52

A regular pattern of sediment distribution in the swash zone that has a raised horn and a low embayment. Forms because of the result of wave interference. There is an alternating patter of larger and smaller waves breaking on the shoreline. The larger waves create low embayments composed of return flow from the embayment and the smaller waves create the horns and the coarse sediment in them.

Question 53

What is a barrier island and how does it form?

Answer 53

a linear ridge of sediment parallel to the coast that is some distance offshore. they may form if a spit becomes detached from the coast or if an offshore berm grows in size and is exposed above sea level.

Question 54

What is a beach step and how does it form?

Answer 54

On a shoreline, the upward motion as a wave breaks meets the return flow from the swash zone. As a result, this mixing of water, coarse sediment is concentrated and a depositional feature called a step is formed. A step is a drop off point along the shoreline in the water.