Dynamic Surface L12

Question 1

What is the snowline?

Answer 1

The lower topographic limit of permanent ice and snow

Question 2

What is the main effect on snowline?

Answer 2

Latitude

Question 3

What is snow’s crystal structure?

Answer 3

Hexagonal

Question 4

What is ice’s crystal structure?

Answer 4

Cubic

Question 5

What is glacier ice’s crystal system?

Answer 5

Hexagonal

Question 6

What is frazil ice?

Answer 6

Ice that forms in supercooled turbulent water

Question 7

At what temperature does frazil turn into sea ice?

Answer 7

-1.8C

Question 8

What is pack ice?

Answer 8

Consolidated sea ice

Question 9

How do icebergs affect sedimentation?

Answer 9

Icebergs contain sediment from the continent and float considerable distances away from their source depositing sediment when they melt.

Question 10

Describe the crystal structure of ice.

Answer 10

H2O molecules are arranged in tetrahedral patterns that form hexagonal rings of oxygen atoms. A single crystal of ice consists of stacked layers of these rings.

Question 11

What is the basal plane?

Answer 11

The plane of hexagonal rings in ice

Question 12

What is the c-axis of ice?

Answer 12

The direction of stacking of the layers of hexagonal rings in ice

Question 13

What is polycrystalline ice?

Answer 13

Ice that contains many grains with different orientations of their c-axes.

Question 14

What determines the fabric of ice?

Answer 14

The way in which the c-axes are orientated relative to each other

Question 15

What is basal glide?

Answer 15

The deformation of a single crystal when shear stress is applied along its basal plane

Question 16

What does the pressure on ice needed for it to flow depend on?

Answer 16

Gradient

Question 17

How does cold dry ice flow?

Answer 17

By internal deformation

Question 18

How does meltwater and wet sediment help ice to flow?

Answer 18

By acting as lubricants between the ice and the bedrock

Question 19

What are the 4 types of glacial environments?

Answer 19

Ice sheets
Valley glaciers
Tidewater glaciers
Piedmont glaciers

Question 20

What is a tidewater glacier?

Answer 20

Where a glacier meets the sea

Question 21

What is a piedmont glacier?

Answer 21

A glacier that is found at the foot of a mountain and forms from the amalgamation of several valley glaciers

Question 22

What is the ablation zone?

Answer 22

The zone along a glacier in which ice loss is greater than ice gain

Question 23

What is the accumulation zone?

Answer 23

The zone along a glacier in which ice gain is greater than ice loss

Question 24

When does a glacier retreat?

Answer 24

When ablation > accumulation

Question 25

When does a glacier advance?

Answer 25

When accumulation > ablation

Question 26

How does a temperate glacier flow?

Answer 26

Ice moves over the bedrock

Question 27

How does a polythermal glacier move?

Answer 27

Ice moves by internal shearing but over the bedrock during glacial surges

Question 28

What is a moraine?

Answer 28

Piles of disturbed unsorted material at the sides or front of the glacier

Question 29

Is moraine well or poorly sorted?

Answer 29

Poorly sorted

Question 30

What is a drumlin?

Answer 30

Oval shaped hill composed of ground moraine that form below the glacier in the direction of ice flow

Question 31

What is terminal moraine?

Answer 31

Sediment that has been deposited at the nose of the glacier at its maximum extent

Question 32

What is a kettle hole?

Answer 32

Ice dropped off at the nose of the glacier into the moraine eventually melts leaving behind a pond of melt water

Question 33

What is an esker?

Answer 33

A sinuous deposit of sorted sediment that forms when subglacial streams drop their sediment.

Question 34

What is a lateral margin stream?

Answer 34

Streams of water that flow between the valley side and the glacier that often deposit sediment forming kame terraces.

Question 35

What is a kame terrace?

Answer 35

Sediment deposited by lateral margin streams at the sides of the glacier.

Question 36

What is a sandur?

Answer 36

An outwash plain formed by glacial meltwaters

Question 37

What are some features of sandurs in the geological record?

Answer 37

Sandstone dykes Frozen sand clasts

Question 38

What are glacial dropstones?

Answer 38

Large pieces of sediment that have been carried out to sea by icebergs and dropped to the sea floor during melting

Question 39

What are glacial varves?

Answer 39

A very thin annual layer of sediment deposited during cycles of melting

Question 40

What is isostatic rebound?

Answer 40

The rising of the lithosphere which has previously been depressed by the weight of glacial ice