Glaciers

Question 1

Glacier:

Answer 1

• Mass movement of frozen ice on land
• Form at high latitude or high elevation
• Last extension of ice here began 20,000 years and receded about 10,000 years ago
• Today only covers 10% of land surface

Question 2

Ice Flow:

Answer 2

Glaciers are not static, they are dynamic

Question 3

Formation:

Answer 3

• A stead accumulation of snow piles up and compresses layers beneath,, these compressed layers turn into ice
• Force of gravity continuously pulls ice downward
• Firn

Question 4

Movement:

Answer 4

• Fastest ice is found on the surface at the center of the valley
• Rate varies from a few cm to meters per day

Question 5

Three categories of glaciers:

Answer 5

• Valley (alpine) glaciers
• Ice sheets (continental glaciers)
• Tidewater glacier

Question 6

Valley (alpine):

Answer 6

• Found in mountainous regions
• High altitude
• Alps, Rockies

Question 7

Ice Sheets (continental glaciers):

Answer 7

• Much larger
• Flow direction is form and area of thick ice to thin ice
• Greenland, Antarctica

Question 8

Tidewater glacier:

Answer 8

• Flow far enough to reach out into ocean

- Create icebergs

Question 9

Glacier accumulation:

Answer 9

Snow adds to weight of a glacier

Question 10

Glacier wastage (ablation):

Answer 10

• Breaking of ice forming icebergs

- Melting and calving

Question 11

Accumulation is greater than wastage:

Answer 11

Glacier advances

Question 12

Accumulation is less than wastage:

Answer 12

Glacier retreats

Question 13

Accumulation = wastage:

Answer 13

Glacier remains stationary

Question 14

Glacial erosion & features:

Answer 14

• Plucking and abrasion
• U-shaped valleys, sharp ridges (Aretes), pyramid peaks (horns), water filled valleys (Fjords = hudson river) and bowl shaped valleys (cirques)

Question 15

Deposition features:

Answer 15

• Drift
• Stratified Drift
• Till

Question 16

Drift:

Answer 16

Any sediment deposited by moving ice

Question 17

Stratified Drift (Fluvio):

Answer 17

Well-sorted sediments deposited by streams (meltwater)

Question 18

Till:

Answer 18

Unsorted sediment, deposited by moving ice

Question 19

Deposits of till:

Answer 19

• Lateral moraines
• Medial moraines
• End moraine
• Drumlin
• Glacial erractics

Question 20

Lateral moraines:

Answer 20

Form along valley walls

Question 21

Medial moraines:

Answer 21

Form where two later moraines meet

Question 22

End moraine:

Answer 22

Left at terminus of glaciers where it retreats

Question 23

Drumlin:

Answer 23

A tear-shaped ridge showing direction of ice flow

Question 24

Glacial erratics:

Answer 24

Large boulder left behind a glacier

Question 25

Deposits of stratified drift:

Answer 25

• Kame
• Esker
• Kettle

Question 26

Kame:

Answer 26

A small hill forms where sorted sediments accumulate beneath ice

Question 27

Esker:

Answer 27

• Winding path of stratified drift

- Forms under glacier streams

Question 28

Kettle:

Answer 28

A depression caused by a block of ice that melts and can be water-filled