12 Glacial History

Question 1

Define Ablation

Answer 1

refers to melting, runoff, evaporation or sublimation of the ice, resulting in a thinning of the ice if it is not replenished by some other process.

Question 2

Define sublimation

Answer 2

transformation from solid to gaseous state

Question 3

How does glacial ice move and why is it like that?

Answer 3

The lower layer of a glacier moves plastically because of the pressure. Allowing glaciers to move like viscous fluid

Question 4

What is the name of the cool period in the Precambrian?

Answer 4

Proterozoic Snowball Earth

Question 5

What changes naturally on earth and what are the two kinds of periods?

Answer 5

Climate and periods of WARM and COOL have alternated over geologic time

Question 6

What is the name of the cool period from Carboninoferous- Permian?

Answer 6

Late paleozoic Gondwana glaciation

Question 7

What did the Late Paleozoic Gondwana glaciation form and what one place can you see that?

Answer 7

Carbonate cycles and can find this at the Johnston Canyon Formation

Question 8

What is the cool period called from Tertiary- today?
Slide 28

Answer 8

Pleistocene glaciations

Question 9

Define a glacial period

Answer 9

An interval of time (thousands of years) within an ice age that is marked by colder temperatures and glacier
advances.

Question 10

Define an interglacial period

Answer 10

Period of warmer climate between glacial periods

Question 11

Define a stadial period

Answer 11

A period of lower temperatures during an interglacial
* Like the Little Ice Age

Question 12

What glacial period are we currently in and are we in a glacial or interglacial period?

Answer 12

We are currently living in the Holocene epoch, which is an interglacial.

Question 13

What happened during the last Pleistocene glaciation?
Slide 33

Answer 13

The whole Canadian Cordillera was covered with a glacier

Question 14

What time frame did the Cordilleran ice sheet deglaciate in the last Pleistocene glaciation?

Answer 14

16,500 - 5,700 years ago

Question 15

When was the last glacial maximum for the Cordilleran ice sheet and what glacial period?

Answer 15

~20,000-30,000 years ago during the Wisconsin glacial

Question 16

When was the start, peak and end of the Wisconsin glacial? And how much ice did it cover the Cordillera with?

Answer 16

Start; ~110,000 years
Peak: ~20,000-30,000 years
Ended: ~11,000 years
Covered the cordillera with 1-2 KM of ice

Question 17

What period followed the Wisconsin Glacial and what time did it start?

Answer 17

Holocene interglacial began ~11,000 years ago

Question 18

Little ice age
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Question 19

What are the two ways that glaciers form the landscape?

Answer 19

• Erosional features – sculpting of the mountains
• Glacial deposits – layers of sediment moved by glacial activity

Question 20

What are 6 formations from glaciation?

Answer 20

1. U-shape valley
2. Hanging valley with waterfall
3. Arete
4. Horn
5. Cirques
6. Sharp mountain profiles

Question 21

Describe glacial abrasion and striations.

Answer 21

Abrasion occurs when the ice and the load of rock
fragments slide over the bedrock and function as
sandpaper that smooths and polishes the surface
situated below.

Question 22

What are the glacial dispositional features? (6)

Answer 22

1.Lateral moraine
2. Terminal moraine
3. Till
4. Outwash
5. Drumlin
6. Erratics

Question 23

Slides 71-81

Question 24

Slides 84-88

Question 25

When do researchers believe that 95% of the glaciers in the Canadian Rockies will be gone?

Answer 25

2100

Question 26

Slide 96