Lesson 15: Glaciers

Question 1

Compare high altitude and high latitude glaciers.

Answer 1

High Altitude: temperate/mountain/valley/alpine glaciers
High Latitude: Continental glaciers/polar ice caps/ice sheets and is unaffected by topography

Question 2

What is an example of a high latitude glacier?

Answer 2

Greenland and Antarctica

Question 3

What are the 2 types of glacial erosion?

Answer 3

1. plucking
2. abrasion

Question 4

What is plucking?

Answer 4

a type of glacial erosion where as a glacier flows over bedrock, it loosens and lifts rocks resulting in glacial erratic

Question 5

what is abrasion?

Answer 5

a type of glacial erosion where rocks in the glacier act like sandpaper to smooth and polish a rock surface

Question 6

What is glacial drift?

Answer 6

all sediments of glacial origin

Question 7

What are the 2 types of glacial drift?

Answer 7

1. Till
2. Striated

Question 8

Compare till and striated glacial drift.

Answer 8

Till: material is deposited directly by the ice (unsorted)
Stratified Drift: sediments laid down by melt water (sorted)

Question 9

What is a moraine?

Answer 9

a land form made of glacial till in terms of lateral or medial, and end or ground

Question 10

What is an ice age?

Answer 10

a long interval of time when global temperatures are very cold and large areas of the earth are covered by high latitude and high altitude glaciers.

Question 11

What is the difference between glacial and inter-glacial periods in an ice age?

Answer 11

inter-glacial periods: multiple shorter-term periods of warmer temperatures when glaciers retreat

Glacial periods: long terms of colder temperatures when glacials advance

Question 12

Are we living in an ice age? If so, what period of the ice age are we in?

Answer 12

Yes, inter-glacial

Question 13

How many significant ice ages have been identified by geologists?

Answer 13

1. Huronian
2. Cryogenian
3. Andean-Saharan
4. Late Paleozoic
5. Quaternary

Question 14

When did the last glacial maximum occur?

Answer 14

~20K years ago

Question 15

How does sea level change with ice ages?

Answer 15

Melting glaciers: rise sea level
Forming glaciers: lower sea level

Question 16

What are the potential causes for ice ages? (7)

Answer 16

1. plate tectonics
2. atmospheric composition
3. volcanoes
4. earth’s albedo
5. orbital variations
6. solar output
7. asteroids

Question 17

How can plate tectonics affect the climate system and potentially cause an ice age?

Answer 17

Continents move toward and away from the poles that affect the ocean and atmospheric circulation patterns.

Question 18

How can atmospheric composition affect the climate system and potentially cause an ice age?

Answer 18

Greenhouse Gases can absorb the light of the sun or reflect it

Question 19

How can volcanoes affect the climate system and potentially cause an ice age?

Answer 19

Sulfur-injecting eruptions can trigger an ice age as sulfate aerosols are more reflective

Question 20

How can Earth’s albedo affect the climate system and potentially cause an ice age?

Answer 20

Dark colored materials absorb the most sunlight and warm the earth
Light colored materials reflect most sunlight which can lead to further drops in temperature

Question 21

How can orbital variations affect the climate system and potentially cause an ice age?

Answer 21

Less eccentricity = less seasonality; cooler polar summers; glaciers more likely to survive/grow
More eccentricity = greater seasonality; warmer polar summers; glaciers less likely to survive/grow

More Obliquity = more sever seasons; warmer summers and cooler winters; glaciers cannot grow
Less Obliquity = less severe seasons; cooler polar summers; warmer winters; glaciers can grow

Precession: hemispheres pointed towards the sun at perihelion and away from the sun at aphelion the differences in seasons will be more extreme; reversed for the opposite hemisphere

Question 22

How can solar output affect the climate system and potentially cause an ice age?

Answer 22

Sunspots increase magnetic field which lowers the temperature surrounding the sun and inhibits the flow of hot new gas from the sun which can help the triggering of an ice age.

Question 23

How can asteroids affect the climate system and potentially cause an ice age?

Answer 23

Asteroids create a lot of dust that floods the solar system that can result in cooling of the earth; thus can contribute to the triggering of an ice age

Question 24

Atmospheric carbon dioxide plays an important role in ice ages. Antarctic ice core data shows that CO2 concentration is generally _____ in the cold glacial times.

Answer 24

low

Question 25

What has a higher albedo glacial ice or grass?

Answer 25

glacial ice

Question 26

Does increasing the angle of the axial tilt favor the formation/growth of glaciers?

Answer 26

No

Question 27

Ice ages typically develop (abruptly/slowly) and end (abruptly/slowly)

Answer 27

slowly;abruptly

Question 28

When glaciers melt, sea level ____.

Answer 28

rises

Question 29

Most geoscientists agree that Earth has experienced __ significant ice ages in the last 4.6 billion years.

Answer 29

5

Question 30

T/F: a significant trigger in initiating ice ages is the changing positions of the Earth’s continents, which affect ocean and atmospheric circulation patterns.

Answer 30

True