Glaciers

Question 1

Glacier

Answer 1

A stream of ice that stays mostly frozen all year and flows under the influence of gravity.

Question 2

Mountain Glaciers

Answer 2

1.) Cirque Glacier
2.) Valley Glacier

Question 3

Cirque Glacier

Answer 3

Mountain Glacier- forms near the top of mountains. When melting/refreezing occurs, ice wedging can occur leaving a glacier nestled into the mountain
ex: Swiss Alps

Question 4

Valley Glacier

Answer 4

Mountain Glacier-where rivers of ice come down through valleys, eroding sides and bottoms.
-forms lateral moraines

Question 5

Moraines

Answer 5

Poorly sorted sediment deposited by glacial processes
-tells us how far an ice sheet/glacier went

Question 6

Types of Glacial Moraines

Answer 6

1.) End Moraine: front of glacier
2.) Lateral Moraine: At the sides of the glacier
3.) Medial Moraine: At the bottom of the glacier

Question 7

Polish

Answer 7

Grit and dirt on the bottom of glaciers can smooth surfaces as glacial ice travels over it

Question 8

Striations

Answer 8

Big chunks of rock dragged by glaciers can scratch surface leaving behind striations.

Question 9

Eskers

Answer 9

Well sorted gravel deposits formed in channels below a glacier, sometimes top of rivers

Question 10

Erratics

Answer 10

Large boulders left behind by glaciers

Question 11

Fjords

Answer 11

Flooded Glacial valley due to glaciers forming valleys, then retreating with sea water following it.

Question 12

Dropstones

Answer 12

Glaciers pick up rocks, goes into an ocean, breakings into an iceberg, iceberg melts and drops rocks to the bottom of the sea.

Question 13

Continental Ice Sheets

Answer 13

1.) Antarctica
2.) Greenland

Question 14

Antarctica

Answer 14

Ice sheet is 3-4 km thick
-weight of glaciers sheet pushes down the crust because the asthenosphere deforms plastically
-sheets bedrock below sea level
-If Ice in Antarctica melts; sea level will rise 58.3m
-90% total surface fresh water
-60% total fresh water (including groundwater)

Question 15

Greenland

Answer 15

10% global ice volume

Question 16

Small changes in Earth’s orbit around the sun have influenced Earth’s climate during “Ice Age’s”

1.) __a__ of earths orbit is governed by a __b__ year cycle

2.) The __c__ of earths spin axis changes over a __d__ year cycle.

3.) The wobble of Earth’s spin axis, its __e__ varies in a __f__ year cycle.

Answer 16

1.) Eccentricity; 100,000
2.) Tilt; 41,000
3.) Precession; 23,000

Question 17

Pleistocene Ice Age (2.6 Ma-Present)

Answer 17

Last glacial max=18,000 yrs ago
-sea level dropped 120m
-Land bridge across Bering Strait
-Australia, New Guinea, and Tasmania=1 continent

Question 18

Where do Glaciers Form?

Answer 18

High Latitudes
-solar radiation spread over larger area at high latitude

Question 19

Glacial Advance

Answer 19

Ice accumulation> Ice Lost

Question 20

Glacial Retreat

Answer 20

Ice Accumulation < Ice Lost

Question 21

Glacial Erosion

Answer 21

1.) Abrasions
-form U-shaped valleys as it erodes side and bottom by picking up parts of rocks and sand through contact with surface
ex: Yosemite Valley
2.) Plucking
-Part of glacier melts due to pressure increase, when pressure equalizes; water freezes, plucking bits of rock taken with the glacier.

Question 22

Milankovic Cycles

Answer 22

Changes in Earth’s orbital parameters (eccentricity, tilt, and procession) change the amount of exposure to solar energy/radiation.
-Glacial periods occur when Milankovic forcing leads to a cooler summer (snow isnt melted and stays for the next winter)

Question 23

Which of the following two processes are most important to converting snow into glacial ice as its buried within a glacier

Answer 23

1.) Recrystallization
2.) Compaction

Question 24

Snowball Earth

Answer 24

3 snowball events (2.22 Ga, 717-660Ma, and 635Ma)
evidence:
-glacial till
-drop stones
-striations
(glacier evidence covering things around the equator; so therefore the entire world).

Question 25

Causes of Snowball Earth

Answer 25

Early sun wasn’t as intense; less solar radiation
-continents closer to equator (Pangea)
-Higher albedo (reflectivity); cooler temps