Glacial

Question 1

When does glacial ice form? (What must be greater?)

Answer 1

When accumulation (snowfall) in winter is greater than ablation (melting) in summer

Accumulation > ablation

Question 2

What are some possibilities in which glaciers can form?

Answer 2

Global cooling due to elliptical orbit of earth (every 97,000 years)

Earth’s axis tilts every 41,000 years (maximum tilt means north pole gets less sunlight, more accumulation)

Simultaneous volcanic eruptions could trigger an ice age

A large asteroid with the same catastrophic climatic result as volcanic activity

Question 3

How do glaciers form?

Answer 3

If snow accumulates enough, the snowflakes become compact from the compression to become ice

Question 4

Firn

Answer 4

The halfway stage between snow and solid glacial ice where periodic freezing and thawing creates a semisolid crystallized slush

Question 5

Blue glacier

Answer 5

A glacier where the ice is so concentrated that it squeezes out all of the air to the point where it looks blue

Question 6

What’s the difference between an alpine and a continental glacier?

Answer 6

Alpine/valley glaciers originate from the mountains and move down into lowland areas, while continental glaciers form on flat land and spread out.

Question 7

Isostatic sinking

Answer 7

The enormous weight of ice sheets pushing the continent down (during the last ice age)

Question 8

Isostatic rebound/readjustment

Answer 8

The rise of landmasses that were weighed down by ice sheets during the ice age (bounce back)

Will result in the drying of the Hudson Bay and the altering of drainage patterns

Question 9

What are raised beaches and how are they formed?

Answer 9

Raised beaches are landforms that were originally beaches, but now lie above sea level. They form during Isostatic rebound, when the land rises after glacial ice melts

Question 10

What is the difference between till and outwash?

Answer 10

Till is unsorted and unstratified glacial debris, meaning that it can consist of very large rocks and boulders.

Outwash is sorted and stratified glacial deposits and have a limit to the size of particles that it can carry

(Till = when glacial ice melts
Outwash = deposit left by running glacial meltwater)

Question 11

Cirque

Answer 11

A hillside hollow formed by plucking and abrasion where glacial ice accumulates, deepening the depression

Question 12

Tarn

Answer 12

When a cirque fills up with water after glaciation to form a small lake

Question 13

Arete

Answer 13

A sharp ridge created by the action of two cirques eroding the mountain between them

Question 14

Col

Answer 14

If erosion continues to wear down the wall of rock between two cirques, a mountain pass known as a col will form

Question 15

Horn

Answer 15

The sharp peak formed when several cirque glaciers erode a mountain from more than two sides

Ex: the Matterhorn in the Swiss Alps and Mt. Assinaboine in the Rockies

Question 16

Striations

Answer 16

Scrape marks left in the bedrock that are carved out by debris carried in the bottom of the glacier

Question 17

Lateral moraine

Answer 17

Debris carried along and deposited at the side of a glacier as it melts

Question 18

Medial moraine

Answer 18

As alpine/valley glaciers come together, lateral moraines join to become medial moraines > dark lines in the middle of the main valley glacier

Question 19

Terminal moraine

Answer 19

The mound of debris left at the farthest point of glacial advance

Question 20

Recessional moraine

Answer 20

As a glacier receded, ridges of debris are deposited. This occurs when melting is equal to the snowfall and the glacier remains stationary, depositing debris at its snout

Question 21

Esker

Answer 21

When meltwater flows below the ice and emerge at the snout. The moving water carries debris with it, and over time the deposits are dropped off at the snout of the glacier. Eventually, a long snake-like deposit called an esker will take shape

Question 22

Recess

Answer 22

When glaciers take breaks and leave behind mounts of dirt

Question 23

Truncated spurs

Answer 23

Steep, often vertical valley walls created when a glacier moves through a river valley and shave off the sides

Question 24

Hanging valleys

Answer 24

Small tributary streams that, before glaciation, flowed down the slopes to the main valley floor (tributary valleys were left hanging high along the side of the U-shaped valley)

Have waterfalls cascading down the steep walls

Question 25

Crevasses

Answer 25

Deep cracks in ice that are created when a glacier moves over uneven bedrock

Question 26

What shape are glacier valleys?

Answer 26

U-shaped

Question 27

Drumlins

Answer 27

Small teardrop-shaped deposits left behind when a continental glacier stops to remove some of its load

Question 28

Kettle lake/pool

Answer 28

A lake created when a block of ice is left behind in a depression

Question 29

Ribbon/finger lakes

Answer 29

A long, narrow glacial lake (very deep and cold year-round

Question 30

Erratics

Answer 30

Random rocks left behind by glaciers that get deposited in the middle of nowhere

Question 31

Roche moutonee

Answer 31

When glacial ice advances over bedrock, leaving the side facing the glacier to be polished smooth, while the other side is rough, steep, and jagged

Question 32

What are some evidence of glacial action?

Answer 32

Glaciers rearranged soil in North America, with some areas getting rich farming soil, while others are left with a dump of unsorted till and almost all soil removed

Valleys running north to south were eroded into U-shaped valleys

Moraines left behind

Question 33

What are some benefits of glaciation?

Answer 33

*Rich prairie souls and glacial lake bed that are well suited for farming and grazing

*Shaped the land

*Left behind an abundance of fresh water

Glacial lakes (Great Lakes) valuable waterways for shipping

Tarns used to generate hydroelectric power in Norway

Glaciers are tourist attractions

Cols are used as transportation routes

Gravel and sand deposits can be used for road construction

Question 34

Toe/snout

Answer 34

The foot/end of the glacier