Glacial Motion and Deposition

Question 1

The mass balance of a glacier is any net _____ or net _____ of ice.

Answer 1

gain, loss

Question 2

What is mass balance?

Answer 2

any net gain or net loss of ice

Question 3

Net gain is ______ of ice

Answer 3

accumulation

Question 4

Net loss is _______ of ice

Answer 4

ablation

Question 5

what is the single most important factor on whether a glacier is growing or shrinking?

Answer 5

summer temperature

Question 6

During the winter months _____ falls and recharges the glacier in the uphill areas and flows downhill

Answer 6

snow

Question 7

Where do glaciers melt in the summer?

Answer 7

at the terminus

Question 8

Glacial motion occurs due to _____

Answer 8

gravity

Question 9

Ice in a glacier behaves like a _____ until you get 50 meters deep, where the ice gets more plastic/moldable

Answer 9

solid

Question 10

Glaciers flow _______

Answer 10

downslope

Question 11

glaciers move _____ at less than ___ inches per day

Answer 11

slowly, 10

Question 12

Increased weight or pressure on ice causes the crystal ____ to align which causes the ice to be more moldable

Answer 12

axes

Question 13

What two processes do glaciers move by?

Answer 13

• Internal flow
• basal sliding

Question 14

what happens during internal flow?

Answer 14

after the crystal axis align, they can mold and ooze past one another.

Question 15

Is internal flow fast or slow?

Answer 15

slow - molecule to molecule movement

Question 16

Is Basal sliding a slow or rapid process?

Answer 16

rapid

Question 17

basal sliding happens as a result of ____ moving against the ground surface below it.

Answer 17

ice

Question 18

the movement of ice against the ground surface creates ______ which produces _____ which causes ____

Answer 18

friction, heat, melting.

Question 19

As melt water accumulates at the basis of a glacier it acts as a _______ for the glacier to slide down on top of

Answer 19

lubricant

Question 20

Glaciers are the most powerful _____ of erosion

Answer 20

agents

Question 21

Glaciers can pick up large rocks from the ground and _____ them to different locations

Answer 21

move

Question 22

Glaciers erode efficiently by…

Answer 22

• filing rock surfaces smooth
• Plowing rocks from the ground
• Transporting sediments

Question 23

How are rocks filed and plowed by glaciers?

Answer 23

• rock fragments are carried within the glacier
• Near the base, rock fragments scrape the ground

Question 24

Near the base, rock fragments ______ the ground.

Answer 24

scrape

Question 25

What happens to rock fragments near the ground?

Answer 25

they scrape the ground

Question 26

When large rock fragments scrape the ground they cause...

Answer 26

glacial striations

Question 27

rock fragments at the base of a glacier can rub and scratch ______ into the rocks that they are moving over.

Answer 27

grooves - called glacial striations

Question 28

Glacial Striations help us understand the _______ that glaciers moved over the surface

Answer 28

direction

Question 29

What are the four distinctive land marks that mountain glaciers produce?

Answer 29

- cirques - arete - Horns - U-shaped valleys

Question 30

What are cirques?

Answer 30

bowl-shaped depressions at the head of the glacier.

Question 31

\_\_\_\_\_\_ are sharp ridges between valleys

Answer 31

aretes

Question 32

what are horns?

Answer 32

pyramidal peaks from which a number of valley glaciers descend

Question 33

How are horns developed?

Answer 33

when cirques are cut out on all sides of a mountain

Question 34

Glaciers ______ a lot of sediment

Answer 34

deposit

Question 35

what is the main feature that distinguishes glacially deposited sediment from sediment that is deposited by streams or wind?

Answer 35

sediment deposited by glaciers is not sorted

Question 36

When glaciers pick up sediments they pick up different ______ sediments and move them \_\_\_\_\_\_

Answer 36

sized, together

Question 37

The sediment deposed by glacial erosion is \_\_\_\_\_.

Answer 37

unsorted

Question 38

Unsorted rock and sediment is called \_\_\_\_

Answer 38

till

Question 39

What is glacial till?

Answer 39

Unsorted rock and sediment

Question 40

what is a distinct glacial depositional feature?

Answer 40

Moraines

Question 41

What are moraines?

Answer 41

narrow ridges of deposited materials

Question 42

How are moraines categorized?

Answer 42

They are given different names according to where they form in the glacier

Question 43

\_\_\_\_\_ moraines form along the sides of a glacier

Answer 43

lateral

Question 44

Where do lateral moraines form?

Answer 44

along the sides of a glacier

Question 45

Where do terminal moraines form?

Answer 45

at the end of a glacier

Question 46

Converging glaciers leave a ridge of till called a _____ moraine

Answer 46

median

Question 47

Where do medial moraines form?

Answer 47

in the middle of a glacier, especially when two glaciers combine

Question 48

What are two other depositional glacier features?

Answer 48

- Kettle lakes - eskers

Question 49

what are eskers?

Answer 49

raised beds that are formed underneath the glaciers by sediment left behind from meltwater streams in a glacier's body

Question 50

How are kettle lakes formed?

Answer 50

As glaciers dig out pockets of ground those pockets fill with water from the trapped ice left behind in the deposited till/outwash

Question 51

Kettle lakes form as glaciers dig out pockets of ____ and then those pockets fill with \_\_\_\_

Answer 51

ground, water

Question 52

Trapped ice left behind in the deposited till creates _____ \_\_\_\_

Answer 52

kettle lakes

Question 53

Melt water streams in a glacier's body leave behind sediment in a raised bed called an \_\_\_\_\_\_.

Answer 53

esker