Glaciers

Front 1

Define: Firn

Back 1

snow that survived through the winter that converts to rounded ice grains

Front 2

If firn is buried deeper in the snowpack, it converts to _____ _____

Back 2

glacial ice

Front 3

Define: Glacier

Back 3

a massive, long-lasting mass of compacted snow and ice

Front 4

Where do glaciers form?

Back 4

land wherever the amount of snowfall in winter exceeds the amount melted in summer

Front 5

ice under pressure is _____ to glaciers flow _____

Back 5

plastic, downhill

Front 6

on level land, glaciers flow _____

Back 6

outward

Front 7

2 types of glaciers

Back 7

1. Alpine

2. Continental

Front 8

Define: Alpine Glaciers

Back 8

glaciers that form at all latitudes on high, snowy mountains

Front 9

Define: Continental Glaciers

Back 9

form at all elevations in cold polar regions

Front 10

What conditions form alpine glaciers?

Back 10

deep winter in snowfall and cool, short summers

Front 11

What conditions form continental glaciers?

Back 11

winters are very long and summers are very short

Front 12

The rate of glacial movement varies with 3 things:

Back 12

1. slope steepness

2. precipitation

3. air temperature

Front 13

2 ways glaciers move

Back 13

1. basal slip

2. plastic flow

Front 14

Define: Basal Slip

Back 14

the entire glacier slides over bedrock

Front 15

Define: Plastic Flow

Back 15

the ice flows like a fluid

Front 16

Define: Crevasses

Back 16

cracks in the brittle upper layer of a glacier formed by it moving over uneven bedrock

Front 17

Define: Ice Fall

Back 17

a section of a glacier consisting of crevasses and ice pinnacles

Front 18

Define: The Zone of Accumulation

Back 18

the higher level part of a glacier where the surface of the glacier is covered year round

Front 19

Define: The Zone of Ablation

Back 19

the lower part of the glacier, where more snow melts in the summer that accumulates in the winter

Front 20

Define: Snow Line

Back 20

the boundary between permanent snow and seasonal snow

Front 21

Define: Terminus

Back 21

where the glacier ends

Front 22

Define: Icebergs

Back 22

when a glacier extends into the sea and giant chunks of ice break off

Front 23

Define: Glacial Striations

Back 23

deep, parallel grooves and scratches caused by rocks embedded in the ice that scrape across the bedrock

Front 24

What do glacial striations show?

Back 24

direction of ice movement

Front 25

Define: U-shaped Valley

Back 25

a broad, round valley caused by a glacier scouring the sides and bottom of a valley

Front 26

Define: Cirque

Back 26

a horseshoe shaped depression in the mountainside

Front 27

Define: Tarn

Back 27

a small lake nestled at the base of a cirque

Front 28

How does a tarn form?

Back 28

as a cirque forms, a glacier may erode a depression in the bedrock and this may flood with water

Front 29

Define: Paternoster Lake

Back 29

a series of lakes below the cirque that are connected by waterfalls and rapids

Front 30

Define: Horn

Back 30

a steep, pyramid shaped rock summit

Front 31

How does a horn form?

Back 31

glaciers erode 3 or more cirques into different sides of a peak

Front 32

Define: Arete

Back 32

a sharp, narrow rib of rocks that lies perpendicular to the main mountain ridge

Front 33

How does an arete form?

Back 33

when 2 alpine glaciers erode both sides of a ridge

Front 34

Define: Hanging Valley

Back 34

a small glacial valley lying high above the floor of the main valley

Front 35

Define: Fjord

Back 35

a deep narrow inlet that extends inland

Front 36

Define: Drift

Back 36

all rock or sediment transported and deposited by a glacier

Front 37

2 categories of drift

Back 37

1. till

2. stratified drift

Front 38

Define: Till

Back 38

drift deposited directly by glacial ice

Front 39

Define: Stratified Drift

Back 39

drift that was first carried by a glacier and then transported and deposited by a stream

Front 40

Glacial transport doesn't ____ sediment

Back 40

round

Front 41

Define: Erratics

Back 41

boulders of a rock type different from the bedrock in the area

Front 42

Define: Moraines

Back 42

a mound or ridge of till

Front 43

Define: End Moraine

Back 43

sediment accumulated at the terminus forming a ridge

Front 44

Define: Terminal Moraine

Back 44

an end moraine that forms when a glacier is at its greatest advance before it retreats

Front 45

Define: Recessional Moraine

Back 45

a new end moraine formed when a glacier stabilizes again during its retreat and the terminus remains in the same place for a year or more

Front 46

Define: Ground Moraine

Back 46

formed when till is deposited in a thin layer over a broad area

Front 47

Define: Lateral Moraine

Back 47

sediment near the glacial margins

Front 48

Define: Medial Moraine

Back 48

a dark stripe on the surface of the ice when two alpine glaciers converge

Front 49

Define: Drumlins

Back 49

elongated hills

Front 50

What are drumlins usually made of?

Back 50

till

Front 51

Define: Outwash

Back 51

sediment deposited beyond the glacier terminus by a stream

Front 52

Define: Valley Train

Back 52

outwash deposited in a narrow valley

Front 53

Define: Outwash Plain

Back 53

sediment spread out from a valley into a larger valley or plain

Front 54

Define: Kames

Back 54

mounds of sediment deposited by streams at the margin of a receding glacier

Front 55

Define: Esker

Back 55

a long, sinuous ridge that forms as the channel deposit of a stream that flowed within/beneath a melting glacier