Glaciation

Question 1

ICE SHEET SCORING

Answer 1

the action of an ice Sheet / glacier in eroding the land due to englacial till

Question 2

MORAINE - Lowland depositional landform

Answer 2

Landforms associated with deposition of angular / unsorted till from within, on top or below a glacier

Question 3

TILL

Answer 3

Unsorted glacial sediment derived from erosion and entrainment of material by glacial movement

Question 4

TERMINAL MORAINE

Answer 4

Snout of glacier and shows the furthest extent of the advancing glacier

Question 5

RECESSIONAL MORAINE

Answer 5

Same characteristics as terminal moraine but does not show the furthest extent due to periods of stability allowing a second ridge to accumulate at snout of glacier

Question 6

GROUND MORAINE

Answer 6

Subglacial till

Question 7

LATERAL MORAINE

Answer 7

High and almost symetrical ridge formed along the outer edge of glacier and can be several meters high

Question 8

Medial Moraine

Answer 8

Lateral moraine from two glaciers join, leaving a line of debris in the center to form a low ridge

Question 9

DRUMLIN

Answer 9

Formed when a glacier moves over moraine in a valley as it cant entrain/erode but smooths top as it travels over. « Oval Shaped Hills»

Question 10

DRUMLIN - Features

Answer 10

Blunt end facing upstream, gently sloping tail downstream. Usually occur in clusters on flat valley floors or lowland plains in previously glaciated regions

Question 11

GLACIAL DEPOSITS

Answer 11

• Unstratified
• Unsorted (striations from plucking)
• Angular (physical weathering + erosion)

Question 12

FLUVIOGLACIAL DEPOSITS

Answer 12

• Stratified (layers due to seasonal variations in sediment accumulation / meltwater discharge)
• Sorted (meltwater loses energy)
• Smooth / Rounded (attrition)

Question 13

OUTWASH PLAIN

Answer 13

Largest material first as finest material travels furthest along the plain

Question 14

ESKERS - Ice contact

Answer 14

A curvy ridge of deposited material roughly parallel to valley sides. Discontinuous hills formed by subglacial streams carrying sediments

Question 15

KAMES - Ice contact

Answer 15

A mount of sediment deposited at the snout of a retreating glacier that form on the ice surface

Question 16

KAME TERRACE

Answer 16

Ridge on the valley sides resulting from the infilling of a marginal glacial lake

Question 17

ERRATIC - Lowland Depositional landform

Answer 17

large boulder different to the bedrock it’s on, transported + deposited by a glacier far from origin when the glacier ice melts - give clues to origin of ice and direction of ice movement

Question 18

Till plain - Lowland Depositional Feature

Answer 18

Created by melting of a large ice sheet detached from a glacier.

Angular unsorted till is often divided into:
- Lodgement till (dropped by moving glaciers)
- ablation till (dropped by stagnant or retreating ice)

Question 19

Till fabric analysis

Answer 19

the study of the orientation and ‘plunge’ of rock fragments within a till deposit can suggest direction of ice flow at the time of deposition - studies involving 50 or more rock fragments, conducted at several localities, provide glaciologists with evidence of ice-flow patterns - especially in association with other evidence e.g. erratic and drumlin - orientation

Question 20

What is Pleistocene Glaciation?

Answer 20

Geological period from 2 million years to around 10,000 years ago. 1/3 of lands surface during , whereas currently only 10%

Question 21

Short term causes of climate change

Answer 21

• ↑ in greenhouse gases enhanced greenhouse effect (agriculture/ industry/ deforestation)

• Changes in the Earth’s reflectivity / albedo effect

• Volcanic Activity - ash clouds (colder - higher albedo) and greenhouse gases (hotter) emitted from the volcano

Question 22

Long term causes of climate change

Answer 22

• Sunspots - sun isn’t uniform in the amount of energy it releases - 11 year cycle (variations in solar output from sun)

• Milankovitch cycles

Question 23

Long term evidence of climate change … Antarctic ice cores

Answer 23

bubbles trapped in ice can be assessed for their oxygen isotopes. Ice cores show low CO2 through cool periods + high CO2 in warm periods

Question 24

Glacial trough - Lower land glacial erosional landforms

Answer 24

steep-sided, flat-bottomed, deep valleys

normally straight due to the power + inflexibility of the glaciers

abrasion through basal slip (plucking also takes place

Question 25

Ribbon lakes - Lowland glacial erosional landforms

Answer 25

deep and narrow lakes

resulting from localised over deepening of valley floor due to enhanced erosion that is caused by weaker bedrock + thicker ice (possibly from merging of tributary glacier increased ice mass) allowing increased vertical erosion

Question 26

Hanging valleys - Lower land glacial erosional landforms

Answer 26

smaller, tributary valley left ‘hanging’ above the main glacial trough, often containing a waterfall

Question 27

Truncated spurs - Lower land glacial erosional landforms

Answer 27

Areas of land rounded at the top with steep sides formed when glaciers are unable to flow around existing interlocking spurs so cut straight through them