Glaciation

Question 1

Cold based glaciers (movement + example)

Answer 1

Meserve Antarctica 3m per year
Internal deformation:
Granular flow
Laminar flow

Question 2

Warm based glaciers (movement + example)

Answer 2

Mer de glace 300m per year
Basal sliding:
Slippage
Creep
Ground deformation

Question 3

Glacial budget/mass balance

Answer 3

Balance between amount of inputs and outputs

/total accumulation or loss

Question 4

Patterned ground

Answer 4

As hydrostatic pressure increases in the ground, the moisture within the ground begins to freeze and rise forming an ice lens, this ice lens grows, due to capillary action attracting more, it begins to push stones up (that are already in soil above it) this is due to their specific heat capacity, smaller sediment in soil will fill the gap left by rising soil, preventing it from falling back down, the stones now poke out of the ground, larger ones may fall due to gravity, finer sediment is left at the top

Question 5

Closed Pingo

Answer 5

Closed system - lake
lake insulates talik beneath, surrounded by permafrost
In winter lake freezes, talik no longer insulated, due to artesian pressure water is attracted together in talik then freezes and forms ice core, this rises and creates a bump
EXAMPLE: Mackenzie delta, Canada (home to over 1400 pingos)

Question 6

Open Pingo

Answer 6

Open system - Patch of talik in discontinuous permafrost, artesian pressure means water migrates to talik, talik freezes into ice core and rises
EXAMPLE: East Greenland

Question 7

Ognip

Answer 7

Collapsed pingo, due to thawing of ice core, can leave lake and restart process

Question 8

What factors can influence a glacial landscape system

Answer 8

Anthropogenic activity
Climate
Aspect / relief
Latitude / Altitude
Geology

Question 9

Fluvio-glacial

Kames and eskers

Answer 9

Eskers are sediment in subglacial tunnels (underneath glacier) when glacier retreats looses energy and drops load in long sinuous (winding) line of material

Kames are material in supra-glacial tunnels (on top of glaciers) drops as mounds of discontinuous material

This material is sorted and stratified, found in Canada

Question 10

Corries

Answer 10

EXAMPLE: coire an t-sneachda
Corries are an accumulation of snow in a pre-existing hollow on the side of a mountain, nivation deepens hollow due to abrasion and pressure, plucking of back wall, formation of corrie lip from rotational flow, can leave tarn lake behind, faces away from sun

âretes - two back to back corries, narrow edge = Striding edge in USA
Pyramidal peak - two or more back to back, creating point = Matterhorn, Switzerland

Question 11

Troughs - U-shaped valley

Answer 11

EXAMPLE: Yosemite valley
For V-shaped valley, glaciers based through erodes interlocking spurs forms truncated spurs, sometimes have misfit streams which are tiny rivers too small for the valley

Question 12

Roche Moutonee + striations

Answer 12

A mound with a smooth long side and a short jagged side, formed by advancing glaciers over rock and plucks jagged side, typically made of schist/granite or resistant rock
Pressure melting point of smooths side, makes it smooth as melting helps

Question 13

Erractics

Answer 13

EXAMPLE: Yorkshire dales
A piece of rock from pebble to boulder which has a different geology to surrounding area, depositional landform
deposited by glacier after it moves, supra-glaical debris, plucking or rockfall

Question 14

Drumlins

Answer 14

3 main theories to formation
1. Re-advance over pre deposited material
2. re-erosion by meltwater
3. Core of resistant rock under glacier
Pear shaped lump caused by the re-erosion of pre deposited material
swarm in called a basket of eggs
EXAMPLE: Central Wisconsin

Question 15

Till sheets

Answer 15

When an area of a glacier or ice sheet detaches from main glacier melts in place dropping sediments it was carrying over large area.

Question 16

Morainnes

Answer 16

Terminal - end of snout, start of retreat
lateral - scree form mountain sides and eroded material form glacier against mountain sides
Recessional - end of retreat
Medial - when two glaciers meet making the two lateral moraines meet
Ground moraine - gradually dropped between terminal and recessional moraine

Question 17

Prudhoe, Alaska

Answer 17

Oil extraction site, proven reserves of 3000 million barrels, 1300km pipeline form Alaska into Valdez transports 1.4million barrels a day
Alaska became a part of USA in 1867, since 2014 demands risen, 40% oil is imports (political implications are lack of energy security)

Processes and flow =>
Palmer gravel extraction - ground water fell over a meter 2km away from site
Barrow urban heat island - Urban area 2.2C higher than surrounding rural area, 9% fewer days that are around 0 degrees, also melts active layer further
Gas flaring - Burning of drilling gases released, methane and CO2, necessary due to build up of gases can lead to explosions

Impacts
Changing landforms - eg. solifluction
Active layer is seasonal, but rising temps means that longer melting period and therefore permafrost can melt, this can results in subsidence (sinking of the ground) and increased mobility of the active layer, possibly resulting in solifluction the downslope movement of the thawed active layer

Thermokarst - eg. Alases
A landscape dominated by large surface depressions due to thawing of ground, distinguished by water logged hollows which can form shallow lakes 1-2km wide
On a larger scale these are alases flat floored steep side, 100m-15km long
several combined = alas valley

Question 18

Minnesota

Answer 18

Quaternary period, 2 million years ago, most recent advance was Wisconsin glaciation around 100k-10k years ago
Minnesota part of Laurentide ice sheet (covered most of Canada)
Oldest rocks of sedimentary rock and volcanic rock formed of 2,700 million years ago
Tectonic activity led to formation of massive mountains, however ice sheet eroded it to mountains only 500-700m high
Ice sheet was 1km thick in some places
A large ellipsoidal basin was also created, leading to thousands of proglacial lakes formed, including lake Agassiz
Wadena lobe, deposited red till and Alexander moraine
Des Moines lobe deposited tan till from NW
Prairie coteau = terminal moraine

LAKE AGASSIZ - proglacial lake, a small part occupied red river valley of Minnesota
Glaciers to the north blocked its natural drainage
Covered 400,000km2, nearly size of current day Spain, same as present day black sea
drainage river = river Warren
when drained left behind fertile silt deposits, making rich farmland in red river valley

Question 19

Cairngorms

Answer 19

Influential physical factors - climate, aspect, geology, latitude and latitude
Formed around 425 million years ago, Britians largest single area of Granite (which formed 400million years ago)
22,000 years ago once sheet covered all of Scotland during peak glaciation => 16,000 years ago most of the melting creating dramatic landscape
Granite hills are smooth and rounded domed tops, schist hills are craggier (rough) due to being less resistant, granite formed UKs highest plateau above 1000 meters
Varying geology, some weaker rock = dramatic landscape
Over past 2.5 million years of the Pleistocene glaciation, glaciers advance + re-advance
400m deep valleys and corries
most recent glaciation = loch lomand stadial around 12k years ago

Specific landforms:
Lairig Ghru = Distinctive valley stretching 14km through cairngorms
Coire an-t sneachda = formed by numerous glacial advances, 400m cliff for its backwall
Glen avon = U shaped valley, 300m cliffs at end
Lock avon = Ribbon lake
Drumochter - swarm of drumlins at base of U-shaped valley, 5m high, 30km long

Question 20

Inter-relation

Answer 20

Eg. volcanoes to tectonic activity/plate boundaries
Eg. Corries to glacial systems
the range of landforms within the characteristics landscape system