Last Look

Question 1

Formation of corries

Answer 1

• diagenesis
• hollow formed by nivation
• GPE, relief of land and meltwater result from friction = glacier moves downhill
• bc of hollow and overlying pressure glacier moves rotationally
• ice freezes back to wall
• weathering: plucking and freeze thaw takes place = debris into glacier supra, en and sub glacially and bergschurd crevasses
• sub- debris abrades hollow = kinetic energy and friction
• pressure melting point exceeded = water sub-glacially = basal slippage
• steep back wall growth via increased weathering from bergschurd crevasses
• front of glacier thins as it gains speed from moving down valley
• as G retreats leaves debris as lip = natural dam = Corrie tarn

Question 2

Formation of Roche moutonnée

Answer 2

• mass of resistant rock
• smooth rounded end = stoss and faces the direction of the ice
• lee = direction of plucking
• pressure melting point occurred as ice passes over obstacle on glacial bed
• material plucked from lee side
• ice refreezes on down side as less pressure and plucks rock as it moved
• striated surface created by abrasion from moraine sub-glacially

Question 3

Mass movement

Answer 3

• occurs when GPE and friction are working against each other against material on a slope
• main processes involved: rock fall and slides

Question 4

Nivation

Answer 4

• Process including freeze-thaw action, solifluction and chemical weathering
• responsible for enlargements of hillside hollows

Question 5

Rock fall

Answer 5

• physical weathering causes debris to fall at foot of the slope under gravity
• transport processes remove this material or may accumulate as scree slope

Question 6

Slides

Answer 6

• Occur due to steepening or undercutting of valley sides by erosion at the base of the slope
• Slumps common in weaker rocks

Question 7

The deforming bed model

Answer 7

• widely accepted
• forward motion of ice achieved by deformation of the soft sedimentary bed
• if sediments of the bed are weak they may deform as a result of the stress imparted by overlying ice
• if layer varies in strength then more resistant portions will deform less remaining static
• explains the cores of drumlins surrounded by more easily deformed till responsible for streamlining
• explains folds and thrusts

Question 8

The cavity-fill meltwater model

Answer 8

• views drumlin’s as meltwater erosion and deposition as consequence of large floods beneath the ice
• regional scale outburst floods from central regions of the ice sheets = sheet flows of water
• wide and deep enough to separate the ice from its bed
• water eroded during the flood stage eroding the drumlin shaped under the ice and fills with sediment as flood wanes as ice presses down onto its bed
• explains how fluvially derived sediments may appear in drumlins

Question 9

Formations on pattered ground

Answer 9

Patterned ground

• Relict polygons are a result of the cracking of permafrost -> Evidence of past periglacial conditions
• Frost contraction via gravity causing ground to crack then large rocks fall into the cracks
• frost cracking = expansion & contraction
• Frost heave and sorting

Question 10

Open system pingos

Answer 10

• Landscape before pingo
• Active layer freezes the water in the talik trapped between the permafrost and active layer creating an ice lens
• Water migrates to the lens due to hydraulic pressure & on contact freezes the water = swelling the size of lens.
  = Ground cracks appear where surface ruptures

Question 11

Closed system pingos

Answer 11

• Found on the small lakes, flat low lying areas in continuous permafrost
• Water is enclosed between freezing surface and permafrost
• Permafrost advances during colder periods and ice forms
• Ice lens increases due to hydrostatic pressure
• Lake sediment is pushed up into the dome shaped pingo
• Expansion = ruptures in the surface which may lead to pingo collapse
  EX Mckenzie type from delta region of Mackenzie river in Canada

Question 12

overland flow

Answer 12

transfers water through the basin either as sheetwash, across the surface, or in tiny channels called rills.

Question 13

saturated flow

Answer 13

when the combination of precipitation intensity and duration (and run-on from higher areas) saturates the soil and raises the water table to the surface.

Question 14

natural sequestion

Answer 14

the process of storing carbon dioxide (CO2) in underground geologic formations

Question 15

carbon management techniques

Answer 15

afforestation - planting trees
wetland restoration - Johns River Upper Basin Project’s
improving agricultural practices
reducing emissions - carbon trading and international agreements

Question 16

short term changes

Answer 16

diurnal - within a day change 
seasonal - increase P etc = flooding
changes of climate 
temperature
foliage 
sunlight - controlled by intensity of solar radiation

Question 17

could forms when

Answer 17

water molecules aggregate (join)

frequently at altitude where dew point occurs

Question 18

the collision coalescence theory of precipitation

Answer 18

• water droplets collide against via conventional currents
• initial small droplets are kept suspended in cloud until large enough to drop
• once they coalesce they’re unable to be suspended
• when falling droplets are ripped apart by conventional currents and air friction = rainfall
• most applies to convectional clouds in tropical areas

Question 19

the Bergeron Findeisen theory of rainfall

Answer 19

• supercooled water and ice crystals exist together
• water vapour around ice crystals have no time to condense = straight to a solid, freeze and merge
• ice crystals becomes heavy and falls experiencing warm temperatures and melt as rainfall
• cumulonimbus clouds focused, finals to apply tropical areas