Glaciation Flashcards
(23 cards)
Glacial landforms
Erosional
- Glacial troughs (Snowdonia - Nant Ffrancon)
- Pyramidal peaks (Snowdonia - Mt. Snowdon, 1085m)
- Corries (Snowdonia - Cwm Idwal)
- Ellipsoidal basins (Minnesota - erosion in Arrowhead region)
Depositional
- Drumlins
- Moraines
- Erratics
Periglacial landforms
Pingos
Patterned ground
Thermokarst landscapes
Glaciofluvial landforms
Kames
Outwash plains
Eskers
Impact of geology on glaciated landscapes
Lithology (chemical and physical composition of rock)
- Weaker lithology = less resistance to erosion
- Faster formation of erosional formations
Structure (properties of rock: joining, bedding, faulting)
- High permeability creates water channels (more freeze-thaw)
Impact of relief and aspect on glaciated landscapes
- Impact the microclimate
- Slopes facing away from the sun are likely to stay colder so have a positive mass balance
- More mass = more GPE
- Steeper relief also = more GPE
Impact of latitude on glaciated landscapes
- Drier, colder climate 66.5 degrees and above so ice sheets form
- More input and output in dynamic valley glaciers at lower latitudes
- Laurentide ice sheet thinner in the south
Impact of altitude on glaciated landscapes
- Temperature decreases 0.6 degrees per 100m of altitude
- May experience more relief precipitation
Impact of climate on glaciated landscapes
- Wind is a moving force (AEOLIAN PROCESS)
- Increases erosion, transportation, deposition
- Precipitation
- Temperature
- Warm-based vs cold-based glaciers behave differently
Periglacial landscape example
Prudhoe Bay, Alaska
Human activity occurring in periglacial landscape
Oil drilling and burning
Impacts of human activity on processes and flows of material/energy (periglacial)
[3]
- Increased heat produced by buildings (urban heat island effect)
- Solifluction (0.5-5cm/yr)
- More precipitation (due to climate change) = more insulation of ground and less permafrost regeneration
Effect of impacts of human activity (periglacial)
[4]
- Permafrost melting/thickening of active layer
- Disrupts migration routes
- Damage to local housing
- Contributes to global warming
Human activity on glaciated landscape example
Grande Dixence, Switzerland
- Fed by 35 glaciers
Human activity occurring in glaciated landscape
Dams/HEP
Impacts of human activity on processes and flows of material/energy (glaciated)
- Reduced river discharge
- Risk of flooding when purged
- Excess energy downstream due to lack of suspended sediment
Effect of impacts of human activity (glaciated)
- Higher concentration of pollutants (agricultural/domestic) in the Borgne River
Geomorphic processes
- Nivation (Formation of hollows due to erosion AND weathering)
- Mass movement
- Plucking
- Weathering (Chemical, biological, freeze-thaw)
- Deposition
- Transportation
- Abrasion
Snowdonia geology periods
Cambrian - sedimentary rock
Ordovician - igneous rock
Devonian - metamorphic rock (shale->slate)
Quaternary - erosion of existing rock
Minnesota PSF
[4]
- Laurentide ice sheet
- Present until end of last glacial (11,000 years ago)
- 4 lobes (Rainy, Superior, Wadena, Red River)
- Eagle mountain 701m tall
Permeability
Channels through the rock
Porosity
Concentration of air pockets/pores within the rock
E.g. Basalt has a high porosity
Strategies to minimise impacts of human activity on periglacial landscapes
- Gravel pads
- Raised pipelines
- Specialised computers to find oil pockets
Strategies to minimise impacts of human activity on glaciated landscapes
- 10% of total water is used to purge sediment and prevent blockages
- Only essential infrastructure has been built
- Infrastructure is primarily underground
