Geog Final Exam PDF

Test 4 (lec 11 and 12) mass movements,glacials 86 marks 32 q 1.​ Drag and drop 6 marks mass movements 2.​ 3 marks-drag and drop-glacial geomorphology 3.​ Essay style- 3 marks -mass movements 4.​ Matching drop down arrow- 3 marks- glacial geomorphology 5.​ 5 marks matching - glacial m...

Test 4 (lec 11 and 12) mass movements,glacials 86 marks 32 q 1.​ Drag and drop 6 marks mass movements 2.​ 3 marks-drag and drop-glacial geomorphology 3.​ Essay style- 3 marks -mass movements 4.​ Matching drop down arrow- 3 marks- glacial geomorphology 5.​ 5 marks matching - glacial morphology 6.​ 5 marks- matching -mass movements (type,diagram) 7.​ 4 marks drop down arrow-physical and chemical changes 8.​ 4 marks drop down arrow sea level changes 9.​ Drop down arrow - 6 marks - mass movements 10.​Drop down arrow 6 marks weathering 11.​Mc 1 mark glaciers 12.​1- glaciers 13.​1- glaciers 14.​1-glacials all 15.​Mc--photo lec notes*-weather 16.​Fill in the blank--photo lec notes*- mass movements - 17.​Fill in the blank - photo based-glaciers 18.​ Tof -weathering 19.​T o f -contents of rissa quick slide (why did this slide occur, and why it occurred there and why those formation occur where they do) 20.​T o f -contents of rissa quick slide 21.​ Essay style- mass movements *photo*-4 marks 22.​Essay style-photo -3 marks - mass movements 23.​Matching - 5 marks - periglacial and permafrost geomorphology 24.​Matching - 5 marks - periglacial and permafrost geomorphology 25.​Mc-permafrost 26.​Mc- permafrost 27.​Mc- permafrost 28.​Mc-permafrost 29.​1 mark - fill in the blank-permafrost - term 30.​Tof - 1 mark-permafrost 31.​Tof - 1 mark-permafrost 32.​Tof - 1 mark-permafrost Mass movements and intro to glaciers Slides vs slumps- how to differentiate between them ​ Slides: movements along one or more discrete failure surface ​ Slump: failure surface is deep and curved ​ Rock slide: failure along a flat plane parallel to the ground ;occurs where bedding planes and slopes dip in the same direction ○​ Occurs 5 times a century in the canadian cordillera (e.g turtle mountain and frank) ​ Debris slide: failure of unconsolidated material on the plane parallel to the ground Falls -rapid mass movements Rock fall: ​ vertical or near ventricle movement of particles through air ​ produces talus at the base of the slope ​ caused by freeze thaw weathering Blockfall ​ vertical movement of an entire piece of slope ​ Occurs most often in frozen sediments undermined by thermal erosion Glacier ​ A mass of ice originating on and by teh recryslistiizatition of snow or other forms of solid precipitation and showing evidence of past and present movement ​ Powerful agent of geomorphic change ​ 77% of freshwater is locked up in glaciers (only 2.78% of water on earth is freshwater) ​ Nutrient release from rocks Sea level and glaciers  ​ Glacier contribute to changes in sea level ​ -Eustatic sea level change -change in volume of water ​ -isostatic sea level change- change in land position ★​ Formation of glaciers → eustatic sea level fall ★​ Continued growth of glaciers → isostatic sea level rise due to ground depression of weight on ice ★​ Glaciers begin to melt → eustatic sea level rise ★​ Further decline of glaciers → isostatic sea level fall as land rebounds from the weight if glacier being removed Formation of glacial ice ​ fresh snow compacts and undergo freeze-thaw to become more dense firn (600-700 kg/m3) ​ it continues to freeze thaw and compact to glacial ice Types of glaciers Continental ​ Ice sheet -large areas,unconfined due to gravity ,ex; greenland ​ Ice caps - largely affected by climate change, they are unstable not constrained,smaller than ice sheets (= 80% CaCO3 and have jointing -​ Climate- precip ,temp. -​ Vegetation increases CO2 in regolith Ex; caves,tower karst In general ; ​ physical /mechanical weathering dominates in drier,cooler climates ​ Chemical weathering dominates in moisture,wetter climates ○​ why? ​ But they are inseparable and each tend to accelerate the other Slide 23* Lecture 19 nov 20th 1 of 3 processes of denudation- exogenic process that happens after endogenic processes Benefits of weathering- easiest to understand, this is how we surface modify stuff ​ Produces parent material for soils: clay silt, sand and gravel ​ Releases nutrients and produces minerals Mass movement- movement of surface material under the influence of gravity ​ Now that surface rock is weakened, transformed, and/or in smaller fragments through physical and chemical weathering... ​ More susceptible to the pull of gravity! Mass movement/mass wasting: the processes by which a body of material is moved downslope under the influence of gravity This is different from erosion ​ Transport processes do not usually involve incorporation by water, air or glacier ice. These may reduce strength of soil and rock & contribute to plastic and fluid behaviour of soils ​ Differentiate the differences between the types of mass movement (HINT) Gravity: a force created by the mass of objects Opposite force of gravity = normal force  We calculate these numbers using trigonometry Testable: describe the diagram or fill in the blank of the missing elements, understand what this is used for and how we calculate slope ​ As we increase the angle of the table, the object would start sliding cause the FP gets larger and larger as the table gets steeper ​ Definition of forces is also testable (HINT) Forces ​ Fp is the component of gravity acting parallel to the slope ​ Ff is the force that resists movement ​ As slope increases Fp becomes greater as does Ff ​ Fp = Ff provided there is no movement ​ Ff depends on object and surface material- this is why things slide on some surfaces and not others  ​ Once a critical angle (max angle at which the object will not slide) is reached failure occurs ​ Slope=90°then Fp =Fg Driving force: Gravity Resisting force: Friction (HINT) Angle of repose: Steepest angle that can be attained by loose material without moving downslope (typically 33° – 37°) ie., angle at which sliding ceases àFriction balances gravity Angle of sliding friction: (HINT) Angle at which dry, unconsolidated material(ex; sand in a sandbox) fails ie., angle at which sliding commences Factors influencing angle of repose and sliding friction 1.​ Size 2.​ Shape 3.​ Sorting 4.​ Water content Landslides happen when thing exceed the cohesion limit and then If we consider a slope as a whole, we replace the term force by stress (which is simply force per unit area) (Pressure). We want to be able to understand when things are going to fail Thus Ff =Fp = Fn tan θbecomes the Coulomb equation (1773): S=Ђ=Sn tanФi+C Objects lose shear stress through time due to weathering ​ S is the shear strength (the force trying to stop failure and resisting movement) ​ Ђistheshearstress(the force trying to cause movement) ​ Sn is normal stress (as slope increases Sn gets lower, this force acts at right angles) ​ Фi is the angle of internal friction (this is a property of the slope and materials) ​ C is cohesion (how sticky it is) Important to know: what does the equation do? Allows us to figure out weather or not the slope will fail and know the different properties Effects of water  ​ If S = Ђ then there is no movement ​ Water affects soil cohesion (low when very dry; low when saturated; high when pores are partly full and under suction) Not completely dry and not completely saturated= max cohesion Taking into affect water: S = Ђ = (Sn – Sp) tan Фi + C ​ Where Sp is the pore water pressure ​ This modified equation explains why landslides often occur follow heavy rains ​ In this equation C is not constant and follows Sp ​ Water affects the normal stress (Sn) as particles are supported by water (buoyancy) ​ We want to understand that this is variable and how likely something is to fail ​ Understand the role of water in effecting this equation Factor of safety (HINT) ​ Factor of safety = S / Ђ ​ Factor of safety = Shear Strength / Shear Stress ​ If FoS ≥ 1, slope is stable ​ If FoS < 1, slope is unstable ​ FoS will change through time Understand difference between shear strength and stress Initiation of movement (trigger) ​ Precipitation ​ Weathering ​ Earthquakes ​ Changes in loading ​ Changes in slope (undercutting) river is an example of this ​ Vegetation changes- clear cutting or forest fire Know the triggers HINT You can change slope angle and profile to mitigate harm of slope failure Mass movements Discontin Difference in major morphology and differences in flows and types as well as the specifics in each category Slow mass movements Discontinuous creep​ Ratchet-like movement due to soil expansion and contraction ​ Movements are shallow (generally 100 m lower during peak of last ice age) 1) Isostatic sea-level changes: related to land ‘position’ (HINT) 2) Eustatic sea-level changes: related to water volume (HINT) Environmental significance of glaciers Sea level and glaciers: ​ Glaciers store water in a alternative source ​ Seal levels are gonna decrease ​ And sea water is gonna be saltier when glaciers are formed ​ The pressure of the glacier causes the ground to fall (isostatic sea level change) ○​ (HINT) ​ 1) Formation of glaciers and ice sheets: eustatic fall in the sea ​ 2) Further growth of ice sheets isostatic depression of land, ​ 3) The ice sheets melted (increasing the volume of water in the ocean) eustatic rise in the sea level ​ 4) Decline of ice sheets and glaciers sea level is increasing because glacial ice is falling into the ocean which rises sea level- isostatic uplift of the land, decreases sea level but at the same time, continuing eustatic rise in the sea level. Air is a paleoclimatological tool that tells us how were able to tell that the atmospheric co2 levels are different than present Formation of glacial ice  ​ First year snow lots of air – not dense (50 - 300 kg/m3 ) ​ Subsequent years snow is compacted freeze/thaw, water makes it more dense firn (600 - 700 kg/m3 ) ​ Compaction and freeze/thaw eventually forms dense glacial ice (850 kg/m3 ) Pure glacial ice: blue because it absorbs everything but shortwave lengths Main canadian glaciers ​ The cordillera regions ​ Glacier on baffin island ​ Queen elizabeth islands - largest place with glaciers 2 major types: continental vs. alpine Variety of sizes, shapes, amount of ice Types of glaciers Continental glaciers: Ice sheets ​ Collapse of these glacier have dire consequences on climate ​ They operate is a spreading centre ​ Extensive areas ​ Ice covers topography ​ Unconfined flow due to gravity ​ Laurentide Ice Sheet ​ E.g., Greenland, Antarctica Ice caps ​ Also not constrained: ice covers underlying topography ​ Smaller than ice sheets 90% coverage) ​ Often very high latitude ​ Ex; ellesmere island Discontinuous permafrost ​ Two types Extensive (50-90% coverage) & Sporadic (10 – 50% coverage) not connected. ​ Mid (upper) latitudes or high mountains ​ Ex; wolf creek Mountain (Alpine) permafrost ​ Refers to permafrost which is present at high elevation sites but absent from adjacent lowlands and valleys. ​ Controlled by microclimates ​ Ex; castle reign/top of mount hag Sub sea permafrost ​ Relict from times when sea levels were lower ​ Maintained because the temperature of sea water is depressed (-2°C) Controls on Permafrost ​ So why is permafrost able to exist in the various zones? ​ Continuous (very low temperatures [