Produce a module summary on Canadian Shield region. This summary should highlight the major processes and landforms found in each region, and can be used as a review tool for the final exam. This sum

Page%|%1%%%MODULE'5:'CANADIAN'SHIELD'UNIT'2:'CLIMATE'AND'GLACIERS'Slide%1:%In%this%second%unit%of%Module%5%we%are%going%to%examine%the%various%climate%types%located%within%the%Canadian%Shield%physiographic%region,%as%well%as%the%most%recent%glacial%period%and%the%landforms%created%by%these%glaciers.%%The%large%spatial%arrangement%of%this%region%creates%a%unique%climate%region,%compared%to%the%previous%regions%we%discussed.%%As%well,%since%this%physiographic%region%was%created%a%long%time%ago%in%the%geological%past,%it%has%been%influenced%by%many%glacial,%as%well%as%other%geomorphic%processes.%As%we%progress%through%this%unit,%note%the%differences%and%similarities%within%this%region,%as%well%as%the%comparison%with%other%physiographic%regions.%Additional%readings%on%the%climate%and%glaciation%within%the%Canadian%Shield%region%are%provided%in%the%supplementary%information%provided%with%this%module.%%Slide%2:%The%red%box%on%this%figure%indicates%the%approximate%location%of%the%Canadian%Shield%physiographic%region.%%As%you%can%seen%this%region%is%dominated%by%three%main%climate%types%–%Dfc%(shown%in%the%teal%colour),%Dfb%(shown%in%the%light%blue%colour)%and%ET%(shown%in%the%grey%colour).%%These%correspond%to%a%subarctic%climate%(Dfc),%moist%continental%climate%(Dfb)%and%tundra%climate%(ET).%%These%climate%types%will%be%discussed%further%in%the%next%couple%of%slides.%%There%is%a%spatial%pattern%to%the%location%of%these%climates%–%the%moist%continental%climate%is%found%in%the%southern%portion%of%this%region,%the%subarctic%climate%is%located%northward%and%finally%the%tundra%climate%can%be%found%in%the%northern%areas%of%the%Canadian%Shield.%%This%spatial%pattern%is%primarily%a%result%of%latitudinal%influences%on%temperature;%higher%latitudes%will%receive%less%radiation%with%more%interannual%variability%compared%to%locations%at%lower%latitudes.%%This%is%exemplified%in%this%region%due%to%the%large%spatial%extent%in%a%northMsouth%direction.%%%% Page%|%2%%%Slide%3:%As%mentioned%in%the%previous%slide,%the%climate%in%the%Canadian%Shield%varies%and%this%variation%is%due%in%large%part%to%the%northMsouth%extent.%%In%the%northern%areas,%the%climate%is%characterized%by%very%cold%winters%(with%average%temperatures%of%M25%degrees%Celsius)%and%cooler%summers%(with%average%temperatures%of%10%degrees%Celsius).%%This%relatively%cooler%temperature%results%in%a%shorter%growing%season%(of%approximately%60%days),%influencing%the%type%of%flora%found%in%these%regions%(which%will%be%discussed%in%the%next%unit).%%Due%to%its%more%northern%latitude,%there%is%a%large%annual%pattern%in%the%incoming%solar%radiation%or%sunlight%reaching%this%area%–%with%high%amounts%in%the%summer%(approximately%18.5%hours%of%sunlight)%and%very%low%amounts%in%the%winter%season%(about%5.5%hours%of%sunlight).%In%the%southern%part%of%this%region,%the%climate%is%quite%different.%%Warmer%temperatures,%averaging%M8%degrees%Celsius%in%the%winter%and%22%degrees%Celsius%in%the%summer,%characterize%the%winters%and%summers.%%This%warmer%temperature%also%increases%the%growing%season%to%approximately%120%days.%%There%is%still%an%annual%pattern%in%sunlight%received%at%the%surface%(due%in%large%part%to%its%location%in%the%northern%hemisphere)%but%the%annual%range%is%much%smaller%than%in%the%northern%areas%of%the%region%–%winter%experiences%about%8.5%hours%of%sunlight,%while%the%summer%has%about%15.5%hours.%%More%sunlight%in%the%winter%but%less%in%the%summer%compared%to%the%northern%Canadian%Shield.%The%other%component%of%climate%is%precipitation.%%On%average,%200M300%millimeters%of%rain%falls%in%this%region%in%the%summer.%%Much%higher%amounts%of%precipitation%falls%in%the%winter%(in%the%form%of%snow),%with%average%values%between%1200%and%1500%millimeters.%%Slide%4:%As%you%may%have%noticed%on%slide%2,%most%of%the%Canadian%Shield%region%is%dominated%by%a%subarctic%climate.%%This%climate%type%is%found%mostly%in%the%upper%areas%of%the%middle%latitudes%(in%the%50s%and%low%60s%north%latitude).%%This%climate%type%is%characterized%by%long,%usually%cold%winters%and%short,%cool%summers%(as%discussed%in%the%previous%slide%and%shown%in%the%climographs%for%Churchill%Manitoba%and%Sudbury%Ontario).%%The%location%of%the%Canadian%Shield%in%the%middle%of%a%large%continent%creates%this%climate.%%It%is%away%from%large%water%masses%that%may%moderate%the%annual%temperatures.%%Even%though%Hudson%Bay%(a%large%water%body)%is%in%the%center%of%the%Canadian%Shield,%it%is%covered%by%sea%ice%from%approximately%November%to%July%each%year,%limiting%the%impact%it%would%have%on%the%climate.%%The%temperature%pattern%is%also%controlled%by%the%cold%continental%polar%and%Arctic%air%masses%that%dominate%the%region%for%most%of%the%year.%%Due%to%the%low%temperatures%in%the%winter,%the%soil%or%subsurface%water%may%freeze%creating%areas%of%permafrost%in%the%region.%%The%precipitation%in%this%climate%type%typically%occurs%in%the%warmer%months.%%This%again%is%shown%in%the%climograph%for%Churchill.%%Both%locations%shown%on%the%climographs%have%low%amounts%of%precipitation%(relative%to%lower%latitudes),%which%is%another%characteristic%of%the%subarctic%climate.%%The%pattern%of%precipitation%is%influenced%by%the%northward%progression%of%midMlatitude%cyclones%in%the%spring%and%summer%months;%these%storms%bring%with%them%precipitation.%%%%%% Page%|%3%%%Slide%5:%The%Canadian%Shield,%as%with%the%other%physiographic%regions%we%have%discussed%–%namely%the%Western%Cordillera%and%Interior%Plains,%is%also%influenced%by%a%moist%continental%climate.%%As%discussed%in%previous%modules,%this%climate%has%a%cold%winter%(with%temperatures%for%the%coldest%month%being%less%than%M3%degrees%Celsius)%and%a%warm%to%cool%summer%(with%the%warmest%month%having%temperatures%greater%than%10%degrees%Celsius,%but%less%than%22%degrees%Celsius).%In%terms%of%precipitation,%this%climate%type%receives%ample%precipitation%all%seasons.%The%climate%(both%temperature%and%precipitation)%is%controlled%by%midMlatitude%cyclones%that%form%along%the%polar%front,%typically%in%the%autumn,%winter%and%spring%seasons.%%%Slide%6:%The%tundra%climate%is%the%third%main%climate%type%found%in%the%Canadian%Shield%region,%and%as%with%the%previous%climate%type,%has%been%discussed%extensively%in%a%previous%module%–%the%Arctic%North.%%Locations%in%this%region%with%this%climate%are%typically%cold%year%round.%%The%average%temperature%of%the%warmest%month%is%below%10%degrees%Celsius%but%above%0%degrees%Celsius.%%Due%to%the%relatively%cold%temperatures%(on%average%9%months%below%freezing),%this%climate%type%typically%does%not%receive%large%amounts%of%precipitation%in%any%month,%with%annual%totals%less%than%250%millimeters.%%Slide%7:%Let’s%now%focus%on%the%glacial%influences%on%the%region.%%As%indicated%in%the%previous%unit,%the%Canadian%Shield%was%formed%a%very%long%time%ago,%and%therefore%the%environment%has%been%shaped%by%numerous%glacial%periods.%%Each%glacial%advance%and%retreat%has%modified%the%topography%and%influenced%the%climate,%hydrology%and%biology%of%the%region.%%For%this%course%however,%we%will%be%focusing%on%the%most%recent%glacial%period%during%the%Pleistocene%era,%as%we%have%done%with%the%regions%discussed%previously.%%Slide%8:%During%the%Pleistocene%glaciation%(approximately%18%thousand%years%ago),%the%Canadian%Shield%region%was%under%extensive%continental%glaciers.%%As%you%can%see%in%this%figure,%the%ice%mass%was%more%than%2000%meters%thick%at%the%height%of%the%last%glacial%period.%%%This%region%is%also%one%of%the%last%areas%in%North%America%to%be%covered%by%glacial%ice,%with%retreat%occurring%less%than%8000%years%ago%(compared%to%retreat%occurring%earlier%than%11,000%years%ago%for%the%Western%Cordillera%and%Interior%Plains%regions).%This%has%resulted%in%‘newly’%formed%glacial%environments%and%considerable%isostatic%rebound%(with%will%be%discussed%in%the%next%few%slides).%%%%% Page%|%4%%%Slide%9:%During%the%retreat%of%the%Laurentide%ice%sheet%(approximately%8,000%years%ago),%the%remaining%glacier%split%into%two%lobes%–%one%centered%over%QuebecMLabrador%(on%the%eastern%half%of%the%Canadian%Shield)%and%the%other%over%the%Keewatin%area%(on%the%western%part%of%the%Canadian%Shield).%%Prior%to%this%division,%a%large%proglacial%lake%(a%lake%formed%in%front%of%a%glacier%by%meltwater)%was%located%south%of%the%glacier.%%The%splitting%of%the%glacier%caused%this%lake%to%drain%forming%the%Tyrrell%Sea%over%what%is%now%Hudson%Bay%and%James%Bay.%%This%large%flooded%area%was%a%result%of%the%depression%in%land%that%occurred%due%to%the%immense%weight%of%the%ice%sheet%(causing%the%surface%to%be%depressed%by%more%than%250%meters%below%its%current%level).%%This%therefore%results%in%the%shoreline%being%pushed%inland%by%more%than%200%kilometers%(compared%to%present%day%location).%%Hudson%Bay%is%actually%a%relict%of%this%larger,%much%older%sea.%%%%Slide%10:%As%discussed%in%the%previous%slides,%the%glacier%over%the%Canadian%Shield%during%the%Quaternary%period%was%very%thick,%resulting%in%considerable%depression%of%the%crustal%material.%%Once%that%weight%was%removed%by%the%retreat%and%eventual%disappearance%of%the%Laurentide%ice%sheet%in%the%area,%the%surface%began%to%rebound.%%This%is%known%as%isostatic%rebound.%%As%you%can%see%on%the%map%on%this%slide,%the%Canadian%Shield%region%has%undergone%significant%isostatic%rebound,%with%the%largest%vertical%velocities%occurring%around%Hudson%Bay.%%This%region%is%still%undergoing%isostatic%rebound%at%a%rate%of%70%to%100%centimeters%per%century.%%After%the%retreat%of%the%ice%sheet,%the%isostatic%rebound%or%uplift%was%much%more%rapid,%occurring%at%a%rate%of%as%much%as%9%centimeters%per%year%(or%900%centimeters%per%century).%%%%Slide%11:%The%isostatic%rebound%that%was%discussed%in%the%previous%slide%has%resulted%in%very%significant%glacial%features%in%the%Canadian%Shield%region.%%One%such%feature%is%a%raised%beach%or%ridge.%%A%raised%beach%or%ridge%is%a%former%beach%that%lies%above%water%level.%%In%the%Hudson%Bay%region,%these%features%can%be%found%inland%of%the%coast,%as%shown%in%the%photo%on%this%slide.%%These%beaches%or%ridges%have%become%‘raised’%due%to%the%isostatic%rebound.%%Once%raised,%these%features%can%become%covered%with%vegetation.%%The%raised%beaches%are%almost%parallel%to%the%currentMday%beach%and%are%widely%spaced%and%extent%several%kilometers%inland.%%These%features%can%also%be%used%to%determine%the%rate%of%isostatic%rebound.%%If%the%ridge%material%can%be%dated,%the%difference%between%the%date%of%deposition%and%the%current%date,%as%well%as%the%current%position%can%be%used%to%provide%an%estimate%of%the%regional%uplift%that%is%occurring.%%%%%% Page%|%5%%%Slide%12:%Another%feature%common%in%the%region%and%produced%by%glacial%processes%are%the%watershed%and%lake%basins.%%With%the%relatively%recent%advancement%and%retreat%of%the%Laurentide%glacier,%erosion%caused%by%the%ice%scraped%out%a%large%number%of%lake%basins.%%Research%has%suggested%that%over%10%thousand%lake%basins%have%been%produced%in%the%area%due%to%glacial%erosion.%%The%Canadian%Shield%is%one%of%the%regions%in%Canada%with%the%highest%number%of%lake%basins%created%in%this%way.%%An%example%of%one%such%lake%is%Halfway%Lake%in%Pukaskwa%National%Park%(shown%in%the%background%of%the%photo%on%this%slide).%%%The%watersheds%in%the%region%have%also%been%modified%by%the%recent%glacial%erosion.%%This%has%resulted%in%relatively%young%watersheds%that%are%in%a%state%of%change.%%The%fluvial%and%lacustrine%systems%are%continuing%to%erode%the%surface,%causing%current%changes%in%the%environment.%%%%%%Slide%13:%In%addition%to%the%watershed%impacts%as%discussed%in%the%previous%slide,%the%relatively%recent%glacial%erosion%has%caused%significant%changes%to%the%terrestrial%environment.%%The%retreat%of%the%glacier%has%carried%away%much%of%the%soil%leaving%a%very%thin%layer%of%soil%over%most%of%the%Canadian%Shield%region%(excluding%the%Hudson%Bay%Lowlands)%and%significant%bedrock%outcrops%at%the%surface.%%In%addition,%glacial%debris%was%also%deposited%over%the%surface%due%to%the%slower%ice%velocities%encountered%during%the%retreat.%%This%has%resulted%in%a%layer%of%glacial%till%throughout%large%areas%of%the%Shield.%The%retreat%of%the%glacier%also%caused%more%microscale%erosion.%%Particles%entrained%at%the%bottom%of%the%ice%have%resulted%in%striations%(or%tiny%parallel%grooves)%to%form%on%the%land%surface.%%Continual%erosion%of%the%granite%Canadian%Shield%has%resulted%in%glacial%polish,%grinding%and%smoothing%the%underlying%rock%giving%it%a%polished%appearance.%%These%glacial%features%are%shown%in%the%foreground%of%the%photo%on%this%slide.%%%%Slide%14:%As%the%ice%velocities%decreased%in%the%Laurentide%glacier%during%the%last%ice%retreat,%material%eroded%and%transported%by%the%glacier%would%have%been%deposited%forming%a%series%of%depositional%features%found%in%the%Canadian%Shield%region.%%One%such%feature%is%the%esker%(shown%on%the%diagram%on%this%slide).%%As%discussed%in%a%previous%module,%eskers%are%long%sinuous%or%winding%ridges%of%stratified%glacial%debris,%deposited%by%the%meltwater%channels%exiting%within%the%glacier.%%An%example%of%one%such%esker%in%the%Canadian%Shield%region%is%the%Munro%Esker%(located%east%of%Lake%Abitibi%in%northern%Ontario).%%This%esker%is%approximately%250%kilometers%long%and%almost%5%kilometers%wide.%%Eskers%are%also%found%in%northwest%Quebec.%%These%eskers%are%generally%aligned%in%a%northMsouth%direction.%%%% Page%|%6%%%Slide%15:%Moraines%are%also%common%in%the%Canadian%Shield.%%Like%an%esker,%a%moraine%is%a%glacial%ridge%or%hill,%however%this%feature%is%formed%of%unconsolidated%and%nonMstratified%glacial%debris.%%Ground%moraines%common%in%the%Shield%are%tillMcovered%areas%with%irregular%topography%and%no%ridges,%rather%have%the%appearance%of%gently%rolling%hill%that%are%often%grooved%parallel%to%the%direction%of%ice%flow.%%The%glacial%debris%is%accumulated%at%the%base%of%the%ice%as%lodgement%till.%%Ground%moraines%can%be%found%near%Lake%Nipigon%in%Northwestern%Ontario.%%Slide%16:%Drumlins,%another%feature%discussed%in%previous%modules%are%also%glacial%depositional%landforms%found%in%the%Canadian%Shield.%%Drumlins%are%ovalMshaped%elongated%hills%composed%of%unconsolidated%glacial%till%with%a%long%axis%typically%between%1%and%2%kilometers%long%and%less%than%50%meters%high.%%This%feature%typically%occurs%in%groups%known%as%drumlin%fields.%%Drumlins%can%be%found%in%the%Thelon%Plain%found%along%the%border%between%the%Northwest%Territories%and%Nunavut%in%the%northern%Canadian%Shield.%%%%Slide%17:%As%discussed%previously,%the%glacial%erosion%has%resulted%in%a%large%number%of%lake%basins%to%form.%%In%the%central%sections%of%the%Canadian%Shield%(east%and%west%of%Hudson%Bay),%these%lake%basins%are%fairly%irregular%in%shape%and%shallow%in%depth.%%The%depth%of%the%lakes%are%controlled%by%two%factors,%the%hard%resistant%igneous%and%metamorphic%rocks%that%form%the%Canadian%Shield%(and%thus%limiting%the%erosion%by%the%glacier)%and%the%deposition%of%glacial%debris,%which%will%raise%the%lake%bottom.%%%%Slide%18:%This%concludes%the%climate%and%glacier%unit%of%the%module.%%One%of%the%points%I%hope%you%obtained%from%this%unit%is%the%physiographic%control%both%on%the%glacial%processes%and%features,%as%well%as%the%climate%of%the%Canadian%Shield.%%%%%You%should%review%the%supplementary%information%that%corresponds%to%this%unit%and%read%the%readings%listed.%%In%the%next%section%we%will%discuss%the%soil,%flora%and%fauna%present%in%the%Canadian%Shield%physiographic%region.%