Lecture Week 2 Updated: GEO 605 The Canadian North

GEO 605 The Canadian North, Lecture # 2 Sept 11, 2024 Physical Geography / Glaciation ofessor Julie Robertson jule.Robertson@ torontomu.ca 1  Arctic Subarctic 2 Wisconsin Glaciation episode....

GEO 605 The Canadian North, Lecture # 2 Sept 11, 2024 Physical Geography / Glaciation ofessor Julie Robertson jule.Robertson@ torontomu.ca 1  Arctic Subarctic 2 Wisconsin Glaciation episode. 3 Prince Patrick Island Melville Island Banks Island 4  Bering Strait Land bridge Beringia Mammoths roamed the cold grassy plains The land bridge allowed for migration of species of plants and animals to move between Americas and Eurasia. https://www.gi.alaska.edu/alaska-science-forum/was-bering-land-bridge-good-place-live 5  During glaciation periods sea levels dropped as much as 100 - 150 metres The Bearing sea floor was reveled creating a land bridge between current day Siberia and Alaska creating Beringia The landscape differed from the rest of North America as it was ice free. Glaciers did not form because the climate was too dry, the lack of moisture caused the boreal forests to disappear The land was a vast plain with grasses and flowering plants An ecosystem we now call the mammoth steppe Home to large herd grazers: Woolley Mammoths Steppe Bison, Yukon Horses, American lions Giant short-faced bears and the first humans Jefferson ground sloth, giant beaver, and mastodon once roamed Yukon’s ancient glacial 6 7 The first people in Yukon migrated from Asia near the end of the last ice age. There is considerable debate about when the first people arrived in North America. Current consensus places the time about 15,000 years ago. The earliest evidence of people in the Arctic date to around 25,000 at the Yana River Site in northern Siberia. Small groups made their way across the land bridge around 15,000 year ago 8  Bluefish Cave, YT One of the most important records of ice age communities in Beringia. Stone tools and fossilized bones dating to 14,000BCE of a small group of people were located in digs from 1970-90’s Ancestors of Yukon’s First Nations arrived in the Holocene and are known as Dene or Athapaskan language speakers in Alaska and Yukon 9 Stratified soil layers at Bluefish Cave #2 Approx. 25,000 years Mostly limestone rubble and humus which reflects warmer, moister conditions present since the end of the Ice Age Sediments from the last 10,00 years Bedrock: wind-blown silt or loess that accumulated slowly between 25, 000 to 10,000 years ago 10  Glacial landforms 11 Travelalaska.com  12 wich, Toracinta, Wei, Oglesby., (2004) Polar MM5 Simulations of the winter climate of the Laurentide Ice sheet at the LGM Glaciers are one the most powerful forces shaping the landscape. They create unique landforms through a variety of processes: Erosional glacial landforms: In the upper reaches glaciers can erode bedrock leaving marks where the bedrock appears to be polished, have scratches and gouges. 13 The glacier in Greenland had debris embedded , as it moved it scratched and abraded the rocks leaving them appearing rough but actually smooth to touch 14 Large glaciers can excavate a glacial trough which creates a U –shaped valley 15 Trimlines in valley sides mark the former iced surface. The area below the trimline was smoothed by the passage of glacier ice. The trimline was formed during the “ Little Ice Age” when the glacier reached the moraines in the bottom of the photo the valley side above the line were not glaciate at the time so there is more vegetation and weathering 16  Depositional Glacial Features 17 Glaciation of Canada Depositional glacial landforms As the glacier moves it pushes the surface material, as it melts glacial till is deposited in various thicknesses of unsorted sediment. 18 Drumlines & Erratic's Drumlins are egg Erratic is a piece shaped hills with a of rock that has steep side at the been eroded and wide end and a transported by a gentle slope on glacier to a the narrow side. different area and The steep side left behind when points in the the glacier melted direction that the glacier flowed The are usually clustered together in fields 19  Around the margins of the glacier moraines are formed: Lateral moraines are along the sides of the glacier Terminal moraines are form at the front edge https://education.nationalgeographic.org/resource/moraine/ 20 Moraine A moraine is the accumulation of rock debris, till carried and deposited by a glacier. The material varies from rocks and boulders to clay and sand. The material is unstratified when dopped by the glacier. 21 Terminal or end moraines are a ridgelike accumulation of glacial debris pushed forward by the glacial “snout” and dumped at the outermost edge of the ice advance or lobe. A lateral moraine consists of debris derived by erosion and avalanches from the valley walls onto the edge of the glacier and deposited when the glacier recedes. Medial moraines occur between two ice steams or two lobes of a glacier 22 Glaciofluvial landforms Eskers are ridges made of sands and gravels deposited by glacial meltwater flowing through tunnels within and underneath glaciers or through meltwater channels on top of glaciers. As the ice retreats the sediments are left behind as a ridge in the landscape Esker 23 Eskers in Canada 24 Eskers occur more often on the tundra but are still found in forested areas. Often, they are the only well-drained, semi-continuous ridges over vast areas. They are very important to many species who use them as travel corridors. They are very important to wolves, arctic and red fox and grizzly bears. They make good nesting habitat for birds including raptors. The top is exposed, and the steep sides provide micro-habitats for plants and animals to escape biting insects. Lichen are abundant on eskers making them important habitat for caribou 25 Eskers are import and traditionally been used as burial sites 26  twash plains aided, sediment-rich streams that drain downslope away from the gla 27 The east coastline of Hudson’s Bay in a study in Nunavik explores the glaciated landscape and the unique landforms created. 28 Sand dune complexes Skerries : small rocky island 29  De Geer Moraines De Geer moraines are thin elongated parallel ridges usually at regularly spaced intervals. They are a few metres in height and can be seen from a plane. The look like a washboard and are sometimes known as washboard moraines 30 Boisson& Allard, (2020)  Isostatic Rebound Rates in Canada Based on measurements Hudson’s Bay area is still depressed and could rise another 100 meters Current rate of change – 4 feet per 1 foot per century century 31 https://www.ontariobeneathourfeet.com/rising-land-isostatic-rebound 32  Hudson’s Bay Raised Beaches Current shoreline Ancient shorelines 33 https://ancientshore.com/2009/07/30/on-the-level/  34 https://www.ontariobeneathourfeet.com/rising-land-isostatic-rebound 35 Major Drainage Basins 36 Permafrost Zones 37 Mean Annual temperature -20 -15 -10 -5 -0 5 5 38 Extreme North Far north Middle north Near north Near north 39 7 Ecozones in Yukon Range from high arctic to the plains of central Yukon 40 Northwest Territories Ecozones 41  94 major islands greater than Arctic Archipelago 1,302km2 and more than 36,000 minor island totalling 1.4million km2 The area contain 6 of the worlds 30 largest island : Baffin island Victoria Ellesmere Banks Devon Axel Heiberg Melville Prince of Wales 42 43 The geological variety creates rugged mountains, steep-sided fjords and plains of various age and types of rock The Canadian Shield contains mineral deposits like gold and diamonds, Oil and natural gas deposits are found in sedimentary rocks like the Sverdrup Basin Geotrack.com 44 The major islands in the eastern Queen Elizabeth Arctic : Baffin, Devon, Ellesmere, Islands Alex Heiberg are mountainous with peaks over 2,0000 m. The higher lands on the islands are covered with ice caps and contain 75% of the glacier ice and largest glaciers in Canada. The islands are also the northeast extent of the Canadian shield which is fairly flat Paleozoic rock ( 251- 543 millions years old). The Queen Elizabeth Islands are younger , heavily fold sedimentary rocks on Alex Heiberg and parts of Devon and Ellesmere Island 45 The large channels that separate the islands would qualify as seas elsewhere in the world. 46  The sea ice in the eastern archipelago can be 1.5 – 2 metres thick in the winter except for several recurring polynyas which are open areas of water surrounded by sea ice. The largest polynya is north of Baffin Island in the southeastern Beaufort Sea. They freeze late and thaw early https://earthobservatory.nasa.gov/world-of-change/sea-ice- 47 48  Nunangat 49 Bone, R. The Regional Geography of Canada Canadian Shield Zones 50 Nordicity A concept introduced in1979 by Quebec geographer Louis-Edmond Hamelin. The concept combines physical and human factors to measure the degree of “ northernness” at specific places. Provides a quantitative measure of “ northernness” for any placed based on 10 variables noted as polar units which are a combination of physical and human elements. The North Pole is the maximum number of units at 1,000 and the southern limit Hamelin set at 200 51  Latitude Natural vegetation Summer heat Accessibility land or sea Annual cold Accessibility air Types of ice Population Annual Economic activity precipitation Variable have different measures like 0 days above 5.6 c , 60 days above 5.6c Depth of continuous permafrost Frozen ground, floating ice, glaciers Settlement size Population density Maximum Nordicity value 1000 North Pole 52 Physical Characteristics Human Characteristics Cold environment Sparse population Limited biophysical diversity Population stabilization Wilderness High cost of living Remoteness Few highways Permafrost First Nations / Inuit population Vast geographic area Financial dependency Fragile environment Settling land claims Slow biological growth Resource economy Importance of wildlife Reliance on western food Global warming Traditional foods Continental climate Economic hinterland 53  Southern Centres Polar Value Nothern Centres Polar Value Halifax 43 Thompson 258 Montreal 45 Fort Nelson 282 Timmins 67 Whitehorse 283 Calgary 94 Schefferville 295 Winnipeg 111 Uranium City 396 St. John's 115 Kuujjauarapik 414 Edmonton 125 Aklvaik 511 Chibougamau 151 Iqaluit 584 The Pas 185 Old Crow 624 Grande Prairie 198 Sachs harbour 764 54 Bone (2009) p12 Nordicity values Northe n Centre Southern Centre 55 56 Place names and trails are integral parts of Inuit culture and describe features of the land, water and ice since time immemorial Names can be associated can be a description of the features they are associated with. Names are linked to places of significance often denoting important hunting areas, places to camp and good dishing spots. They can describe travel conditions and routes Many are connected to well travelled routes and connect routes together 57