Effects of Glaciation PDF

# Effects of Glaciation All of Canada's current glaciers are considered alpine glaciers, in that they originate in mountain regions. The striking scenery, typical of the Rockies Mountains, is due in large part to the erosive forces of glaciers. 1. **Cirques:** Snow piles up in mountain basins cal...

# Effects of Glaciation All of Canada's current glaciers are considered alpine glaciers, in that they originate in mountain regions. The striking scenery, typical of the Rockies Mountains, is due in large part to the erosive forces of glaciers. 1. **Cirques:** Snow piles up in mountain basins called cirques. 2. **Glaciers:** Slowly the snow is packed into ice to form a glacier that begins to move down the mountain under the force of gravity. 3. **Scouring:** As the glacier moves it picks up rocks that scour out the surrounding mountainside. 4. **Cirque Steepening:** The ice deepens the floor of the cirque and steepens its sides. 5. **Arêtes:** When two cirques form back to back they erode toward each other to create the characteristic knife-edge ridges of mountains called arêtes. 6. **Horns:** When three or more form together they form a pyramidal peak called a horn. * The glacier may continue down the mountain to join a larger valley glacier. These glaciers create large U-shaped valleys. * **Hanging Valleys:** The smaller tributary valleys created by cirques are often left as hanging valleys after glaciers retreat since they may not be eroded to the same depth as the main glacial valley. * **Flords:** The sea may flood the large U-shaped central valleys that occur along the coastline when glaciers retreat, leaving long narrow, steep-walled inlets called flords. ## Continental Glaciers Continental glaciers also create lasting impressions on the landscape. The effects of the last ice age can be seen in the topography of Ontario today. 1. **Great Lakes:** As the ice sheets advanced they deepened existing valleys and lakes, creating today's Great Lakes. 2. **Erosion:** They eroded vast amounts of soil, sand, gravel and rock that was carried by the ice and acted as sandpaper, further gouging out the surface. 3. **Till:** The **clay, sand, and gravel** that are deposited by an ice sheet are referred to as **till**. Ridges or piles of till **are called moraines**. They appear **of a glacier**. 4. **Rivers:** Often glaciers contained rivers flowing under them, depositing large amounts of sand and gravel. When the glacier retreated these now **dry riverbeds created** steep sided ridges **called eskers** that follow the paths of the ancient glacial rivers. 5. **Drumlins:** Another feature produced by glaciers are **drumlins**, which are oval shaped hills made up of glacial till. 6. **Kettle Lakes:** **Kettle lakes** are created when **chunks of glacial ice become buried in layers of till**. The chunks melt leaving behind small deep lakes. ## Benefits of Glaciation in Ontario How has the past period of glaciation been beneficial to the economic development of Ontario? 1. **Great Lakes and Hydropower:** Glaciers carved out the Great Lakes- used for transportation, irrigation for agriculture, supplying water for cities and industries, fishing and the production of power (cooling for nuclear plants and hydro power in Niagara). 2. **Farming and Transportation:** Flattened out the landscape- good for farming and the development of cities and transportation networks. 3. **Tourism and Hydropower:** Carved out lakes and rivers in the Canadian Shield- a tourist destination today and a vital means of transport during the growth of our nation. Dammed rivers provide hydroelectric power. 4. **Farming:** Left behind deep, well drained subsoil - good for farming. 5. **Construction:** Left behind large deposits of sand and gravel- good for the construction industry. ### Oak Ridges Moraine The most significant glacial deposit, the Oakridges Moraine, has been declared a protected area by the Provincial government, as it serves a number of important purposes for this region. * **Wildlife Corridor:** It acts as a wildlife corridor and preserve for an area under increasing threat from urbanization. * **Recreation:** A good number of recreational activities take place in the rolling hills and heavy forests of the moraine, from golf courses to mountain biking and hiking trail systems and of course ski hills. * **Water Filtration:** The gravel of the moraine acts as a huge filter for water that trickles through it and enters Lake Ontario. Protecting the moraine ensures that those communities surrounding it, have access to clean fresh drinking water.