Glaciers Galore Ice Queen Period 1 Earth Science Honors November 30, 2013 The last Ice Age (Wisconsian) occurred over the last 2-3 million years (1). The Laurentide Ice Sheet last covered New England from about 24, ,000 years ago (1, Fig. 1). Latitude: Ranged from about 60W-120W (2). Longitude: Ranged from about 45N-80N (2). Its maximum area was 5,000,000 square miles (1). It began to retreat about 20,000 years ago, and carved out much of the New England landscape (1). The two main types of glaciers are: 1) Ice Sheets (3, Fig. 2a) 2) Alpine glaciers (3, Fig. 2b). Ice Sheets are larger than Alpine glaciers and tend to cover whole countries or continents. They start at one center point and spread out in all directions (3). Greenland and Antarctica are the main two remaining Ice Sheets on Earth (3). Alpine glaciers are small glaciers and flow downhill through mountain valleys and tend to be narrow in width and very long in length (3). Part of the Hubbard Glacier in Alaska is thought to be an Alpine glacier (3). Glacial Ice forms from the accumulation of snow over time (Fig. 3). Scientists determine the age of glaciers by dating the organic matter found in the sediments (4). Scientists know a glacier has retreated or advanced by setting markers along the glaciers. Over time as the glaciers move so will the markers (3). Depending on how much the markers move in a set period of time will the determine the speed (3) Introduction Methods Conclusion Figure 1. Laurentide Ice Sheet (6). I research the Laurentide Ice Sheet, two types glaciers, all of their parts and impact they have on the environment using text books and internet sources Objective To identify and understand the two main types of glaciers. Describe how glaciers form. Provide examples and descriptions of glacial features. Determine how glaciers have and will impact the earth. There are 2 types of glaciers, Alpine and Ice sheets The last glacier retreated from New England about 13,000 years ago. It changed the New England landscape greatly. Carved U-Shaped Valleys Left Glacial Erratics, Till, Moraines, Eskers, outwash plains, aretes, tarns, cirques and whalebacks Glaciers play a major role on Earth by maintaining sea levels and providing fresh water for people (5). Human caused global warming likely will have a negative impact on the earth’s glaciers (11) An increase in the Earth’s temperature will decrease Glacial area, and sea levels will rise greatly (11). A decrease in Earth’s temperature increases glacial area and sea levels will drop (11). Figure 4. Parts of an alpine glacier (7) Valley Trough: The U-Shape valley that is formed when the glacier widens (3) Hanging Valley: A valley of a tributary glacier is found above the main glacier (3) Arête: A ridge that is sharp-edged (3) Tarn: A small lake on a mountain (3) Horn: Peak shaped like a pyramid (3) Cirque: Bowl shaped depression that create areas of snow accumulation and ice formation (3). Figure 6. The different kinds of moraines (9). Terminal Moraine: Ridge of till formed at the end of a glacier (3) Medial Moraine: Two valleys that came together to form an ice stream (3) Lateral Moraine: Leftover debris that formed ridges (3). Figure 7. Parts of a Depositional Landform (10). Kettle Lakes: Esker: An area made of sand and gravel made by streams (3) Outwash Plain: Formed at the end of a glacier meltwater moves in rapid streams (3) Retreating Glacier: A glacier that melts more than it grows (3) Till: Material deposited as the glacier melts (3) Glacial Erratic: Boulders found on till (3) Figure 5. Parts of a Glacial Budget (8 ). Zone of Accumulation: Place where ice and snow accumulate (3) Zone of Wastage: Place where previous snow begins to melt and grow smaller (3) Zone of Fracture: Brittle ice that is located at the top 50 meters of a glacier (3) Crevasses: Cracks created when a glacier moves over irregular terrain (3) Iceberg formed by Calving (3) Abrasion: Part of the erosion process that smoothes the surface underneath (3) (Lutgins and Tarbuck, 2009). Abrasion Zone of Fracture Surprising Facts Figure 2ab. a. Ice sheet, b. Alpine glacier (7). Results Work Cited Ganopolski A, and Calov, R (2012) Simulation of glacial cycles with an Earth system model. In Climate Change, A Berger et al. (eds.), part 2, 49-55, doi: / _3, Spinger-Verlag, Vienna 3.Tarbuck, Edward J. and Frederick K. Lutgens, Kenneth G. Pinzke and Dennis Tasa (Feb 14, 2008) Applications and Investigations in Earth Science (6th Edition) Figure 3. Formation of glacial Ice (9). Glaciers hold a 75% of the world’s fresh water (5). If the glaciers melted, the world’s sea level would rise by 230 feet (5).