Glacial Landscapes Glacier = large moving mass of ice. Glacier = large moving mass of ice. Glaciers erode, transport and deposit massive amount of sediment

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Glacial Landscapes Glacier = large moving mass of ice. Glacier = large moving mass of ice. Glaciers erode, transport and deposit massive amount of sediment called till. Glaciers erode, transport and deposit massive amount of sediment called till. Important to NYS. (last ice age was 10,000 y.a.) Important to NYS. (last ice age was 10,000 y.a.) 2 Types of glaciers: 2 Types of glaciers: Valley glaciers Continental glaciers Slide 2 Valley Glaciers Smaller scale glaciers that form at high elevations. Smaller scale glaciers that form at high elevations. Flow starts when accumulated snow and ice becomes too massive and flows. Flow starts when accumulated snow and ice becomes too massive and flows. Speed of flow is dependent on slope of valley floor. Speed of flow is dependent on slope of valley floor. Sides and bottom of valley glacier move slower than the middle. Why? Sides and bottom of valley glacier move slower than the middle. Why? Slide 3 Continental Glaciers Glaciers that cover broad, continent sized areas. Glaciers that cover broad, continent sized areas. These glaciers move because they are very thick in the center and flow out from that thick center point. Why? These glaciers move because they are very thick in the center and flow out from that thick center point. Why? The Laurentide Ice Sheet covered NYS about 10,000 y.a. The Laurentide Ice Sheet covered NYS about 10,000 y.a. Slide 4 Glacier Movement Advance glacier moves forward. Advance glacier moves forward. Retreat glacier appears to move backward. Retreat glacier appears to move backward. In reality during a glacial retreat, the glacier is still moving forward under gravity, but it is melting faster that its forward motion. Slide 5 Glacial Deposition Most glaciers push, carry and drag great quantities of sediment. Sediments carried by glaciers or the melt-water of glaciers is called glacial drift. There are 2 main types of drift: 1. Once a glacier retreats the unsorted material deposited directly by the glacier is called till. 1. Once a glacier retreats the unsorted material deposited directly by the glacier is called till. 2. Sorted material deposited by the melt- water is called outwash. 2. Sorted material deposited by the melt- water is called outwash. Slide 6 Glacial Deposition Slide 7 Moraine small ridge of till left over by glaciers. End moraine small ridge of till located at the front of a glacier. Terminal moraine small ridge of till left at the furthest extent of the glacial advance. Recessional moraine a series of ridges left behind as the glacier retreats. (formed during pauses) Slide 8 Glacial Deposition Lateral moraine small ridge of till left at the sides of a glacier. Medial moraine small ridges of till formed at the meeting point of two valley glaciers (center). Ground moraine low mound of till left behind under a glacier. Drumlin oblong shaped hill formed during a glacial retreat. Slide 9 End Moraine and Lateral Moraine Slide 10 Lateral moraine and Medial moraine Slide 11 Retreating glacier and ice-marginal lake Slide 12 Drumlin Slide 13 Glacial Deposition Outwash plain plain of till in front of glacier, fed by melt-water. Kettle depressions left in the outwash plain by large blocks of ice that break off the glacier. Esker winding ridge of till that has filled in an old melt-water tunnel. (formed under a glacier) Slide 14 Outwash and braided melt water channels Slide 15 Kettles Slide 16 Esker Slide 17 Glacial Landscapes on Mountains Cirque deep depression carved out of existing mountains by valley glaciers. Horn steepened peak left behind after a glacier erodes a mountain on 3 sides. Arete A ridge of mountain left behind after glacial erosion, usually forming where two cirques on opposite sides of a valley meet. Slide 18 Cirque and horn Slide 19 Aretes Slide 20 Glacial Landscapes Other Important Points to Know: 1.Glaciers carve U-Shaped valleys as they erode. 2.Glacier can leave behind parallel scratches in solid bedrock called striations. 3.U-Shaped valleys that meet or join into other lower valleys can form, hanging valleys that rise higher than the lower valley. Slide 21

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