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Glacial Processes and Landforms

Glacial Processes and Landforms. What is a glacier? How do glaciers form?. What is a glacier? A glacier is simply the existence of year-round ice on the landscape. There are two broad types: continental and alpine . How do glaciers form?

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Glacial Processes and Landforms

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  1. Glacial Processes and Landforms

  2. What is a glacier? How do glaciers form?

  3. What is a glacier? • A glacier is simply the existence of year-round ice on the landscape. • There are two broad types: continental and alpine. How do glaciers form? • Glaciers form whenever snowfall exceeds snowmelt year after year. The snow accumulates incrementally, pressure increases, and it is changed into ice by this pressure.

  4. Maximum Extent of Pleistocene Glaciation - 1/3 of land surface Most recent glacial maximum peaked 18,000 years ago and is considered to have ended 10,000 B.P.

  5. Current Extent of Glaciation - about 10% of land surface

  6. Franz Joseph Glacier and Outwash Plain, New Zealand

  7. Erosion by Glaciers • volume and speed determinesamount of erosion. • erodes slightly more effectively than water. • plucking and abrasion (rock-tipped blade). • polishing and striations. • Continental glaciers removeall soil, plants, and small hills. • Alpine glaciers change V-shaped valleys to U-shaped.

  8. Transportation by Glaciers • will move material of all sizes • Slow transport. • Water in, on, and under glaciers moves much sediment as well.

  9. Deposition by Glaciers • outwash is any material deposited by glaciers or their meltwater. • Till is that unsorted material that is deposited directly by ice. • Morainesare linear features deposited at bottom or along sides of glaciers. • Glacial erraticsare enormous boulders transported and deposited by glaciers, often far from their source region.

  10. Alpine Glaciers

  11. Moraines

  12. Continental Glaciers or Ice Sheets • only two true ice sheets exist today: Greenland and Antarctica • where they meet the sea they can form ice sheets. • vary in thickness from hundreds of feet to two miles deep • scour away all soil and vegetation and dramatically reshape the landscape and ecology of large regions. • much change occurs in the periglacial environment. Ellesmere Island, Canada

  13. Continental Glaciers or Ice Sheets

  14. Continental Glaciers or Ice Sheets

  15. Finger Lakes Region, New York

  16. Fjords

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