Earth systems Chapter 17

Earth systems Chapter 17 - Chapter 17: Glacial and...

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Chapter 17: Glacial and Periglacial processes & Landforms Cryosphere portion of Earth’s hydrosphere that is perennially frozen Areas where water is solid form snow cover, glacier ice, ice sheets, frozen ground(permafrost), sea ice, lake ice I. Rivers of ice 1. Glacier not stationary; move slowly under its own weight and pull of gravity Today, 11% of Earth is covered by Glaciers Last glacial ~16-18000 years ago 2. Snowline temporary line marking the elevation where winter snowfall persists throughout the summer; seasonally, the lowest elevation covered by snow during the summer A. Alpine Glaciers 4. Alpine Glacier a glacier confined in a mountain valley or walled basin, consisting of three subtypes: valley glacier (within a valley), piedmont glacier and outlet glacier 5. Cirque a scooped-out, amphitheater-shaped basin at the head of an alpine glacier valley; an Erosional landform 6. Iceberg a cold episode, with accompanying alpine and continental ice accumulations, that has repeated roughly every 200 to 300 million yrs since the late Precambrian era B. Continental Glaciers 7. Continental glacier a continuous mass of unconfined ice, covering at least 50,000 km; most extensive at present as ice sheets covering Greenland & Antarctica 8. Ice sheet an enormous continuous continental glacier. The bulk of glacial ice on Earth covers Antarctica and Greenland in 2 ice sheets 9. Ice cap a large, dome-shaped glacier, less extensive than an ice sheet although it buries mountain peaks and the local landscape; generally less than 50,000 km 2 10. Ice field the least extensive form of a glacier, with mountain ridges and peaks visible above the ice; less than an ice cap or vice sheet Sea ice does NOT significantly raise sea levels if it melts and discharges its melt water into oceans because it is already in the ocean (only increases sea level by small amounts if it melts) On the hand, melting of glaciers, ice sheets, etc provide a net input of freshwater to the ocean Drivers of sea level changes 1. Thermal expansion of ocean water 2. Ice sheet & glacier melt water & ice discharge II. Glacial Processes Controlled by the action of glaciers, ice fields and ice sheets
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This note was uploaded on 12/14/2011 for the course EARTH SYS 101 taught by Professor Asar during the Fall '11 term at Rutgers.

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Earth systems Chapter 17 - Chapter 17: Glacial and...

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