105_14-glaciers_part_1 - Definition of a glacier A glacier...

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Unformatted text preview: Definition of a glacier A glacier is a large, long-lasting mass longof ice, formed on land, that moves under its own weight. Glaciers and Glaciation Chapter 14 Two types of glaciated terrain Distribution of Glaciers • Most extensive in polar regions 85% of present day glaciation is in Antarctica • Even near equator, in high elevation mountains • South America • Africa • In US: Alaska Washington • Alpine glaciation – in mountainous regions • Continental glaciation – large part of a continent is covered by glacial ice Types of Glaciers Valley glaciers: confined to a valley and flow from Valley higher to lower elevations (alpine glaciation) Types of Glaciers Ice Ice sheet: mass of ice that is not restricted to a valley. Covers a large area of land (>50,000 km³) (continental glaciation) 1 Greenland ice sheet Types of Glaciers Antarctic Antarctic Ice Sheet – Up to 4.5 km (2.79 miles) thick – Covers an area 1.5 times as large as continental U.S. McMurdo Ice Strip Antarctica McMurdo Station Hiking 2 Hiking RVIB Nathaniel B. Palmer Cruise Track Maps seismic airgun.mov Seismic Seismic Multibeam Sonar 3 Multibeam Sonar Coring Coring Coring Seals Orcas 4 Penguins 24 hour sunlight! Icebergs Icebergs Types of Glaciers Ice Ice cap: same as ice sheet, but covers a smaller area. (continental glaciation, usually covers a plateau) Types of Glaciers Quelccaya Ice Cap, Peru 5 Formation of glaciers Snow Snow to firn to glacial ice. ice. Thawing Thawing and refreezing, compacting, looses air spaces. Icebergs Ablation Ablation – loss of glacial material – Melting – Sublimation (evaporation) – Calving – breaking off of ice into a body of water. Forms icebergs Budget of a Glacier Difference Difference between the annual gain and loss of snow and ice 9/10th of volume is under water 6 ...
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This note was uploaded on 05/18/2011 for the course GEOL 105 taught by Professor Jack during the Spring '08 term at University of Louisiana at Lafayette.

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