The global distribution of cold environments

EmmaSmile
Mind Map by , created over 6 years ago

A-Levels Glaciation Mind Map on The global distribution of cold environments, created by EmmaSmile on 05/05/2013.

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EmmaSmile
Created by EmmaSmile over 6 years ago
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The global distribution of cold environments
1 Glaciers are moving bodies of ice formed by accumulation of snow on ground's surface
2 Past distribution of glaciers
2.1 Areas of glacial activity expand and contract due to climate change
2.2 The earth has experienced a number of major periods of ice activity, 'glacials', roughly every 200-250 million years
2.3 The last ice age ended 10,000 years ago. Ice age at maximum extent 18,000 years ago covering UK in north and as far south as British Channel
2.4
3 Possible reasons for climatic fluctuations leading to ice ages
3.1 Changes in Earth's orbit and tilt
3.2 Variations in sunspot activity
3.3 Variations in ocean currents
3.4 Trapping of CO2 by oceans - reducing amount in atmosphere and cooling planet
4 Present day distribution of glaciers
4.1 The distribution of glaciers today is climate controlled; existing where temperatures are cold enough to allow yearly accumulation of ice to exceed the process of ablation (growth occurs where accumulation>ablation)
4.2 Areas of high altitude - atmospheric pressure falls with increased altitude, expansion in volume of air and decreasing temperatures. Alps, Andes and Himalayas have glaciers. Glaciers can even exist at equator above 5000m due to conditions at high altitude; e.g. Cotopaxi Volcano - Ecuador
4.3 Areas of high latitude where annual temperatures low and high albedo, reflecting large amounts of solar radiation back to space
4.3.1 Antarctica and Greenland
5 Types of glacier - classified according to size and area they occupy
5.1 Ice sheets - largest feature - continental sized accumulation above 50,000km2 e.g. Antarctica ice sheet
5.2 Ice caps - huge domed shaped masses of ice on high plateaus
5.3 Ice field - much of an upland area covered by glacial ice with just tallest peaks exposed (nunataks)
5.4 Valley glacier - large masses of ice flowing from ice fields or cirque; often following pre-glacial river valley
5.5 Corrie glacier - small ice masses on N-NE facing mountain slopes, covering area usually 0.5 to 10km2, gradually eroding hollows through glacial erosion
5.6 Piedmont glacier - large lobes of ice formed when glaciers spread out on reaching lowland areas and escape confines of valley
5.7 Ice shelves - extensions of ice sheets reaching out to sea up to 1000m thick

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