Glacial/Interglacial cycles

Sharondeep
Mind Map by , created over 5 years ago

Undergraduate Physical Geography (Global Environmental Change) Mind Map on Glacial/Interglacial cycles, created by Sharondeep on 04/10/2014.

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Sharondeep
Created by Sharondeep over 5 years ago
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Glacial/Interglacial cycles
1 Glacials
1.1 protracted (Extended time) climatic cold periods (ice ages)
1.1.1 ice sheets form in mid-latitude lowlands or low-latitude mountain areas, polar caps extend out to sea.
1.2 global climates were colder and drier than interglacials.
1.3 Modifies atmospheric and oceanic circulation.
1.4 Evidence that the world was more arid, subtropical desert margins more extended towards the equator, savannah grasslands more extensive, restricting the extent of tropical rainforests.
1.5 Increased ice volume in northern hemisphere forced polar front closer to the equator, limiting Gulf stream northern penetration and NADW formation weakening.
2 Interglacials
2.1 phases of warm climate between glacials where ice has retreated, temperate forests replace tundra veg in northern hem.
2.2 Current interglacial period = Holocene, 10.000 years.
2.3 Eamian Interglacial period 125,000 years warmer (marine oxygen isotope stage 5b)
2.4 Past 2.5 myr (millions on years) 100 glacial/interglacial periods formally indentified.
2.4.1 In marine records, assigned numbers (odd=inter) we're in Stage 1, Stage 100 taken as marking the beginning of the Quaternary period when there was a massive buildup of ice in northern hem.
2.4.2 oscillations in global climate have continued over a much longer period of time but before 2.5 Ma overall climate warmer, restricting glaciations to polar regions and high-latitude mountains.
3 climates may oscillate between g/I periods calling for further subdivision
3.1 Stadial short cold phase within an interglacial. Not cold enough to permit full gl conditions local ice advances generally occur.
3.2 Interstadial - short warm phase within a glacial. Temps not as high as interglacial period. In lowland mid-latitude regions the climax veg was boreal woodland.

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