The global temperature fluctuations of the Last Ice Age are relatively well known from polar ice core analysis. In Figure 1, the temperature variations during the last four glacial-interglacial cycles, inferred from the Vostok ice core (Antarctica), are given. Also shown is the high correlation between temperature and methane and carbon dioxide content.
 

1 - Temperature variations during the last four glacial-intergalcial cycles (Vostock ice core, Antarctica) (540K)

During the last ice age, which lasted more than 100 000 years, stadial (relatively cold) and interstadial (relatively warm) periods alternated, with a temperature minimum at about 20,000 years BP. In many mountain areas, this temperature minimum was the period of maximum glacier advances, referred to as the global Last Glacial Maximum (LGM). In Alpine Regions e.g., the LGM is called Würm Maximum (Fig. 3).

In contrast, in very dry mountain areas and many tropical regions the advancement of glaciers was limited due to the lack of moisture. An impressive example is the Central Andes. Like today, glaciation in dry alpine areas was not restricted by temperature but by lack of moisture and high ablation rates. In these regions, maximum glacier advances occurred prior to the LGM and also often in the Late-glacial period after the LGM, when increased humidity enabled ice accumulation of glaciers.
 

2 - Chronostratigraphy of the last 245 000 years. For the Last Ice Age (c. 115 000 – 10 000 years ago) and its stadial and interstadial periods as well as for earlier Ice Ages, different nomenclatures are used in different regions. Figure 3 shows the nomenclatures used in the Alps/Northern Lowlands and in North-western Europe. (Burga & Perret, 1998)
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Comparison of maximum glacier advances in the Alps and in the Andes.

In the following exercise, decide for each region, whether glaciers at about 12 000 BP and at about 20 000 BP were non-existent, retreating or at a maximum. Fill in the following terms in the correct figure bellow:

29 August 2011
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