Glacial period

A cold period referred to in the climate history and also in geology neutral a period with lower average temperatures between two time periods with higher average temperatures, so-called interglacial periods. If a period meant by deeper average temperatures within a ice age, so one speaks also of a glacial. In the literature quartärgeologischen therefore cold period is usually synonymous with glacial. Colloquially, and in the older literature cold periods are often inaccurate referred to as ice ages. Even in the recent scientific literature, the terms and Ice Age cold period are sometimes not clearly separated. [Note 1]

The same cold period is usually named differently in different regions of the world. Thus, the last cold period with its maximum a little more than 20,000 years in northern central Europe as the Vistula, in the northern Alpine region as Würm, in northern Russia as Valdai, in Siberia as Zyryanka, in the British Isles as Devensian, Ireland as Midlandian, Mérida, and Llanquihue referred to in North America as the Wisconsin, in Venezuela than in Chile than in New Zealand as Otira glaciation.

The term glacial

The term glacial is ambiguous and is therefore often not clearly used. To confusion helps that he ( glacial ) is used as a noun ( the glacial ) and as an adjective.

The term glacial as a noun ( glacies of latin, ice ') stands for a period of time, which is strongly influenced by ice and cold. Frequently equated with glacial cold period, and the two terms are often used in the literature quartärgeologischen as synonyms. Equating the two terms is true in the Quaternary to mostly because the local cold periods are often actually characterized by glacier advances and / or very cold climate phases. In the recent literature, the term ice age is now mainly used to illustrate the fact that often the actual " ice age " with glacial deposits occupies only a relatively short period of time the entire cold period.

The adjective is used for all glacial geomorphological and geological phenomena that have arisen directly during a glaciation of the glacial ice. A closer term for such phenomena is glazigen, ie caused by the action of the ice. As an adjective is also used for glacial geomorphological forms that occur in the vicinity of ice in the broadest sense. For this purpose there is a more precise term glaziär such as glaziäre forms.

Sediment deposits during glacial

Material from glacial streams or meltwater of the inland ice is indeed deposited by flowing water; their origin is, however, linked to the presence of glaciers. These phenomena are glazifluvial, glazifluviatil or fluvioglazial called, depending on whether the action of ice or flowing water in the immediate environment dominated. These include the transition cone adjacent to the glacier, whose pebbles are generally rounded slightly. The material sorting is indeed already present but indistinct. With increasing distance from the glacier the glazifluvialen deposits are indeed purely fluviatile, but without the glacier can not be explained. Sander in northern Germany are known.

The glaziäolischen deposits due to the wind and the glacier from its foreland derived their material their education. In Central Europe, including the loess and drift sand deposits ( dunes ).

Glaziolimnische deposits are deposited in the basin of a lake that is dammed by the ice. Again, the origin of the deposits is not possible without the glacier.

Material that has been deposited by glaciers and glacial rivers in the sea, is called glazimarin.