Old and Young Drift are geographic names given to the morainic landscapes that were formed in Central Europe; the Old Drift during the older

ice age An ice age is a long period of reduction in the temperature of Earth's surface and atmosphere, resulting in the presence or expansion of continental and polar ice sheets and alpine glaciers. Earth's climate alternates between ice ages and gre ...

s and the Young Drift during the latest

glaciation A glacial period (alternatively glacial or glaciation) is an interval of time (thousands of years) within an ice age that is marked by colder temperatures and glacier advances. Interglacials, on the other hand, are periods of warmer climate bet ...

s – the

Weichselian The Weichselian glaciation was the last glacial period and its associated glaciation in northern parts of Europe. In the Alpine region it corresponds to the Würm glaciation. It was characterized by a large ice sheet (the Fenno-Scandian ice she ...

in North Germany and the Würm in the

Alps The Alps () ; german: Alpen ; it, Alpi ; rm, Alps ; sl, Alpe . are the highest and most extensive mountain range system that lies entirely in Europe, stretching approximately across seven Alpine countries (from west to east): France, ...

. Their landforms are quite different. Areas of Old Drift have been heavily flattened and transformed as a result of geomorphic processes such as denudation and

erosion Erosion is the action of surface processes (such as water flow or wind) that removes soil, rock, or dissolved material from one location on the Earth's crust, and then transports it to another location where it is deposited. Erosion is di ...

, whilst areas of Young Drift have largely retained their original shape. Whilst the majority of Old Drift moraines were formed during the Saale glaciation about 130,000 to 140,000 years ago, the Young Drift moraines in Central Europe are only about 15,000 to 20,000 years old. The terms Old and Young Drift are used for all elements of the glacial series even though the meltwater deposits and landforms are not strictly moraines.

Old Drift

The Old Drift landscapes were

tundra In physical geography, tundra () is a type of biome where tree growth is hindered by frigid temperatures and short growing seasons. The term ''tundra'' comes through Russian (') from the Kildin Sámi word (') meaning "uplands", "treeless mo ...

s or cold deserts during the last ice age.

Periglacial Periglaciation (adjective: "periglacial", also referring to places at the edges of glacial areas) describes geomorphic processes that result from seasonal thawing of snow in areas of permafrost, the runoff from which refreezes in ice wedges and ...

processes resulted in significant

ablation Ablation ( la, ablatio – removal) is removal or destruction of something from an object by vaporization, chipping, erosive processes or by other means. Examples of ablative materials are described below, and include spacecraft material for a ...

of higher terrain as well as accumulation of

sediments Sediment is a naturally occurring material that is broken down by processes of weathering and erosion, and is subsequently transported by the action of wind, water, or ice or by the force of gravity acting on the particles. For example, sand a ...

in the depressions. As a result of that the old glacial forms have clearly been worn down. In addition almost all closed hollows (e. g. dead ice kettle holes) have been completely filled in. Old Drift landscapes are therefore much less

relief Relief is a sculptural method in which the sculpted pieces are bonded to a solid background of the same material. The term '' relief'' is from the Latin verb ''relevo'', to raise. To create a sculpture in relief is to give the impression that th ...

-intensive than Young Drift regions and have hardly any natural

lake A lake is an area filled with water, localized in a basin, surrounded by land, and distinct from any river or other outlet that serves to feed or drain the lake. Lakes lie on land and are not part of the ocean, although, like the much lar ...

s. The river system of Old Drift areas is normal and hierarchical. Due to advanced

weathering Weathering is the deterioration of rocks, soils and minerals as well as wood and artificial materials through contact with water, atmospheric gases, and biological organisms. Weathering occurs '' in situ'' (on site, with little or no movemen ...

of the sediments near the surface, the

soil Soil, also commonly referred to as earth or dirt, is a mixture of organic matter, minerals, gases, liquids, and organisms that together support life. Some scientific definitions distinguish ''dirt'' from ''soil'' by restricting the former ...

s are more heavily leached ( ( brunified, decalcified and/or podsolized). The glacial till is generally decalcified to 3–4 metres; thinner strata may be entirely decalcified. Very common are wind-formed ablation or accumulation landforms, because during the glacial periods, the wind could easily blow

sand Sand is a granular material composed of finely divided mineral particles. Sand has various compositions but is defined by its grain size. Sand grains are smaller than gravel and coarser than silt. Sand can also refer to a soil texture, textur ...

and

silt Silt is granular material of a size between sand and clay and composed mostly of broken grains of quartz. Silt may occur as a soil (often mixed with sand or clay) or as sediment mixed in suspension with water. Silt usually has a floury feel wh ...

away due to the lack of a layer of vegetation. The presence of ventifacts,

dune A dune is a landform composed of wind- or water-driven sand. It typically takes the form of a mound, ridge, or hill. An area with dunes is called a dune system or a dune complex. A large dune complex is called a dune field, while broad, fl ...

s and loess is thus typical of Old Drift areas.

Young Drift

Young Drift morainic landscapes by contrast have new landforms that are still recognisable as glacial forms.. There are numerous enclosed hollows, many of which are filled with water. The river system is often still immature and rather chaotic. There are numerous inland drainage areas. Ventifacts and dunes do occur; but these landforms are much younger and less intensively formed than in Old Drift country. The soils are markedly less weathered than those of the Old Drift. On areas of ground moraine, the depth of decalcification of the glacial till is thus often less than 1 metre.

Literature

External links

*{{cite web , url=http://satgeo.zum.de/satgeo/beispiele/glossar/altmo.htm , title=Kleines Glossar zur Glazialmorphologie: Moränen: Jungmoräne, Altmoräne , publisher=Zentrale für Unterrichtsmedien im Internet e.V., work=Satellitengeographie im Unterricht, Merzhausen , access-date=2009-12-10 Glacial landforms Geodynamics