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 g ...

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 be ...

s – the Weichselian in North Germany and the

Würm Wurm or Würm may refer to: Places * Wurm (Rur), a river in North Rhine-Westphalia in western Germany * Würm (Amper), a river in Bavaria, southeastern Germany ** Würm glaciation, an Alpine ice age, named after the Bavarian river * Würm (Nagold ...

in the

Alps The Alps () are some of the highest and most extensive mountain ranges in Europe, stretching approximately across eight Alpine countries (from west to east): Monaco, France, Switzerland, Italy, Liechtenstein, Germany, Austria and Slovenia. ...

. Their

landform A landform is a land feature on the solid surface of the Earth or other planetary body. They may be natural or may be anthropogenic (caused or influenced by human activity). Landforms together make up a given terrain, and their arrangement ...

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

denudation Denudation is the geological process in which moving water, ice, wind, and waves erode the Earth's surface, leading to a reduction in elevation and in relief of landforms and landscapes. Although the terms erosion and denudation are used interchang ...

and

erosion Erosion is the action of surface processes (such as Surface runoff, water flow or wind) that removes soil, Rock (geology), rock, or dissolved material from one location on the Earth's crust#Crust, Earth's crust and then sediment transport, tran ...

, 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 The glacial series refers to a particular sequence of landforms in Central Europe that were formed during the Last glacial period, Pleistocene glaciation beneath the ice sheets, along their margins and on their forelands during each glacial advance ...

even though the meltwater deposits and landforms are not strictly moraines.

Old Drift

The Old Drift landscapes were

tundra In physical geography, a tundra () is a type of biome where tree growth is hindered by frigid temperatures and short growing seasons. There are three regions and associated types of tundra: #Arctic, Arctic, Alpine tundra, Alpine, and #Antarctic ...

s or cold deserts during the last ice age.

Periglacial Periglaciation (adjective: "periglacial", referring to places at the edges of glacial areas) describes geomorphic processes that result from seasonal thawing and freezing, very often in areas of permafrost. The meltwater may refreeze in ice wedg ...

processes resulted in significant

ablation Ablation ( – removal) is the removal or destruction of something from an object by vaporization, chipping, erosion, erosive processes, or by other means. Examples of ablative materials are described below, including spacecraft material for as ...

of higher terrain as well as accumulation of

sediments Sediment is a solid material that is transported to a new location where it is deposited. It occurs naturally and, through the processes of weathering and erosion, is broken down and subsequently sediment transport, transported by the action of ...

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 sculpture, sculptural method in which the sculpted pieces remain attached to a solid background of the same material. The term ''wikt:relief, relief'' is from the Latin verb , to raise (). To create a sculpture in relief is to give ...

-intensive than Young Drift regions and have hardly any natural

lake A lake is often a naturally occurring, relatively large and fixed body of water on or near the Earth's surface. It is localized in a basin or interconnected basins surrounded by dry land. Lakes lie completely on land and are separate from ...

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, sunlight, and biological organisms. It occurs '' in situ'' (on-site, with little or no move ...

of the sediments near the surface, the

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

s are more heavily leached ( ( brunified, decalcified and/or

podsol Podzols, also known as podosols, spodosols, or espodossolos, are the typical soils of coniferous or Taiga, boreal forests and also the typical soils of eucalypt forests and heathlands in southern Australia. In Western Europe, podzols develop on he ...

ized). The

glacial till image:Geschiebemergel.JPG, Closeup of glacial till. Note that the larger grains (pebbles and gravel) in the till are completely surrounded by the matrix of finer material (silt and sand), and this characteristic, known as ''matrix support'', is d ...

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 period 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 betw ...

s, the wind could easily blow

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

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 (chemistry), suspension with water. Silt usually ...

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

ventifact A ventifact (also wind-faceted stone, windkanter) is a rock (geology), rock that has been abraded, pitted, etched, grooved, or polished by wind-driven sand or ice crystals. The word "Ventifact" is derived from the Latin word "Ventus" meaning 'wind ...

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, flat ...

s and

loess A loess (, ; from ) is a clastic rock, clastic, predominantly silt-sized sediment that is formed by the accumulation of wind-blown dust. Ten percent of Earth's land area is covered by loesses or similar deposition (geology), deposits. A 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 A glacier (; or ) is a persistent body of dense ice, a form of rock, that is constantly moving downhill under its own weight. A glacier forms where the accumulation of snow exceeds its ablation over many years, often centuries. It acquires ...

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.

Ventifact A ventifact (also wind-faceted stone, windkanter) is a rock (geology), rock that has been abraded, pitted, etched, grooved, or polished by wind-driven sand or ice crystals. The word "Ventifact" is derived from the Latin word "Ventus" meaning 'wind ...

s and

dunes 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, flat ...

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

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