Old and Young Drift are geographic names given to themorainic landscapes that were formed in Central Europe; the Old Drift during the olderice ages and the Young Drift during the latestglaciations – theWeichselian in North Germany and theWürm in theAlps. Theirlandforms are quite different. Areas of Old Drift have been heavily flattened and transformed as a result of geomorphic processes such asdenudation anderosion, whilst areas of Young Drift have largely retained their original shape. Whilst the majority of Old Drift moraines were formed during theSaale 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 theglacial series even though the meltwater deposits and landforms are not strictly moraines.
The Old Drift landscapes weretundras orcold deserts during the last ice age.Periglacial processes resulted in significantablation of higher terrain as well asaccumulation ofsediments 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 icekettle holes) have been completely filled in. Old Drift landscapes are therefore much lessrelief-intensive than Young Drift regions and have hardly any naturallakes. Theriver system of Old Drift areas is normal and hierarchical.
Due to advancedweathering of the sediments near the surface, thesoils are more heavily leached ( (brunified,decalcified and/orpodsolized). Theglacial 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 theglacial periods, the wind could easily blowsand andsilt away due to the lack of a layer of vegetation. The presence ofventifacts,dunes andloess is thus typical of Old Drift areas.
Young Drift morainic landscapes by contrast have new landforms that are still recognisable asglacial 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 anddunes 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 ofground moraine, the depth of decalcification of theglacial till is thus often less than 1 metre.