ancient river valley

An urstromtal (plural: Urstromtäler) is a type of broad glacial valley, for example, in northern Central Europe, that appeared during the ice ages, or individual glacial periods of an ice age, at the edge of the Scandinavian ice sheet and was formed by meltwaters that flowed more or less parallel to the ice margin. Urstromtäler are an element of the glacial series. The term is German and means "ancient stream valley". Although often translated as "glacial valley", it should not be confused with a valley carved out by a glacier. More accurately some sources call them "meltwater valleys" or "ice-marginal valleys".

== Emergence and structure == thumb|Section through an Urstromtal Important for the emergence of the Urstromtäler is the fact that the general lie of the land on the North German Plain and in Poland slopes down from south to north. Thus the ice sheet that advanced from Scandinavia flowed into a rising terrain. The meltwaters could therefore only flow for a short distance southwards over the sandurs (outwash plains) before having to find a way to the North Sea basin that was parallel to the ice margin. At that time, the area that is now the North Sea was dry as a result of the low level of the sea.