återgångsmoräns

Återgångsmoräns, also known as recessional moraines, are ridges of glacial till deposited at the margin of a retreating glacier. They form when a glacier temporarily stabilizes or pauses its retreat, allowing a significant accumulation of debris to build up at its snout. These pauses can be caused by variations in meltwater flow, calving events, or changes in glacial dynamics.

Unlike terminal moraines, which mark the furthest extent of a glacier's advance, recessional moraines are typically found behind the terminal moraine. They often occur in a series of parallel ridges, reflecting repeated pauses in the glacial retreat. The material within a recessional moraine is unsorted and unstratified, characteristic of glacial till, and can include a wide range of particle sizes from fine clay to large boulders.

The study of recessional moraines is important for understanding past glacial behavior and climate change. Their spacing and size can provide clues about the rate of glacial retreat and the duration of stable periods during deglaciation. In landscapes shaped by past ice sheets, chains of recessional moraines can be prominent features, influencing local topography and drainage patterns. They are a testament to the dynamic nature of glaciers and their profound impact on the Earth's surface.