Eskers
Eskers are sinuous, ridge-like landforms composed of stratified sand and gravel. They are formed by meltwater streams flowing within ice tunnels (englacial) or beneath glaciers (subglacial), with sediment deposited as the stream slows upon glacier retreat.
Real World
The Punkaharju esker in Finland stretches over 7 km between two lakes and is so well-preserved that a main road runs along its crest, designated a national landscape since the 1800s.
Exam Focus
Emphasise that esker sediment is sorted and stratified — this distinguishes fluvioglacial deposits from unsorted glacial till.
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