CHAPTER 9: GLACIAL PROCESSES, PATTERNS AND LANDFORMS
Over time, weathering and mass movement reduced the height of eskers making
them perfect for routeways. The ancient route An tSlighe Mhór was constructed on esker deposits extending from Galway to Dublin known as the Esker Riada. Today, part of the Dublin–Galway rail line runs upon the Esker Riada.
Fig. 37 An esker deposited by the Brúarjökull glacier in Iceland
Fig. 38 The Kilcormac Esker, County Offaly
Esker ridge Tunnel Meltwater stream
Finer sands above Heavier gravels
deposited at base
Esker deposits are layered. They contain
bands of sand and gravel.
Fig. 39 Esker formation: Meltwater streams deposit sand and gravel under the ice as they flow. Over time, a winding ridge of sand and gravel is exposed as the ice retreats. See enlarged esker ridge diagram in Fig. 40.
Fig. 40 Exam Diagram: Enlarged diagram to show how eskers are formed from layers of sand and gravel.