At the end of an ice age, when global temperatures began to rise and glaciers started to melt, the meltwater flowed out from the melting ice sheet and deposited material across the land surface. The heaviest material, such as stones and gravel, was dropped first, then the lighter material, such as sand and silt.
Esker An esker is a long, winding ridge of sand or gravel.
Example: Trim esker system, Co. Meath.
Material deposited in a long narrow ridge.
Glacial retreat
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Esker Now Formation
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As the ice melts, large tunnels of meltwater flow in tunnels beneath the ice.
When a river leaves an ice tunnel, it slows down immediately and deposits material at the mouth of the tunnel.
As the ice slowly melts back, the deposited material is dropped in the form of a long, narrow ridge of sand and gravel.
Then
Working with others:
Take 30 seconds to examine figure 4. Then turn to the person next to you and together identify the esker in the image. Compare your answer with those given by your classmates.
