Here's why:
* Meltwater Channels: Glaciers, as they move, carve out channels in the ice through the flow of meltwater.
* Tunnel Formation: These channels can become tunnels, especially when the glacier is retreating and the ice melts, forming a hollow space.
* Sediment Fill: As the glacier retreats further, meltwater carries sand and gravel, filling these tunnels and channels.
* Esker Formation: The filled tunnels and channels then remain as long, winding ridges of sand and gravel known as eskers.
So, eskers are essentially the fossilized remnants of meltwater channels and tunnels within a glacier. They are a common feature in glaciated areas, providing evidence of past glacial activity.
