Which term describes a long, narrow hill of sand and gravel formed by glacial action?

Which term describes a long, narrow hill of sand and gravel formed by glacial action?

• A. Moraine
• B. Drumlin
• C. Wrack
• D. Esker

Answer: (D)

An esker is a long, winding ridge of sand and gravel formed by a meltwater stream that flowed within or beneath a glacier. As the glacier retreats, the sediment carried by that stream is left behind, creating a sinuous ridge that marks the path of the former subglacial channel. This specific origin distinguishes esker ridges from other glacial features: a moraine is an accumulation of till deposited at the glacier’s edge, a drumlin is a smooth, elongated hill shaped by reshaping glacial till in the direction of ice flow, and wrack refers to coastal debris, not a glacial landform. So the term that best fits the description is esker.

An esker is a long, winding ridge of sand and gravel formed by a meltwater stream that flowed within or beneath a glacier. As the glacier retreats, the sediment carried by that stream is left behind, creating a sinuous ridge that marks the path of the former subglacial channel. This specific origin distinguishes esker ridges from other glacial features: a moraine is an accumulation of till deposited at the glacier’s edge, a drumlin is a smooth, elongated hill shaped by reshaping glacial till in the direction of ice flow, and wrack refers to coastal debris, not a glacial landform. So the term that best fits the description is esker.