Here's a breakdown of their key features:
* Shape: Drumlins are typically elongated and tear-drop shaped, with a blunt, steeper end facing the direction from which the ice sheet advanced (the upstream end), and a gentler, more sloping end pointing in the direction of ice flow (the downstream end).
* Composition: They are composed of glacial till, a heterogeneous mixture of unsorted sediment deposited directly by the glacier. This till can include clay, silt, sand, gravel, and even boulders.
* Formation: Drumlins form when a glacier moves over previously deposited till. The ice flow reshapes the till, creating a streamlined hill. They are often found in clusters or fields, indicating the direction of past glacial movement.
Drumlins are valuable indicators of past glacial activity, providing insights into the direction, thickness, and movement of former ice sheets.
