Question

Eskers and Drumlins are features formed by __________.
A) Running water
B) Underground water
C) The action of wind
D) Glacial action

Answer 1

Hint: Drumlins are oval-shaped ridge-like features that are mainly composed of ‘glacial till' with few masses of sand and gravel. Glacial till refers to the unassorted coarse and fine debris dropped by the melting glaciers. Eskers are ridges that are made up of sand and gravel.

Complete answer:
Eskers and Drumlins are “Depositional landforms”. Deposition refers to the geological process in which sediments, soil, rocks, sand, and pebbles are added to the landforms and increase their size. The depositional landforms are generally formed when the accumulation of sediments and sand is more than what is being removed.
Option A. Running water: Important depositional landforms formed due to running water are Alluvial Fans, Deltas, Flood Plains, Natural Levees, Meanders and oxbow lakes, Braided channels. Thus, this option is incorrect.
Option B) Underground water: Depositional landforms formed due to underground water are Stalactites, Stalagmites and Pillars. Thus, this option is incorrect.
Option C) The action of wind: Three types of landforms created due to wind action, namely Dunes, Yardangs, Deflation hollows. Thus, this option is incorrect.
Option D) Glacial action: Depositional landforms formed due to glacial action include Moraines, Eskers, Outwash Plains and Drumlins.

Drumlins are oval-shaped ridge-like features that are mainly composed of glacial till with few masses of sand and gravel. Their long axis is parallel to the direction of the movement of the ice. They are believed to have been formed due to the streamlined movement of glacial ice sheets, during which dumping of rock debris occurs beneath heavily loaded ice via fissures caused in the glacier. The end of the drumline that faces the glacier is called the “stoss end”, while the other end is called the “tail”. The moving ice pushes the stoss end because of which it gets blunter and steeper. Generally, drumlins are found in clusters having thousands in number. They indicate the direction of glacier movement.

Eskers are ridges that are made up of sand and gravel. They are believed to form when the sediments that are carried by glacial meltwater get accumulated in subglacial tunnels. During the melting of glaciers in summers, the water flows on the surface of the ice or seeps down along the margins or even moves through the holes present in the ice. The sediments are left behind as a ridge in the landscape as the ice retreats.

Thus, the correct answer is Option ‘D’ Glacial action i.e, Eskers and Drumlins are features formed by glacial action.

Note: Drumlins are often arranged in belts and help in the formation of small lakes and swamps between them by disrupting drainage. Esker’s help in providing essential information about the behaviour of ice sheets and glaciers. They tell us about meltwater and help us reconstruct the former ice surface and the orientation of the snout of the glacier.