What types of moraine are shown at A and B? State whether each moraine is subglacial, englacial or supraglacial.
A B
Feature: Drumlins
Drumlins are oval-shaped hills that are made of deposited boulder clay (a mixture of sand and clay). They often occur in large numbers known as swarms.
How Drumlins Form 1 Glacial ice deposits boulder clay in irregular heaps.
2 The ice retreats and then advances again. This time it shapes and smooths the boulder clay into rounded oval-shaped hills.
3 The steep slope of the drumlin is the direction from which the ice advanced. The gentle slope points to the direction in which the ice was travelling.
Map view (elevation contour lines)
Examples: Drumlins can be found at Clew Bay, Co. Mayo, and Lower Lough Erne, Co. Fermanagh.
Direction of glacial flow
Height
Direction of glacial flow
11. How a drumlin forms
When close together, contour lines indicate a steep slope.
182
10 20 30 40 50
Length
When far apart, contour lines indicate a gentle slope.
Drumlins
Side view of the drumlin
This is the view from above, using contour lines on OS maps.