Glaciation

Question 1

Terminal Moraine

Answer 1

terminal moraines are made up of plucked, abraded and frost shattered material that has been pushed forward by the glacier as it moves and eventually deposited in place. Terminal moraines are a ridge across the valley and is made up of glacial deposits/ till/ boulder clay. This material is unsorted. As the glacier moves down hill it acts like a bulldozer, pushing sediment in front of its snout as it goes. On reaching lower altitudes or higher temperature, the glacier melts. The glacier loses power and deposits the moraine. The glaciers surface acts like a conveyer belt for scree because small amounts of meltwater transports it towards the snout, creating a rock lip. Terminal moraine marks the furthest point that the glacier reaches. Once the ice was retreated, the terminal moraine can often cause ribbon lakes.

Question 2

Drumlins

Answer 2

drumlins are “swarms” of small hills formed of terminal moraine. Drumlins have a steep stoss side and a gentle lee. They can reach 50m in hight and 1km in length. Drumlins are elongated hills made up of unsorted glacial deposits/till. Drumlins are formed it. The steep “stoss” slopes faces up-valley and the more gently-sloping “lee” slope faces down valley. If there is a small obstacle on the ground this may act as a trigger point and till can build up around it. Drumlins may be reshaped by further ice movements after being originally deposited. Drumlins are found in swarms or in a “basket” of eggs topography

Question 3

Esker

Answer 3

eskers are ice contact fluvio-glacial features. Eskers are meandering ridges along a valley floor, formed by meltwater streams in or underneath a glacier. They re made up of meltwater, sand and gravel. These are sorted by size because heavier stones are dropped first by flowing water. The stones also tend to more rounded than glacial deposits, because of the action of flowing water round the edges by erosion. On reaching lower altitudes or when temperatures rise, the glacier melts.