Glaciers - Depositional Landforms

Question 1

drumlins

Answer 1

1. drumlins = elongated hills made up of unsorted glacial deposits/till/boulder clay. (1 mark)
2. formed as the glacier becomes overloaded w/ sediment & deposits it, streamlining the sediment as it flows over it (1 mark)
3. steep ‘stoss’ slope faces up-valley + vice versa for gently sloping lee slope (1 mark)
4. if theres a small obstacle on the ground = a trigger point = till/boulder clay can build up around it (1 mark)
5. drumlins are reshaped by more movements post original depositition, drumlins found in swarms (1 mark)
6. made of deposits that are unsorted, unstratified and angular (1 mark)
7. EXAMPLE: glasgow is built on a swarm (1 mark)

Question 2

eskers

Answer 2

1. eskers (fluvoglacial features) = meandering ridges along a valley floor formed by meltwater streams en/subglacier (1 mark)
2. they’re made up of meltwater sands & gravels (1) they’re sorted by size w/ large stones at the base bc larger stones are dropped first by flowing water (1 mark)
3. stones are more rounded than glacial deposits, bc the action of flowing water rounding the edges by erosion = attrition. (1 mark)
4. glacier melts, sub-glacial streams flow through tunnels & load is deposited on the channel bed (1 mark)
5. EXAMPLE: Flemington Eskers, south west of Nairn (1 mark)

for a 10 marker, briefly describe how a glacier forms

Question 3

terminal moraine

Answer 3

1. terminal moraine = ridge across valley perp to the movement of the glacier (1 mark) made up of glacial deposits/till/boulder clay (1 mark)
2. angular deposits, unstratified & unsorted as they are deposited directly by ice (1 mark)
3. glacier moves downhill it acts like a bulldozer (1), pushing sediment in front of its snout as it goes (1)
4. reaching lower altitudes/when temps rise, glacier melts (1), losing power and depositing the moraine (1)
5. terminal moraine = furthest point that the glacier reaches (1)
6. when ice retreats, the terminan moraine can form a dam = ribbon lake (1)
7. e.g. Loch Don, Mull

Question 4

ribbon lake

Answer 4

1. ribbon lakes r formed in a U shaped valley
2. explain a u-shaped valley in full detail
3. ribbon lakes form where softer bedrock is eroded deeper than surrounding harder rock
4. = fills w/ glacial meltwater & added to by precipitation over time
5. ribbon lakes also form where terminal moraine creates a dam
6. lakes get their name from their long, narrow shape
7. e.g. Lake Avon, Cairngorms