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
e.g. Loch Don, Mull

Answer 3

1. drumlin 1
2. glacier reaches lower altitude/temperatures rise = ice melts & deposits moraine at snout = an unjumbled mass of unsorted material stretchkng across the valley floor = marks furthest extent of glacier = terminal moraine
3. ridges of till 20m high extend in arcs across the valley
4. ice retreats = terminal moraine forms a natural dam to create a ribbon lake

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