Glaciers Flashcards
What is an erratic?
A piece of rock that is out of place in terms of size and type of rock.
It is carried by ice and deposited when the glacier melts.
What is till?
All unsorted sediments (eg. Erratics, moraine) deposited directly by ice
What is outwash?
Sorted sediment deposited when a glacier retreats (AKA fluvioglacial material)
What are eskers?
Formed when meltwater deposits sand and gravel as a long winding ridge
What is loess?
The accumulation of wind-blown silt and sand
How is a drumlins formed? (4)
- Melting glacier moves over obstacle
- Moraine transported by the glacier begins to accumulate next to the rock
- Ice melts and sediment builds up, forming the tapered end
- The glacier melts completely, leaving behind an accumulation of sediment in an egg-shaped mound
How is a glacial trough formed?
When a glacier moves down a valley, plucking, abrasion and sub-glacial meltwater cause the valley to erode. The result is a ‘U-shaped’ valley.
Characteristics of a glacial trough? (4)
Hanging valleys
Misfit stream
Steep valley sides
Truncated spurs
Impacts of glacial retreat?
Fresh water available
Level of oceans rise
What is the movement of moraine on the top of a glacier called?
Supra-glacial transportation
What is the movement of moraine on the bottom of a glacier called?
Sub glacial transportation
What is the movement of moraine in the centre of a glacier called?
Englacial transportation
What is chemical sub-glacial meltwater erosion?
When meltwater reacts with chemicals and/or minerals in rock and dissolve it.
What is physical sub glacial meltwater erosion?
Sediment carried by meltwater erodes the valley bed as it is carried beneath the glacier
