Glacial Landforms 3 Flashcards
(11 cards)
What are Eskers?
Long, sinuous ridges on the valley floor.
Eskers are formed by subglacial streams under pressure in the tunnels at the base of the ice.
What are Kames?
Small mounds on the valley floor.
Kames are formed by supraglacial streams depositing material on the valley floor as the glacier retreats.
What are Kame terraces?
Ridges of material running along the edge of the valley floor.
Kame terraces are formed when supraglacial streams carry lateral moraine and deposit it on the valley floor.
What are Sandurs?
A flat expanse of sediment in the proglacial area.
Sandurs are formed as meltwater streams lose energy and deposit their material in lowland areas.
What are Proglacial lakes?
A lake formed in front of the glacier snout.
Proglacial lakes can form due to the damming action of moraines or hills blocking meltwater.
What are Meltwater channels?
A narrow channel cut into bedrock along the front of an ice margin.
Meltwater channels can erode deep channels or gorges due to high sediment load and unique flow characteristics.
What are Kettleholes?
Hollows formed when blocks of dead ice melt and water accumulates.
These are created during ice retreat when sediment builds up around detached blocks of ice.
Fill in the blank: A proglacial lake is often formed by the _______.
[damming action of a terminal or recessional moraine]
This occurs during the retreat of a melting glacier.
True or False: Meltwater streams can flow uphill under hydrostatic pressure.
True
Meltwater streams have unique characteristics that allow them to flow uphill beneath a glacier.
What happens to the largest material deposited by meltwater streams?
It is deposited nearest the snout of the glacier.
The finest material is deposited further away as the stream loses energy.
What causes the braiding of proglacial streams?
Seasonal variations in discharge.
Braiding is common in proglacial streams due to fluctuations in the volume of meltwater.
