Glacial deposition Flashcards
Drift
All glacial deposits
When does deposition occur?
- When glacial ice melts
- When a glacier becomes overloaded with material
Till
- Includes all material deposited directly by ice;
- Till
- Erratics
- Drumlins
- Moraines
- Unsorted mixture of angular rocks, clay and sand that was mainly transported as supraglacial and englacial debris and then deposited
Types of glacial till
- Lodgement till
2. Ablation till
Lodgement till
Subglacial mixture that was deposited by the actively moving glacier
eg/ Drumlin
Ablation till
Produced at the snout when the ice melts
eg/ terminal, push and recessional moraine
Moraine
Type of landform that develops when the debris carried by the glacier is deposited
Lateral moraine
Moraine produced at the side of the glacier, rolled there from falling from top of ice or having fallen from the side (frost-shattering)
Medial moraine
Found at the confluence of two glaciers; two lateral moraines merged = form a deposit
Terminal/ End moraine
Marks the furthest point of the glacier, found at the snout.
Recessional moraine
Formed where the ice has retreated up the valley from terminal moraine and left a new pile of till
Push moraine
Forms when the ice has advanced down the valley and pushed materials ahead of it, leaving a ridge of moraine
Types of moraine
- Lateral
- Medial
- Terminal/end
- Recessional
- Push
Glacial till fabric analysis
- When plotting the data find the mid-point of the degrees
- Till fabric analysis suggest two possible orientations of the pebbles and suggest the origin.
Glacialfluvial material
Includes all the material deposited by meltwater streams
- unsorted material deposited by meltwater streams
- Sandur
- Kames and kettle terraces
- Eskers
- Kettles
- Braided streams
