Glacial Landscapes Flashcards
What are the two types of glacial landform?
- Depositional
- Erosional
What are the depositional landforms?
Moraines
Drumlins
Erratics
Till Plains
What is moraine?
The accumulation of debris (till) deposited directly by a glacier as it advances and retreats
What is till?
Unstratified (no layers) and unsorted sediment containing a mix of rock particles (clay, sand, gravel, boulders) deposited by a glacier
What are the six different types of moraine?
- Lateral
- Medial
- Terminal
- Ground
- Recessional
- Push
Where are the different types of moraine found?
- LATERAL
- sides - MEDIAL
- middle of two merging - TERMINAL
- end - GROUND
- underneath - RECESSIONAL/PUSH
- behind terminal moraine, marking stages of glacial retreat and/or readvancement
How is lateral moraine formed?
Debris falling from the cliffs at the side of the glacier due to freeze-thaw action gets trapped at the edges and transported as the glacier moves
How is medial moraine formed?
When the lateral moraines of two converging glaciers join together
How is terminal moraine formed?
When the debris pushed at the glaciers snout is deposited as a ridge when the glacier reaches its maximum extent and begins to retreat
How is ground moraine formed?
As the glacier moves it deposits a thin irregular layer of till at its base
How is recessional moraine formed?
When a retreating glacier temporarily stabilises, depositing a ridge of debris before continuing to melt back
How is push moraine formed?
If the glacier advances again after retreating then ridges of sediment previously deposited get shoved up into little hills
What does recessional/push moraine look like?
A series of ridges behind the terminal moraine, showing pauses in the glaciers retreat.
Can show folding/faulting/tilting due to the force of the glacier moving forward
Often curved and perpendicular to the direction of the glaciers advancement
What are drumlins?
Elongated, egg-shaped hills made of till
