What is a drumlin ?
Are streamlined hills which point towards the
Direction of ice flow and formed beneath a
glacier.
How is a drumlin formed?
- as the glacier meets the moraine, it begins to travel over it
- It does not entrain the moraine as it does not have enough energy to erode the resistant rock within the moraine
- As the glacier moves over the moraine it sculpts/ smooths the sediment underneath (subglacial sediment deformation
4.produces a smooth lee side
How is the shape of a drumlin usually designed ?
like a half buried egg laying on its long axis
Ways they may have formed
- by sucessive build up of sediment to create a hill
- pre-existing sediments eroded in laces leaving hills
- Meltwater and deposition as a result of large floods underneath the ice.
What is an erratic ?
Are rocks that have been transported by ice and deposited elsewhere as glaciers retreat.
How are eratic formed?
- Glacier moves over it can erode bedrock
- Ice pick up or, entrain the eroded rock and adds it to the supraglacial debris.
- As the ice flows it transports the bedrock in direction of the flow
- Ice then deposited the entrained sediment once it retreats.
Terminal moraine
A ridge of till extending across glacial trough at the snout of the glacier
- marks maximum advance
recessional moraine
a series of ridges running transversely across glacial troughs - forms during a temporary still-stand retreat
Medial moraine
lateral moraines come together and is transported down the centre of the glacier
Lateral moraine
small rocks deposited at the side of the valley glacier as the glacier melts or retreats
Hummocky
Formed when a big part of the glacier breaks off and it melts dropping the sediment
Outwash plains
formed in front of a glacier due to melting a the snout and the emergence of meltwater streams
