Glaciated Landscapes: Glacial Depositional Landform Formations Flashcards
The main landform formed by lodgement till
Drumlins
Material deposited by advancing ice
Lodgement till
Material deposited by glaciers that are stagnant/in retreat
Ablation till
Why are terminal and recessional moraines crescent shaped?
The ice in the middle of a glacier has no friction and so moves faster than the edges
Why do terminal and recessional moraines have steeper up-valley sides?
As the glacial ice behind it that hasn’t melted yet gives it support whilst it is deposited
How is lateral moraine formed?
Debris accumulates on top of the glacier due to weathering, which is then deposited when the glacier melts
What causes recessional moraines to form?
A temporary stand-still when the glacier is in retreat
What can be used to identify push moraine?
The rocks orientation being upwards, from its original horizontal position
How are erratics formed?
Erratics are eroded (typically by plucking) or added to the supraglacial debris by weathering, which is then deposited in an area of a different rock type
Which end is the blunt, higher wide end of a drumlin?
Stoss
Which is the thinner, gentle tapered end of a drumlin?
Lee
What is the name of a drumlin that’s material accumulated around a bedrock obstruction?
Rock-cored drumlins
What are the four potential drumlin formations?
Lodgement of subglacial debris, reshaping of previously deposited material during re-advance, accumulation of material around a bedrock obstruction (rock-cored), and thinning of ice as it spreads out in a low area
Why do drumlins have four potential formations?
They are not completely understood yet
What topography do drumlins tend to form in?
“Basket of eggs” or large groups/swarms of drumlins
