Glacial deposition and landforms

• what is till

  is a mixture of clay, silt, gravel and boulders that have been eroded transported and deposited by the glacier. It is angular and poorly sorted. They are extensive features ;eft behind as glacier retreat. The deposition of glacial till over large areas level out the relief of the underlying land leaving flat or gently undulating surface.
• what is lodgment till

  is formed when a glacier moves over the landscape plucking and grinding rocks from the underlying bedrocks.
• What is ablation till

  depositied at the glaciers snout as a result of the melting and ablation of the glacier. IT consists of materials that was once part of the glacier but has been released as the ice melts. It is the material that composes recessional and terminal moraines
• What is drumlins

  elongated hills or mounds of till that are formed beneath a moving glacier and aligned with the direction glacial movement they can vary in length from a few hundred meters to several kilometers and be up to around 50 meter in height they usually appear in swarms.
• what are moraines

  are deposits of poorly sorted angular sediment found at different locations along the glacier
• what are lateral moraines

  formed between a glacier and the valley sides
• what are the medial moraines

  when two glaciers meet the lateral moraine from each merges to form a medial moraine
• what are terminal moraines

  formed furthest downslope and indicates the greatest extent of the glacier
• what are recessional moraines

  formed at successive points of the retreating snout at each terminal point of recession
• what are ground moraines

  deposited beneath a glacier as it transported sediment on top of the underlying rock base
• what are the glacial depositional landforms

  erratic's

  moraines

  crag and tail

  drumlin orientation
• what are erratic's

  large fragments of rock which are clearly different to the geological surroundings indicating that they have been moved by glaciers.
• what are moraines

  till that remains in various locations after the glacier has melted.
• what is crag and tail

  prominent steep-sided rock hill on the up-ice side followed by a gentle elongated slope extending in the down-ice direction. Formed by the erosional action of the glacier on solid rock
• what is drumlin orientation

  formed of till deposited by the glacier although a few do have a rock core the up-glacial side is a gentle slope and there is a steeper tapered slope on the down-ice side.