glacio-fluvial landforms

• What is a delta kame?

  Hill/Hummock composed of stratified sand and grave laid down by glacial meltwater
• How are delta kames formed?

  - Englacial streams emerge at snout and lose energy, depositing their load

  - Supraglacial streams deposit material on entering ice marginal lakes, losing energy entering static body of water

  - Debris filled crevasses collapse during periods of glacial retreat depositing debris
• What is a kame terrace?

  Ridges of material running along the edge of the valley floor. Composed of outwash deposits - rounded + sorted
• How are kame terraces formed?

  - supraglacial streams are formed due to the melting of ice warmer in contact with the valley sides as a result of friction

  - supraglacial streams on the edge of the glacial pick up lateral moraine which is deposited on the valley floor as the glacier retreats
• What is an esker?

  Long, sinuous ridge of stratified sand and gravel deposited by glacial meltwater
• How are eskers formed?

  - Subglacial streams carry huge amounts of debris under pressure in confined tunnels

  - Deposition occurs when pressure is released as meltwater emerges at snout

  - As snout retreats during deglaciation, point of deposition gradually moves backwards up valley

  - Some eskers are beaded: ridge showing variations in height and width, with tallest and widest due to. periods when rate of retreat slowed
• What is an outwash plain?

  Flat exposure of sediment in proglacial area (front of snout). Typically drained by braided streams (rivers subdivided by numerous small islands and channels)
• How are outwash plains formed?

  - Meltwater streams gradually lose energy as they enter lowland areas beyond ice front and deposit their load

  - Largest material deposited nearest the ice front

  - Finest material deposited furthest away